1
|
Esaki H, Izumi S, Nishikawa K, Nagayasu K, Kaneko S, Nishitani N, Deyama S, Kaneda K. Role of medial prefrontal cortex voltage-dependent potassium 4.3 channels in nicotine-induced enhancement of object recognition memory in male mice. Eur J Pharmacol 2024; 978:176790. [PMID: 38942263 DOI: 10.1016/j.ejphar.2024.176790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 06/26/2024] [Indexed: 06/30/2024]
Abstract
Nicotine has been shown to enhance object recognition memory in the novel object recognition (NOR) test by activating excitatory neurons in the medial prefrontal cortex (mPFC). However, the exact neuronal mechanisms underlying the nicotine-induced activation of mPFC neurons and the resultant memory enhancement remain poorly understood. To address this issue, we performed brain-slice electrophysiology and the NOR test in male C57BL/6J mice. Whole-cell patch-clamp recordings from layer V pyramidal neurons in the mPFC revealed that nicotine augments the summation of evoked excitatory postsynaptic potentials (eEPSPs) and that this effect was suppressed by N-[3,5-Bis(trifluoromethyl)phenyl]-N'-[2,4-dibromo-6-(2H-tetrazol-5-yl)phenyl]urea (NS5806), a voltage-dependent potassium (Kv) 4.3 channel activator. In line with these findings, intra-mPFC infusion of NS5806 suppressed systemically administered nicotine-induced memory enhancement in the NOR test. Additionally, miRNA-mediated knockdown of Kv4.3 channels in mPFC pyramidal neurons enhanced object recognition memory. Furthermore, inhibition of A-type Kv channels by intra-mPFC infusion of 4-aminopyridine was found to enhance object recognition memory, while this effect was abrogated by prior intra-mPFC NS5806 infusion. These results suggest that nicotine augments the summation of eEPSPs via the inhibition of Kv4.3 channels in mPFC layer V pyramidal neurons, resulting in the enhancement of object recognition memory.
Collapse
Affiliation(s)
- Hirohito Esaki
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Shoma Izumi
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Keisuke Nishikawa
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Kazuki Nagayasu
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Shuji Kaneko
- Department of Molecular Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Naoya Nishitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Satoshi Deyama
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
| |
Collapse
|
2
|
Laine MA, Greiner EM, Shansky RM. Sex differences in the rodent medial prefrontal cortex - What Do and Don't we know? Neuropharmacology 2024; 248:109867. [PMID: 38387553 DOI: 10.1016/j.neuropharm.2024.109867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/22/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024]
Abstract
The prefrontal cortex, particularly its medial subregions (mPFC), mediates critical functions such as executive control, behavioral inhibition, and memory formation, with relevance for everyday functioning and psychopathology. Despite broad characterization of the mPFC in multiple model organisms, the extent to which mPFC structure and function vary according to an individual's sex is unclear - a knowledge gap that can be attributed to a historical bias for male subjects in neuroscience research. Recent efforts to consider sex as a biological variable in basic science highlight the great need to close this gap. Here we review the knowns and unknowns about how rodents categorized as male or female compare in mPFC neuroanatomy, pharmacology, as well as in aversive, appetitive, and goal- or habit-directed behaviors that recruit the mPFC. We propose that long-standing dogmatic concepts of mPFC structure and function may not remain supported when we move beyond male-only studies, and that empirical challenges to these dogmas are warranted. Additionally, we note some common pitfalls in this work. Most preclinical studies operationalize sex as a binary categorization, and while this approach has furthered the inclusion of non-male rodents it is not as such generalizable to what we know of sex as a multidimensional, dynamic variable. Exploration of sex variability may uncover both sex differences and sex similarities, but care must be taken in their interpretation. Including females in preclinical research needs to go beyond the investigation of sex differences, improving our knowledge of how this brain region and its subregions mediate behavior and health. This article is part of the Special Issue on "PFC circuit function in psychiatric disease and relevant models".
Collapse
Affiliation(s)
- M A Laine
- Department of Psychology, Northeastern University, Boston, MA, USA
| | - E M Greiner
- Department of Psychology, Northeastern University, Boston, MA, USA.
| | - R M Shansky
- Department of Psychology, Northeastern University, Boston, MA, USA
| |
Collapse
|
3
|
Ramos-Medina L, Rosas-Vidal LE, Patel S. Pharmacological diacylglycerol lipase inhibition impairs contextual fear extinction in mice. Psychopharmacology (Berl) 2024; 241:569-584. [PMID: 38182791 PMCID: PMC10884152 DOI: 10.1007/s00213-023-06523-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 12/21/2023] [Indexed: 01/07/2024]
Abstract
Acquisition and extinction of associative fear memories are critical for guiding adaptive behavioral responses to environmental threats, and dysregulation of these processes is thought to represent important neurobehavioral substrates of trauma and stress-related disorders including posttraumatic stress disorder (PTSD). Endogenous cannabinoid (eCB) signaling has been heavily implicated in the extinction of aversive fear memories and we have recently shown that pharmacological inhibition of 2-arachidonoylglycerol (2-AG) synthesis, a major eCB regulating synaptic suppression, impairs fear extinction in an auditory cue conditioning paradigm. Despite these data, the role of 2-AG signaling in contextual fear conditioning is not well understood. Here, we show that systemic pharmacological blockade of diacylglycerol lipase, the rate-limiting enzyme catalyzing in the synthesis of 2-AG, enhances contextual fear learning and impairs within-session extinction. In sham-conditioned mice, 2-AG synthesis inhibition causes a small increase in unconditioned freezing behavior. No effects of 2-AG synthesis inhibition were noted in the Elevated Plus Maze in mice tested after fear extinction. These data provide support for 2-AG signaling in the suppression of contextual fear learning and the expression of within-session extinction of contextual fear memories.
Collapse
Affiliation(s)
| | - Luis E Rosas-Vidal
- Northwestern Center for Psychiatric Neuroscience, Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Sachin Patel
- Northwestern Center for Psychiatric Neuroscience, Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
| |
Collapse
|
4
|
Zhang K, Shen D, Huang S, Iqbal J, Huang G, Si J, Xue Y, Yang JL. The sexually divergent cFos activation map of fear extinction. Heliyon 2024; 10:e23748. [PMID: 38205315 PMCID: PMC10777019 DOI: 10.1016/j.heliyon.2023.e23748] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/24/2023] [Accepted: 12/12/2023] [Indexed: 01/12/2024] Open
Abstract
Objective Post-traumatic stress disorder (PTSD) is a neuropsychiatric disorder that can develop after experiencing or witnessing a traumatic event. Exposure therapy is a common treatment for PTSD, but it has varying levels of efficacy depending on sex. In this study, we aimed to compare the sexual dimorphism in brain activation during the extinction of fear conditioning in male and female rats by detecting the c-fos levels in the whole brain. Methods Thirty-two rats (Male: n = 16; Female: n = 16) were randomly separated into the extinction group as well as the non-extinction group, and fear conditioning was followed by extinction and non-extinction, respectively. Subsequently, brain sections from the sacrificed animal were performed immunofluorescence and the collected data were analyzed by repeated two-way ANOVAs as well as Pearson Correlation Coefficient. Results Our findings showed that most brain areas activated during extinction were similar in both male and female rats, except for the reuniens thalamic nucleus and ventral hippocampi. Furthermore, we found differences in the correlation between c-fos activation levels and freezing behavior during extinction between male and female rats. Specifically, in male rats, c-fos activation in the anterior cingulate cortex was negatively correlated with the freezing level, while c-fos activation in the retrosplenial granular cortex was positively correlated with the freezing level; but in female rats did not exhibit any correlation between c-fos activation and freezing level. Finally, the functional connectivity analysis revealed differences in the neural networks involved in extinction learning between male and female rats. In male rats, the infralimbic cortex and insular cortex, anterior cingulate cortex and retrosplenial granular cortex, and dorsal dentate gyrus and dCA3 were strongly correlated after extinction. In female rats, prelimbic cortex and basolateral amygdala, insular cortex and dCA3, and anterior cingulate cortex and dCA1 were significantly correlated. Conclusion These results suggest divergent neural networks involved in extinction learning in male and female rats and provide a clue for improving the clinical treatment of exposure therapy based on the sexual difference.
Collapse
Affiliation(s)
- Kai Zhang
- Department of Clinical Psychology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Medical University, Tianjin, China
| | - Dan Shen
- Xinxiang Medical University, 601 Jinsui Dadao, Hongqi District, Xinxiang City, Henan Province, China
| | - Shihao Huang
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Peking University, 100191, Beijing, China
| | - Javed Iqbal
- Shenzhen Kangning Hospital & Shenzhen Mental Health Center, No. 77 Zhenbi Road, Shenzhen, 518118, China
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Gengdi Huang
- Shenzhen Kangning Hospital & Shenzhen Mental Health Center, No. 77 Zhenbi Road, Shenzhen, 518118, China
- Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Jijian Si
- Department of Clinical Psychology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yanxue Xue
- National Institute on Drug Dependence and Beijing Key Laboratory on Drug Dependence Research, Peking University, 100191, Beijing, China
- Xinxiang Medical University, 601 Jinsui Dadao, Hongqi District, Xinxiang City, Henan Province, China
| | - Jian-Li Yang
- Department of Clinical Psychology, Tianjin Medical University General Hospital, Tianjin, China
- Tianjin Medical University, Tianjin, China
| |
Collapse
|
5
|
Esaki H, Deyama S, Izumi S, Katsura A, Nishikawa K, Nishitani N, Kaneda K. Varenicline enhances recognition memory via α7 nicotinic acetylcholine receptors in the medial prefrontal cortex in male mice. Neuropharmacology 2023; 239:109672. [PMID: 37506875 DOI: 10.1016/j.neuropharm.2023.109672] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 07/30/2023]
Abstract
Previous studies postulated that chronic administration of varenicline, a partial and full agonist at α4β2 and α7 nicotinic acetylcholine receptors (nAChRs), respectively, enhances recognition memory. However, whether its acute administration is effective, on which brain region(s) it acts, and in what signaling it is involved, remain unknown. To address these issues, we conducted a novel object recognition test using male C57BL/6J mice, focusing on the medial prefrontal cortex (mPFC), a brain region associated with nicotine-induced enhancement of recognition memory. Systemic administration of varenicline before the training dose-dependently enhanced recognition memory. Intra-mPFC varenicline infusion also enhanced recognition memory, and this enhancement was blocked by intra-mPFC co-infusion of a selective α7, but not α4β2, nAChR antagonist. Consistent with this, intra-mPFC infusion of a selective α7 nAChR agonist augmented object recognition memory. Furthermore, intra-mPFC co-infusion of U-73122, a phospholipase C (PLC) inhibitor, or 2-aminoethoxydiphenylborane (2-APB), an inositol trisphosphate (IP3) receptor inhibitor, suppressed the varenicline-induced memory enhancement, suggesting that α7 nAChRs may also act as Gq-coupled metabotropic receptors. Additionally, whole-cell recordings from mPFC layer V pyramidal neurons in vitro revealed that varenicline significantly increased the summation of evoked excitatory postsynaptic potentials, and this effect was suppressed by U-73122 or 2-APB. These findings suggest that varenicline might acutely enhance recognition memory via mPFC α7 nAChR stimulation, followed by mPFC neuronal excitation, which is mediated by the activation of PLC and IP3 receptor signaling. Our study provides evidence supporting the potential repositioning of varenicline as a treatment for cognitive impairment.
