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Whitley K, Briggs SB, Sharma K, Parent MB. Don't ignore the middle: Distinct mnemonic functions of intermediate hippocampus. Hippocampus 2024. [PMID: 39096197 DOI: 10.1002/hipo.23629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 06/21/2024] [Accepted: 07/18/2024] [Indexed: 08/05/2024]
Abstract
The dorsal region of the hippocampus (dHC) mediates many of the mnemonic functions traditionally associated with the hippocampus proper, such as spatial and episodic memory, whereas ventral hippocampus (vHC) has been extensively implicated in emotional memory and motivational processes. By contrast, the functions of the intermediate hippocampus (iHC) are far less understood. In this study, we aimed to investigate the mnemonic functions of iHC by reversibly inactivating iHC prior to testing memory in behavioral tasks dependent on the integrity of dHC, iHC, or vHC, namely, rapid place water maze, inhibitory avoidance, spontaneous alternation, and temporal ordering of odors. Given our previous findings showing that dHC and vHC are involved in mnemonic control of ingestive behavior, we also assessed the effects of iHC inactivation on sucrose intake. The results showed that pharmacological inhibition of iHC impairs rapid place water maze memory, which has been previously shown to be dependent on iHC but not dHC or vHC. iHC inactivation does not impact memory dependent on dHC (spontaneous alternation), vHC (temporal odor memory), or either dHC or vHC (inhibitory avoidance), and only modestly affects sucrose intake. These findings provide support for the involvement of iHC in mnemonic functions that are distinct from dHC and vHC and highlight the need to further advance our understanding of the functions of this hippocampal region that has been relatively understudied.
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Affiliation(s)
- Kathryn Whitley
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Sherri B Briggs
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Karan Sharma
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
| | - Marise B Parent
- Neuroscience Institute, Georgia State University, Atlanta, Georgia, USA
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2
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Cliver KG, Gregory DF, Martinez SA, Mitchell WJ, Stasiak JE, Reisman SS, Helion C, Murty VP. Temporal memory for threatening events encoded in a haunted house. Cogn Emot 2024:1-17. [PMID: 38625561 DOI: 10.1080/02699931.2024.2338962] [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: 12/05/2022] [Accepted: 02/27/2024] [Indexed: 04/17/2024]
Abstract
Despite the salient experience of encoding threatening events, these memories are prone to distortions and often non-veridical from encoding to recall. Further, threat has been shown to preferentially disrupt the binding of event details and enhance goal-relevant information. While extensive work has characterised distinctive features of emotional memory, research has not fully explored the influence threat has on temporal memory, a process putatively supported by the binding of event details into a temporal context. Two primary competing hypotheses have been proposed; that threat can impair or enhance temporal memory. We analysed two datasets to assess temporal memory for an in-person haunted house experience. In study 1, we examined the temporal structure of memory by characterising memory contiguity in free recall as a function of individual levels of heart rate as a proxy of threat. In study 2, we replicated marginal findings of threat-related increases in memory contiguity found in study 1. We extended these findings by showing threat-related increases in recency discriminations, an explicit test of temporal memory. Together, these findings demonstrate that threat enhances temporal memory regarding free recall structure and during explicit memory judgments.
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Affiliation(s)
- Katelyn G Cliver
- Department of Applied Cognitive and Brain Sciences, Drexel University, Philadelphia, PA, USA
| | - David F Gregory
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA, USA
| | - Steven A Martinez
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA, USA
| | - William J Mitchell
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA, USA
| | - Joanne E Stasiak
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA, USA
| | - Samantha S Reisman
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, RI, USA
| | - Chelsea Helion
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA, USA
| | - Vishnu P Murty
- Department of Psychology and Neuroscience, Temple University, Philadelphia, PA, USA
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3
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Lopez MR, Wasberg SMH, Gagliardi CM, Normandin ME, Muzzio IA. Mystery of the memory engram: History, current knowledge, and unanswered questions. Neurosci Biobehav Rev 2024; 159:105574. [PMID: 38331127 DOI: 10.1016/j.neubiorev.2024.105574] [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: 09/18/2023] [Revised: 12/22/2023] [Accepted: 02/03/2024] [Indexed: 02/10/2024]
Abstract
The quest to understand the memory engram has intrigued humans for centuries. Recent technological advances, including genetic labelling, imaging, optogenetic and chemogenetic techniques, have propelled the field of memory research forward. These tools have enabled researchers to create and erase memory components. While these innovative techniques have yielded invaluable insights, they often focus on specific elements of the memory trace. Genetic labelling may rely on a particular immediate early gene as a marker of activity, optogenetics may activate or inhibit one specific type of neuron, and imaging may capture activity snapshots in a given brain region at specific times. Yet, memories are multifaceted, involving diverse arrays of neuronal subpopulations, circuits, and regions that work in concert to create, store, and retrieve information. Consideration of contributions of both excitatory and inhibitory neurons, micro and macro circuits across brain regions, the dynamic nature of active ensembles, and representational drift is crucial for a comprehensive understanding of the complex nature of memory.
