1
|
Shih CW, Chang CH. Inactivation of medial or lateral orbitofrontal cortex during fear extinction did not interfere with fear renewal. Neurobiol Learn Mem 2023; 204:107800. [PMID: 37524199 DOI: 10.1016/j.nlm.2023.107800] [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: 03/27/2023] [Revised: 07/17/2023] [Accepted: 07/28/2023] [Indexed: 08/02/2023]
Abstract
Hyperactive orbitofrontal cortical activation is commonly seen in patients of obsessive-compulsive disorder (OCD). Previous studies from our laboratory showed that for rats with aberrant activation of the orbitofrontal cortex (OFC) during the extinction phase, they were unable to use contexts as the reference for proper retrieval of fear memory during renewal test. This result supported the phenomenon that many OCD patients show poor regulation of fear-related behavior. Since there are robust anatomical connections of the OFC with the fear-circuit, we aim to further examine whether the OFC is actively engaged in fear regulation under normal circumstances. In this study, the lateral or medial OFC was inactivated during the extinction phase using the ABA fear renewal procedure. We found that these animals showed intact fear renewal during retrieval test with their freezing levels equivalent to the control rats, revealing that the OFC did not have decisive roles in extinction acquisition. Together with our previous study, we suggest that the OFC only interferes with fear regulation when it becomes pathophysiologically hyperactive.
Collapse
Affiliation(s)
- Cheng-Wei Shih
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Chun-Hui Chang
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 30013, Taiwan; Brain Research Center, National Tsing Hua University, Hsinchu 30013, Taiwan.
| |
Collapse
|
2
|
Hegde P, O'Mara S, Laxmi TR. Extinction of Contextual Fear with Timed Exposure to Enriched Environment: A Differential Effect. Ann Neurosci 2017; 24:90-104. [PMID: 28588364 DOI: 10.1159/000475898] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 01/30/2017] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Extinction of fear memory depends on the environmental and emotional cues. Furthermore, consolidation of extinction is also dependent on the environmental exposure. But, the relationship of the time of the exposure to a variety of environmental cues is not well known. The important region involved in facilitation of extinction of fear memory is through diversion of the flow of information leaving the lateral nucleus of amygdala. PURPOSE The study aimed to address a question to explain how these brain regions react to environmental stimulation during the retention and extinction of fear memory. METHODS An enriched environment (EE) is assumed to mediate extinction of fear memory, we examined the apparent discrepancy between the effects of defensive response, the freezing behavior induced by Pavlovian classical fear conditioning by subjecting them to variance in the timing to EE. The different timing of EE exposure was 10 days of EE either before fear conditioning and/or after extinction training to the rats. The local field potentials was recorded from CA1 hippocampus, lateral nucleus of amygdala and infralimbic region of medial prefrontal cortex (mPFC) during the fear learning and extinction from the control rats and rats exposed to EE before and after fear conditioning. RESULTS Exposure to EE before the fear conditioning and after extinction training was more effective in the extinction fear memory. In addition, we also found switching from exploratory locomotion to freezing during retention of contextual fear memory which was associated with decreased theta power and reduced synchronized theta oscillations in CA1-hippocampus, lateral nucleus of amygdala, and infralimbic region of mPFC. CONCLUSION Thus, we propose that the timing of exposure to EE play a key role in the extinction of fear memory.