Collapse
Affiliation(s)
- Hirohito Esaki
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Satoshi Deyama
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Shoma Izumi
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Ayano Katsura
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Keisuke Nishikawa
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Naoya Nishitani
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, 920-1192, Japan.
| |
Collapse
|
6
|
Olivera-Pasilio V, Dabrowska J. Fear-Conditioning to Unpredictable Threats Reveals Sex and Strain Differences in Rat Fear-Potentiated Startle (FPS). Neuroscience 2023; 530:108-132. [PMID: 37640137 PMCID: PMC10726736 DOI: 10.1016/j.neuroscience.2023.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 08/17/2023] [Accepted: 08/22/2023] [Indexed: 08/31/2023]
Abstract
Fear-potentiated startle (FPS) has been widely used to study fear processing in humans and rodents. Human studies showed higher startle amplitudes and exaggerated fear reactivity to unpredictable vs. predictable threats in individuals suffering from post-traumatic stress disorder (PTSD). Although human FPS studies use both sexes, a surprisingly limited number of rodent FPS studies use females. Here we investigate the effects of signal-threat contingency, signal-threat order and threat predictability on FPS in both sexes. We use a classic fear-conditioning protocol (100% contingency of cue and shock pairings, with forward conditioning such that the cue co-terminates with the shock) and compare it to modified fear-conditioning protocols (70% contingency; backward conditioning; or cue and shock un-paired). Although there are no sex differences in the startle amplitudes when corrected for body weight, females consistently demonstrate higher shock reactivity during fear-conditioning. Both sexes and strains demonstrate comparable levels of cued, non-cued, and contextual fear in the classic FPS and FPS following fear-conditioning with 70% contingency or backward order (cue co-starts with shock). However, in the classic FPS, Sprague-Dawley females show reduced proportion between cued fear and cue-elicited vigilant state than males. Lastly, a prominent sex difference is uncovered following unpredictable fear-conditioning (cue and shock un-paired), with Wistar, but not Sprague-Dawley, females showing significantly higher startle overall during the FPS recall, regardless of trial type, and higher contextual fear than males. This striking sex difference in processing unpredictable threats in rodent FPS might help to understand the mechanisms underlying higher incidence of PTSD in women.
Collapse
Affiliation(s)
- Valentina Olivera-Pasilio
- Center for the Neurobiology of Stress Resilience and Psychiatric Disorders, Discipline of Cellular and Molecular Pharmacology, The Chicago Medical School, School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL, USA
| | - Joanna Dabrowska
- Center for the Neurobiology of Stress Resilience and Psychiatric Disorders, Discipline of Cellular and Molecular Pharmacology, The Chicago Medical School, School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL, USA.
| |
Collapse
|
7
|
Koszałka A, Lustyk K, Pytka K. Sex-dependent differences in animal cognition. Neurosci Biobehav Rev 2023; 153:105374. [PMID: 37634555 DOI: 10.1016/j.neubiorev.2023.105374] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/17/2023] [Accepted: 08/23/2023] [Indexed: 08/29/2023]
Abstract
The differences in cognitive processes driven by biological sex are the issues that have gotten growing attention recently. Considering the increasing population suffering from various cognitive impairments and the development of therapeutic strategies, it is essential that we recognize the mechanisms responsible for discrepancies observed in male and female learning and memory functions. In this review, we discuss recent reports from preclinical studies on rodents regarding selected cognitive domains to explore the state of knowledge on sex-dependent differences and point to challenges encountered during such research. We focus on spatial, recognition, and emotional memory, as well as on executive functions, such as attention, cognitive flexibility, and working memory. This review will help to acknowledge sex-related differences in cognition and indicate some fields that lack sufficient data.
Collapse
Affiliation(s)
- Aleksandra Koszałka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Pharmacodynamics, Medyczna 9, 30-688 Krakow, Poland; Jagiellonian University Medical College, Doctoral School of Medical and Health Sciences, Św. Łazarza 16, 31-530 Krakow, Poland
| | - Klaudia Lustyk
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Pharmacodynamics, Medyczna 9, 30-688 Krakow, Poland
| | - Karolina Pytka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Pharmacodynamics, Medyczna 9, 30-688 Krakow, Poland.
| |
Collapse
|
8
|
Chen HF, Lambers H, Nagelmann N, Sandbrink M, Segelcke D, Pogatzki-Zahn E, Faber C, Pradier B. Generation of a whole-brain hemodynamic response function and sex-specific differences in cerebral processing of mechano-sensation in mice detected by BOLD fMRI. Front Neurosci 2023; 17:1187328. [PMID: 37700753 PMCID: PMC10493293 DOI: 10.3389/fnins.2023.1187328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/05/2023] [Indexed: 09/14/2023] Open
Abstract
BOLD fMRI has become a prevalent method to study cerebral sensory processing in rodent disease models, including pain and mechanical hypersensitivity. fMRI data analysis is frequently combined with a general-linear-model (GLM) -based analysis, which uses the convolution of a hemodynamic response function (HRF) with the stimulus paradigm. However, several studies indicated that the HRF differs across species, sexes, brain structures, and experimental factors, including stimulation modalities or anesthesia, and hence might strongly affect the outcome of BOLD analyzes. While considerable work has been done in humans and rats to understand the HRF, much less is known in mice. As a prerequisite to investigate mechano-sensory processing and BOLD fMRI data in male and female mice, we (1) designed a rotating stimulator that allows application of two different mechanical modalities, including innocuous von Frey and noxious pinprick stimuli and (2) determined and statistically compared HRFs across 30 brain structures and experimental conditions, including sex and, stimulus modalities. We found that mechanical stimulation lead to brain-wide BOLD signal changes thereby allowing extraction of HRFs from multiple brain structures. However, we did not find differences in HRFs across all brain structures and experimental conditions. Hence, we computed a whole-brain mouse HRF, which is based on 88 functional scans from 30 mice. A comparison of this mouse-specific HRF with our previously reported rat-derived HRF showed significantly slower kinetics in mice. Finally, we detected pronounced differences in cerebral BOLD activation between male and female mice with mechanical stimulation, thereby exposing divergent processing of noxious and innocuous stimuli in both sexes.
Collapse
Affiliation(s)
- Hui-Fen Chen
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Henriette Lambers
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Nina Nagelmann
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Martin Sandbrink
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Daniel Segelcke
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Münster, Germany
| | - Esther Pogatzki-Zahn
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Münster, Germany
| | - Cornelius Faber
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
| | - Bruno Pradier
- Clinic of Radiology, Translational Research Imaging Center (TRIC), University of Münster, Münster, Germany
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Münster, Münster, Germany
| |
Collapse
|
9
|
Gancarz AM, Mitchell SH, George AM, Martin CD, Turk MC, Bool HM, Aktar F, Kwarteng F, Palmer AA, Meyer PJ, Richards JB, Dietz DM, Ishiwari K. Reward maximization assessed using a sequential patch depletion task in a large sample of heterogeneous stock rats. Sci Rep 2023; 13:7027. [PMID: 37120610 PMCID: PMC10148848 DOI: 10.1038/s41598-023-34179-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 04/25/2023] [Indexed: 05/01/2023] Open
Abstract
Choice behavior requires animals to evaluate both short- and long-term advantages and disadvantages of all potential alternatives. Impulsive choice is traditionally measured in laboratory tasks by utilizing delay discounting (DD), a paradigm that offers a choice between a smaller immediate reward, or a larger more delayed reward. This study tested a large sample of Heterogeneous Stock (HS) male (n = 896) and female (n = 898) rats, part of a larger genetic study, to investigate whether measures of reward maximization overlapped with traditional models of delay discounting via the patch depletion model using a Sequential Patch Depletion procedure. In this task, rats were offered a concurrent choice between two water "patches" and could elect to "stay" in the current patch or "leave" for an alternative patch. Staying in the current patch resulted in decreasing subsequent reward magnitudes, whereas the choice to leave a patch was followed by a delay and a resetting to the maximum reward magnitude. Based on the delay in a given session, different visit durations were necessary to obtain the maximum number of rewards. Visit duration may be analogous to an indifference point in traditional DD tasks. Males and females did not significantly differ on traditional measures of DD (e.g. delay gradient; AUC). When examining measures of patch utilization, females made fewer patch changes at all delays and spent more time in the patch before leaving for the alternative patch compared to males. Consistent with this, there was some evidence that females deviated from reward maximization more than males. However, when controlling for body weight, females had a higher normalized rate of reinforcement than males. Measures of reward maximization were only weakly associated with traditional DD measures and may represent distinctive underlying processes. Taken together, females performance differed from males with regard to reward maximization that were not observed utilizing traditional measures of DD, suggesting that the patch depletion model was more sensitive to modest sex differences when compared to traditional DD measures in a large sample of HS rats.
Collapse
Affiliation(s)
- Amy M Gancarz
- Department of Psychology, California State University, Bakersfield, Bakersfield, CA, 93311, USA.
| | - Suzanne H Mitchell
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, 97239, USA
- Department of Psychiatry, Oregon Health & Science University, Portland, OR, 97239, USA
- Oregon Institute for Occupational Health Sciences, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Anthony M George
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
| | - Connor D Martin
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Marisa C Turk
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Heather M Bool
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Fahmida Aktar
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Francis Kwarteng
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Abraham A Palmer
- Department of Psychiatry, University of California San Diego, La Jolla, CA, 92093, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Paul J Meyer
- Department of Psychology, University at Buffalo, Buffalo, NY, 14260, USA
| | - Jerry B Richards
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - David M Dietz
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA
| | - Keita Ishiwari
- Clinical and Research Institute on Addictions, University at Buffalo, Buffalo, NY, 14203, USA.
- Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA.
| |
Collapse
|
10
|
Olivera-Pasilio V, Dabrowska J. Fear-conditioning to unpredictable threats reveals sex differences in rat fear-potentiated startle (FPS). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.06.531430. [PMID: 36945466 PMCID: PMC10028867 DOI: 10.1101/2023.03.06.531430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Fear-potentiated startle (FPS) has been widely used to study fear processing in humans and rodents. Human studies have shown higher startle amplitudes and exaggerated fear reactivity to unpredictable vs. predictable threats in individuals suffering from post-traumatic stress disorder (PTSD). Although human FPS studies often use both sexes, a surprisingly limited number of rodent FPS studies use females. Here we investigate the effects of signal-threat contingency, signal-threat order and threat predictability on FPS in both sexes. We use a classic fear-conditioning protocol (100% contingency of cue and shock pairings, with forward conditioning such that the cue co-terminates with the shock) and compare it to modified fear-conditioning protocols (70% contingency; backward conditioning; or cue and shock unpaired). Although there are no sex differences in the startle amplitudes when corrected for body weight, females demonstrate higher shock reactivity during fear-conditioning. Both sexes demonstrate comparable levels of cued, non-cued, and contextual fear in the classic FPS but females show reduced fear discrimination vs. males. Fear-conditioning with 70% contingency or backward order (cue co-starts with shock) induces similar levels of cued, non-cued, and contextual fear in both sexes but they differ in contextual fear extinction. Lastly, a prominent sex difference is uncovered following unpredictable fear-conditioning protocol (cue and shock un-paired), with females showing significantly higher startle overall during the FPS recall, regardless of trial type, and higher contextual fear than males. This striking sex difference in processing unpredictable threats in rodent FPS might help to understand the mechanisms underlying higher incidence of PTSD in women. Highlights Male and female rats have comparable startle amplitudes when corrected for body weightFemale rats show higher foot-shock reactivity than males during fear-conditioningFemale rats show reduced fear discrimination vs. males in the classic FPSReversed signal-threat order increases contextual fear in both sexesExposure to unpredictable threats increases startle in general and contextual fear only in females.