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Affiliation(s)
- M R Lopez
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - S M H Wasberg
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - C M Gagliardi
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - M E Normandin
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA
| | - I A Muzzio
- Department of Psychological and Brain Sciences, University of Iowa, Iowa City, IA 52242, USA.
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4
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Fukuyama K, Motomura E, Okada M. A Candidate Gliotransmitter, L-β-Aminoisobutyrate, Contributes to Weight Gain and Metabolic Complication Induced by Atypical Antipsychotics. Nutrients 2023; 15:nu15071621. [PMID: 37049464 PMCID: PMC10097171 DOI: 10.3390/nu15071621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 03/15/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
Lurasidone and quetiapine are effective atypical mood-stabilizing antipsychotics, but lurasidone and quetiapine are listed as lower-risk and high-risk for weight gain/metabolic complications, respectively. The pathophysiology of the discrepancy of metabolic adverse reactions between these antipsychotics remains to be clarified. The GABA isomer, β-aminoisobutyric acid (BAIBA) enantiomer, was recently re-discovered as myokine via an AMP-activated protein kinase activator (AMPK) enhancer and inhibitory gliotransmitter. Notably, activation of AMPK in peripheral organs improves, but in the hypothalamus, it aggravates metabolic disturbances. Therefore, we determined effects of chronic administration of lurasidone and quetiapine on intracellular and extracellular levels of the BAIBA enantiomer. L-BAIBA is a major BAIBA enantiomer in the hypothalamus and astrocytes, whereas L-BAIBA only accounted for about 5% of total plasma BAIBA enantiomers. Chronic lurasidone administration did not affect body weight but decreased the L-BAIBA level in hypothalamus and cultured astrocytes, whereas chronic quetiapine administration increased body weight and the L-BAIBA level in hypothalamus and astrocytes. Contrary, neither lurasidone nor quetiapine affected total plasma levels of the BAIBA enantiomer since D-BAIBA levels were not affected by these antipsychotics. These results suggest that activation of intracellular L-BAIBA signaling is, at least partially, involved in the pathophysiology of metabolic adverse reaction of quetiapine. Furthermore, this study also demonstrated that lurasidone and quetiapine suppressed and enhanced astroglial L-BAIBA release induced by ripple-burst stimulation (which physiologically contributes to cognitive memory integration during sleep), respectively. Therefore, L-BAIBA probably contributes to the pathophysiology of not only metabolic adverse reactions, but also a part of clinical action of lurasidone or quetiapine.
