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Nist AN, Walsh SJ, Shahan TA. Ketamine produces no detectable long-term positive or negative effects on cognitive flexibility or reinforcement learning of male rats. Psychopharmacology (Berl) 2024; 241:849-863. [PMID: 38062167 DOI: 10.1007/s00213-023-06514-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 11/25/2023] [Indexed: 03/13/2024]
Abstract
RATIONALE Patients with major depressive disorder (MDD) often experience abnormalities in behavioral adaptation following environmental changes (i.e., cognitive flexibility) and tend to undervalue positive outcomes but overvalue negative outcomes. The probabilistic reversal learning task (PRL) is used to study these deficits across species and to explore drugs that may have therapeutic value. Selective serotonin-reuptake inhibitors (SSRIs) have limited effectiveness in treating MDD and produce inconsistent effects in non-human versions of the PRL. As such, ketamine, a novel and potentially rapid-acting therapeutic, has begun to be examined using the PRL. Two previous studies examining the effects of ketamine in the PRL have shown conflicting results and only examined short-term effects of ketamine. OBJECTIVE This experiment examined PRL performance across a 2-week period following a single exposure to a ketamine dose that varied across groups. METHODS After five sessions of PRL training, groups of rats received an injection of either 0, 10, 20 or 30 mg/kg ketamine. One-hour post-injection, rats engaged in the PRL, and subsequently sessions continued daily for 2 weeks. Traditional behavioral and computational reinforcement learning-derived measures were examined. RESULTS Results showed that ketamine had acute effects 1-h post-injection, including a significant decrease in the value of the punishment learning rate. Beyond 1 h, ketamine produced no detectable improvements nor decrements in performance across 2 weeks. CONCLUSION Overall, the present results suggest that the range of ketamine doses examined do not have long-term positive or negative effects on cognitive flexibility or reward processing in healthy rats as measured by the PRL.
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Affiliation(s)
- Anthony N Nist
- Department of Psychology, Utah State University, Logan, USA.
| | - Stephen J Walsh
- Department of Mathematics and Statistics, Utah State University, Logan, USA
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Sellinger EP, Brinks AS, Javeri RR, Theurer SL, Wang R, Juraska JM. Region- and age-specific effects of perinatal phthalate exposure on developmental cell death and adult anatomy of dorsal and ventral hippocampus and associated cognitive behaviors. Neurotoxicol Teratol 2023; 99:107288. [PMID: 37595675 PMCID: PMC10530334 DOI: 10.1016/j.ntt.2023.107288] [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: 02/16/2023] [Revised: 08/01/2023] [Accepted: 08/10/2023] [Indexed: 08/20/2023]
Abstract
Humans are exposed to phthalates, a class of endocrine-disrupting chemicals used in food packaging/processing, PVC plastics, and personal care products. Gestational exposure may lead to adverse neurodevelopmental outcomes. In a rat model, perinatal exposure to an environmentally relevant mixture and dose of phthalates leads to increased developmental apoptosis in the medial prefrontal cortex (mPFC) and a subsequent reduction in neurons and in cognitive flexibility measured in adults of both sexes (Sellinger et al., 2021b; Kougias et al., 2018b). However, whether these effects generalize to other cognitive regions, like the hippocampus, is less well understood as existing studies used single phthalates at large doses, unrepresentative of human exposure. In the current study, patterns of naturally occurring cell death were first established in the dorsal and ventral hippocampal subfields (CA3 and CA1). Both dorsal and ventral CA3 reached high levels of cell death on P2 while levels in dorsal and ventral CA1 peaked on P5 in both sexes. Exposure to a phthalate mixture (0.2 and 1 mg/kg/day) throughout gestation through postnatal day 10 resulted in subtle age- and region-specific decreases in developmental cell death, however there were no significant changes in adult neuron number or associated behaviors: the Morris water maze and social recognition. Therefore, perinatal exposure to a low dose mixture of phthalates does not result in the dramatic structural and behavioral changes seen with high doses of single phthalates. This study also adds to our understanding of the distinct neurodevelopmental effects of phthalates on different brain regions.
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Affiliation(s)
- Elli P Sellinger
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Amara S Brinks
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Rajvi R Javeri
- Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Savannah L Theurer
- Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Ruibin Wang
- Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
| | - Janice M Juraska
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America; Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL 61820, United States of America.
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3
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Yegla B, Rani A, Kumar A. Viral vector-mediated upregulation of serine racemase expression in medial prefrontal cortex improves learning and synaptic function in middle age rats. Aging (Albany NY) 2023; 15:2433-2449. [PMID: 37052995 PMCID: PMC10120901 DOI: 10.18632/aging.204652] [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: 01/19/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
An age-associated decrease in N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic function contributes to impaired synaptic plasticity and is associated with cognitive impairments. Levels of serine racemase (SR), an enzyme that synthesizes D-serine, an NMDAR co-agonist, decline with age. Thus, enhancing NMDAR function via increased SR expression in middle age, when subtle declines in cognition emerge, was predicted to enhance performance on a prefrontal cortex-mediated task sensitive to aging. Middle-aged (~12 mo) male Fischer-344 rats were injected bilaterally in the medial prefrontal cortex (mPFC) with viral vector (LV), SR (LV-SR) or control (LV-GFP). Rats were trained on the operant attentional set-shift task (AST) to examine cognitive flexibility and attentional function. LV-SR rats exhibited a faster rate of learning compared to controls during visual discrimination of the AST. Extradimensional set shifting and reversal were not impacted. Immunohistochemical analyses demonstrated that LV-SR significantly increased SR expression in the mPFC. Electrophysiological characterization of synaptic transmission in the mPFC slices obtained from LV-GFP and LV-SR animals indicated a significant increase in isolated NMDAR-mediated synaptic responses in LV-SR slices. Thus, results of the current study demonstrated that prefrontal SR upregulation in middle age rats can improve learning of task contingencies for visual discrimination and increase glutamatergic synaptic transmission, including NMDAR activity.
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Affiliation(s)
- Brittney Yegla
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Asha Rani
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
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Latuske P, von Heimendahl M, Deiana S, Wotjak CT, du Hoffmann J. Sustained MK-801 induced deficit in a novel probabilistic reversal learning task. Front Pharmacol 2022; 13:898548. [PMID: 36313373 PMCID: PMC9614101 DOI: 10.3389/fphar.2022.898548] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 08/02/2022] [Indexed: 12/01/2022] Open
Abstract
Cognitive flexibility, the ability to adapt to unexpected changes, is critical for healthy environmental and social interactions, and thus to everyday functioning. In neuropsychiatric diseases, cognitive flexibility is often impaired and treatment options are lacking. Probabilistic reversal learning (PRL) is commonly used to measure cognitive flexibility in rodents and humans. In PRL tasks, subjects must sample choice options and, from probabilistic feedback, find the current best choice which then changes without warning. However, in rodents, pharmacological models of human cognitive impairment tend to disrupt only the first (or few) of several contingency reversals, making quantitative assessment of behavioral effects difficult. To address this limitation, we developed a novel rat PRL where reversals occur at relatively long intervals in time that demonstrates increased sensitivity to the non-competitive NMDA receptor antagonist MK-801. Here, we quantitively compare behavior in time-based PRL with a widely used task where reversals occur based on choice behavior. In time-based PRL, MK-801 induced sustained reversal learning deficits both in time and across reversal blocks but, at the same dose, only transient weak effects in performance-based PRL. Moreover, time-based PRL yielded better estimates of behavior and reinforcement learning model parameters, which opens meaningful pharmacological windows to efficiently test and develop novel drugs preclinically with the goal of improving cognitive impairment in human patients.
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Patel RR, Wolfe SA, Borgonetti V, Gandhi PJ, Rodriguez L, Snyder AE, D'Ambrosio S, Bajo M, Domissy A, Head S, Contet C, Dayne Mayfield R, Roberts AJ, Roberto M. Ethanol withdrawal-induced adaptations in prefrontal corticotropin releasing factor receptor 1-expressing neurons regulate anxiety and conditioned rewarding effects of ethanol. Mol Psychiatry 2022; 27:3441-3451. [PMID: 35668157 PMCID: PMC9708587 DOI: 10.1038/s41380-022-01642-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 04/22/2022] [Accepted: 05/23/2022] [Indexed: 11/09/2022]
Abstract
Prefrontal circuits are thought to underlie aberrant emotion contributing to relapse in abstinence; however, the discrete cell-types and mechanisms remain largely unknown. Corticotropin-releasing factor and its cognate type-1 receptor, a prominent brain stress system, is implicated in anxiety and alcohol use disorder (AUD). Here, we tested the hypothesis that medial prefrontal cortex CRF1-expressing (mPFCCRF1+) neurons comprise a distinct population that exhibits neuroadaptations following withdrawal from chronic ethanol underlying AUD-related behavior. We found that mPFCCRF1+ neurons comprise a glutamatergic population with distinct electrophysiological properties and regulate anxiety and conditioned rewarding effects of ethanol. Notably, mPFCCRF1+ neurons undergo unique neuroadaptations compared to neighboring neurons including a remarkable decrease in excitability and glutamatergic signaling selectively in withdrawal, which is driven in part by the basolateral amygdala. To gain mechanistic insight into these electrophysiological adaptations, we sequenced the transcriptome of mPFCCRF1+ neurons and found that withdrawal leads to an increase in colony-stimulating factor 1 (CSF1) in this population. We found that selective overexpression of CSF1 in mPFCCRF1+ neurons is sufficient to decrease glutamate transmission, heighten anxiety, and abolish ethanol reinforcement, providing mechanistic insight into the observed mPFCCRF1+ synaptic adaptations in withdrawal that drive these behavioral phenotypes. Together, these findings highlight mPFCCRF1+ neurons as a critical site of enduring adaptations that may contribute to the persistent vulnerability to ethanol misuse in abstinence, and CSF1 as a novel target for therapeutic intervention for withdrawal-related negative affect.
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Affiliation(s)
- Reesha R Patel
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Sarah A Wolfe
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Vittoria Borgonetti
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
- Dipartimento di Neuroscienze, Psicologia, Area del Farmaco e Salute del Bambino, Università degli Studi di Firenze, 50139, Firenze (FI), Italy
| | - Pauravi J Gandhi
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Larry Rodriguez
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Angela E Snyder
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Shannon D'Ambrosio
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Michal Bajo
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Alain Domissy
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Steven Head
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Candice Contet
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - R Dayne Mayfield
- Department of Neuroscience, The University of Texas at Austin, Austin, TX, 78712, USA
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Amanda J Roberts
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA
| | - Marisa Roberto
- The Scripps Research Institute, 10550N. Torrey Pines Rd, La Jolla, CA, 92037, USA.
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Lissek S, Klass A, Tegenthoff M. NMDA receptor-mediated processing in inferior frontal gyrus facilitates acquisition and extinction learning and strengthens renewal. Neurobiol Learn Mem 2022; 194:107672. [PMID: 35917993 DOI: 10.1016/j.nlm.2022.107672] [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: 02/15/2022] [Revised: 06/14/2022] [Accepted: 07/27/2022] [Indexed: 11/17/2022]
Abstract
While the renewal effect of extinction is considered to be invoked by attention to context during the extinction phase, there is also evidence that processing during initial learning (acquisition) may be important for later renewal. A noradrenergic agonist and a dopaminergic antagonist, administered before acquisition, did not affect renewal, however, the effects of NMDAergic neurotransmission in this regard are as yet unknown. In a previous study, administration of a single dose of the NMDA agonist D-cycloserine (DCS) before extinction learning facilitated extinction in the context of acquisition (AAA), but had no effect upon renewal. In the present fMRI study, DCS was administered prior to the initial acquisition of a predictive learning task, in order to investigate whether NMDA receptor (NMDAR) stimulation at this timepoint will modulate overall learning as well as the level of renewal, while increasing activation in the extinction- and renewal-relevant brain regions of inferior frontal gyrus (iFG) and hippocampus (HC). DCS facilitated acquisition, as well as extinction learning in the context of acquisition (AAA), and raised the level of ABA renewal. While BOLD activation during acquisition did not differ between treatment groups, activation in bilateral iFG showed a double dissociation during processing of AAA extinction trials, with DCS-mediated higher activation in right iFG and deactivation in left iFG. In contrast, placebo showed higher activation in left iFG and deactivation in right iFG. During the test (recall) phase, left iFG and right anterior hippocampus activation was increased in DCS participants who showed renewal, with activation in this region correlating with the ABA renewal level. The results demonstrate that NMDA receptor stimulation can facilitate both initial learning and extinction of associations, and in this way has an impact upon the resultant level of renewal. In particular NMDAergic processing in iFG appears relevant for the facilitation of AAA extinction and ABA recall in the test phase.