Collapse
Affiliation(s)
- Valentina Olivera-Pasilio
- Center for the Neurobiology of Stress Resilience and Psychiatric Disorders, Discipline of Cellular and Molecular Pharmacology, The Chicago Medical School, School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, Illinois, USA
| | - Joanna Dabrowska
- Center for the Neurobiology of Stress Resilience and Psychiatric Disorders, Discipline of Cellular and Molecular Pharmacology, The Chicago Medical School, School of Graduate and Postdoctoral Studies, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, Illinois, USA
| |
Collapse
|
11
|
Gancarz AM, Mitchell SH, George AM, Martin CD, Turk MC, Bool HM, Aktar F, Kwarteng F, Palmer AA, Meyer PJ, Richards JB, Dietz DM, Isiwari K. Reward Maximization Assessed Using a Sequential Patch Depletion Task in a Large Sample of Heterogeneous Stock Rats. RESEARCH SQUARE 2023:rs.3.rs-2525080. [PMID: 36778344 PMCID: PMC9915773 DOI: 10.21203/rs.3.rs-2525080/v1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Choice behavior requires animals to evaluate both short- and long-term advantages and disadvantages of all potential alternatives. Impulsive choice is traditionally measured in laboratory tasks by utilizing delay discounting (DD), a paradigm that offers a choice between a smaller immediate reward, or a larger more delayed reward. This study tested a large sample of Heterogeneous Stock (HS) male (n = 896) and female (n = 898) rats, part of a larger genetic study, to investigate whether measures of reward maximization overlapped with traditional models of delay discounting via the patch depletion model using a Sequential Patch Depletion procedure. In this task, rats were offered a concurrent choice between two water "patches" and could elect to "stay" in the current patch or "leave" for an alternative patch. Staying in the current patch resulted in decreasing subsequent reward magnitudes, whereas the choice to leave a patch was followed by a delay and a resetting to the maximum reward magnitude. Based on the delay in a given session, different visit durations were necessary to obtain the maximum number of rewards. Visit duration may be analogous to an indifference point in traditional DD tasks. While differences in traditional DD measures (e.g., delay gradient) have been detected between males and females, these effects were small and inconsistent. However, when examining measures of reward maximization, females made fewer patch changes at all delays and spent more time in the patch before leaving for the alternative patch compared to males. This pattern of choice resulted in males having a higher rate of reinforcement than females. Consistent with this, there was some evidence that females deviated from the optimal more, leading to less reward. Measures of reward maximization were only weakly associated with traditional DD measures and may represent distinctive underlying processes. Taken together, females performance differed from males with regard to reward maximization that were not observed utilizing traditional measures of DD, suggesting that the patch depletion model was more sensitive to modest sex differences when compared to traditional DD measures in a large sample of HS rats.
Collapse
|
12
|
Bauer EP. Sex differences in fear responses: Neural circuits. Neuropharmacology 2023; 222:109298. [PMID: 36328063 PMCID: PMC11267399 DOI: 10.1016/j.neuropharm.2022.109298] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/26/2022] [Accepted: 10/19/2022] [Indexed: 11/06/2022]
Abstract
Women have increased vulnerability to PTSD and anxiety disorders compared to men. Understanding the neurobiological underpinnings of these disorders is critical for identifying risk factors and developing appropriate sex-specific interventions. Despite the clear clinical relevance of an examination of sex differences in fear responses, the vast majority of pre-clinical research on fear learning and memory formation has exclusively used male animals. This review highlights sex differences in context and cued fear conditioning, fear extinction and fear generalization with a focus on the neural circuits underlying these behaviors in rodents. There are mixed reports of behavioral sex differences in context and cued fear conditioning paradigms, which can depend upon the behavioral indices of fear. However, there is greater evidence of differential activation of the hippocampus, amygdalar nuclei and the prefrontal cortical regions in male and female rodents during context and cued fear conditioning. The bed nucleus of the stria terminalis (BNST), a sexually dimorphic structure, is of particular interest as it differentially contributes to fear responses in males and females. In addition, while the influence of the estrous cycle on different phases of fear conditioning is delineated, the clearest modulatory effect of estrogen is on fear extinction processes. Examining the variability in neural responses and behavior in both sexes should increase our understanding of how that variability contributes to the neurobiology of affective disorders. This article is part of the Special Issue on 'Fear, anxiety and PTSD'.
Collapse
Affiliation(s)
- Elizabeth P Bauer
- Departments of Biology and Neuroscience & Behavior, Barnard College of Columbia University, 3009 Broadway, New York, NY, 10027, United States.
| |
Collapse
|
13
|
Rose TR, Marron Fernandez de Velasco E, Mitten EH, Wickman K. GIRK channel activity in prelimbic pyramidal neurons regulates the extinction of cocaine conditioned place preference in male mice. Addict Biol 2023; 28:e13256. [PMID: 36577727 PMCID: PMC10078116 DOI: 10.1111/adb.13256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 11/03/2022] [Accepted: 11/07/2022] [Indexed: 11/25/2022]
Abstract
Drug-induced neuroadaptations in the prefrontal cortex (PFC) have been implicated in drug-associated memories that motivate continued drug use. Chronic cocaine exposure increases pyramidal neuron excitability in the prelimbic subregion of the PFC (PL), an adaptation that has been attributed in part to a suppression of inhibitory signalling mediated by the GABAB receptor (GABAB R) and G protein-gated inwardly rectifying K+ (GIRK/Kir3) channels. Although reduced GIRK channel activity in PL pyramidal neurons enhances the motor-stimulatory effect of cocaine in mice, the impact on cocaine reward and associated memories remains unclear. Here, we employed Cre- and CRISPR/Cas9-based viral manipulation strategies to evaluate the impact of GIRK channel or GABAB R ablation in PL pyramidal neurons on cocaine-induced conditioned place preference (CPP) and extinction. Neither ablation of GIRK channels nor GABAB R impacted the acquisition of cocaine CPP. GIRK channel ablation in PL pyramidal neurons, however, impaired extinction of cocaine CPP in male but not female mice. Since ablation of GIRK channels but not GABAB R increased PL pyramidal neuron excitability, we used a chemogenetic approach to determine if acute excitation of PL pyramidal neurons impaired the expression of extinction in male mice. While acute chemogenetic excitation of PL pyramidal neurons induced locomotor hyperactivity, it did not impair the extinction of cocaine CPP. Lastly, we found that persistent enhancement of GIRK channel activity in PL pyramidal neurons accelerated the extinction of cocaine CPP. Collectively, our findings show that the strength of GIRK channel activity in PL pyramidal neurons bi-directionally regulates cocaine CPP extinction in male mice.
Collapse
Affiliation(s)
- Timothy R Rose
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Eric H Mitten
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kevin Wickman
- Department of Pharmacology, University of Minnesota, Minneapolis, Minnesota, USA
| |
Collapse
|
14
|
Yagi S, Lee A, Truter N, Galea LAM. Sex differences in contextual pattern separation, neurogenesis, and functional connectivity within the limbic system. Biol Sex Differ 2022; 13:42. [PMID: 35870952 PMCID: PMC9308289 DOI: 10.1186/s13293-022-00450-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/05/2022] [Indexed: 01/04/2023] Open
Abstract
Background Females are more likely to present with anxiety disorders such as post-traumatic stress disorder (PTSD) compared to males, which are associated with disrupted hippocampal integrity. Sex differences in the structure and function of hippocampus exist. Here, we examined sex differences in contextual pattern separation, functional connectivity, and activation of new neurons during fear memory. Methods Two-month-old male and female Sprague-Dawley rats were injected with the DNA synthesis markers, iododeoxyuridine (IdU) and chlorodeoxyuridine (CldU) 3 weeks and 4 weeks before perfusion, respectively. One week after CldU injection, the rats underwent a context discrimination task in which rats were placed in context A (shock) and context A’ (no shock) every day for 12 days. On the test day, rats were placed in the shock context (context A) to measure fear memory and expression of zif268, an immediate early gene across 16 different limbic and reward regions. Repeated-measures or factorial analysis of variance was conducted on our variables of interest. Pearson product-moment calculations and principal component analyses on zif268 expression across regions were also performed. Results We found that females, but not males, showed contextual discrimination during the last days of training. On the test day, both sexes displayed similar levels of freezing, indicating equivalent fear memory for context A. Despite similar fear memory, males showed more positive correlations of zif268 activation between the limbic regions and the striatum, whereas females showed more negative correlations among these regions. Females showed greater activation of the frontal cortex, dorsal CA1, and 3-week-old adult-born dentate granular cells compared to males. Conclusions These results highlight the importance of studying sex differences in fear memory and the contribution of adult neurogenesis to the neuronal network and may contribute to differences in susceptibility to fear-related disorders such as post-traumatic stress disorder. HighlightsFemale rats, but not male rats, show faster discrimination during a contextual pattern separation task. Three-week-old adult-born neurons are more active in response to fear memory in females compared to males. Females had greater neural activation compared to males in the frontal cortex and dorsal CA1 region of the hippocampus in response to fear memory. Males and females show distinct patterns in functional connectivity for fear memory across limbic regions. Males have many positive correlations between activated new neurons of different ages between the dorsal and ventral hippocampus, while females show more correlations between activated new neurons and other limbic regions.
Supplementary Information The online version contains supplementary material available at 10.1186/s13293-022-00450-2.
Collapse
|
15
|
Wen Z, Fried J, Pace-Schott EF, Lazar SW, Milad MR. Revisiting sex differences in the acquisition and extinction of threat conditioning in humans. Learn Mem 2022; 29:274-282. [PMID: 36206388 PMCID: PMC9488021 DOI: 10.1101/lm.053521.121] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 06/21/2022] [Indexed: 11/25/2022]
Abstract
Findings pertaining to sex differences in the acquisition and extinction of threat conditioning, a paradigm widely used to study emotional homeostasis, remain inconsistent, particularly in humans. This inconsistency is likely due to multiple factors, one of which is sample size. Here, we pooled functional magnetic resonance imaging (fMRI) and skin conductance response (SCR) data from multiple studies in healthy humans to examine sex differences during threat conditioning, extinction learning, and extinction memory recall. We observed increased functional activation in males, relative to females, in multiple parietal and frontal (medial and lateral) cortical regions during acquisition of threat conditioning and extinction learning. Females mainly exhibited higher amygdala activation during extinction memory recall to the extinguished conditioned stimulus and also while responding to the unconditioned stimulus (presentation of the shock) during threat conditioning. Whole-brain functional connectivity analyses revealed that females showed increased connectivity across multiple networks including visual, ventral attention, and somatomotor networks during late extinction learning. At the psychophysiological level, a sex difference was only observed during shock delivery, with males exhibiting higher unconditioned responses relative to females. Our findings point to minimal to no sex differences in the expression of conditioned responses during acquisition and extinction of such responses. Functional MRI findings, however, show some distinct functional activations and connectivities between the sexes. These data suggest that males and females might use different neural mechanisms, mainly related to cognitive processing, to achieve comparable levels of acquired conditioned responses to threating cues.