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Duvelle É, Grieves RM, van der Meer MAA. Temporal context and latent state inference in the hippocampal splitter signal. eLife 2023; 12:e82357. [PMID: 36622350 PMCID: PMC9829411 DOI: 10.7554/elife.82357] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/06/2022] [Indexed: 01/10/2023] Open
Abstract
The hippocampus is thought to enable the encoding and retrieval of ongoing experience, the organization of that experience into structured representations like contexts, maps, and schemas, and the use of these structures to plan for the future. A central goal is to understand what the core computations supporting these functions are, and how these computations are realized in the collective action of single neurons. A potential access point into this issue is provided by 'splitter cells', hippocampal neurons that fire differentially on the overlapping segment of trajectories that differ in their past and/or future. However, the literature on splitter cells has been fragmented and confusing, owing to differences in terminology, behavioral tasks, and analysis methods across studies. In this review, we synthesize consistent findings from this literature, establish a common set of terms, and translate between single-cell and ensemble perspectives. Most importantly, we examine the combined findings through the lens of two major theoretical ideas about hippocampal function: representation of temporal context and latent state inference. We find that unique signature properties of each of these models are necessary to account for the data, but neither theory, by itself, explains all of its features. Specifically, the temporal gradedness of the splitter signal is strong support for temporal context, but is hard to explain using state models, while its flexibility and task-dependence is naturally accounted for using state inference, but poses a challenge otherwise. These theories suggest a number of avenues for future work, and we believe their application to splitter cells is a timely and informative domain for testing and refining theoretical ideas about hippocampal function.
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Affiliation(s)
- Éléonore Duvelle
- Department of Psychological and Brain Sciences, Dartmouth CollegeHanoverUnited States
| | - Roddy M Grieves
- Department of Psychological and Brain Sciences, Dartmouth CollegeHanoverUnited States
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Flanagin VL, Klinkowski S, Brodt S, Graetsch M, Roselli C, Glasauer S, Gais S. The precuneus as a central node in declarative memory retrieval. Cereb Cortex 2023; 33:5981-5990. [PMID: 36610736 DOI: 10.1093/cercor/bhac476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 11/11/2022] [Accepted: 11/17/2022] [Indexed: 01/09/2023] Open
Abstract
Both, the hippocampal formation and the neocortex are contributing to declarative memory, but their functional specialization remains unclear. We investigated the differential contribution of both memory systems during free recall of word lists. In total, 21 women and 17 men studied the same list but with the help of different encoding associations. Participants associated the words either sequentially with the previous word on the list, with spatial locations on a well-known path, or with unique autobiographical events. After intensive rehearsal, subjects recalled the words during functional magnetic resonance imaging (fMRI). Common activity to all three types of encoding associations was identified in the posterior parietal cortex, in particular in the precuneus. Additionally, when associating spatial or autobiographical material, retrosplenial cortex activity was elicited during word list recall, while hippocampal activity emerged only for autobiographically associated words. These findings support a general, critical function of the precuneus in episodic memory storage and retrieval. The encoding-retrieval repetitions during learning seem to have accelerated hippocampus-independence and lead to direct neocortical integration in the sequentially associated and spatially associated word list tasks. During recall of words associated with autobiographical memories, the hippocampus might add spatiotemporal information supporting detailed scenic and contextual memories.
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Affiliation(s)
- Virginia L Flanagin
- Bernstein Center for Computational Neuroscience, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany.,IFB-LMU, Dept. of Neurology, Marchioninistr. 15, 81377 München, Germany
| | - Svenja Klinkowski
- Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, Silcherstr. 5, 72076 Tübingen, Germany
| | - Svenja Brodt
- Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, Silcherstr. 5, 72076 Tübingen, Germany
| | - Melanie Graetsch
- General and Experimental Psychology, Ludwig Maximilians University München, Leopoldstr. 13, 80802 München, Germany
| | - Carolina Roselli
- General and Experimental Psychology, Ludwig Maximilians University München, Leopoldstr. 13, 80802 München, Germany
| | - Stefan Glasauer
- Bernstein Center for Computational Neuroscience, Großhaderner Str. 2, 82152 Planegg-Martinsried, Germany.,Computational Neuroscience, Brandenburg University of Technology Cottbus-Senftenberg, Universitätsplatz 1, 01968 Senftenberg, Germany
| | - Steffen Gais
- Institute of Medical Psychology and Behavioural Neurobiology, University of Tübingen, Silcherstr. 5, 72076 Tübingen, Germany
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Froula JM, Hastings SD, Krook-Magnuson E. The little brain and the seahorse: Cerebellar-hippocampal interactions. Front Syst Neurosci 2023; 17:1158492. [PMID: 37034014 PMCID: PMC10076554 DOI: 10.3389/fnsys.2023.1158492] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 03/06/2023] [Indexed: 04/11/2023] Open
Abstract
There is a growing appreciation for the cerebellum beyond its role in motor function and accumulating evidence that the cerebellum and hippocampus interact across a range of brain states and behaviors. Acute and chronic manipulations, simultaneous recordings, and imaging studies together indicate coordinated coactivation and a bidirectional functional connectivity relevant for various physiological functions, including spatiotemporal processing. This bidirectional functional connectivity is likely supported by multiple circuit paths. It is also important in temporal lobe epilepsy: the cerebellum is impacted by seizures and epilepsy, and modulation of cerebellar circuitry can be an effective strategy to inhibit hippocampal seizures. This review highlights some of the recent key hippobellum literature.