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Affiliation(s)
- Silke Lissek
- Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Germany.
| | - Anne Klass
- Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Germany
| | - Martin Tegenthoff
- Department of Neurology, BG University Hospital Bergmannsheil, Ruhr-University Bochum, Germany
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7
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Sellinger EP, Riesgo VR, Brinks AS, Willing J, Juraska JM. Perinatal phthalate exposure increases developmental apoptosis in the rat medial prefrontal cortex. Neurotoxicology 2021; 87:167-173. [PMID: 34599995 DOI: 10.1016/j.neuro.2021.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/24/2021] [Accepted: 09/27/2021] [Indexed: 01/08/2023]
Abstract
Phthalates are a class of endocrine disruptors found in a variety of consumer goods, and offspring can be exposed to these compounds during gestation and lactation. Our laboratory has found that perinatal exposure to an environmentally relevant mixture of phthalates resulted in a decrease in cognitive flexibility and in neuron number in the adult rat medial prefrontal cortex (mPFC). Here, we examine effects of phthalate treatment on prenatal cellular proliferation and perinatal apoptosis in the mPFC. To examine the phthalate effects on cellular proliferation, dams consumed 0, 1, or 5 mg/kg of the phthalate mixture daily from embryonic day 2 (E2) through the day of birth (P0), and on E16 and E17, they were injected with BrdU. The mPFC of offspring was analyzed on P5 and showed a decrease in labelled cells in the phthalate exposed groups. To examine whether changes in BrdU density observed on P5 were due to altered cell survival, cell death was measured on E18, P0, and P5 using a TUNEL assay in a separate cohort of prenatally exposed offspring. There was an increase in TUNEL labelled cells at E18 in the phthalate exposed groups. In the final experiment, dams consumed the phthalate mixture from E2 through P10, at which time mPFC tissue was stained with TUNEL. Phthalate treated subjects showed a higher density of apoptotic cells at P10. These results indicate both pre- and postnatal phthalate exposure increases apoptosis in the male and female rat mPFC. While the impact of phthalates on proliferation cannot be ruled out, these data do not allow for definitive conclusions.
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Affiliation(s)
- Elli P Sellinger
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL, 61820, United States
| | - Victoria R Riesgo
- Department of Psychology, Bowling Green State University, 822 E Merry Ave, Bowling Green, OH, 43403, United States
| | - Amara S Brinks
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL, 61820, United States
| | - Jari Willing
- Department of Psychology, Bowling Green State University, 822 E Merry Ave, Bowling Green, OH, 43403, United States
| | - Janice M Juraska
- Neuroscience Program, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL, 61820, United States; Department of Psychology, University of Illinois at Urbana-Champaign, 603 E. Daniel Street, Champaign, IL, 61820, United States.
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8
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Evaluation of acute and chronic nociception in subchronically administered MK-801-induced rat model of schizophrenia. Behav Pharmacol 2021; 32:571-580. [PMID: 34494988 DOI: 10.1097/fbp.0000000000000651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Patients diagnosed with schizophrenia have been reported to exhibit atypically low pain sensitivity and to vary in their experience of chronic pain. To the best of our knowledge, there has yet to be an animal study that provides information concerning the relationship between models of schizophrenia and pain. In the present study, we investigated several distinct nociceptive behaviors in a translational rat model of schizophrenia (0. 5 mg/kg MK-801, twice a day for 7 days followed by a 7-day washout period). The presence of the expected cognitive deficit was confirmed with novel object recognition (NOR) paradigm prior to nociception testing. MK-801-treated rats with lack of novelty interest in NOR testing showed: hyposensitivity to thermal and mechanical stimuli; short-term hypoalgesia followed by augmented hyperalgesia in response to formalin-induced spontaneous nociception and increased thermal and mechanical hyperalgesia in the complete Freund's adjuvant (CFA) induced chronic pain model. In conclusion, MK-801 induced antinociception effects for thermal stimuli in rats that were consistent with the decreased pain sensitivity observed in schizophrenia patients. Additionally, the amplified biphasic response exhibited by the MK-801 group in the formalin-induced spontaneous nociception test affirms the suitability of the test as a model of acute to delayed pain transition.
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McQuail JA, Beas BS, Kelly KB, Hernandez CM, Bizon JL, Frazier CJ. Attenuated NMDAR signaling on fast-spiking interneurons in prefrontal cortex contributes to age-related decline of cognitive flexibility. Neuropharmacology 2021; 197:108720. [PMID: 34273386 DOI: 10.1016/j.neuropharm.2021.108720] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 07/08/2021] [Accepted: 07/13/2021] [Indexed: 02/01/2023]
Abstract
Ionotropic glutamate receptors of the NMDA and AMPA subtypes transduce excitatory signaling on neurons in the prefrontal cortex (PFC) in support of cognitive flexibility. Cognitive flexibility is reliably observed to decline at advanced ages, coinciding with changes in PFC glutamate receptor expression and neuronal physiology. However, the relationship between age-related impairment of cognitive flexibility and changes to excitatory signaling on distinct classes of PFC neurons is not known. In this study, one cohort of young adult (4 months) and aged (20 months) male F344 rats were characterized for cognitive flexibility on an operant set-shifting task. Expression of the essential NMDAR subunit, NR1, was correlated with individual differences in set-shifting abilities such that lower NR1 in the aged PFC was associated with worse set-shifting. In contrast, lower expression of two AMPAR subunits, GluR1 and GluR2, was not associated with set-shift abilities in aging. As NMDARs are expressed by both pyramidal cells and fast-spiking interneurons (FSI) in PFC, whole-cell patch clamp recordings were performed in a second cohort of age-matched rats to compare age-associated changes on these neuronal subtypes. Evoked excitatory postsynaptic currents were generated using a bipolar stimulator while AMPAR vs. NMDAR-mediated components were isolated using pharmacological tools. The results revealed a clear increase in AMPA/NMDA ratio in FSIs that was not present in pyramidal neurons. Together, these data indicate that loss of NMDARs on interneurons in PFC contributes to age-related impairment of cognitive flexibility.
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Affiliation(s)
- Joseph A McQuail
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, 29208, USA.
| | - B Sofia Beas
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA; Unit on the Neurobiology of Affective Memory, National Institute of Mental Health, Bethesda, MD, 20892, USA
| | - Kyle B Kelly
- Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, FL, 32610, USA
| | - Caesar M Hernandez
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA; Department of Cellular, Development, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Jennifer L Bizon
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Charles J Frazier
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, 32610, USA; Department of Pharmacodynamics, University of Florida College of Pharmacy, Gainesville, FL, 32610, USA.
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Higgins GA, Brown M, MacMillan C, Silenieks LB, Thevarkunnel S. Contrasting effects of d-amphetamine and atomoxetine on measures of impulsive action and choice. Pharmacol Biochem Behav 2021; 207:173220. [PMID: 34175329 DOI: 10.1016/j.pbb.2021.173220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 06/14/2021] [Accepted: 06/15/2021] [Indexed: 10/21/2022]
Abstract
Amphetamine (AMP) and atomoxetine (ATX) represent two of the most widely studied drug treatments used in the investigation of impulsive behaviour. While both drugs have relatively well defined effects in tests designed to investigate impulsive action (e.g. 5-choice task; 5-CSRTT), the effects of both drugs in tests of impulsive choice (e.g. delay discounting) are less consistent. In the present study both AMP and ATX were tested in a rodent gambling task (rGT) and delay discounting in rats separately trained to either an ascending or descending delay schedule. Effects of both drugs were compared to measures of impulsive action (premature (PREM) responses) and perseverative (PSV) responses measured in the 5-choice and rGT tasks. Consistent with previous studies, AMP (0.1-1 mg/kg) increased both PREM and PSV responses, and ATX (0.5-2 mg/kg) reduced both measures in the 5-choice and rGT tasks. At equivalent doses ATX had no reliable effect on choice behaviour in either the rGT or delay discounting suggesting a null effect of this drug on impulsive choice and risky decision making. The effects of AMP were more complex, with a subtle shift in preference to a low risk (P1) choice in the rGT, and an effect on discounting that was unrelated to reinforcer value, but instead dependent on delay sequence and baseline choice preference. One aspect to these outcomes is to highlight the importance of multiple methodological factors when assessing drug effects on complex behaviours such as impulsive choice, and question what are the most appropriate test conditions under which to examine these drugs on discounting.
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Affiliation(s)
- Guy A Higgins
- InterVivo Solutions Inc., Toronto, ON M5A 4K2, Canada; Dept. Pharmacology & Toxicology, U. Toronto, Toronto, ON M5S 4K2, Canada.
| | - Matt Brown
- InterVivo Solutions Inc., Toronto, ON M5A 4K2, Canada
| | - Cam MacMillan
- InterVivo Solutions Inc., Toronto, ON M5A 4K2, Canada
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Jacobs DS, Moghaddam B. Medial prefrontal cortex encoding of stress and anxiety. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2021; 158:29-55. [PMID: 33785149 DOI: 10.1016/bs.irn.2020.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The prefrontal cortex (PFC) is involved in adaptive control of behavior and optimizing action selection. When an organism is experiencing an aversive event, such as a sustained state of anxiety or an overt experience of fear or stress, the mechanisms that govern PFC regulation of action selection may be critical for survival. A large body of literature has shown that acute aversive states influence the activity of PFC neurons and the release of neurotransmitters in this region. These states also result in long-term neurobiological changes in the PFC and expression of PFC-dependent motivated behaviors. The mechanism for how these changes lead to modifying action selection is only recently beginning to emerge. Here, we review animal and human studies into the neural mechanisms which may mediate the adaptive changes in the PFC that emerge during negative affective states. We then highlight recent advances in approaches for understanding how anxiety influences action selection and related cortical processes. We conclude by proposing that PFC neurons selectively influence action encoding during conditions where actions toward obtaining a reward or avoiding harm are executed under a fog of fear and anxiety.
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Affiliation(s)
- David S Jacobs
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States
| | - Bita Moghaddam
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, United States.