Collapse
Affiliation(s)
- Zhenfu Wen
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York 10016, USA
| | - Jamie Fried
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York 10016, USA
| | - Edward F Pace-Schott
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Sara W Lazar
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02114, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| | - Mohammed R Milad
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York 10016, USA
- The Neuroscience Institute, New York University Grossman School of Medicine, New York, New York 10016, USA
- Nathan Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA
| |
Collapse
|
16
|
Becegato M, Silva RH. Object recognition tasks in rats: Does sex matter? Front Behav Neurosci 2022; 16:970452. [PMID: 36035023 PMCID: PMC9412164 DOI: 10.3389/fnbeh.2022.970452] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Novelty recognition tasks based on object exploration are frequently used for the evaluation of cognitive abilities and investigation of neurobiological and molecular aspects of memory in rodents. This is an interesting approach because variations of the object recognition tasks focus on different aspects of the memory events such as novelty, location, context, and combinations of these elements. Nevertheless, as in most animal neuroscience research, female subjects are underrepresented in object recognition studies. When studies include females, the particularities of this sex are not always considered. For example, appropriate controls for manipulations conducted exclusively in females (such as estrous cycle verification) are not included. In addition, interpretation of data is often based on standardizations conducted with male subjects. Despite that, females are frequently reported as deficient and unable to adequately perform some memory tests. Thus, our study aims to review studies that describe similarities and differences between male and female performances in the different variations of object recognition tasks. In summary, although females are commonly described with deficits and the articles emphasize sex differences, most published data reveal similar performances when sexes are compared.
Collapse
Affiliation(s)
- Marcela Becegato
- Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Regina H. Silva
- Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
- MaternaCiência, Federal University of São Paulo, São Paulo, Brazil
- *Correspondence: Regina H. Silva,
| |
Collapse
|
17
|
Wang J, Zhao H, Girgenti MJ. Posttraumatic Stress Disorder Brain Transcriptomics: Convergent Genomic Signatures Across Biological Sex. Biol Psychiatry 2022; 91:6-13. [PMID: 33840456 DOI: 10.1016/j.biopsych.2021.02.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 02/09/2021] [Accepted: 02/09/2021] [Indexed: 11/29/2022]
Abstract
While a definitive understanding of the molecular pathology of posttraumatic stress disorder (PTSD) is far from a current reality, it has become increasingly clear that many of the molecular effects of PTSD are sex specific. Women are twice as likely as men to develop PTSD after a traumatic event, and neurobiological evidence suggests that there are structural differences between the brains of males versus females with PTSD. Recent advances in genomic technologies have begun to shed light on the sex-specific molecular determinants of PTSD, which seem to be governed predominantly by dysfunction of GABAergic (gamma-aminobutyric acidergic) signaling and immune function. We review the current state of the field of PTSD genomics focusing on the effect of sex. We provide an overview of difference in heritability of PTSD based on sex, how difference in gene regulation based on sex impacts the PTSD brain, and what is known about genomic regulation that is dysregulated in specific cell types in PTSD.
Collapse
Affiliation(s)
- Jiawei Wang
- Program of Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut; Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut
| | - Hongyu Zhao
- Program of Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut; Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut
| | - Matthew J Girgenti
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut; Psychiatry Service, Veterans Administration Connecticut Healthcare System, West Haven, Connecticut; Veterans Administration National Center for PTSD, West Haven, Connecticut.
| |
Collapse
|
18
|
Sexually Dimorphic Expression of Fear-conditioned Analgesia in Rats and Associated Alterations in the Endocannabinoid System in the Periaqueductal Grey. Neuroscience 2021; 480:117-130. [PMID: 34774710 DOI: 10.1016/j.neuroscience.2021.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/16/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022]
Abstract
The endocannabinoid system within the periaqueductal grey (PAG) has been implicated in fear-conditioned analgesia (FCA), the profound suppression of pain upon re-exposure to a context previously paired with an aversive stimulus. Since the endocannabinoid and nociceptive systems exhibit sexual dimorphism, the aim of the present study was to assess possible sex differences in the expression of FCA, fear in the presence of nociceptive tone, and associated sex-dependent alterations in the endocannabinoid system within the PAG. Male and female Sprague-Dawley rats received footshock (10 × 1s; 0.4 mA; every 60 s) or no-footshock in a conditioning arena and 23.5 h later received intraplantar injection of formalin (2.5%) under brief isoflourane anaesthetic into the right hind paw. Nociceptive and fear-related behaviours were assessed 30 min later. Levels of endocannabinoids, N-acylethanolamines and neurotransmitters in the PAG were assessed by LC-MS/MS and expression of endocannabinoid system-related proteins by Western immunoblotting. Male, but not female, rats exhibited robust FCA and greater expression of fear-related behaviours than females. Fear-conditioned formalin-treated males, but not females, had higher levels of N-oleoylethanolamine (OEA) and γ-aminobutyric acid (GABA) in the PAG, compared with non-fear-conditioned controls. There was no effect of fear conditioning on the levels of FAAH or CB1 receptor expression (CB1R) in the PAG of male or female formalin-treated rats. Non-fear-conditioned females had higher levels of CB1R and PPARγ expression than non-fear-conditioned male counterparts. In summary, our results provide evidence of sexual dimorphism in the expression of FCA and fear-related behaviours, and associated alterations in components of the endocannabinoid system and GABA within the PAG.
Collapse
|
19
|
Presto P, Ji G, Junell R, Griffin Z, Neugebauer V. Fear Extinction-Based Inter-Individual and Sex Differences in Pain-Related Vocalizations and Anxiety-like Behaviors but Not Nocifensive Reflexes. Brain Sci 2021; 11:brainsci11101339. [PMID: 34679403 PMCID: PMC8533751 DOI: 10.3390/brainsci11101339] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 02/06/2023] Open
Abstract
Inter-individual and sex differences in pain responses are recognized but their mechanisms are not well understood. This study was intended to provide the behavioral framework for analyses of pain mechanisms using fear extinction learning as a predictor of phenotypic and sex differences in sensory (mechanical withdrawal thresholds) and emotional-affective aspects (open field tests for anxiety-like behaviors and audible and ultrasonic components of vocalizations) of acute and chronic pain. In acute arthritis and chronic neuropathic pain models, greater increases in vocalizations were found in females than males and in females with poor fear extinction abilities than females with strong fear extinction, particularly in the neuropathic pain model. Female rats showed higher anxiety-like behavior than males under baseline conditions but no inter-individual or sex differences were seen in the pain models. No inter-individual and sex differences in mechanosensitivity were observed. The data suggest that vocalizations are uniquely suited to detect inter-individual and sex differences in pain models, particularly in chronic neuropathic pain, whereas no such differences were found for mechanosensitivity, and baseline differences in anxiety-like behaviors disappeared in the pain models.
Collapse
Affiliation(s)
- Peyton Presto
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
| | - Guangchen Ji
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6592, USA
| | - Riley Junell
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
| | - Zach Griffin
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th St, Lubbock, TX 79430-6592, USA; (P.P.); (G.J.); (R.J.); (Z.G.)
- Center of Excellence for Translational Neuroscience and Therapeutics, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6592, USA
- Garrison Institute on Aging, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6592, USA
- Correspondence: ; Tel.: +1-806-743-3880; Fax: +1-806-732-2744
| |
Collapse
|
20
|
Tryon SC, Sakamoto IM, Kellis DM, Kaigler KF, Wilson MA. Individual Differences in Conditioned Fear and Extinction in Female Rats. Front Behav Neurosci 2021; 15:740313. [PMID: 34489657 PMCID: PMC8418198 DOI: 10.3389/fnbeh.2021.740313] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 07/29/2021] [Indexed: 11/13/2022] Open
Abstract
The inability to extinguish a traumatic memory is a key aspect of post-traumatic stress disorder (PTSD). While PTSD affects 10–20% of individuals who experience a trauma, women are particularly susceptible to developing the disorder. Despite this notable female vulnerability, few studies have investigated this particular resistance to fear extinction observed in females. Similar to humans, rodent models of Pavlovian fear learning and extinction show a wide range of individual differences in fear learning and extinction, although female rodents are considerably understudied. Therefore, the present study examined individual differences in fear responses, including freezing behavior and ultrasonic vocalizations (USVs), of female Long–Evans rats during acquisition of fear conditioning and cued fear extinction. Similar to prior studies in males, female rats displayed individual variation in freezing during cued fear extinction and were divided into extinction competent (EC) and extinction resistant (ER) phenotypes. Differences in freezing between ER and EC females were accompanied by shifts in rearing during extinction, but no darting was seen in any trial. Freezing behavior during fear learning did not differ between the EC and ER females. Vocalizations emitted in the 22 and 50 kHz ranges during fear learning and extinction were also examined. Unlike vocalizations seen in previous studies in males, very few 22 kHz distress vocalizations were emitted by female rats during fear acquisition and extinction, with no difference between ER and EC groups. Interestingly, all female rats produced significant levels of 50 kHz USVs, and EC females emitted significantly more 50 kHz USVs than ER rats. This difference in 50 kHz USVs was most apparent during initial exposure to the testing environment. These results suggest that like males, female rodents show individual differences in both freezing and USVs during fear extinction, although females appear to vocalize more in the 50 kHz range, especially during initial periods of exposure to the testing environment, and emit very few of the 22 kHz distress calls that are typically observed in males during fear learning or extinction paradigms. Overall, these findings show that female rodents display fear behavior repertoires divergent from males.
Collapse
Affiliation(s)
- Sarah C Tryon
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Iris M Sakamoto
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Devin M Kellis
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Kris F Kaigler
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Marlene A Wilson
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States.,Columbia VA Health Care System, Columbia, SC, United States
| |
Collapse
|
21
|
Guajardo HM, Valentino RJ. Sex differences in μ-opioid regulation of coerulear-cortical transmission. Neurosci Lett 2021; 746:135651. [PMID: 33482313 DOI: 10.1016/j.neulet.2021.135651] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/06/2021] [Accepted: 01/07/2021] [Indexed: 11/26/2022]
Abstract
Stress-induced activation of locus coeruleus (LC)-norepinephrine (NE) projections to the prefrontal cortex are thought to promote cognitive responses to stressors. LC activation by stressors is modulated by endogenous opioids that restrain LC activation and facilitate a return to baseline activity upon stress termination. Sex differences in this opioid influence could be a basis for sex differences in stress vulnerability. Consistent with this, we recently demonstrated that μ-opioid receptor (MOR) expression is decreased in the female rat LC compared to the male LC, and this was associated with sexually distinct consequences of activating MOR in the LC on cognitive flexibility. Given that the LC-NE system affects cognitive flexibility through its projections to the medial prefrontal cortex (mPFC), the present study quantified and compared the effects of LC-MOR activation on mPFC neural activity in male and female rats. Local field potential (LFPs) were recorded from the mPFC of freely behaving male and female rats before and following local LC microinjection of the MOR agonist, DAMGO, or vehicle. Intra-LC DAMGO altered the LFP power spectrum selectively in male but not female rats, resulting in a time-dependent increase in the power in delta and alpha frequency bands. LC microinfusion of ACSF had no effect on either sex. Together, the results are consistent with previous evidence for decreased MOR function in the female rat LC and demonstrate that this translates to a diminished effect on cortical activity that can account for sex differences in cognitive consequences. Decreased LC-MOR function in females could contribute to greater stress-induced activation of the LC and increased vulnerability of females to hyperarousal symptoms of stress-related neuropsychiatric pathologies.