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Xiang L, Harel A, Todorova R, Gao H, Sara SJ, Wiener SI. Locus coeruleus noradrenergic neurons phase-lock to prefrontal and hippocampal infra-slow rhythms that synchronize to behavioral events. Front Cell Neurosci 2023; 17:1131151. [PMID: 37025702 PMCID: PMC10070758 DOI: 10.3389/fncel.2023.1131151] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Accepted: 02/23/2023] [Indexed: 04/08/2023] Open
Abstract
The locus coeruleus (LC) is the primary source of noradrenergic projections to the forebrain, and, in prefrontal cortex, is implicated in decision-making and executive function. LC neurons phase-lock to cortical infra-slow wave oscillations during sleep. Such infra-slow rhythms are rarely reported in awake states, despite their interest, since they correspond to the time scale of behavior. Thus, we investigated LC neuronal synchrony with infra-slow rhythms in awake rats performing an attentional set-shifting task. Local field potential (LFP) oscillation cycles in prefrontal cortex and hippocampus on the order of 0.4 Hz phase-locked to task events at crucial maze locations. Indeed, successive cycles of the infra-slow rhythms showed different wavelengths, as if they are periodic oscillations that can reset phase relative to salient events. Simultaneously recorded infra-slow rhythms in prefrontal cortex and hippocampus could show different cycle durations as well, suggesting independent control. Most LC neurons (including optogenetically identified noradrenergic neurons) recorded here were phase-locked to these infra-slow rhythms, as were hippocampal and prefrontal units recorded on the LFP probes. The infra-slow oscillations also phase-modulated gamma amplitude, linking these rhythms at the time scale of behavior to those coordinating neuronal synchrony. This would provide a potential mechanism where noradrenaline, released by LC neurons in concert with the infra-slow rhythm, would facilitate synchronization or reset of these brain networks, underlying behavioral adaptation.
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Affiliation(s)
- Liyang Xiang
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
- Zhejiang Key Laboratory of Neuroelectronics and Brain Computer Interface Technology, Hangzhou, China
| | - Antoine Harel
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Ralitsa Todorova
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - HongYing Gao
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
| | - Susan J. Sara
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
- Department of Child and Adolescent Psychiatry, New York University Medical School, New York, NY, United States
| | - Sidney I. Wiener
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, Paris, France
- *Correspondence: Sidney I. Wiener,
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9
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Billig AJ, Lad M, Sedley W, Griffiths TD. The hearing hippocampus. Prog Neurobiol 2022; 218:102326. [PMID: 35870677 PMCID: PMC10510040 DOI: 10.1016/j.pneurobio.2022.102326] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 06/08/2022] [Accepted: 07/18/2022] [Indexed: 11/17/2022]
Abstract
The hippocampus has a well-established role in spatial and episodic memory but a broader function has been proposed including aspects of perception and relational processing. Neural bases of sound analysis have been described in the pathway to auditory cortex, but wider networks supporting auditory cognition are still being established. We review what is known about the role of the hippocampus in processing auditory information, and how the hippocampus itself is shaped by sound. In examining imaging, recording, and lesion studies in species from rodents to humans, we uncover a hierarchy of hippocampal responses to sound including during passive exposure, active listening, and the learning of associations between sounds and other stimuli. We describe how the hippocampus' connectivity and computational architecture allow it to track and manipulate auditory information - whether in the form of speech, music, or environmental, emotional, or phantom sounds. Functional and structural correlates of auditory experience are also identified. The extent of auditory-hippocampal interactions is consistent with the view that the hippocampus makes broad contributions to perception and cognition, beyond spatial and episodic memory. More deeply understanding these interactions may unlock applications including entraining hippocampal rhythms to support cognition, and intervening in links between hearing loss and dementia.