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12
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Zhang C, Liu Q, Yu CY, Wang F, Shao Y, Sun KS, Sun T, Liu J. G Protein-Coupled Estrogen Receptor 1 Knockout Deteriorates MK-801-Induced Learning and Memory Impairment in Mice. Front Behav Neurosci 2020; 14:157. [PMID: 33324181 PMCID: PMC7726131 DOI: 10.3389/fnbeh.2020.00157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 08/10/2020] [Indexed: 12/13/2022] Open
Abstract
The role of estrogen receptors in neuroprotection and cognition has been extensively studied in humans over the past 20 years. Recently, studies have shifted their focus to the use of selective estrogen receptor modulators in the treatment of mental illnesses in the central nervous system. We conducted this study to test the behavioral changes shown by G protein-coupled estrogen receptor 1 knockout (GPER1 KO) and wild-type (WT) mice with MK-801-induced schizophrenia (SZ). GPER1 KO and WT mice received intraperitoneal injections of MK-801 for 14 continuous days. Behavioral, learning and memory, and social interaction changes were evaluated by using the IntelliCage system, open-field, three-chamber social interaction, and novel object recognition tests (NORT). The protein expression levels of the NR2B/CaMKII/CREB signaling pathway were tested via Western blot analysis. The KO SZ group was more likely to show impaired long-term learning and memory function than the WT SZ group. Learning and memory functions were also impaired in the KO Con group. MK-801 administration to the GPER1-KO and WT groups resulted in memory deficiencies and declining learning capabilities. GPER1 deficiency downregulated the expression levels of proteins related to the NR2B/CaMKII/CREB signaling pathway. Our study suggested that GPER1 played an important role in cognitive, learning, and memory functions in the MK-801-induced mouse model of SZ. The mechanism of this role might partially involve the downregulation of the proteins related to the NR2B/CaMKII/CREB signaling pathway. Further studies should focus on the effect of GPER1 on the pathogenesis of SZ in vivo and in vitro.
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Affiliation(s)
- Chun Zhang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan, China.,Institute of Basic Medical Sciences, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Qiang Liu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan, China
| | - Chun-Yang Yu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan, China
| | - Feng Wang
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan, China
| | - Yu Shao
- Institute of Basic Medical Sciences, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
| | - Kui-Sheng Sun
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan, China
| | - Tao Sun
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan, China
| | - Juan Liu
- Ningxia Key Laboratory of Cerebrocranial Diseases, Ningxia Medical University, Yinchuan, China.,Institute of Basic Medical Sciences, School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, China
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13
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Wang X, Li Y, Chen J, Li Z, Li J, Qin L. Aberrant Auditory Steady-State Response of Awake Mice After Single Application of the NMDA Receptor Antagonist MK-801 Into the Medial Geniculate Body. Int J Neuropsychopharmacol 2020; 23:459-468. [PMID: 32725129 PMCID: PMC7387767 DOI: 10.1093/ijnp/pyaa022] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 03/18/2020] [Accepted: 03/21/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Systemic administration of noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonists such as MK-801 is widely used to model psychosis of schizophrenia (SZ). Acute systemic MK-801 in rodents caused an increase of the auditory steady-state responses (ASSRs), the oscillatory neural responses to periodic auditory stimulation, while most studies in patients with SZ reported a decrease of ASSRs. This inconsistency may be attributable to the comprehensive effects of systemic administration of MK-801. Here, we examined how the ASSR is affected by selectively blocking NMDAR in the thalamus. METHODS We implanted multiple electrodes in the auditory cortex (AC) and prefrontal cortex to simultaneously record the local field potential and spike activity (SA) of multiple sites from awake mice. Click-trains at a 40-Hz repetition rate were used to evoke the ASSR. We compared the mean trial power and phase-locking factor and the firing rate of SA before and after microinjection of MK-801 (1.5 µg) into the medial geniculate body (MGB). RESULTS We found that both the AC and prefrontal cortex showed a transient local field potential response at the onset of click-train stimulus, which was less affected by the application of MK-801 in the MGB. Following the onset response, the AC also showed a response continuing throughout the stimulus period, corresponding to the ASSR, which was suppressed by the application of MK-801. CONCLUSION Our data suggest that the MGB is one of the generators of ASSR, and NMDAR hypofunction in the thalamocortical projection may account for the ASSR deficits in SZ.
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Affiliation(s)
- Xuejiao Wang
- Department of Physiology, China Medical University, Shenyang, People’s Republic of China
| | - Yingzhuo Li
- Department of Physiology, China Medical University, Shenyang, People’s Republic of China
| | - Jingyu Chen
- Department of Physiology, China Medical University, Shenyang, People’s Republic of China
| | - Zijie Li
- Department of Physiology, China Medical University, Shenyang, People’s Republic of China
| | - Jinhong Li
- Department of Physiology, China Medical University, Shenyang, People’s Republic of China
| | - Ling Qin
- Department of Physiology, China Medical University, Shenyang, People’s Republic of China,Correspondence: Ling Qin, MD, PhD, Department of Physiology, China Medical University, Shenyang, 110122, People’s Republic of China ()
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14
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Sellinger EP, Kougias DG, Drzewiecki CM, Juraska JM. Behavioral effects in adult rats exposed to low doses of a phthalate mixture during the perinatal or adolescent period. Neurotoxicol Teratol 2020; 79:106886. [PMID: 32315766 DOI: 10.1016/j.ntt.2020.106886] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/13/2020] [Accepted: 04/13/2020] [Indexed: 11/30/2022]
Abstract
Hormones influence neurodevelopment which can result in vulnerability to endocrine disruptors such as phthalates during both the perinatal period and adolescence. Using a rat model, we have previously shown that perinatal exposure to an environmentally relevant phthalate mixture at low doses results in cognitive flexibility deficits in adults and a reduction in neuron and synapse number within the medial prefrontal cortex. Here, we further examined the behavioral effects of exposure to an environmentally relevant mixture of phthalates at low doses during either perinatal development or adolescence. Using the elevated plus maze, adult females, not males, exposed to phthalates during adolescence showed indications of reduced anxiety-like behavior while perinatal exposed animals were unaffected. There was no effect of adolescent phthalate exposure on cognitive flexibility using the attentional set shift paradigm in either sex, unlike the impairments we have previously reported following perinatal exposure (Kougias et al., 2018b). Finally, there was no effect of phthalate exposure during either time frame on sensorimotor gating measured using prepulse inhibition. Environmentally relevant phthalate exposure during the perinatal period or during adolescence did not induce widespread changes in the adult behaviors measured here.
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Affiliation(s)
- Elli P Sellinger
- Neuroscience Program, University of Illinois, 603 E. Daniel St., Champaign, IL 61820, United States of America
| | - Daniel G Kougias
- Neuroscience Program, University of Illinois, 603 E. Daniel St., Champaign, IL 61820, United States of America
| | - Carly M Drzewiecki
- Neuroscience Program, University of Illinois, 603 E. Daniel St., Champaign, IL 61820, United States of America
| | - Janice M Juraska
- Department of Psychology, University of Illinois, 603 E. Daniel St., Champaign, IL 61820, United States of America; Neuroscience Program, University of Illinois, 603 E. Daniel St., Champaign, IL 61820, United States of America.
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15
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Lee G, Zhou Y. NMDAR Hypofunction Animal Models of Schizophrenia. Front Mol Neurosci 2019; 12:185. [PMID: 31417356 PMCID: PMC6685005 DOI: 10.3389/fnmol.2019.00185] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 07/17/2019] [Indexed: 12/20/2022] Open
Abstract
The N-methyl-d-aspartate receptor (NMDAR) hypofunction hypothesis has been proposed to help understand the etiology and pathophysiology of schizophrenia. This hypothesis was based on early observations that NMDAR antagonists could induce a full range of symptoms of schizophrenia in normal human subjects. Accumulating evidence in humans and animal studies points to NMDAR hypofunctionality as a convergence point for various symptoms of schizophrenia. Here we review animal models of NMDAR hypofunction generated by pharmacological and genetic approaches, and how they relate to the pathophysiology of schizophrenia. In addition, we discuss the limitations of animal models of NMDAR hypofunction and their potential utility for therapeutic applications.
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Affiliation(s)
| | - Yi Zhou
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, United States
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16
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Beversdorf DQ. Neuropsychopharmacological regulation of performance on creativity-related tasks. Curr Opin Behav Sci 2019; 27:55-63. [PMID: 31106256 PMCID: PMC6519931 DOI: 10.1016/j.cobeha.2018.09.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A number of factors affect performance on tasks associated with creativity. Two pharmacological systems in particularly been identified as important for their impact on creativity, the noradrenergic system and the dopaminergic systems. Furthermore, stress is also established as an important factor impacting performance, most likely mediated by its effects on these neurotransmitter systems. Herein, we review the current literature on the relationships between stress, the noradrenergic system, the dopaminergic system, and other pharmacological factors and their effects on performance on tasks associated with creativity.
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Affiliation(s)
- David Q Beversdorf
- William and Nancy Thompson Endowed Chair in Radiology, University of Missouri
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17
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Thonnard D, Dreesen E, Callaerts-Vegh Z, D'Hooge R. NMDA receptor dependence of reversal learning and the flexible use of cognitively demanding search strategies in mice. Prog Neuropsychopharmacol Biol Psychiatry 2019; 90:235-244. [PMID: 30529376 DOI: 10.1016/j.pnpbp.2018.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 11/29/2018] [Accepted: 12/05/2018] [Indexed: 10/27/2022]
Abstract
Cognitive flexibility helps organisms to respond adaptively to environmental changes. Deficits in this executive function have been associated with a variety of brain disorders, and it has been shown to rely on various concomitant neurobiological mechanisms. However, the involvement of the glutamatergic system in general, and NMDA receptors in particular, has been debated. Therefore, we injected C57BL/6 mice repeatedly with low-doses of the non-competitive NMDA receptor antagonist MK-801 (dizocilpine, 0.1 mg/kg, i.p.). Reversal learning and the use of specific cognitive strategies were assessed in a non-spatial discrimination touchscreen task and the Morris water maze (MWM) spatial learning task. In addition, mice were subjected to a non-mnemonic test battery. Although initial acquisition learning was not affected by MK-801 administration, it did induce deficits in reversal learning, both in the non-spatial and spatial task. Defects in non-spatial reversal learning appeared to be caused by perseverative errors. Also, MK-801 administration induced perseverative behaviours as well as inefficient spatial strategy use during MWM reversal learning. These effects could not be reduced to changes in exploratory (anxiety-related) behaviours, nor to motor deficits. This was consistent with results in the non-mnemonic test battery, during which MK-801 evoked hyperlocomotion and subtle motor defects, but failed to alter general motor activity and exploratory behaviours. In conclusion, NMDA receptors appear to be involved in the flexible cognitive processes that underlie reversal learning in spatial as well as non-spatial tasks. Our results also indicate that reversal learning as well as the use of cognitively demanding strategies are more sensitive to NMDA receptor blockage than some other functions that have been suggested to be NMDA receptor dependent.
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Affiliation(s)
- David Thonnard
- Laboratory of Biological Psychology, University of Leuven, Belgium
| | - Eline Dreesen
- Laboratory of Biological Psychology, University of Leuven, Belgium
| | | | - Rudi D'Hooge
- Laboratory of Biological Psychology, University of Leuven, Belgium.
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18
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Girotti M, Adler SM, Bulin SE, Fucich EA, Paredes D, Morilak DA. Prefrontal cortex executive processes affected by stress in health and disease. Prog Neuropsychopharmacol Biol Psychiatry 2018; 85:161-179. [PMID: 28690203 PMCID: PMC5756532 DOI: 10.1016/j.pnpbp.2017.07.004] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/01/2017] [Accepted: 07/05/2017] [Indexed: 11/23/2022]
Abstract
Prefrontal cortical executive functions comprise a number of cognitive capabilities necessary for goal directed behavior and adaptation to a changing environment. Executive dysfunction that leads to maladaptive behavior and is a symptom of psychiatric pathology can be instigated or exacerbated by stress. In this review we survey research addressing the impact of stress on executive function, with specific focus on working memory, attention, response inhibition, and cognitive flexibility. We then consider the neurochemical pathways underlying these cognitive capabilities and, where known, how stress alters them. Finally, we review work exploring potential pharmacological and non-pharmacological approaches that can ameliorate deficits in executive function. Both preclinical and clinical literature indicates that chronic stress negatively affects executive function. Although some of the circuitry and neurochemical processes underlying executive function have been characterized, a great deal is still unknown regarding how stress affects these processes. Additional work focusing on this question is needed in order to make progress on developing interventions that ameliorate executive dysfunction.