Collapse
Affiliation(s)
- Herminio M Guajardo
- Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
| | - Rita J Valentino
- Neuroscience Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA; Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| |
Collapse
|
22
|
Tan SZK, Kim JH. mGlu5: A double-edged sword for aversive learning related therapeutics. NEUROANATOMY AND BEHAVIOUR 2021. [DOI: 10.35430/nab.2021.e16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Aversive memories underlie many types of anxiety disorders. One area of research to more effectively treat anxiety disorders has therefore been identifying pharmacological targets to affect memory processes. Among these targets, the metabotropic glutamate 5 receptor (mGlu5) has received attention due to the availability of drugs to utilize its role in learning and memory. In this review, we highlight preclinical studies examining the role of mGlu5 at various stages of aversive learning and its inhibition via extinction in order to gain a better understanding of its therapeutic potential. We suggest that mGlu5 has distinct roles at different stages of memory that not only makes it a tricky target, but a double-edged sword as a therapeutic. However, the selective involvement of mGlu5 in different memory stages allows for certain precision that could be harnessed clinically. We therefore suggest potential applications, limitations, and pitfalls when considering use of mGlu5 modulators as therapeutics. In addition, we recommend future studies to address important gaps in this literature, such as sex and age factors in light of anxiety disorders being more prevalent in those demographics.
Collapse
Affiliation(s)
- Shawn Zheng Kai Tan
- School of Biomedical Science, Li Ka Shing Faculty of Medicine, The University of Hong Kong
- European Bioinformatics Institute (EMBL-EBI), Wellcome Trust Genome Campus, Cambridgeshire, United Kingdom
| | - Jee Hyun Kim
- IMPACT – the Institute for Mental and Physical Health and Clinical Translation, School of Medicine, Deakin University, Geelong, VIC, Australia
| |
Collapse
|
23
|
Girgenti MJ, Wang J, Ji D, Cruz DA, Stein MB, Gelernter J, Young KA, Huber BR, Williamson DE, Friedman MJ, Krystal JH, Zhao H, Duman RS. Transcriptomic organization of the human brain in post-traumatic stress disorder. Nat Neurosci 2021; 24:24-33. [PMID: 33349712 DOI: 10.1038/s41593-020-00748-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 10/26/2020] [Indexed: 12/22/2022]
Abstract
Despite extensive study of the neurobiological correlates of post-traumatic stress disorder (PTSD), little is known about its molecular determinants. Here, differential gene expression and network analyses of four prefrontal cortex subregions from postmortem tissue of people with PTSD demonstrate extensive remodeling of the transcriptomic landscape. A highly connected downregulated set of interneuron transcripts is present in the most significant gene network associated with PTSD. Integration of this dataset with genotype data from the largest PTSD genome-wide association study identified the interneuron synaptic gene ELFN1 as conferring significant genetic liability for PTSD. We also identified marked transcriptomic sexual dimorphism that could contribute to higher rates of PTSD in women. Comparison with a matched major depressive disorder cohort revealed significant divergence between the molecular profiles of individuals with PTSD and major depressive disorder despite their high comorbidity. Our analysis provides convergent systems-level evidence of genomic networks within the prefrontal cortex that contribute to the pathophysiology of PTSD in humans.
Collapse
Affiliation(s)
- Matthew J Girgenti
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
- Psychiatry Service, VA Connecticut Health Care System, West Haven, CT, USA.
- National Center for PTSD, US Department of Veterans Affairs, White River Junction, VT, USA.
| | - Jiawei Wang
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA
- Program of Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA
| | - Dingjue Ji
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA
- Program of Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA
| | - Dianne A Cruz
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
| | - Murray B Stein
- VA San Diego Healthcare System, San Diego, CA, USA
- Departments of Psychiatry and of Family Medicine and Public Health, University of California, San Diego, La Jolla, CA, USA
| | - Joel Gelernter
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- Psychiatry Service, VA Connecticut Health Care System, West Haven, CT, USA
- National Center for PTSD, US Department of Veterans Affairs, White River Junction, VT, USA
| | - Keith A Young
- Baylor Scott and White Psychiatry, Temple, TX, USA
- Department of Psychiatry, Texas A&M College of Medicine, Bryan, Texas, USA
- Department of Veterans Affairs, VISN 17 Center of Excellence for Research on Returning War Veterans, Waco, Texas, USA
- Central Texas Veterans Health Care System, Temple, TX, USA
| | - Bertrand R Huber
- National Center for PTSD, US Department of Veterans Affairs, White River Junction, VT, USA
- VA Boston Healthcare System, Boston, MA, USA
- Boston University Alzheimer's Disease Center and CTE Center, Department of Neurology, Boston University School of Medicine, Boston, MA, USA
| | - Douglas E Williamson
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA
- Durham VA Healthcare System, Durham, NC, USA
| | - Matthew J Friedman
- National Center for PTSD, US Department of Veterans Affairs, White River Junction, VT, USA.
- Department of Psychiatry, Geisel School of Medicine at Dartmouth College, Hanover, NH, USA.
| | - John H Krystal
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
- Psychiatry Service, VA Connecticut Health Care System, West Haven, CT, USA.
- National Center for PTSD, US Department of Veterans Affairs, White River Junction, VT, USA.
| | - Hongyu Zhao
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA.
- Program of Computational Biology and Bioinformatics, Yale University, New Haven, CT, USA.
| | - Ronald S Duman
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA
- National Center for PTSD, US Department of Veterans Affairs, White River Junction, VT, USA
| |
Collapse
|
24
|
Premachandran H, Zhao M, Arruda-Carvalho M. Sex Differences in the Development of the Rodent Corticolimbic System. Front Neurosci 2020; 14:583477. [PMID: 33100964 PMCID: PMC7554619 DOI: 10.3389/fnins.2020.583477] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/01/2020] [Indexed: 12/18/2022] Open
Abstract
In recent years, a growing body of research has shown sex differences in the prevalence and symptomatology of psychopathologies, such as depression, anxiety, and fear-related disorders, all of which show high incidence rates in early life. This has highlighted the importance of including female subjects in animal studies, as well as delineating sex differences in neural processing across development. Of particular interest is the corticolimbic system, comprising the hippocampus, amygdala, and medial prefrontal cortex. In rodents, these corticolimbic regions undergo dynamic changes in early life, and disruption to their normative development is believed to underlie the age and sex-dependent effects of stress on affective processing. In this review, we consolidate research on sex differences in the hippocampus, amygdala, and medial prefrontal cortex across early development. First, we briefly introduce current principles on sexual differentiation of the rodent brain. We then showcase corticolimbic regional sex differences in volume, morphology, synaptic organization, cell proliferation, microglia, and GABAergic signaling, and explain how these differences are influenced by perinatal and pubertal gonadal hormones. In compiling this research, we outline evidence of what and when sex differences emerge in the developing corticolimbic system, and illustrate how temporal dynamics of its maturational trajectory may differ in male and female rodents. This will help provide insight into potential neural mechanisms underlying sex-specific critical windows for stress susceptibility and behavioral emergence.
Collapse
Affiliation(s)
| | - Mudi Zhao
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Maithe Arruda-Carvalho
- Department of Psychology, University of Toronto Scarborough, Toronto, ON, Canada.,Department of Cell and Systems Biology, University of Toronto Scarborough, Toronto, ON, Canada
| |
Collapse
|
25
|
Costa R, Carvalho MSM, Brandão JDP, Moreira RP, Cunha TS, Casarini DE, Marcondes FK. Modulatory action of environmental enrichment on hormonal and behavioral responses induced by chronic stress in rats: Hypothalamic renin-angiotensin system components. Behav Brain Res 2020; 397:112928. [PMID: 32987059 DOI: 10.1016/j.bbr.2020.112928] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 09/10/2020] [Accepted: 09/18/2020] [Indexed: 02/07/2023]
Abstract
Environmental enrichment (EE) has been studied as a protocol that can improve brain plasticity and may protect against negative insults such as chronic stress. The aim of this study was to evaluate the effects of EE on the hormonal and behavioral responses induced by chronic mild unpredictable stress (CMS) in rats, considering the involvement of the renin-angiotensin system. Male adult rats were divided into 4 groups: control, CMS, EE, and CMS + EE, and the experimental protocol lasted for 7 weeks. EE was performed during 7 weeks, 5 days per week, 2 h per day. CMS was applied during weeks 3, 4, and 5. After the CMS (week 6), depression-like behavior was evaluated by forced swimming and sucrose consumption tests, anxiety level was evaluated using the elevated plus-maze test, and memory was evaluated using the Y-maze test. On week 7, the animals were euthanized and basal plasma levels of corticosterone and catecholamines were determined. The hypothalamus was isolated and tissue levels of angiotensin peptides were evaluated. CMS increased plasma corticosterone, norepinephrine, and epinephrine basal concentrations, induced depression-like behaviors, impaired memory, and increased hypothalamic angiotensin I, II, and IV concentrations. EE decreased stress hormones secretion, depression-like behaviors, memory impairment, and hypothalamic angiotensin II induced by stress. Reductions of anxiety-like behavior and norepinephrine secretion were observed in both stressed and unstressed groups. The results indicated that EE seemed to protect adult rats against hormonal and behavioral CMS effects, and that the reduction of angiotensin II could contribute to these effects.
Collapse
Affiliation(s)
- Rafaela Costa
- Department of Biosciences, Laboratory of Stress, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | - Maeline Santos Morais Carvalho
- Department of Biosciences, Laboratory of Stress, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil
| | | | - Roseli Peres Moreira
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Tatiana Sousa Cunha
- Science and Technology Institute, Federal University of São Paulo, São José Dos Campos, SP, Brazil
| | - Dulce Elena Casarini
- Nephrology Division, Department of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Fernanda Klein Marcondes
- Department of Biosciences, Laboratory of Stress, Piracicaba Dental School, University of Campinas, Piracicaba, SP, Brazil.
| |
Collapse
|
26
|
Day HLL, Stevenson CW. The neurobiological basis of sex differences in learned fear and its inhibition. Eur J Neurosci 2020; 52:2466-2486. [PMID: 31631413 PMCID: PMC7496972 DOI: 10.1111/ejn.14602] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 10/07/2019] [Accepted: 10/15/2019] [Indexed: 12/16/2022]
Abstract
Learning that certain cues or environments predict threat enhances survival by promoting appropriate fear and the resulting defensive responses. Adapting to changing stimulus contingencies by learning that such cues no longer predict threat, or distinguishing between these threat-related and other innocuous stimuli, also enhances survival by limiting fear responding in an appropriate manner to conserve resources. Importantly, a failure to inhibit fear in response to harmless stimuli is a feature of certain anxiety and trauma-related disorders, which are also associated with dysfunction of the neural circuitry underlying learned fear and its inhibition. Interestingly, these disorders are up to twice as common in women, compared to men. Despite this striking sex difference in disease prevalence, the neurobiological factors involved remain poorly understood. This is due in part to the majority of relevant preclinical studies having neglected to include female subjects alongside males, which has greatly hindered progress in this field. However, more recent studies have begun to redress this imbalance and emerging evidence indicates that there are significant sex differences in the inhibition of learned fear and associated neural circuit function. This paper provides a narrative review on sex differences in learned fear and its inhibition through extinction and discrimination, along with the key gonadal hormone and brain mechanisms involved. Understanding the endocrine and neural basis of sex differences in learned fear inhibition may lead to novel insights on the neurobiological mechanisms underlying the enhanced vulnerability to develop anxiety-related disorders that are observed in women.