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Affiliation(s)
| | - Meher Lad
- Translational and Clinical Research Institute, Newcastle University Medical School, Newcastle upon Tyne, UK
| | - William Sedley
- Translational and Clinical Research Institute, Newcastle University Medical School, Newcastle upon Tyne, UK
| | - Timothy D Griffiths
- Biosciences Institute, Newcastle University Medical School, Newcastle upon Tyne, UK; Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, UK; Human Brain Research Laboratory, Department of Neurosurgery, University of Iowa Hospitals and Clinics, Iowa City, USA
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Parent MB. Using Postmeal Measures and Manipulations to Investigate Hippocampal Mnemonic Control of Eating Behavior. Neuroscience 2022; 497:228-238. [PMID: 34998891 PMCID: PMC9256844 DOI: 10.1016/j.neuroscience.2021.12.040] [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: 09/12/2021] [Revised: 12/27/2021] [Accepted: 12/30/2021] [Indexed: 10/19/2022]
Abstract
Episodic meal-related memories provide the brain with a powerful mechanism for tracking and controlling eating behavior because they contain a detailed record of recent energy intake that likely outlasts the physiological signals generated by feeding bouts. This review briefly summarizes evidence from human participants showing that episodic meal-related memory limits later eating behavior and then describes our research aimed at investigating whether hippocampal neurons mediate the inhibitory effects of meal-related memory on subsequent feeding. Our approach has been inspired by pioneering work conducted by Ivan Izquierdo and others who used posttraining manipulations to investigate memory consolidation. This review describes the rationale and value of posttraining manipulations, how Izquierdo used them to demonstrate that dorsal hippocampal (dHC) neurons are critical for memory consolidation, and how we have adapted this strategy to investigate whether dHC neurons are necessary for mnemonic control of energy intake. I describe our evidence showing that ingestion activates the molecular processes necessary for synaptic plasticity and memory during the early postprandial period, when the memory of the meal would be undergoing consolidation, and then summarize our findings showing that neural activity in dHC neurons is critical during the early postprandial period for limiting future intake. Collectively, our evidence supports the hypothesis that dHC neurons mediate the inhibitory effects of ingestion-related memory on future intake and demonstrates that post-experience memory modulation is not confined to artificial laboratory memory tasks.
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Affiliation(s)
- M B Parent
- Neuroscience Institute & Department of Psychology, Georgia State University, PO Box 5030, Atlanta, GA 30303, USA.
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11
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Burmeister SS. Ecology, Cognition, and the Hippocampus: A Tale of Two Frogs. BRAIN, BEHAVIOR AND EVOLUTION 2022; 97:211-224. [PMID: 35051940 DOI: 10.1159/000522108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/17/2022] [Indexed: 06/14/2023]
Abstract
The underlying hypothesis that motivates research into the relationship between ecology, cognition, and the hippocampus is that selection to solve problems in nature shapes cognition through changes in the hippocampus. This hypothesis has been explored almost exclusively in mammals and birds. However, if one is interested in the principles that shape the evolution of vertebrate cognition, work in amphibians is essential. To address this gap, we have developed a research program contrasting cognitive abilities and hippocampal neurobiology in two species of frog with distinct social and spatial ecologies. We have found that the poison frog Dendrobates auratus, a diurnal species whose interactions with the physical and social environment are complex, is more adept and flexible at spatial learning and learned inhibition than the túngara frog, a nocturnal species that lacks complex interactions with the spatial and social environment. Because spatial learning and learned inhibition are closely associated with hippocampal function in other vertebrates, we used RNA sequencing to characterize molecular differences in the hippocampus of the two species. We have found that D. auratus has greater levels of expression of genes associated with neurogenesis, synaptic plasticity, and cellular activity, and lower levels of expression of genes associated with apoptosis, compared to the túngara frog. Our studies are consistent with the idea that D. auratus, with their more complex social and spatial ecology, have enhanced hippocampally dependent cognitive abilities compared to túngara frogs. Further characterization of the features of hippocampal neurobiology that confer distinctive cognitive abilities will help elucidate the neural features that are necessary for the evolution of enhanced hippocampally dependent cognition.