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Affiliation(s)
- Milena Girotti
- Department of Pharmacology, Center for Biomedical Neuroscience, UT Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78229, USA.
| | - Samantha M Adler
- Department of Pharmacology, Center for Biomedical Neuroscience, UT Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Sarah E Bulin
- Department of Pharmacology, Center for Biomedical Neuroscience, UT Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Elizabeth A Fucich
- Department of Pharmacology, Center for Biomedical Neuroscience, UT Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - Denisse Paredes
- Department of Pharmacology, Center for Biomedical Neuroscience, UT Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78229, USA
| | - David A Morilak
- Department of Pharmacology, Center for Biomedical Neuroscience, UT Health San Antonio, 7703 Floyd Curl Dr, San Antonio, TX 78229, USA
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19
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Effects of the NMDA receptor antagonists dizocilpine and Ro 63-1908 on delay-discounting and risky decision-making in a gambling task. Behav Brain Res 2018; 348:201-210. [PMID: 29689373 DOI: 10.1016/j.bbr.2018.04.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/14/2018] [Accepted: 04/18/2018] [Indexed: 12/19/2022]
Abstract
Previous studies demonstrated that NMDA receptor antagonists such as dizocilpine (MK801) and the GluN2B NMDA antagonist Ro 63-1908 promote impulsive action (motor impulsivity). The effects of these treatments on impulsive choice and decision-making is less well characterized. Two experiments were undertaken. In the first experiment, given evidence for delay order as a factor in choice selection, the effect of dizocilpine was examined in a delay discounting task with separate groups of male Long-Evans rats trained to a schedule of either ascending (i.e. 0-40 s), or descending delays (i.e. 40-0 s). Under the ascending-delay schedule, dizocilpine (0.03-0.06 mg/kg SC) reduced discounting, yet on the descending-delay schedule discounting was increased. Subgrouping rats according to discounting rate under vehicle pretreatment were consistent with a treatment-induced choice perseveration. In a second experiment, male Long-Evans rats were trained to a gambling task (rGT). Neither dizocilpine (0.01-0.06 mg/kg SC) nor Ro 63-1908 (0.1-1 mg/kg SC) shifted choice from the advantageous to the disadvantageous options. However dizocilpine, and marginally Ro 63-1908, increased choice of the least risky, but suboptimal option. This effect was most evident in rats that initially preferred the disadvantageous options. Consistent with previous studies, both treatments increased measures of motor impulsivity. These results demonstrate that dizocilpine has effects on discounting dependent on delay order and likely reflective of perseveration. On the rGT task, neither dizocilpine nor Ro 63-1908 promoted risky choice, yet both NMDA receptor antagonists increased impulsive action.
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20
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Jett JD, Bulin SE, Hatherall LC, McCartney CM, Morilak DA. Deficits in cognitive flexibility induced by chronic unpredictable stress are associated with impaired glutamate neurotransmission in the rat medial prefrontal cortex. Neuroscience 2017; 346:284-297. [PMID: 28131625 PMCID: PMC5344040 DOI: 10.1016/j.neuroscience.2017.01.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 12/21/2016] [Accepted: 01/10/2017] [Indexed: 12/25/2022]
Abstract
Deficits in cognitive flexibility, the ability to modify behavior in response to changes in the environment, contribute to the onset and maintenance of stress-related neuropsychiatric illnesses, such as depression. Cognitive flexibility depends on medial prefrontal cortex (mPFC) function, and in depressed patients, cognitive inflexibility is associated with hypoactivity and decreased glutamate receptor expression in the mPFC. Rats exposed to chronic unpredictable stress (CUS) exhibit compromised mPFC function on the extradimensional (ED) set-shifting task of the attentional set-shifting test. Moreover, CUS-induced ED deficits are associated with dendritic atrophy and decreased glutamate receptor expression in the mPFC. This evidence suggests that impaired glutamate signaling may underlie stress-induced deficits in cognitive flexibility. To test this hypothesis, we first demonstrated that blocking NMDA or AMPA receptors in the mPFC during ED replicated CUS-induced deficits in naïve rats. Secondly, we found that expression of activity-regulated cytoskeleton-associated protein (Arc) mRNA, a marker of behaviorally induced glutamate-mediated plasticity, was increased in the mPFC following ED. We then showed that CUS compromised excitatory afferent activation of the mPFC following pharmacological stimulation of the mediodorsal thalamus (MDT), indicated by a reduced induction of c-fos expression. Subsequently, in vivo recordings of evoked potentials in the mPFC indicated that CUS impaired afferent activation of the mPFC evoked by MDT stimulation, but not the ventral hippocampus. Lastly, glutamate microdialysis showed that CUS attenuated the acute stress-evoked increase in extracellular glutamate in the mPFC. Together, these results demonstrate that CUS-induced ED deficits are associated with compromised glutamate neurotransmission in the mPFC.
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Affiliation(s)
- Julianne D Jett
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Sarah E Bulin
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Lauren C Hatherall
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - Carlie M McCartney
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA
| | - David A Morilak
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229, USA.
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21
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Auger ML, Floresco SB. Prefrontal cortical GABAergic and NMDA glutamatergic regulation of delayed responding. Neuropharmacology 2017; 113:10-20. [DOI: 10.1016/j.neuropharm.2016.09.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/13/2016] [Accepted: 09/22/2016] [Indexed: 02/03/2023]
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22
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Desai SJ, Allman BL, Rajakumar N. Combination of behaviorally sub-effective doses of glutamate NMDA and dopamine D 1 receptor antagonists impairs executive function. Behav Brain Res 2017; 323:24-31. [PMID: 28115219 DOI: 10.1016/j.bbr.2017.01.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/14/2017] [Accepted: 01/17/2017] [Indexed: 02/02/2023]
Abstract
Impairment of executive function is a core feature of schizophrenia. Preclinical studies indicate that injections of either N-methyl d-aspartate (NMDA) or dopamine D1 receptor blockers impair executive function. Despite the prevailing notion based on postmortem findings in schizophrenia that cortical areas have marked suppression of glutamate and dopamine, recent in vivo imaging studies suggest that abnormalities of these neurotransmitters in living patients may be quite subtle. Thus, we hypothesized that modest impairments in both glutamate and dopamine function can act synergistically to cause executive dysfunction. In the present study, we investigated the effect of combined administration of "behaviorally sub-effective" doses of NMDA and dopamine D1 receptor antagonists on executive function. An operant conditioning-based set-shifting task was used to assess behavioral flexibility in rats that were systemically injected with NMDA and dopamine D1 receptor antagonists individually or in combination prior to task performance. Separate injections of the NMDA receptor antagonist, MK-801, and the dopamine D1 receptor antagonist, SCH 23390, at low doses did not impair set-shifting; however, the combined administration of these same behaviorally sub-effective doses of the antagonists significantly impaired the performance during set-shifting without affecting learning, retrieval of the memory of the initial rule, latency of responses or the number of omissions. The combined treatment also produced an increased number of perseverative errors. Our results indicate that NMDA and D1 receptor blockade act synergistically to cause behavioral inflexibility, and as such, subtle abnormalities in glutamatergic and dopaminergic systems may act cooperatively to cause deficits in executive function.
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Affiliation(s)
- Sagar J Desai
- Department of Anatomy & Cell Biology, The University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Brian L Allman
- Department of Anatomy & Cell Biology, The University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | - Nagalingam Rajakumar
- Department of Anatomy & Cell Biology, The University of Western Ontario, London, Ontario, N6A 5C1, Canada; Department of Psychiatry, The University of Western Ontario, London, Ontario, N6A 5C1, Canada.
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23
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Dynamic brain network reconfiguration as a potential schizophrenia genetic risk mechanism modulated by NMDA receptor function. Proc Natl Acad Sci U S A 2016; 113:12568-12573. [PMID: 27791105 DOI: 10.1073/pnas.1608819113] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Schizophrenia is increasingly recognized as a disorder of distributed neural dynamics, but the molecular and genetic contributions are poorly understood. Recent work highlights a role for altered N-methyl-d-aspartate (NMDA) receptor signaling and related impairments in the excitation-inhibitory balance and synchrony of large-scale neural networks. Here, we combined a pharmacological intervention with novel techniques from dynamic network neuroscience applied to functional magnetic resonance imaging (fMRI) to identify alterations in the dynamic reconfiguration of brain networks related to schizophrenia genetic risk and NMDA receptor hypofunction. We quantified "network flexibility," a measure of the dynamic reconfiguration of the community structure of time-variant brain networks during working memory performance. Comparing 28 patients with schizophrenia, 37 unaffected first-degree relatives, and 139 healthy controls, we detected significant differences in network flexibility [F(2,196) = 6.541, P = 0.002] in a pattern consistent with the assumed genetic risk load of the groups (highest for patients, intermediate for relatives, and lowest for controls). In an observer-blinded, placebo-controlled, randomized, cross-over pharmacological challenge study in 37 healthy controls, we further detected a significant increase in network flexibility as a result of NMDA receptor antagonism with 120 mg dextromethorphan [F(1,34) = 5.291, P = 0.028]. Our results identify a potential dynamic network intermediate phenotype related to the genetic liability for schizophrenia that manifests as altered reconfiguration of brain networks during working memory. The phenotype appears to be influenced by NMDA receptor antagonism, consistent with a critical role for glutamate in the temporal coordination of neural networks and the pathophysiology of schizophrenia.
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Ianov L, Rani A, Beas BS, Kumar A, Foster TC. Transcription Profile of Aging and Cognition-Related Genes in the Medial Prefrontal Cortex. Front Aging Neurosci 2016; 8:113. [PMID: 27242522 PMCID: PMC4868850 DOI: 10.3389/fnagi.2016.00113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 04/29/2016] [Indexed: 12/22/2022] Open
Abstract
Cognitive function depends on transcription; however, there is little information linking altered gene expression to impaired prefrontal cortex function during aging. Young and aged F344 rats were characterized on attentional set shift and spatial memory tasks. Transcriptional differences associated with age and cognition were examined using RNA sequencing to construct transcriptomic profiles for the medial prefrontal cortex (mPFC), white matter, and region CA1 of the hippocampus. The results indicate regional differences in vulnerability to aging. Age-related gene expression in the mPFC was similar to, though less robust than, changes in the dorsolateral PFC of aging humans suggesting that aging processes may be similar. Importantly, the pattern of transcription associated with aging did not predict cognitive decline. Rather, increased mPFC expression of genes involved in regulation of transcription, including transcription factors that regulate the strength of excitatory and inhibitory inputs, and neural activity-related immediate-early genes was observed in aged animals that exhibit delayed set shift behavior. The specificity of impairment on a mPFC-dependent task, associated with a particular mPFC transcriptional profile indicates that impaired executive function involves altered transcriptional regulation and neural activity/plasticity processes that are distinct from that described for impaired hippocampal function.