Collapse
Affiliation(s)
- Harriet L. L. Day
- School of BiosciencesUniversity of NottinghamLoughboroughUK
- Present address:
RenaSci LtdBioCity, Pennyfoot StreetNottinghamNG1 1GFUK
| | | |
Collapse
|
27
|
Assessment of conditioned fear extinction in male and female adolescent rats. Psychoneuroendocrinology 2020; 116:104670. [PMID: 32334346 DOI: 10.1016/j.psyneuen.2020.104670] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/25/2020] [Accepted: 03/29/2020] [Indexed: 12/22/2022]
Abstract
Pavlovian fear conditioning and extinction have been widely studied across many species to understand emotional learning and memory. Importantly, it is becoming clear that these processes are affected by sex and age. In adult rodents and humans, sex differences are evident in extinction, with estradiol playing a significant role. In adolescence, an extinction deficit has been reported in rodents and humans. However, the influence of sex on extinction during adolescence is unknown. This is surprising, since adolescence coincides with the onset of hormone cycling, and therefore it might be expected that hormones fluctuations exert a more profound effect at this time. Therefore, we examined Pavlovian fear conditioning and extinction in adolescent male and female rats. In experiment 1, 35-day-old male and female rats were exposed to 6 pairings of a conditioned stimulus (CS, a tone) with an aversive unconditioned stimulus (US, a footshock). The next day they were extinguished in a contextually distinct chamber, via 60 presentations of the CS without the US. Extinction recall was tested 24 hours later in the extinction context. Estrous phase was monitored by cytology on vaginal smears taken 1 hour after each behavioral session. In experiment 2, male and female rats were given sham surgery or gonadectomy at 21 days of age. They were then trained and tested as for experiment 1. We observed that females in proestrus or met/diestrus during extinction showed delayed extinction and impaired extinction recall the next day compared to males. Ovariectomy enhanced extinction for female rats, but orchidectomy delayed extinction for males. Plasma analyses showed that met/di/proestrus phases were associated with high estradiol levels. These findings suggest that high plasma estradiol levels impair extinction for adolescent females. These results contradict what is reported in adult animals, suggesting that hormonal influences on extinction are dependent on age. Given that impaired extinction is widely used as a model to understand resistance to exposure-based therapies, our findings have important implications for understanding mental health treatments in adolescents.
Collapse
|
28
|
Sex differences in behavioral responses during a conditioned flight paradigm. Behav Brain Res 2020; 389:112623. [PMID: 32348872 DOI: 10.1016/j.bbr.2020.112623] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/05/2020] [Accepted: 03/22/2020] [Indexed: 12/22/2022]
Abstract
Females exhibit greater susceptibility to trauma- and stress-related disorders compared to males; therefore, it is imperative to study sex differences in the mode and magnitude of defensive responses in the face of threat. To test for sex differences in defensive behavior, we used a modified Pavlovian fear conditioning paradigm that elicits clear transitions between freezing and flight behaviors within individual subjects. Female mice subjected to this paradigm exhibited more freezing behavior compared to males, especially during the intertrial interval period. Female mice also exhibited more freezing in response to conditioned auditory stimuli in the last block of extinction training. Furthermore, there were sex differences in the expression of other adaptive behaviors during fear conditioning. Assaying rearing, grooming, and tail rattling behaviors during the conditioned flight paradigm yielded measurable differences across sessions and between males and females. Overall, these results provide insight into sex-dependent alterations in mouse behavior induced by fear conditioning.
Collapse
|
29
|
Sex differences in auditory fear discrimination are associated with altered medial prefrontal cortex function. Sci Rep 2020; 10:6300. [PMID: 32286467 PMCID: PMC7156682 DOI: 10.1038/s41598-020-63405-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/28/2020] [Indexed: 01/05/2023] Open
Abstract
The increased prevalence of post-traumatic stress disorder (PTSD) that is observed in women may involve sex differences in learned fear inhibition and medial prefrontal cortex (mPFC) function. PTSD is characterized by fear overgeneralization involving impaired fear regulation by safety signals. We recently found that males show fear discrimination and females show fear generalization involving reduced safety signalling after extended fear discrimination training. Here we determined if these sex differences involve altered mPFC function. Male and female rats underwent three days of auditory fear discrimination training, where one tone (CS+) was paired with footshock and another tone (CS−) was presented alone. Local field potentials were recorded from prelimbic (PL) and infralimbic (IL) mPFC during retrieval. We found that males discriminated and females generalized based on cue-induced freezing at retrieval. This was accompanied by sex differences in basal theta and gamma oscillations in PL and IL. Importantly, males also showed PL/IL theta activation during safety signalling by the CS− and IL gamma activation in response to the threat-related CS+, both of which were absent in females. These results add to growing evidence indicating that sex differences in learned fear inhibition are associated with altered mPFC function.
Collapse
|
30
|
The medial prefrontal cortex - hippocampus circuit that integrates information of object, place and time to construct episodic memory in rodents: Behavioral, anatomical and neurochemical properties. Neurosci Biobehav Rev 2020; 113:373-407. [PMID: 32298711 DOI: 10.1016/j.neubiorev.2020.04.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/25/2020] [Accepted: 04/06/2020] [Indexed: 12/31/2022]
Abstract
Rats and mice have been demonstrated to show episodic-like memory, a prototype of episodic memory, as defined by an integrated memory of the experience of an object or event, in a particular place and time. Such memory can be assessed via the use of spontaneous object exploration paradigms, variably designed to measure memory for object, place, temporal order and object-location inter-relationships. We review the methodological properties of these tests, the neurobiology about time and discuss the evidence for the involvement of the medial prefrontal cortex (mPFC), entorhinal cortex (EC) and hippocampus, with respect to their anatomy, neurotransmitter systems and functional circuits. The systematic analysis suggests that a specific circuit between the mPFC, lateral EC and hippocampus encodes the information for event, place and time of occurrence into the complex episodic-like memory, as a top-down regulation from the mPFC onto the hippocampus. This circuit can be distinguished from the neuronal component memory systems for processing the individual information of object, time and place.
Collapse
|
31
|
Costa R, Tamascia ML, Sanches A, Moreira RP, Cunha TS, Nogueira MD, Casarini DE, Marcondes FK. Tactile stimulation of adult rats modulates hormonal responses, depression-like behaviors, and memory impairment induced by chronic mild stress: Role of angiotensin II. Behav Brain Res 2020; 379:112250. [DOI: 10.1016/j.bbr.2019.112250] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 09/17/2019] [Accepted: 09/17/2019] [Indexed: 12/19/2022]
|
32
|
Breach MR, Moench KM, Wellman CL. Social instability in adolescence differentially alters dendritic morphology in the medial prefrontal cortex and its response to stress in adult male and female rats. Dev Neurobiol 2019; 79:839-856. [PMID: 31612626 DOI: 10.1002/dneu.22723] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 01/01/2023]
Abstract
Adolescence is an important period for HPA axis development and synapse maturation and reorganization in the prefrontal cortex (PFC). Thus, stress during adolescence could alter stress-sensitive brain regions such as the PFC and may alter the impact of future stressors on these brain regions. Given that women are more susceptible to many stress-linked psychological disorders in which dysfunction of PFC is implicated, and that this increased vulnerability emerges in adolescence, stress during this time could have sex-dependent effects. Therefore, we investigated the effects of adolescent social instability stress (SIS) on dendritic morphology of Golgi-stained pyramidal cells in the medial PFC of adult male and female rats. We then examined dendritic reorganization following chronic restraint stress (CRS) with and without a rest period in adult rats that had been stressed in adolescence. Adolescent SIS conferred long-term alterations in prelimbic of males and females, whereby females show reduced apical length and basilar thin spine density and males show reduced basilar length. CRS in adulthood failed to produce immediate dendritic remodeling in SIS rats. However, CRS followed by a rest period reduced apical dendritic length and increases mushroom spine density in adolescently stressed adult males. Conversely, CRS followed by rest produced apical outgrowth and decreased mushroom spine density in adolescently stressed adult females. These results suggest that stress during adolescence alters development of the PFC and modulates stress-induced dendritic changes in adulthood.
Collapse
Affiliation(s)
- Michaela R Breach
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Kelly M Moench
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA
| | - Cara L Wellman
- Department of Psychological & Brain Sciences, Indiana University, Bloomington, IN, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, USA
- Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN, USA
| |
Collapse
|
33
|
Velasco ER, Florido A, Milad MR, Andero R. Sex differences in fear extinction. Neurosci Biobehav Rev 2019; 103:81-108. [PMID: 31129235 PMCID: PMC6692252 DOI: 10.1016/j.neubiorev.2019.05.020] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 03/08/2019] [Accepted: 05/19/2019] [Indexed: 12/18/2022]
Abstract
Despite the exponential increase in fear research during the last years, few studies have included female subjects in their design. The need to include females arises from the knowledge gap of mechanistic processes underlying the behavioral and neural differences observed in fear extinction. Moreover, the exact contribution of sex and hormones in relation to learning and behavior is still largely unknown. Insights from this field could be beneficial as fear-related disorders are twice as prevalent in women compared to men. Here, we review an up-to-date summary of animal and human studies in adulthood that report sex differences in fear extinction from a structural and functional approach. Furthermore, we describe how these factors could contribute to the observed sex differences in fear extinction during normal and pathological conditions.
Collapse
Affiliation(s)
- E R Velasco
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - A Florido
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain
| | - M R Milad
- Department of Psychiatry, University of Illinois at Chicago, USA
| | - R Andero
- Institut de Neurociències, Universitat Autònoma de Barcelona, Spain; CIBERSAM, Corporació Sanitaria Parc Taulí, Sabadell, Spain; Department of Psychobiology and Methodology of Health Sciences, Universitat Autònoma de Barcelona, Spain.
| |
Collapse
|
34
|
Mollayeva T, Mollayeva S, Colantonio A. Traumatic brain injury: sex, gender and intersecting vulnerabilities. Nat Rev Neurol 2018; 14:711-722. [DOI: 10.1038/s41582-018-0091-y] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
35
|
Proaño SB, Morris HJ, Kunz LM, Dorris DM, Meitzen J. Estrous cycle-induced sex differences in medium spiny neuron excitatory synaptic transmission and intrinsic excitability in adult rat nucleus accumbens core. J Neurophysiol 2018; 120:1356-1373. [PMID: 29947588 DOI: 10.1152/jn.00263.2018] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Naturally occurring hormone cycles in adult female humans and rodents create a dynamic neuroendocrine environment. These cycles include the menstrual cycle in humans and its counterpart in rodents, the estrous cycle. These hormone fluctuations induce sex differences in the phenotypes of many behaviors, including those related to motivation, and associated disorders such as depression and addiction. This suggests that the neural substrate instrumental for these behaviors, including the nucleus accumbens core (AcbC), likewise differs between estrous cycle phases. It is unknown whether the electrophysiological properties of AcbC output neurons, medium spiny neurons (MSNs), change between estrous cycle phases. This is a critical knowledge gap given that MSN electrophysiological properties are instrumental for determining AcbC output to efferent targets. Here we test whether the intrinsic electrophysiological properties of adult rat AcbC MSNs differ across female estrous cycle phases and from males. We recorded MSNs with whole cell patch-clamp technique in two experiments, the first using gonad-intact adult males and females in differing phases of the estrous cycle and the second using gonadectomized males and females in which the estrous cycle was eliminated. MSN intrinsic electrophysiological and excitatory synaptic input properties robustly changed between female estrous cycle phases and males. Sex differences in MSN electrophysiology disappeared when the estrous cycle was eliminated. These novel findings indicate that AcbC MSN electrophysiological properties change across the estrous cycle, providing a new framework for understanding how biological sex and hormone cyclicity regulate motivated behaviors and other AcbC functions and disorders. NEW & NOTEWORTHY This research is the first demonstration that medium spiny neuron electrophysiological properties change across adult female hormone cycle phases in any striatal region. This influence of estrous cycle engenders sex differences in electrophysiological properties that are eliminated by gonadectomy. Broadly, these findings indicate that adult female hormone cycles are an important factor for neurophysiology.