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Affiliation(s)
- Sabrina S Burmeister
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina, USA
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Yan N, Xu Z, Qu C, Zhang J. Dimethyl fumarate improves cognitive deficits in chronic cerebral hypoperfusion rats by alleviating inflammation, oxidative stress, and ferroptosis via NRF2/ARE/NF-κB signal pathway. Int Immunopharmacol 2021; 98:107844. [PMID: 34153667 DOI: 10.1016/j.intimp.2021.107844] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/12/2022]
Abstract
Cerebrovascular disease and its risk factors cause persistent decrease of cerebral blood flow, chronic cerebral hypoperfusion (CCH) is the major foundation of vascular cognitive impairment (VCI). The hippocampus is extremely vulnerable to cerebral ischemia and hypoxia. Oxidative stress and neuroinflammation injury are important pathophysiological mechanisms of this process, which is closely related to hippocampal neurons damage and loss. Dimethyl fumarate (DMF), an FDA-approved therapeutic for multiple sclerosis (MS), plays a protective role in multiple neurological disorders. Studies have shown that DMF exerts anti-inflammatory and antioxidant effects via the NRF2/ARE/NF-κB signaling pathway. Thus, this study aimed to evaluate the neuroprotective effect of DMF in the CCH rat model. Ferroptosis, a novel defined iron-dependent cell death form, were found to be strongly associated with the pathophysiology of CCH. Emerging evidences have shown that inhibition of ferroptosis by targeting NRF2 exerted neuroprotective effect in neurodegeneration diseases. We also investigated whether DMF can alleviate cognitive deficits through inhibition of ferroptosis by the NRF2 signaling pathway in this study. DMF was intragastric for consecutive five weeks (100 mg/kg/day). Then behavior test and histological, molecular, and biochemical analysis were performed. We found that DMF treatment significantly improved cognitive deficits and partially reversed hippocampus neuronal damage and loss caused by CCH. And DMF treatment decreased hippocampus IL-1β, TNF-α, and IL-6 pro-inflammatory cytokines concentration, and mediated the NF-κB signaling pathway. And DMF also alleviated hippocampus oxidative stress through reducing MDA, and increasing GSH and SOD levels, which are also closely associated with ferroptosis. Besides, DMF treatment reduced the expression of PTGS2, and increased the expression of FTH1 and xCT, and the iron content is also reduced, which were the important features related to ferroptosis. Furthermore, DMF activated the NRF2/ARE signaling pathway and upregulated the expression of HO-1, NQO1 and GPX4. These outcomes indicated that DMF can improve cognitive impairment in rats with CCH, possibly through alleviating neuroinflammation, oxidative stress damage and inhibiting ferroptosis of hippocampal neurons. Overall, our results provide new evidence for the neuroprotective role of DMF.
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Affiliation(s)
- Nao Yan
- Department of Neurology, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China; Hubei Clinical Research Center for Dementias and Cognitive Impairments, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China
| | - Zhipeng Xu
- Department of Neurology, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China; Hubei Clinical Research Center for Dementias and Cognitive Impairments, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China
| | - Changhua Qu
- Department of Neurology, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China; Hubei Clinical Research Center for Dementias and Cognitive Impairments, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China
| | - JunJian Zhang
- Department of Neurology, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China; Hubei Clinical Research Center for Dementias and Cognitive Impairments, Zhongnan Hospital of Wuhan University, No. 169, Donghu Road, Wuhan 430071, Hubei, China.