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Affiliation(s)
- Lara Ianov
- Department of Neuroscience, McKnight Brain Institute, University of FloridaGainesville, FL, USA
- Genetics and Genomics Program, Genetics Institute, University of FloridaGainesville, FL, USA
| | - Asha Rani
- Department of Neuroscience, McKnight Brain Institute, University of FloridaGainesville, FL, USA
| | - Blanca S. Beas
- Department of Neuroscience, McKnight Brain Institute, University of FloridaGainesville, FL, USA
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of FloridaGainesville, FL, USA
| | - Thomas C. Foster
- Department of Neuroscience, McKnight Brain Institute, University of FloridaGainesville, FL, USA
- Genetics and Genomics Program, Genetics Institute, University of FloridaGainesville, FL, USA
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25
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Park J, Wood J, Bondi C, Del Arco A, Moghaddam B. Anxiety Evokes Hypofrontality and Disrupts Rule-Relevant Encoding by Dorsomedial Prefrontal Cortex Neurons. J Neurosci 2016; 36:3322-35. [PMID: 26985040 PMCID: PMC4792942 DOI: 10.1523/jneurosci.4250-15.2016] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/29/2016] [Accepted: 02/02/2016] [Indexed: 01/05/2023] Open
Abstract
Anxiety is a debilitating symptom of most psychiatric disorders, including major depression, post-traumatic stress disorder, schizophrenia, and addiction. A detrimental aspect of anxiety is disruption of prefrontal cortex (PFC)-mediated executive functions, such as flexible decision making. Here we sought to understand how anxiety modulates PFC neuronal encoding of flexible shifting between behavioral strategies. We used a clinically substantiated anxiogenic treatment to induce sustained anxiety in rats and recorded from dorsomedial PFC (dmPFC) and orbitofrontal cortex (OFC) neurons while they were freely moving in a home cage and while they performed a PFC-dependent task that required flexible switches between rules in two distinct perceptual dimensions. Anxiety elicited a sustained background "hypofrontality" in dmPFC and OFC by reducing the firing rate of spontaneously active neuronal subpopulations. During task performance, the impact of anxiety was subtle, but, consistent with human data, behavior was selectively impaired when previously correct conditions were presented as conflicting choices. This impairment was associated with reduced recruitment of dmPFC neurons that selectively represented task rules at the time of action. OFC rule representation was not affected by anxiety. These data indicate that a neural substrate of the decision-making deficits in anxiety is diminished dmPFC neuronal encoding of task rules during conflict-related actions. Given the translational relevance of the model used here, the data provide a neuronal encoding mechanism for how anxiety biases decision making when the choice involves overcoming a conflict. They also demonstrate that PFC encoding of actions, as opposed to cues or outcome, is especially vulnerable to anxiety. SIGNIFICANCE STATEMENT A debilitating aspect of anxiety is its impact on decision making and flexible control of behavior. These cognitive constructs depend on proper functioning of the prefrontal cortex (PFC). Understanding how anxiety affects PFC encoding of cognitive events is of great clinical and evolutionary significance. Using a clinically valid experimental model, we find that, under anxiety, decision making may be skewed by salient and conflicting environmental stimuli at the expense of flexible top-down guided choices. We also find that anxiety suppresses spontaneous activity of PFC neurons, and weakens encoding of task rules by dorsomedial PFC neurons. These data provide a neuronal encoding scheme for how anxiety disengages PFC during decision making.
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Affiliation(s)
- Junchol Park
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Jesse Wood
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Corina Bondi
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Alberto Del Arco
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Bita Moghaddam
- Departments of Neuroscience and Psychiatry, Center for Neuroscience, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
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Beas BS, McQuail JA, Ban Uelos C, Setlow B, Bizon JL. Prefrontal cortical GABAergic signaling and impaired behavioral flexibility in aged F344 rats. Neuroscience 2016; 345:274-286. [PMID: 26873002 DOI: 10.1016/j.neuroscience.2016.02.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Revised: 02/03/2016] [Accepted: 02/05/2016] [Indexed: 02/07/2023]
Abstract
The prefrontal cortex (PFC) is critical for the ability to flexibly adapt established patterns of behavior in response to a change in environmental contingencies. Impaired behavioral flexibility results in maladaptive strategies such as perseveration on response options that no longer produce a desired outcome. Pharmacological manipulations of prefrontal cortical GABAergic signaling modulate behavioral flexibility in animal models, and prefrontal cortical interneuron dysfunction is implicated in impaired behavioral flexibility that accompanies neuropsychiatric disease. As deficits in behavioral flexibility also emerge during the normal aging process, the goal of this study was to determine the role of GABAergic signaling, specifically via prefrontal cortical GABA(B) receptors, in such age-related deficits. Young and aged rats were trained in a set shifting task performed in operant chambers. First, rats learned to discriminate between two response levers to obtain a food reward on the basis of a cue light illuminated above the correct lever. Upon acquisition of this initial discrimination, the contingencies were shifted such that rats had to ignore the cue light and respond on the levers according to their left/right positions. Both young and aged rats acquired the initial discrimination similarly; however, aged rats were impaired relative to young following the set shift. Among aged rats, GABA(B) receptor expression in the medial prefrontal cortex (mPFC) was strongly correlated with set shifting, such that lower expression was associated with worse performance. Subsequent experiments showed that intra-mPFC administration of the GABA(B) receptor agonist baclofen enhanced set shifting performance in aged rats. These data directly link GABAergic signaling via GABA(B) receptors to impaired behavioral flexibility associated with normal aging.
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Affiliation(s)
- B S Beas
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States.
| | - J A McQuail
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States.
| | - C Ban Uelos
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States.
| | - B Setlow
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States; Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL, United States; Department of Psychology, University of Florida, Gainesville, FL, United States.
| | - J L Bizon
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL, United States; Department of Psychiatry, University of Florida College of Medicine, Gainesville, FL, United States.
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27
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Thompson SM, Josey M, Holmes A, Brigman JL. Conditional loss of GluN2B in cortex and hippocampus impairs attentional set formation. Behav Neurosci 2015; 129:105-12. [PMID: 25798630 DOI: 10.1037/bne0000045] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ability to attend to appropriate stimuli, to plan actions and then alter those actions when environmental conditions change, is essential for an organism to thrive. There is increasing evidence that these executive control processes are mediated in part by N-methyl-D-aspartate receptors (NMDAR). NMDAR subunits confer different physiological properties to the receptor, interact with distinct intracellular postsynaptic scaffolding and signaling molecules and are differentially expressed during development. Recent findings have suggested that the GluN2B subunit may play a unique role in both the acquisition of adaptive choice and the behavioral flexibility required to shift between choices. Here we investigated the role of GluN2B containing NMDARs in the ability to learn, reverse and shift between stimulus dimensions. Mutant mice (floxed-GluN2B x CaMKII-Cre) lacking GluN2B in the dorsal CA1 of the hippocampus and throughout the cortex were tested on an attentional set-shifting task. To explore the role that alterations in motor behavior may have on these behaviors, gross and fine motor behaviors were analyzed in mutant and floxed-control mice. Results show that corticohippocampal loss of GluN2B selectively impaired an initial reversal in a stimulus specific manner and impaired the ability of mutant mice to form an attentional set. Further, GluN2B mice showed normal motor behavior in both overall movement and individual limb behaviors. Together, these results further support the role of NMDAR, and GluN2B in particular, in aspects of executive control including behavioral flexibility and attentional processes.
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Affiliation(s)
- Shannon M Thompson
- Department of Neurosciences, University of New Mexico School of Medicine
| | - Megan Josey
- Department of Neurosciences, University of New Mexico School of Medicine
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institutes of Health
| | - Jonathan L Brigman
- Department of Neurosciences, University of New Mexico School of Medicine
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28
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Jo YS, Mizumori SJY. Prefrontal Regulation of Neuronal Activity in the Ventral Tegmental Area. Cereb Cortex 2015; 26:4057-4068. [PMID: 26400913 DOI: 10.1093/cercor/bhv215] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Growing evidence indicates that midbrain dopamine (DA) cells integrate reward expectancy-related information from the prefrontal cortex to properly compute errors in reward prediction. Here we investigated how 2 major prefrontal subregions, the orbitofrontal cortex (OFC) and the medial prefrontal cortex (mPFC), contributed to DAergic prediction errors while rats performed a delay discounting task on a T-maze. Most putative DA cells in the task showed phasic responses to salient cues that predicted delayed rewards, but not to the actual rewards. After temporary inactivation of the OFC, putative DA cells exhibited strikingly reduced phasic responses to reward-predicting cues but increased responses to rewards. In contrast, mPFC inactivation significantly elevated DA responses to both predictive cues and rewards. In addition, OFC, but not mPFC, inactivation disrupted the activity of putative non-DA cells that encoded expected reward values during waiting periods. These results suggest that the 2 prefrontal subregions differentially regulate DAergic prediction errors and the OFC conveys value signals to midbrain dopamine systems.
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Affiliation(s)
- Yong Sang Jo
- Department of Psychology, University of Washington, Seattle, WA, USA
| | - Sheri J Y Mizumori
- Department of Psychology, University of Washington, Seattle, WA, USA.,Neuroscience Program, University of Washington, Seattle, WA 98195, USA
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29
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Svoboda J, Stankova A, Entlerova M, Stuchlik A. Acute administration of MK-801 in an animal model of psychosis in rats interferes with cognitively demanding forms of behavioral flexibility on a rotating arena. Front Behav Neurosci 2015; 9:75. [PMID: 25883558 PMCID: PMC4381641 DOI: 10.3389/fnbeh.2015.00075] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 03/10/2015] [Indexed: 01/10/2023] Open
Abstract
Patients with schizophrenia often manifest deficits in behavioral flexibility. Non-competitive NMDA receptor antagonists such as MK-801 induce schizophrenia-like symptoms in rodents, including cognitive functions. Despite work exploring flexibility has been done employing behavioral paradigms with simple stimuli, much less is known about what kinds of flexibility are affected in an MK-801 model of schizophrenia-like behavior in the spatial domain. We used a rotating arena-based apparatus (Carousel) requiring rats to avoid an unmarked sector defined in either the reference frame of the rotating arena (arena frame task, AF) or the stationary room (room frame task, RF). We investigated behavioral flexibility in four conditions involving different cognitive loads. Each condition encompassed an initial (five sessions) and a test phase (five sessions) in which some aspects of the task were changed to test flexibility and in which rats were given saline, 0.05 mg/kg or 0.1 mg/kg MK-801 thirty minutes prior to a session. In the first condition, rats acquired avoidance in RF with clockwise rotation of the arena while in the test phase the arena rotated counterclockwise. In the second condition, rats initially acquired avoidance in RF with the sector on the north and then it was reversed to south (spatial reversal). In the third and fourth conditions, rats initially performed an AF (RF, respectively) task, followed by an RF (AF, respectively) task, testing the ability of cognitive set-shifting. We found no effect of MK-801 either on simple motor adjustment after reversal of arena rotation or on spatial reversal within the RF. In contrast, administration of MK-801 at a dose of 0.1 mg/kg interfered with set-shifting in both conditions. Furthermore, we observed MK-801 0.1 mg/kg elevated locomotion in all cases. These data suggest that blockade of NMDA receptors by acute system administration of MK-801 preferentially affects set-shifting in the cognitive domain rather than reversal.
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Affiliation(s)
- Jan Svoboda
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | - Anna Stankova
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic ; Laboratory of Neurobehavioral Studies, National Institute of Mental Health Klecany, Prague, Czech Republic
| | - Marie Entlerova
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic
| | - Ales Stuchlik
- Institute of Physiology of the Czech Academy of Sciences Prague, Czech Republic ; Laboratory of Neurobehavioral Studies, National Institute of Mental Health Klecany, Prague, Czech Republic
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30
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Guidi M, Kumar A, Foster TC. Impaired attention and synaptic senescence of the prefrontal cortex involves redox regulation of NMDA receptors. J Neurosci 2015; 35:3966-77. [PMID: 25740525 PMCID: PMC4348191 DOI: 10.1523/jneurosci.3523-14.2015] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 12/23/2014] [Accepted: 01/21/2015] [Indexed: 01/05/2023] Open
Abstract
Young (3-6 months) and middle-age (10-14 months) rats were trained on the five-choice serial reaction time task. Attention and executive function deficits were apparent in middle-age animals observed as a decrease in choice accuracy, increase in omissions, and increased response latency. The behavioral differences were not due to alterations in sensorimotor function or a diminished motivational state. Electrophysiological characterization of synaptic transmission in slices from the mPFC indicated an age-related decrease in glutamatergic transmission. In particular, a robust decrease in N-methyl-D-aspartate receptor (NMDAR)-mediated synaptic responses in the mPFC was correlated with several measures of attention. The decrease in NMDAR function was due in part to an altered redox state as bath application of the reducing agent, dithiothreitol, increased the NMDAR component of the synaptic response to a greater extent in middle-age animals. Together with previous work indicating that redox state mediates senescent physiology in the hippocampus, the results indicate that redox changes contribute to senescent synaptic function in vulnerable brain regions involved in age-related cognitive decline.