Collapse
Affiliation(s)
- Stephanie B Proaño
- Graduate Program in Biology, North Carolina State University , Raleigh, North Carolina.,W. M. Keck Center for Behavioral Biology, North Carolina State University , Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina
| | - Hannah J Morris
- Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina
| | - Lindsey M Kunz
- Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina
| | - David M Dorris
- Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina
| | - John Meitzen
- W. M. Keck Center for Behavioral Biology, North Carolina State University , Raleigh, North Carolina.,Department of Biological Sciences, North Carolina State University , Raleigh, North Carolina.,Center for Human Health and the Environment, North Carolina State University , Raleigh, North Carolina.,Comparative Medicine Institute, North Carolina State University , Raleigh, North Carolina
| |
Collapse
|
36
|
Kornfield SL, Hantsoo L, Epperson CN. What Does Sex Have to Do with It? The Role of Sex as a Biological Variable in the Development of Posttraumatic Stress Disorder. Curr Psychiatry Rep 2018; 20:39. [PMID: 29777319 PMCID: PMC6354938 DOI: 10.1007/s11920-018-0907-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE OF REVIEW This review highlights the neurobiological aspects of sex differences in posttraumatic stress disorder (PTSD), specifically focusing on the physiological responses to trauma and presents evidence supporting hormone and neurosteroid/peptide differences from both preclinical and clinical research. RECENT FINDINGS While others have suggested that trauma type or acute emotional reaction are responsible for women's disproportionate risk to PTSD, neither of these explanations fully accounts for the sex differences in PTSD. Sex differences in brain neurocircuitry, anatomy, and neurobiological processes, such as those involved in learning and memory, are discussed as they have been implicated in risk and resilience for the development of PTSD. Gonadal and stress hormones have been found to modulate sex differences in the neurocircuitry and neurochemistry underlying fear learning and extinction. Preclinical research has not consistently controlled for hormonal and reproductive status of rodents nor have clinical studies consistently examined these factors as potential moderators of risk for PTSD. Sex as a biological variable (SABV) should be considered, in addition to the endocrine and reproductive status of participants, in all stress physiology and PTSD research.
Collapse
Affiliation(s)
- Sara L Kornfield
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, 3535 Market Street, Room 3005, Philadelphia, PA, 19104, USA.
| | - Liisa Hantsoo
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, 3535 Market Street, Room 3005, Philadelphia, PA, 19104, USA
| | - C Neill Epperson
- Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, 3535 Market Street, Room 3005, Philadelphia, PA, 19104, USA
- Department of Obstetrics and Gynecology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
- Penn PROMOTES Research on Sex and Gender in Health, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
37
|
Mechanisms of Sex Differences in Fear and Posttraumatic Stress Disorder. Biol Psychiatry 2018; 83:876-885. [PMID: 29331353 DOI: 10.1016/j.biopsych.2017.11.016] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 11/24/2022]
Abstract
Following sexual maturity, females disproportionately have higher rates of posttraumatic stress disorder (PTSD) and experience greater symptom severity and chronicity as compared with males. This observation has led many to examine sex differences in PTSD risk factors. Though relatively few, these studies reveal that the root causes of PTSD sex differences are complex, and partly represent interactions between sex-specific nonbiological and biological risk factors, which differentially shape PTSD vulnerability. Moreover, these studies suggest that sex-specific PTSD vulnerability is partly regulated by sex differences in fear systems. Fear, which represents a highly conserved adaptive response to threatening environmental stimuli, becomes pathological in trauma- and stress-based psychiatric syndromes, such as PTSD. Over the last 30 years, considerable progress has been made in understanding normal and pathological molecular and behavioral fear processes in humans and animal models. Thus, fear mechanisms represent a tractable PTSD biomarker in the study of sex differences in fear. In this review, we discuss studies that examine nonbiological and biological sex differences that contribute to normal and pathological fear behaviors in humans and animal models. This, we hope, will shed greater light on the potential mechanisms that contribute to increased PTSD vulnerability in females.
Collapse
|
38
|
Common Biological Mechanisms of Alcohol Use Disorder and Post-Traumatic Stress Disorder. Alcohol Res 2018; 39:131-145. [PMID: 31198653 PMCID: PMC6561401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are highly comorbid. Although recent clinical studies provide some understanding of biological and subsequent behavioral changes that define each of these disorders, the neurobiological basis of interactions between PTSD and AUD has not been well-understood. In this review, we summarize the relevant animal models that parallel the human conditions, as well as the clinical findings in these disorders, to delineate key gaps in our knowledge and to provide potential clinical strategies for alleviating the comorbid conditions.
Collapse
|
39
|
Foilb AR, Bals J, Sarlitto MC, Christianson JP. Sex differences in fear discrimination do not manifest as differences in conditioned inhibition. ACTA ACUST UNITED AC 2017; 25:49-53. [PMID: 29246981 PMCID: PMC5733464 DOI: 10.1101/lm.045500.117] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 09/26/2017] [Indexed: 01/11/2023]
Abstract
Distinguishing safety from danger is necessary for survival, but is aberrant in individuals with post-traumatic stress disorder (PTSD). While PTSD is more prevalent in women than men, research on sex differences in safety learning is limited. Here, female rats demonstrated greater fear discrimination than males in a CS+/CS− paradigm. To determine if this sex difference transferred to fear inhibition, rats were tested for conditioned inhibition in a summation test with the CS+ and CS− presented in compound; no sex difference emerged. The results suggest sex differences in the neural mechanisms of discrimination learning but not recall of a fear inhibitor.
Collapse
Affiliation(s)
- Allison R Foilb
- Department of Psychology, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Julia Bals
- Department of Psychology, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Mary C Sarlitto
- Department of Psychology, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - John P Christianson
- Department of Psychology, Boston College, Chestnut Hill, Massachusetts 02467, USA
| |
Collapse
|
40
|
Maeng LY, Cover KK, Taha MB, Landau AJ, Milad MR, Lebrón-Milad K. Estradiol shifts interactions between the infralimbic cortex and central amygdala to enhance fear extinction memory in female rats. J Neurosci Res 2017; 95:163-175. [PMID: 27870439 DOI: 10.1002/jnr.23826] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/27/2016] [Accepted: 06/20/2016] [Indexed: 01/01/2023]
Abstract
There is growing evidence that estradiol (E2) enhances fear extinction memory consolidation. However, it is unclear how E2 influences the nodes of the fear extinction network to enhance extinction memory. This study begins to delineate the neural circuits underlying the influence of E2 on fear extinction acquisition and consolidation in female rats. After fear conditioning (day 1), naturally cycling female rats underwent extinction learning (day 2) in a low-E2 state, receiving a systemic administration of either E2 or vehicle prior to extinction training. Extinction memory recall was then tested 24 hr later (day 3). We measured immediate early gene c-fos expression within the extinction network during fear extinction learning and extinction recall. During extinction learning, E2 treatment increased centrolateral amygdala c-fos activity and reduced lateral amygdala activity relative to vehicle. During extinction recall, E2-treated rats exhibited reduced c-fos expression in the centromedial amygdala. There were no group differences in c-fos expression within the medial prefrontal cortex or dorsal hippocampus. Examining c-fos ratios with the infralimbic cortex (IL) revealed that, despite the lack of group differences within the IL, E2 treatment induced greater IL activity relative to both prelimbic cortex and central amygdala (CeA) activity during extinction memory recall. Only the relationship between IL and CeA activity positively correlated with extinction retention. In conclusion, E2 appears to modify interactions between the IL and the CeA in females, shifting from stronger amygdalar modulation of fear during extinction learning to stronger IL control during extinction recall. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Lisa Y Maeng
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Kara K Cover
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Mohamad B Taha
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Aaron J Landau
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Mohammed R Milad
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| | - Kelimer Lebrón-Milad
- Department of Psychiatry, Massachusetts General Hospital, Charlestown, Massachusetts.,Department of Psychiatry, Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
41
|
Sex- and Estrus-Dependent Differences in Rat Basolateral Amygdala. J Neurosci 2017; 37:10567-10586. [PMID: 28954870 DOI: 10.1523/jneurosci.0758-17.2017] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 01/24/2023] Open
Abstract
Depression and anxiety are diagnosed almost twice as often in women, and the symptomology differs in men and women and is sensitive to sex hormones. The basolateral amygdala (BLA) contributes to emotion-related behaviors that differ between males and females and across the reproductive cycle. This hints at sex- or estrus-dependent features of BLA function, about which very little is known. The purpose of this study was to test whether there are sex differences or estrous cyclicity in rat BLA physiology and to determine their mechanistic correlates. We found substantial sex differences in the activity of neurons in lateral nuclei (LAT) and basal nuclei (BA) of the BLA that were associated with greater excitatory synaptic input in females. We also found strong differences in the activity of LAT and BA neurons across the estrous cycle. These differences were associated with a shift in the inhibition-excitation balance such that LAT had relatively greater inhibition during proestrus which paralleled more rapid cued fear extinction. In contrast, BA had relatively greater inhibition during diestrus that paralleled more rapid contextual fear extinction. These results are the first to demonstrate sex differences in BLA neuronal activity and the impact of estrous cyclicity on these measures. The shift between LAT and BA predominance across the estrous cycle provides a simple construct for understanding the effects of the estrous cycle on BLA-dependent behaviors. These results provide a novel framework to understand the cyclicity of emotional memory and highlight the importance of considering ovarian cycle when studying the BLA of females.SIGNIFICANCE STATEMENT There are differences in emotional responses and many psychiatric symptoms between males and females. This may point to sex differences in limbic brain regions. Here we demonstrate sex differences in neuronal activity in one key limbic region, the basolateral amygdala (BLA), whose activity fluctuates across the estrous cycle due to a shift in the balance of inhibition and excitation across two BLA regions, the lateral and basal nuclei. By uncovering this push-pull shift between lateral and basal nuclei, these results help to explain disparate findings about the effects of biological sex and estrous cyclicity on emotion and provide a framework for understanding fluctuations in emotional memory and psychiatric symptoms.
Collapse
|
42
|
Voulo ME, Parsons RG. Response-specific sex difference in the retention of fear extinction. ACTA ACUST UNITED AC 2017; 24:245-251. [PMID: 28507033 PMCID: PMC5435884 DOI: 10.1101/lm.045641.117] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/04/2017] [Indexed: 01/21/2023]
Abstract
Fear conditioning studies in rodents allow us to assess vulnerability factors which might underlie fear-based psychopathology such as post-traumatic stress disorder (PTSD). Despite PTSD being more prevalent in females than males, very few fear conditioning studies in rodents have tested females. Our study assessed fear conditioning and extinction in male and female rats using both fear-potentiated startle and freezing behavior as measures. Rats were trained to fear cues that predicted the occurrence of shock and then subsequently exposed to an extinction training procedure where the cue was presented repeatedly in the absence of shock. Retention of the extinction memory was assessed the next day. Our results showed that females exhibited less retention of fear extinction, but only when measured by fear-potentiated startle. Our results highlight the importance of using multiple indices of fear behavior, particularly when comparing sexes on measures of extinction learning.