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Zhang D, Wang M, Gao J, Huang Y, Qi F, Lei Y, Ai K, Yan X, Cheng M, Su Y, Lei X, Zhang X. Altered Functional Connectivity of Insular Subregions in Type 2 Diabetes Mellitus. Front Neurosci 2021; 15:676624. [PMID: 34220433 PMCID: PMC8242202 DOI: 10.3389/fnins.2021.676624] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/06/2021] [Indexed: 01/09/2023] Open
Abstract
Diabetes-related brain damage can lead to cognitive decline and increase the risk of depression, but the neuropathological mechanism of this phenomenon remains unclear. Different insular subregions have obvious functional heterogeneity, which is related to many aspects of type 2 diabetes mellitus (T2DM)-related brain damage. However, little is known about changes in functional connectivity (FC) in insular subregions in patients with T2DM. Therefore, we aimed to investigate FC between different insular subregions and clinical/cognitive variables in patients with T2DM. Fifty-seven patients with T2DM and 55 healthy controls (HCs) underwent a neuropsychological assessment and resting-state FC examination. We defined three insular subregions, including the bilateral dorsal anterior insula (dAI), bilateral ventral anterior insula (vAI), and bilateral posterior insula (PI). We examined differences in FC between insular subregions and the whole brain in patients with T2DM compared with HCs. A correlation analysis was performed to examine the relationship between FC and clinical/cognitive variables. Compared with HCs, patients with T2DM showed significantly decreased FC between the dAI and the right inferior frontal gyrus, right superior/middle temporal gyrus, right hippocampus, and right precentral gyrus. FC between the vAI and the right supramarginal gyrus, as well as the PI and the right precentral/postcentral gyrus, was reduced in the T2DM group compared with the control group. In the T2DM group, we showed a significant negative correlation between glycated hemoglobin concentration and FC in the dAI and right hippocampus (r = −0.428, P = 0.001) after Bonferroni correction. We conclude that different insular subregions present distinct FC patterns with functional regions and that abnormal FC in these insular subregions may affect cognitive, emotional, and sensorimotor functions in patients with T2DM.
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Affiliation(s)
- Dongsheng Zhang
- Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Man Wang
- Department of Graduate, Xi'an Medical University, Xi'an, China
| | - Jie Gao
- Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Yang Huang
- Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Fei Qi
- Department of Graduate, Xi'an Medical University, Xi'an, China
| | - Yumeng Lei
- Department of Graduate, Xi'an Medical University, Xi'an, China
| | - Kai Ai
- Department of Clinical Science, Philips Healthcare, Xi'an, China
| | - Xuejiao Yan
- Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Miao Cheng
- Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Yu Su
- Department of Graduate, Xi'an Medical University, Xi'an, China
| | - Xiaoyan Lei
- Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Xiaoling Zhang
- Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China
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Grossberg S. A Neural Model of Intrinsic and Extrinsic Hippocampal Theta Rhythms: Anatomy, Neurophysiology, and Function. Front Syst Neurosci 2021; 15:665052. [PMID: 33994965 PMCID: PMC8113652 DOI: 10.3389/fnsys.2021.665052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/29/2021] [Indexed: 11/21/2022] Open
Abstract
This article describes a neural model of the anatomy, neurophysiology, and functions of intrinsic and extrinsic theta rhythms in the brains of multiple species. Topics include how theta rhythms were discovered; how theta rhythms organize brain information processing into temporal series of spatial patterns; how distinct theta rhythms occur within area CA1 of the hippocampus and between the septum and area CA3 of the hippocampus; what functions theta rhythms carry out in different brain regions, notably CA1-supported functions like learning, recognition, and memory that involve visual, cognitive, and emotional processes; how spatial navigation, adaptively timed learning, and category learning interact with hippocampal theta rhythms; how parallel cortical streams through the lateral entorhinal cortex (LEC) and the medial entorhinal cortex (MEC) represent the end-points of the What cortical stream for perception and cognition and the Where cortical stream for spatial representation and action; how the neuromodulator acetylcholine interacts with the septo-hippocampal theta rhythm and modulates category learning; what functions are carried out by other brain rhythms, such as gamma and beta oscillations; and how gamma and beta oscillations interact with theta rhythms. Multiple experimental facts about theta rhythms are unified and functionally explained by this theoretical synthesis.
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Affiliation(s)
- Stephen Grossberg
- Center for Adaptive Systems, Department of Mathematics and Statistics, Department of Psychological and Brain Sciences, and Department of Biomedical Engineering, Boston University, Boston, MA, United States
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