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Affiliation(s)
- Michael Guidi
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Ashok Kumar
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
| | - Thomas C Foster
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610
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31
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Ghoshal A, Conn PJ. The hippocampo-prefrontal pathway: a possible therapeutic target for negative and cognitive symptoms of schizophrenia. FUTURE NEUROLOGY 2015; 10:115-128. [PMID: 25825588 DOI: 10.2217/fnl.14.63] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The hippocampo-prefrontal (H-PFC) pathway has been linked to cognitive and emotional disturbances in several psychiatric disorders including schizophrenia. Preclinical evidence from the NMDA receptor antagonism rodent model of schizophrenia shows severe pathology selective to the H-PFC pathway. It is speculated that there is an increased excitatory drive from the hippocampus to the prefrontal cortex due to dysfunctions in the H-PFC plasticity, which may serve as the basis for the behavioral consequences observed in this rodent model. Thus, the H-PFC pathway is currently emerging as a promising therapeutic target for the negative and cognitive symptom clusters of schizophrenia. Here, we have reviewed the physiological, pharmacological and functional characteristics of the H-PFC pathway and we propose that allosteric activation of glutamatergic and cholinergic neurotransmission can serve as a plausible therapeutic approach.
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Affiliation(s)
- Ayan Ghoshal
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232 0697, USA
| | - P Jeffrey Conn
- Vanderbilt Center for Neuroscience Drug Discovery, Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232 0697, USA
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32
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Pershing ML, Bortz DM, Pocivavsek A, Fredericks PJ, Jørgensen CV, Vunck SA, Leuner B, Schwarcz R, Bruno JP. Elevated levels of kynurenic acid during gestation produce neurochemical, morphological, and cognitive deficits in adulthood: implications for schizophrenia. Neuropharmacology 2015; 90:33-41. [PMID: 25446576 PMCID: PMC4731221 DOI: 10.1016/j.neuropharm.2014.10.017] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/17/2014] [Accepted: 10/21/2014] [Indexed: 11/16/2022]
Abstract
The levels of kynurenic acid (KYNA), an endogenous negative modulator of alpha7 nicotinic acetylcholine receptors (α7nAChRs), are elevated in the brains of patients with schizophrenia (SZ). We reported that increases of brain KYNA in rats, through dietary exposure to its precursor kynurenine from embryonic day (ED)15 to postnatal day (PD) 21, result in neurochemical and cognitive deficits in adulthood. The present experiments focused on the effects of prenatal exposure to elevated kynurenine on measures of prefrontal excitability known to be impaired in SZ. Pregnant dams were fed a mash containing kynurenine (100 mg/day; progeny = EKYNs) from ED15 until ED22. Controls were fed an unadulterated mash (progeny = ECONs). The dietary loading procedure elevated maternal and fetal plasma kynurenine (2223% and 693% above controls, respectively) and increased fetal KYNA (forebrain; 500% above controls) on ED21. Elevations in forebrain KYNA disappeared after termination of the loading (PD2), but KYNA levels in the prefrontal cortex (PFC) were unexpectedly increased again when measured in adults (PD56-80; 75% above controls). We also observed changes in several markers of prefrontal excitability, including expression of the α7nAChR (22% and 17% reductions at PD2 and PD56-80), expression of mGluR2 (31% and 24% reductions at ED21 and PD56-80), dendritic spine density (11-14% decrease at PD56-80), subsensitive mesolimbic stimulation of glutamate release in PFC, and reversal/extra-dimensional shift deficits in the prefrontally-mediated set-shifting task. These results highlight the deleterious impact of elevated KYNA levels during sensitive periods of early development, which model the pathophysiological and cognitive deficits seen in SZ.
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Affiliation(s)
| | - David M Bortz
- Department of Psychology, The Ohio State University, Columbus, OH, USA
| | - Ana Pocivavsek
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland College of Medicine, Baltimore, MD, USA
| | | | | | - Sarah A Vunck
- Department of Psychology, The Ohio State University, Columbus, OH, USA
| | - Benedetta Leuner
- Department of Psychology, The Ohio State University, Columbus, OH, USA; Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | - Robert Schwarcz
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland College of Medicine, Baltimore, MD, USA
| | - John P Bruno
- Department of Psychology, The Ohio State University, Columbus, OH, USA; Department of Neuroscience, The Ohio State University, Columbus, OH, USA.
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33
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Abstract
Executive functions consist of multiple high-level cognitive processes that drive rule generation and behavioral selection. An emergent property of these processes is the ability to adjust behavior in response to changes in one's environment (i.e., behavioral flexibility). These processes are essential to normal human behavior, and may be disrupted in diverse neuropsychiatric conditions, including schizophrenia, alcoholism, depression, stroke, and Alzheimer's disease. Understanding of the neurobiology of executive functions has been greatly advanced by the availability of animal tasks for assessing discrete components of behavioral flexibility, particularly strategy shifting and reversal learning. While several types of tasks have been developed, most are non-automated, labor intensive, and allow testing of only one animal at a time. The recent development of automated, operant-based tasks for assessing behavioral flexibility streamlines testing, standardizes stimulus presentation and data recording, and dramatically improves throughput. Here, we describe automated strategy shifting and reversal tasks, using operant chambers controlled by custom written software programs. Using these tasks, we have shown that the medial prefrontal cortex governs strategy shifting but not reversal learning in the rat, similar to the dissociation observed in humans. Moreover, animals with a neonatal hippocampal lesion, a neurodevelopmental model of schizophrenia, are selectively impaired on the strategy shifting task but not the reversal task. The strategy shifting task also allows the identification of separate types of performance errors, each of which is attributable to distinct neural substrates. The availability of these automated tasks, and the evidence supporting the dissociable contributions of separate prefrontal areas, makes them particularly well-suited assays for the investigation of basic neurobiological processes as well as drug discovery and screening in disease models.
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34
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Locklear MN, Bhamidipaty S, Kritzer MF. Local N-methyl-d-aspartate receptor antagonism in the prefrontal cortex attenuates spatial cognitive deficits induced by gonadectomy in adult male rats. Neuroscience 2014; 288:73-85. [PMID: 25545712 DOI: 10.1016/j.neuroscience.2014.12.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 12/11/2014] [Accepted: 12/13/2014] [Indexed: 02/08/2023]
Abstract
Gonadectomy in adult male rats significantly impairs spatial working memory, behavioral flexibility and other functions associated with the prefrontal cortex (PFC). However, the mechanisms through which this occurs are largely unknown. In this study, intracortical drug challenge with the selective N-methyl-d-aspartate receptor (NMDAR) antagonist D(-)-2-amino-5-phosphonopentanoic acid (APV) was combined with Barnes maze testing, gonadectomy (GDX) and hormone replacement (17β-estradiol, testosterone propionate) to explore the contributions of NMDAR-mediated activity within the PFC to hormone effects on spatial cognition in adult male rats. Previous studies have shown that Barnes maze testing reveals significant estrogen-dependent, GDX-induced deficits in spatial working memory and androgen-sensitive, GDX-induced deficits in spatial search strategy. Here we found that bilateral infusion of APV into the medial PFC prior to testing significantly improved both sets of behaviors in gonadectomized rats and significantly worsened performance measures in gonadally intact controls. In hormone-replaced cohorts, we further found that behaviors that are normally similar to controls were significantly disrupted by APV, and those that are normally similar to gonadectomized rats were rescued by intracortical APV infusion. There were, however, no residual effects of APV on retention testing conducted 24h later. Together these findings suggest that hormone regulation of NMDAR-mediated activity specifically within the PFC may be fundamental to the effects of gonadal steroids on spatial cognition in males. Our findings further identify NMDAR antagonists as potentially novel, non-steroidal means of attenuating the cognitive deficits that can accompany gonadal hormone decline in human males in aging, clinical cases of hypogonadalism and in certain neurologic and psychiatric illnesses. Accordingly, it may be important to obtain in males the kind of detailed knowledge concerning hormone effects on, for example, the channel and electrophysiological properties of NMDAR that currently exists for the female brain.
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Affiliation(s)
- M N Locklear
- Graduate Program in Neuroscience, Stony Brook University, Stony Brook, New York 11794-5230, United States
| | - S Bhamidipaty
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794-5230, United States
| | - M F Kritzer
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York 11794-5230, United States.
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Adolescent alcohol exposure reduces behavioral flexibility, promotes disinhibition, and increases resistance to extinction of ethanol self-administration in adulthood. Neuropsychopharmacology 2014; 39:2570-83. [PMID: 24820536 PMCID: PMC4207336 DOI: 10.1038/npp.2014.109] [Citation(s) in RCA: 154] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 05/01/2014] [Accepted: 05/02/2014] [Indexed: 02/07/2023]
Abstract
The prefrontal cortex (PFC) is a brain region that is critically involved in cognitive function and inhibitory control of behavior, and adolescence represents an important period of continued PFC development that parallels the maturation of these functions. Evidence suggests that this period of continued development of the PFC may render it especially vulnerable to environmental insults that impact PFC function in adulthood. Experimentation with alcohol typically begins during adolescence when binge-like consumption of large quantities is common. In the present study, we investigated the effects of repeated cycles of adolescent intermittent ethanol (AIE) exposure (postnatal days 28-42) by vapor inhalation on different aspects of executive functioning in the adult rat. In an operant set-shifting task, AIE-exposed rats exhibited deficits in their ability to shift their response strategy when the rules of the task changed, indicating reduced behavioral flexibility. There were no differences in progressive ratio response for the reinforcer suggesting that AIE did not alter reinforcer motivation. Examination of performance on the elevated plus maze under conditions designed to minimize stress revealed that AIE exposure enhanced the number of entries into the open arms, which may reflect either reduced anxiety and/or disinhibition of exploratory-like behavior. In rats that trained to self-administer ethanol in an operant paradigm, AIE increased resistance to extinction of ethanol-seeking behavior. This resistance to extinction was reversed by positive allosteric modulation of mGluR5 during extinction training, an effect that is thought to reflect promotion of extinction learning mechanisms within the medial PFC. Consistent with this, CDPPB was also observed to reverse the deficits in behavioral flexibility. Finally, diffusion tensor imaging with multivariate analysis of 32 brain areas revealed that while there were no differences in the total brain volume, the volume of a subgroup of regions (hippocampus, thalamus, dorsal striatum, neocortex, and hypothalamus) were significantly different in AIE-exposed adults compared with litter-matched Control rats. Taken together, these findings demonstrate that binge-like exposure to alcohol during early to middle adolescence results in deficits in PFC-mediated behavioral control in adulthood.