Collapse
Affiliation(s)
- Meagan E Voulo
- Department of Psychology, Stony Brook University, Stony Brook, New York 11794, USA
| | - Ryan G Parsons
- Department of Psychology, Stony Brook University, Stony Brook, New York 11794, USA
| |
Collapse
|
43
|
Li SH, Graham BM. Why are women so vulnerable to anxiety, trauma-related and stress-related disorders? The potential role of sex hormones. Lancet Psychiatry 2017; 4:73-82. [PMID: 27856395 DOI: 10.1016/s2215-0366(16)30358-3] [Citation(s) in RCA: 311] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 02/08/2023]
Abstract
Increased prevalence, severity, and burden of anxiety, trauma-related and stress-related disorders in women compared with men has been well documented. Evidence from a variety of fields has emerged suggesting that sex hormones, particularly oestradiol and progesterone, play a significant part in generation of these sex differences. In this Series paper, we aim to integrate the literature reporting on the effects of sex hormones on biological, behavioural, and cognitive pathways, to propose two broad mechanisms by which oestradiol and progesterone influence sex differences in anxiety disorders: augmentation of vulnerability factors associated with anxiety disorder development; and facilitation of the maintenance of anxious symptoms post-development. The implications for future research, along with novel approaches to psychological and pharmacological treatment of anxiety disorders, are also considered.
Collapse
Affiliation(s)
- Sophie H Li
- School of Psychology, The University of New South Wales, Sydney, NSW, Australia
| | - Bronwyn M Graham
- School of Psychology, The University of New South Wales, Sydney, NSW, Australia.
| |
Collapse
|
44
|
Blankenship PA, Stuebing SL, Winter SS, Cheatwood JL, Benson JD, Whishaw IQ, Wallace DG. The medial frontal cortex contributes to but does not organize rat exploratory behavior. Neuroscience 2016; 336:1-11. [DOI: 10.1016/j.neuroscience.2016.08.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/17/2016] [Accepted: 08/24/2016] [Indexed: 10/21/2022]
|
45
|
Day HLL, Reed MM, Stevenson CW. Sex differences in discriminating between cues predicting threat and safety. Neurobiol Learn Mem 2016; 133:196-203. [PMID: 27423522 PMCID: PMC4993817 DOI: 10.1016/j.nlm.2016.07.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 06/03/2016] [Accepted: 07/12/2016] [Indexed: 01/30/2023]
Abstract
We investigated sex differences in auditory fear discrimination in rats. Males that received extended discrimination training showed fear discrimination. Females discriminated after limited training and generalized after extended training. Generalization with extended training in females involved impaired safety signaling.
Post-traumatic stress disorder (PTSD) is more prevalent in women than men. PTSD is characterized by overgeneralization of fear to innocuous stimuli and involves impaired inhibition of learned fear by cues that predict safety. While evidence indicates that learned fear inhibition through extinction differs in males and females, less is known about sex differences in fear discrimination and safety learning. Here we examined auditory fear discrimination in male and female rats. In Experiment 1A, rats underwent 1–3 days of discrimination training consisting of one tone predicting threat (CS+; presented with footshock) and another tone predicting safety (CS−; presented alone). Females, but not males, discriminated between the CS+ and CS− after one day of training. After 2–3 days of training, however, males discriminated whereas females generalized between the CS+ and CS−. In Experiment 1B, females showed enhanced anxiety-like behaviour and locomotor activity in the open field, although these results were unlikely to explain the sex differences in fear discrimination. In Experiment 2, we found no differences in shock sensitivity between males and females. In Experiment 3, males and females again discriminated and generalized, respectively, after three days of training. Moreover, fear generalization in females resulted from impaired safety learning, as shown by a retardation test. Whereas subsequent fear conditioning to the previous CS− retarded learning in males, females showed no such retardation. These results suggest that, while females show fear discrimination with limited training, they show fear generalization with extended training due to impaired safety learning.
Collapse
Affiliation(s)
- Harriet L L Day
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Molly M Reed
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Carl W Stevenson
- School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
| |
Collapse
|
46
|
Sex differences in learned fear expression and extinction involve altered gamma oscillations in medial prefrontal cortex. Neurobiol Learn Mem 2016; 135:66-72. [PMID: 27344940 DOI: 10.1016/j.nlm.2016.06.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/06/2016] [Accepted: 06/21/2016] [Indexed: 11/22/2022]
Abstract
Sex differences in learned fear expression and extinction involve the medial prefrontal cortex (mPFC). We recently demonstrated that enhanced learned fear expression during auditory fear extinction and its recall is linked to persistent theta activation in the prelimbic (PL) but not infralimbic (IL) cortex of female rats. Emerging evidence indicates that gamma oscillations in mPFC are also implicated in the expression and extinction of learned fear. Therefore we re-examined our in vivo electrophysiology data and found that females showed persistent PL gamma activation during extinction and a failure of IL gamma activation during extinction recall. Altered prefrontal gamma oscillations thus accompany sex differences in learned fear expression and its extinction. These findings are relevant for understanding the neural basis of post-traumatic stress disorder, which is more prevalent in women and involves impaired extinction and mPFC dysfunction.
Collapse
|
47
|
Cossio R, Carreira MB, Vásquez CE, Britton GB. Sex differences and estrous cycle effects on foreground contextual fear conditioning. Physiol Behav 2016; 163:305-311. [PMID: 27195460 DOI: 10.1016/j.physbeh.2016.05.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 05/13/2016] [Accepted: 05/15/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Ricardo Cossio
- Centro de Neurociencias, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Ciudad del Saber, Panama
| | - María B Carreira
- Centro de Neurociencias, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Ciudad del Saber, Panama
| | - Carol E Vásquez
- Centro de Neurociencias, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Ciudad del Saber, Panama; Department of Biotechnology, AcharyaNagarjuna University, Guntur, India
| | - Gabrielle B Britton
- Centro de Neurociencias, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Ciudad del Saber, Panama.
| |
Collapse
|
48
|
Keum S, Park J, Kim A, Park J, Kim KK, Jeong J, Shin HS. Variability in empathic fear response among 11 inbred strains of mice. GENES BRAIN AND BEHAVIOR 2016; 15:231-42. [PMID: 26690560 DOI: 10.1111/gbb.12278] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Revised: 11/24/2015] [Accepted: 11/29/2015] [Indexed: 12/21/2022]
Abstract
Empathy is an important emotional process that involves the ability to recognize and share emotions with others. We have previously developed an observational fear learning (OFL) behavioral assay to measure empathic fear in mice. In the OFL task, a mouse is conditioned for context-dependent fear when it observes a conspecific demonstrator receiving aversive stimuli. In the present study, by comparing 11 different inbred mouse strains that are commonly used in the laboratory, we found that empathic fear response was highly variable between different strains. Five strains--C57BL/6J, C57BL/6NTac, 129S1/SvImJ, 129S4/SvJae and BTBR T(+) Itpr3(tf) /J--showed observational fear (OF) responses, whereas AKR/J, BALB/cByJ, C3H/HeJ, DBA/2J, FVB/NJ and NOD/ShiLtJ mice exhibited low empathic fear response. Importantly, day 2 OF memory was significantly correlated with contextual memory in the classical fear conditioning among the 11 strains. Innate differences in anxiety, locomotor activity, sociability and preference for social novelty were not significantly correlated with OFL. Interestingly, early adolescent C57BL/6J mice exhibited an increase in acquisition of OF. The level of OFL in C57BL/6J strain was not affected by sex or strains of the demonstrator. Taken together, these data strongly suggest that there are naturally occurring OFL-specific genetic variations modulating empathic fear behaviors in mice. The identification of causal genes may uncover novel genetic pathways and underlying neural mechanisms that modulate empathic fear and, ultimately, provide new targets for therapeutic intervention in human mental disorders associated with impaired empathy.
Collapse
Affiliation(s)
- S Keum
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - J Park
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea.,Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - A Kim
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - J Park
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - K K Kim
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - J Jeong
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - H-S Shin
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| |
Collapse
|
49
|
Maeng LY, Milad MR. Sex differences in anxiety disorders: Interactions between fear, stress, and gonadal hormones. Horm Behav 2015; 76:106-17. [PMID: 25888456 PMCID: PMC4823998 DOI: 10.1016/j.yhbeh.2015.04.002] [Citation(s) in RCA: 236] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 03/26/2015] [Accepted: 04/06/2015] [Indexed: 12/22/2022]
Abstract
This article is part of a Special Issue "SBN 2014". Women are more vulnerable to stress- and fear-based disorders, such as anxiety and post-traumatic stress disorder. Despite the growing literature on this topic, the neural basis of these sex differences remains unclear, and the findings appear inconsistent. The neurobiological mechanisms of fear and stress in learning and memory processes have been extensively studied, and the crosstalk between these systems is beginning to explain the disproportionate incidence and differences in symptomatology and remission within these psychopathologies. In this review, we discuss the intersect between stress and fear mechanisms and their modulation by gonadal hormones and discuss the relevance of this information to sex differences in anxiety and fear-based disorders. Understanding these converging influences is imperative to the development of more effective, individualized treatments that take sex and hormones into account.
Collapse
Affiliation(s)
- Lisa Y Maeng
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA.
| | - Mohammed R Milad
- Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, 149 13th Street, Charlestown, MA 02129, USA.
| |
Collapse
|
50
|
Glover EM, Jovanovic T, Norrholm SD. Estrogen and extinction of fear memories: implications for posttraumatic stress disorder treatment. Biol Psychiatry 2015; 78:178-85. [PMID: 25796471 PMCID: PMC4757430 DOI: 10.1016/j.biopsych.2015.02.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 01/06/2015] [Accepted: 02/04/2015] [Indexed: 12/11/2022]
Abstract
Posttraumatic stress disorder (PTSD) is a psychiatric illness whose prevalence in women is more than twice the rate as men. Despite a burgeoning literature characterizing sex differences in PTSD incidence and its disproportionate burden on society, there is a dearth of literature describing biological mechanisms underlying these disparities. However, the recent identification of biomarkers of PTSD by translational neuroscientists offers a promising opportunity to explore sex interactions in PTSD phenotypes. A notable observation is that individuals with PTSD show deficits in their ability to inhibit conditioned fear responding after extinction training. Given that extinction procedures, via exposure-based cognitive behavioral therapy, make up one of the predominant modes of treatment in PTSD, there is a critical need for more research on sex interactions in this form of fear regulation. An emerging hypothesis is that fluctuating gonadal hormones, especially estrogen, in the menstrual cycle may play a critical role in fear extinction and, hence, PTSD vulnerability and symptom severity in women. The current review discusses how the study of putative activational effects of estrogen on fear extinction may be harnessed to advance the search for better treatments for PTSD in women. We conclude that estrogen treatment may be a putative pharmacologic adjunct in extinction-based therapies and should be tracked in the menstrual cycle during the course of PTSD treatment.
Collapse
Affiliation(s)
- Ebony M Glover
- Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta; Department of Psychology, Kennesaw State University, Kennesaw
| | - Tanja Jovanovic
- Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta
| | - Seth Davin Norrholm
- Department of Psychiatry & Behavioral Sciences, Emory University, Atlanta; Mental Health Service Line , Atlanta Veterans Affairs Medical Center, Decatur, Georgia.
| |
Collapse
|