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36
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Marquardt K, Saha M, Mishina M, Young JW, Brigman JL. Loss of GluN2A-containing NMDA receptors impairs extra-dimensional set-shifting. GENES BRAIN AND BEHAVIOR 2014; 13:611-7. [PMID: 25059550 DOI: 10.1111/gbb.12156] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 07/08/2014] [Accepted: 07/21/2014] [Indexed: 11/28/2022]
Abstract
Glutamate neurotransmission via the N-methyl-D-aspartate receptor (NMDAR) is thought to mediate the synaptic plasticity underlying learning and memory formation. There is increasing evidence that deficits in NMDAR function are involved in the pathophysiology of cognitive dysfunction seen in neuropsychiatric disorders and addiction. NMDAR subunits confer different physiological properties to the receptor, interact with distinct intracellular postsynaptic scaffolding and signaling molecules, and are differentially expressed during development. Despite these known differences, the relative contribution of individual subunit composition to synaptic plasticity and learning is not fully elucidated. We have previously shown that constitutive deletion of GluN2A subunit in the mouse impairs discrimination and re-learning phase of reversal when exemplars are complex picture stimuli, but spares acquisition and extinction of non-discriminative visually cued instrumental response. To investigate the role of GluN2A containing NMDARs in executive control, we tested GluN2A knockout (GluN2A(KO) ), heterozygous (GluN2A(HET) ) and wild-type (WT) littermates on an attentional set-shifting task using species-specific stimulus dimensions. To further explore the nature of deficits in this model, mice were tested on a visual discrimination reversal paradigm using simplified rotational stimuli. GluN2A(KO) were not impaired on discrimination or reversal problems when tactile or olfactory stimuli were used, or when visual stimuli were sufficiently easy to discriminate. GluN2A(KO) showed a specific and significant impairment in ventromedial prefrontal cortex-mediated set-shifting. Together these results support a role for GluN2A containing NMDAR in modulating executive control that can be masked by overlapping deficits in attentional processes during high task demands.
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Affiliation(s)
- K Marquardt
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, USA
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37
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Fidalgo C, Conejo NM, González-Pardo H, Arias JL. Dynamic functional brain networks involved in simple visual discrimination learning. Neurobiol Learn Mem 2014; 114:165-70. [PMID: 24937013 DOI: 10.1016/j.nlm.2014.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/23/2014] [Accepted: 06/02/2014] [Indexed: 12/23/2022]
Abstract
Visual discrimination tasks have been widely used to evaluate many types of learning and memory processes. However, little is known about the brain regions involved at different stages of visual discrimination learning. We used cytochrome c oxidase histochemistry to evaluate changes in regional brain oxidative metabolism during visual discrimination learning in a water-T maze at different time points during training. As compared with control groups, the results of the present study reveal the gradual activation of cortical (prefrontal and temporal cortices) and subcortical brain regions (including the striatum and the hippocampus) associated to the mastery of a simple visual discrimination task. On the other hand, the brain regions involved and their functional interactions changed progressively over days of training. Regions associated with novelty, emotion, visuo-spatial orientation and motor aspects of the behavioral task seem to be relevant during the earlier phase of training, whereas a brain network comprising the prefrontal cortex was found along the whole learning process. This study highlights the relevance of functional interactions among brain regions to investigate learning and memory processes.
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Affiliation(s)
- Camino Fidalgo
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijóo s/n, E-33003 Oviedo, Spain.
| | - Nélida María Conejo
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijóo s/n, E-33003 Oviedo, Spain.
| | - Héctor González-Pardo
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijóo s/n, E-33003 Oviedo, Spain.
| | - Jorge Luis Arias
- Laboratory of Neuroscience, Department of Psychology, Instituto de Neurociencias del Principado de Asturias (INEUROPA), University of Oviedo, Plaza Feijóo s/n, E-33003 Oviedo, Spain.
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Transient inactivation of the ventral hippocampus in neonatal rats impairs the mesolimbic regulation of prefrontal glutamate release in adulthood. Neuropharmacology 2014; 84:19-30. [PMID: 24747179 DOI: 10.1016/j.neuropharm.2014.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Revised: 03/24/2014] [Accepted: 04/08/2014] [Indexed: 11/21/2022]
Abstract
Cognitive deficits in schizophrenia (SZ) reflect maturational disruptions within a neural system that includes the ventral hippocampus (VH), nucleus accumbens (NAc), basal forebrain, and prefrontal cortex (PFC). A better understanding of these changes may reveal drug targets for more efficacious cognition enhancers. We have utilized an animal model in which the above distributed system is altered, during a sensitive period of development, by transiently inactivating the VH and its efferent projections. We determined the ability of NAc shell activation to evoke prefrontal glutamate release in adult male Wistar rats that had received saline (Sal) or tetrodotoxin (TTX) as neonates (PD7) or as adolescents (PD32). The nucleus accumbens shell (NAcSh) was activated by NMDA infusions (0.05-0.30 μg/0.5 μL). Basal and evoked glutamate levels were measured amperometrically using a glutamate-sensitive microelectrode. There were no differences in basal glutamate levels among the groups tested (overall 1.41 ± 0.26 uM). However, the dose-related stimulation of prefrontal glutamate levels seen in control rats treated with saline on PD7 (4.31 ± 0.22 μM after 0.15 μg) was markedly attenuated in rats treated with TTX on PD7 (0.45 ± 0.12 μM after 0.15 μg). This effect was age-dependent as infusions of TTX on PD32 did not alter the NMDA-induced increases in glutamate release (4.10 ± 0.37 μM after 0.15 μg). Collectively, these findings reveal that transient inactivation of VH transmission, during a sensitive period of development, leads to a functional mesolimbic-cortical disconnection that produces neurochemical and ultimately cognitive impairments resembling those seen in SZ.
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Dubois M, Lapinte N, Villier V, Lecointre C, Roy V, Tonon MC, Gandolfo P, Joly F, Hilber P, Castel H. Chemotherapy-induced long-term alteration of executive functions and hippocampal cell proliferation: Role of glucose as adjuvant. Neuropharmacology 2014; 79:234-48. [DOI: 10.1016/j.neuropharm.2013.11.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 11/18/2013] [Accepted: 11/19/2013] [Indexed: 11/28/2022]
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Bañuelos C, Beas BS, McQuail JA, Gilbert RJ, Frazier CJ, Setlow B, Bizon JL. Prefrontal cortical GABAergic dysfunction contributes to age-related working memory impairment. J Neurosci 2014; 34:3457-66. [PMID: 24599447 PMCID: PMC3942567 DOI: 10.1523/jneurosci.5192-13.2014] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 01/15/2014] [Accepted: 01/20/2014] [Indexed: 12/12/2022] Open
Abstract
Working memory functions supported by the prefrontal cortex decline in normal aging. Disruption of corticolimbic GABAergic inhibitory circuits can impair working memory in young subjects; however, relatively little is known regarding how aging impacts prefrontal cortical GABAergic signaling and whether such changes contribute to cognitive deficits. The current study used a rat model to evaluate the effects of aging on expression of prefrontal GABAergic synaptic proteins in relation to working memory decline, and to test whether pharmacological manipulations of prefrontal GABAergic signaling can improve working memory abilities in aged subjects. Results indicate that in aged medial prefrontal cortex (mPFC), expression of the vesicular GABA transporter VGAT was unchanged; however, there was a significant increase in expression of the GABA synthesizing enzyme GAD67, and a significant decrease in the primary neuronal GABA transporter GAT-1 and in both subunits of the GABA(B) receptor (GABA(B)R). Expression of VGAT, GAD67, and GAT-1 was not associated with working memory ability. In contrast, among aged rats, GABA(B)R expression was significantly and negatively associated with working memory performance, such that lower GABA(B)R expression predicted better working memory. Subsequent experiments showed that systemic administration of a GABA(B)R antagonist, CGP55845, dose-dependently enhanced working memory in aged rats. This enhancing effect of systemic CGP55845 was reproduced by direct intra-mPFC administration. Together, these data suggest that age-related dysregulation of GABAergic signaling in prefrontal cortex may play a causal role in impaired working memory and that targeting GABA(B)Rs may provide therapeutic benefit for age-related impairments in executive functions.
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Affiliation(s)
| | | | | | | | - Charles J. Frazier
- Department of Neuroscience
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida 32610
| | - Barry Setlow
- Department of Neuroscience
- Department of Psychiatry
| | - Jennifer L. Bizon
- Department of Neuroscience
- Department of Psychiatry
- McKnight Brain Institute, and
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Effect of alpha7 nicotinic acetylcholine receptor agonists on attentional set-shifting impairment in rats. Psychopharmacology (Berl) 2014; 231:673-83. [PMID: 24057763 DOI: 10.1007/s00213-013-3275-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 09/03/2013] [Indexed: 11/27/2022]
Abstract
RATIONALE Attentional set shifting, a measure of executive function, is impaired in schizophrenia patients. Current standard of care has little therapeutic benefit for treating cognitive dysfunction in schizophrenia; therefore, novel drugs and animal models for testing novel therapies are needed. The NMDA receptor antagonist, MK-801, produces deficits in a rat maze-based set-shifting paradigm, an effect which parallels deficits observed on tests of executive function in schizophrenia patients. Alpha7 nicotinic acetylcholine receptor (nAChR) agonists, currently under clinical development by several companies, show promise in treating cognitive symptoms in schizophrenia patients and can improve cognition in various animal models. OBJECTIVES The objectives of the present study were to determine whether the MK-801 deficit in set shifting could be reproduced in a drug discovery setting and to determine whether cognitive improvement could be detected for the first time in this task with alpha7 nAChR agonists. RESULTS The data presented here replicate findings that a systemic injection of the NMDA receptor antagonist MK-801 can induce a deficit in set shifting in rats. Furthermore, the deficit could be reversed by the atypical antipsychotic clozapine as well as by several alpha7 nAch receptor agonists (SSR-180711, PNU-282987, GTS-21) with varying in vitro properties. CONCLUSIONS Results indicate that the MK-801 set-shift assay is a useful preclinical tool for measuring prefrontal cortical function in rodents and can be used to identify novel mechanisms for the potential treatment of cognitive deficits in schizophrenia.
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Effects of amphetamine exposure in adolescence or young adulthood on inhibitory control in adult male and female rats. Behav Brain Res 2014; 263:22-33. [PMID: 24462963 DOI: 10.1016/j.bbr.2014.01.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 01/07/2014] [Accepted: 01/15/2014] [Indexed: 01/03/2023]
Abstract
Heightened impulsivity is a feature of some psychiatric disorders, including addiction, that also have sex-specific patterns of expression. The relationship between addiction and impulsivity may be driven by drug-induced changes in behavior caused by long term adaptations in signaling within the medial prefrontal cortex (mPFC). Here, we used a response inhibition task that is sensitive to changes in mPFC function to examine the effects of sex and exposure to amphetamine (AMPH) on impulsive action and vigilance. We also examined drug-induced alterations in glutamatergic and dopaminergic signaling through challenge injections with the NMDA receptor antagonist MK-801 (dizocilpine) and AMPH. Male and female Sprague Dawley rats were injected (i.p.) with saline or 3 mg/kg AMPH every other day during adolescence (postnatal day (P) 27-45) or adulthood (P85-103). Starting on P125-135, rats were tested for their ability to lever press for a food reward during periods of signaled availability and withhold responding during a "premature response" phase. In experiment 1, rats received challenge injections (i.p.) of MK-801 and AMPH followed by tests of task performance and locomotor activity. In experiment 2, rats received intra-mPFC infusion of MK-801. We found that females had better inhibitory control and poorer vigilance than males and that AMPH exposure had both sex- and age-of-exposure dependent effects on impulsivity. Systemic drug challenges disrupted task performance, particularly in females, and increased impulsivity while intra-mPFC infusions had modest effects. AMPH exposure did not affect responses to drug challenges. Together, these results suggest that sex mediates both trait and drug-induced impulsivity.
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Bondi CO, Taha AY, Tock JL, Totah NK, Cheon Y, Torres GE, Rapoport SI, Moghaddam B. Adolescent behavior and dopamine availability are uniquely sensitive to dietary omega-3 fatty acid deficiency. Biol Psychiatry 2014; 75:38-46. [PMID: 23890734 PMCID: PMC3858419 DOI: 10.1016/j.biopsych.2013.06.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 06/04/2013] [Accepted: 06/11/2013] [Indexed: 12/11/2022]
Abstract
BACKGROUND Understanding the nature of environmental factors that contribute to behavioral health is critical for successful prevention strategies in individuals at risk for psychiatric disorders. These factors are typically experiential in nature, such as stress and urbanicity, but nutrition--in particular dietary deficiency of omega-3 polyunsaturated fatty acids (n-3 PUFAs)-has increasingly been implicated in the symptomatic onset of schizophrenia and mood disorders, which typically occurs during adolescence to early adulthood. Thus, adolescence might be the critical age range for the negative impact of diet as an environmental insult. METHODS A rat model involving consecutive generations of n-3 PUFA deficiency was developed on the basis of the assumption that dietary trends toward decreased consumption of these fats began 4-5 decades ago when the parents of current adolescents were born. Behavioral performance in a wide range of tasks as well as markers of dopamine-related neurotransmission was compared in adolescents and adults fed n-3 PUFA adequate and deficient diets. RESULTS In adolescents, dietary n-3 PUFA deficiency across consecutive generations produced a modality-selective and task-dependent impairment in cognitive and motivated behavior distinct from the deficits observed in adults. Although this dietary deficiency affected expression of dopamine-related proteins in both age groups in adolescents but not adults, there was an increase in tyrosine hydroxylase expression that was selective to the dorsal striatum. CONCLUSIONS These data support a nutritional contribution to optimal cognitive and affective functioning in adolescents. Furthermore, they suggest that n-3 PUFA deficiency disrupts adolescent behaviors through enhanced dorsal striatal dopamine availability.
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Affiliation(s)
- Corina O. Bondi
- Department of Neuroscience, Univ. of Pittsburgh, Pittsburgh, PA
| | - Ameer Y. Taha
- Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, NIH, Bethesda, MD
| | - Jody L. Tock
- Department of Neuroscience, Univ. of Pittsburgh, Pittsburgh, PA
| | - Nelson K. Totah
- Department of Neuroscience, Univ. of Pittsburgh, Pittsburgh, PA
| | - Yewon Cheon
- Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, NIH, Bethesda, MD
| | | | - Stanley I. Rapoport
- Brain Physiology and Metabolism Section, Laboratory of Neurosciences, National Institute on Aging, NIH, Bethesda, MD
| | - Bita Moghaddam
- Department of Neuroscience, Univ. of Pittsburgh, Pittsburgh, PA
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Blot K, Kimura SI, Bai J, Kemp A, Manahan-Vaughan D, Giros B, Tzavara E, Otani S. Modulation of Hippocampus-Prefrontal Cortex Synaptic Transmission and Disruption of Executive Cognitive Functions by MK-801. Cereb Cortex 2013; 25:1348-61. [DOI: 10.1093/cercor/bht329] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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D'Amore DE, Tracy BA, Parikh V. Exogenous BDNF facilitates strategy set-shifting by modulating glutamate dynamics in the dorsal striatum. Neuropharmacology 2013; 75:312-23. [DOI: 10.1016/j.neuropharm.2013.07.033] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 07/29/2013] [Accepted: 07/30/2013] [Indexed: 01/19/2023]
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Different MK-801 administration schedules induce mild to severe learning impairments in an operant conditioning task: Role of buspirone and risperidone in ameliorating these cognitive deficits. Behav Brain Res 2013; 257:156-65. [DOI: 10.1016/j.bbr.2013.09.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 09/21/2013] [Accepted: 09/24/2013] [Indexed: 02/07/2023]
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Bortz DM, Mikkelsen JD, Bruno JP. Localized infusions of the partial alpha 7 nicotinic receptor agonist SSR180711 evoke rapid and transient increases in prefrontal glutamate release. Neuroscience 2013; 255:55-67. [PMID: 24095692 DOI: 10.1016/j.neuroscience.2013.09.047] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 09/11/2013] [Accepted: 09/20/2013] [Indexed: 10/26/2022]
Abstract
The ability of local infusions of the alpha 7 nicotinic acetycholine receptor (α7 nAChR) partial agonist SSR180711 to evoke glutamate release in prefrontal cortex was determined in awake rats using a microelectrode array. Infusions of SSR180711 produced dose-dependent increases in glutamate levels. The lower dose (1.0μg in 0.4μL) evoked a rapid rise (∼1.0s) in glutamate (1.41±0.30μM above baseline). The higher dose (5.0μg) produced a similarly rapid, yet larger increase (3.51±0.36μM above baseline). After each dose, the glutamate signal was cleared to basal levels within 7-18s. SSR180711-evoked glutamate was mediated by the α7 nAChR as co-infusion of the selective α7 nAChR antagonist α-bungarotoxin (10.0μM)+SSR1808711 (5.0μg) reduced the effect of 5.0μg alone by 87% (2.62 vs. 0.35μM). Finally, the clearance of the SSR180711 (5.0μg)-evoked glutamate was bidirectionally affected by drugs that inhibited (threo-beta-benzyl-oxy-aspartate (TβOA), 100.0μM) or facilitated (ceftriaxalone, 200mg/kg, i.p.) excitatory amino acid transporters. TβOA slowed both the clearance (s) and rate of clearance (μM/s) by 10-fold, particularly at the mid-late stages of the return to baseline. Ceftriaxone reduced the magnitude of the SSR180711-evoked increase by 65%. These results demonstrate that pharmacological stimulation of α7 nAChRs within the prefrontal cortex is sufficient to evoke rapid yet transient increases in glutamate levels. Such increases may underlie the cognition-enhancing effects of the drug in animals; further justifying studies on the use of α7 nAChR-positive modulators in treating cognition-impairing disorders in humans.
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Affiliation(s)
- D M Bortz
- Department of Psychology, The Ohio State University, Columbus, OH, United States
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Wang X, Pinto-Duarte A, Sejnowski TJ, Behrens MM. How Nox2-containing NADPH oxidase affects cortical circuits in the NMDA receptor antagonist model of schizophrenia. Antioxid Redox Signal 2013; 18:1444-62. [PMID: 22938164 PMCID: PMC3603498 DOI: 10.1089/ars.2012.4907] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 09/02/2012] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE Schizophrenia is a complex neuropsychiatric disorder affecting around 1% of the population worldwide. Its mode of inheritance suggests a multigenic neurodevelopmental disorder with symptoms appearing during late adolescence/early adulthood, with its onset strongly influenced by environmental stimuli. Many neurotransmitter systems, including dopamine, glutamate, and gamma-aminobutyric acid, show alterations in affected individuals, and the behavioral and physiological characteristics of the disease can be mimicked by drugs that produce blockade of N-methyl-d-aspartate glutamate receptors (NMDARs). RECENT ADVANCES Mounting evidence suggests that drugs that block NMDARs specifically impair the inhibitory capacity of parvalbumin-expressing (PV+) fast-spiking neurons in adult and developing rodents, and alterations in these inhibitory neurons is one of the most consistent findings in the schizophrenic postmortem brain. Disruption of the inhibitory capacity of PV+ inhibitory neurons will alter the functional balance between excitation and inhibition in prefrontal cortical circuits producing impairment of working memory processes such as those observed in schizophrenia. CRITICAL ISSUES Mechanistically, the effect of NMDAR antagonists can be attributed to the activation of the Nox2-dependent reduced form of nicotinamide adenine dinucleotide phosphate oxidase pathway in cortical neurons, which is consistent with the emerging role of oxidative stress in the pathogenesis of mental disorders, specifically schizophrenia. Here we review the mechanisms by which NMDAR antagonists produce lasting impairment of the cortical PV+ neuronal system and the roles played by Nox2-dependent oxidative stress mechanisms. FUTURE DIRECTIONS The discovery of the pathways by which oxidative stress leads to unbalanced excitation and inhibition in cortical neural circuits opens a new perspective toward understanding the biological underpinnings of schizophrenia.
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Affiliation(s)
- Xin Wang
- The Salk Institute for Biological Studies, La Jolla, California
- Howard Hughes Medical Institute, La Jolla, California
| | - António Pinto-Duarte
- The Salk Institute for Biological Studies, La Jolla, California
- Howard Hughes Medical Institute, La Jolla, California
- Institute of Pharmacology and Neurosciences, Faculty of Medicine, University of Lisbon, Lisbon, Portugal
- Neurosciences Unit, Institute of Molecular Medicine, University of Lisbon, Lisbon, Portugal
| | - Terrence J. Sejnowski
- The Salk Institute for Biological Studies, La Jolla, California
- Howard Hughes Medical Institute, La Jolla, California
- Division of Biology, University of California San Diego, La Jolla, California
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Bellon A, Le Pen G, Matricon J, Jay TM, Krebs MO. Potential application as screening and drug designing tools of cytoarchitectural deficiencies present in three animal models of schizophrenia. Expert Opin Drug Discov 2013; 4:257-78. [PMID: 23489125 DOI: 10.1517/17460440902762794] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND The development of new treatment alternatives for schizophrenia has been prevented by the unknown etiology of the illness and the divergence of results in the field. However, consistent neuropathological findings are emerging from anatomical areas known to be at the core of schizophrenia. If these deficiencies are replicated in animal models then such anomalies could become the target for a new generation of drugs. OBJECTIVE To determine if the methylazoxymethanol acetate (MAM) model, the heterozygote reeler mouse (HRM) and NMDA-antagonists treated rats replicate neuropathological deficits encountered in patients with schizophrenia and to establish if such changes could lead the search for developing novel treatment alternatives. METHODS Databases including MEDLINE, Cochrane and Ovid were searched; search terms included neuropathology, schizophrenia and animal models. RESULTS/CONCLUSIONS NMDA-antagonist treated animals partially replicate schizophrenia anomalies in parvalbumin positive interneurons. In contrast, neuroanatomical deficiencies replicated by the MAM model and the HRM in the hippocampus and the prefrontal cortex seem promising targets for future pharmacological research in schizophrenia. Such neuroanatomical findings along with evidence from molecules and genes associated with schizophrenia suggest new drugs should aim to correct deficits in the formation of dendrites and axons that seems to be implicated in this illness pathophysiology.
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Affiliation(s)
- Alfredo Bellon
- INSERM, Hôpital Sainte-Anne, Centre de Psychiatrie et Neurosciences, Laboratoire de Physiopathologie des Maladies Psychiatriques, U894, 2 ter rue d'Alésia, 75014 Paris, France +33 1 40788634 ; +33 1 45807293 ;
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Transient inactivation of the neonatal ventral hippocampus impairs attentional set-shifting behavior: reversal with an α7 nicotinic agonist. Neuropsychopharmacology 2012; 37:2476-86. [PMID: 22781844 PMCID: PMC3442342 DOI: 10.1038/npp.2012.106] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cognitive deficits represent a core symptom cluster in schizophrenia that are thought to reflect developmental dysregulations within a neural system involving the ventral hippocampus (VH), nucleus accumbens (NAC), and prefrontal cortex (PFC). The present experiments determined the cognitive effects of transiently inactivating VH in rats during a sensitive period of development. Neonatal (postnatal day 7, PD7) and adolescent (PD32) male rats received a single bilateral infusion of saline or tetrodotoxin (TTX) within the VH to transiently inactivate local circuitry and efferent outflow. Rats were tested as adults on an attentional set-shifting task. Performance in this task depends upon the integrity of the PFC and NAC. TTX infusions did not affect the initial acquisition or ability to learn an intra-dimensional shift. However, TTX rats required a greater number of trials than did controls to acquire the first reversal and extra-dimensional shift (ED) stages. These impairments were age and region-specific as rats infused with TTX into the VH at PD32, or into the dorsal hippocampus at PD7, exhibited performance in the task similar to that of controls. Finally, acute systemic administration of the partial α7 nicotinic acetylcholine receptor (nAChR) agonist SSR 180711 (3.0 mg/kg) eliminated the TTX-induced performance deficits. Given that patients with schizophrenia exhibit hippocampal pathophysiology and deficits in the ED stages of set-shifting tasks, our results support the significance of transient hippocampal inactivation as an animal model for studying the cognitive impairments in schizophrenia as well as the pro-cognitive therapeutic potential of α7 nAChR agonists.
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