Collapse
Affiliation(s)
- Preethi Hegde
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - Shane O'Mara
- School of Psychology and Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
| | - Thenkanidiyoor Rao Laxmi
- Department of Neurophysiology, National Institute of Mental Health and Neurosciences, Bangalore, India
| |
Collapse
|
3
|
Kolu TC. Commentary: Behavior analysis and behavioral neuroscience. Front Hum Neurosci 2016; 10:256. [PMID: 27314216 PMCID: PMC4887495 DOI: 10.3389/fnhum.2016.00256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 05/17/2016] [Indexed: 11/13/2022] Open
|
4
|
Halonen JD, Zoladz PR, Park CR, Diamond DM. Behavioral and Neurobiological Assessments of Predator-Based Fear Conditioning and Extinction. ACTA ACUST UNITED AC 2016. [DOI: 10.4236/jbbs.2016.68033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
5
|
Revillo D, Cotella E, Paglini M, Arias C. Contextual learning and context effects during infancy: 30years of controversial research revisited. Physiol Behav 2015; 148:6-21. [DOI: 10.1016/j.physbeh.2015.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 11/25/2014] [Accepted: 02/03/2015] [Indexed: 12/15/2022]
|
6
|
Krasne FB, Cushman JD, Fanselow MS. A Bayesian context fear learning algorithm/automaton. Front Behav Neurosci 2015; 9:112. [PMID: 26074792 PMCID: PMC4445248 DOI: 10.3389/fnbeh.2015.00112] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/16/2015] [Indexed: 01/10/2023] Open
Abstract
Contextual fear conditioning is thought to involve the synaptic plasticity-dependent establishment in hippocampus of representations of to-be-conditioned contexts which can then become associated with USs in the amygdala. A conceptual and computational model of this process is proposed in which contextual attributes are assumed to be sampled serially and randomly during contextual exposures. Given this assumption, moment-to-moment information about such attributes will often be quite different from one exposure to another and, in particular, between exposures during which representations are created, exposures during which conditioning occurs, and during recall sessions. This presents challenges to current conceptual models of hippocampal function. In order to meet these challenges, our model's hippocampus was made to operate in different modes during representation creation and recall, and non-hippocampal machinery was constructed that controlled these hippocampal modes. This machinery uses a comparison between contextual information currently observed and information associated with existing hippocampal representations of familiar contexts to compute the Bayesian Weight of Evidence that the current context is (or is not) a known one, and it uses this value to assess the appropriateness of creation or recall modes. The model predicts a number of known phenomena such as the immediate shock deficit, spurious fear conditioning to contexts that are absent but similar to actually present ones, and modulation of conditioning by pre-familiarization with contexts. It also predicts a number of as yet unknown phenomena.
Collapse
Affiliation(s)
- Franklin B Krasne
- Department of Psychology, University of California Los Angeles Los Angeles, CA, USA ; Brain Research Institute, University of California Los Angeles Los Angeles, CA, USA
| | - Jesse D Cushman
- Department of Psychology, University of California Los Angeles Los Angeles, CA, USA ; Brain Research Institute, University of California Los Angeles Los Angeles, CA, USA
| | - Michael S Fanselow
- Department of Psychology, University of California Los Angeles Los Angeles, CA, USA ; Brain Research Institute, University of California Los Angeles Los Angeles, CA, USA ; Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles Los Angeles, CA, USA
| |
Collapse
|
7
|
Acute neuroinflammation impairs context discrimination memory and disrupts pattern separation processes in hippocampus. J Neurosci 2015; 34:12470-80. [PMID: 25209285 DOI: 10.1523/jneurosci.0542-14.2014] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Although it is known that immune system activation can impair cognition, no study to date has linked cognitive deficits during acute neuroinflammation to dysregulation of task-relevant neuronal ensemble activity. Here, we assessed both neural circuit activity and context discrimination memory retrieval, in a within-subjects design, of male rats given systemic administration of saline or lipopolysaccharide (LPS). Rats were exposed over several days to two similar contexts: one of which was paired with weak foot shock and the other was not. After reaching criteria for discriminative freezing, rats were given systemic LPS or saline injection and tested for retrieval of context discrimination 6 h later. Importantly, LPS administration produced an acute neuroinflammatory response in dorsal hippocampus at this time (as assessed by elevation of proinflammatory cytokine mRNA levels) and abolished retrieval of the previously acquired discrimination. The impact of neuroinflammation on hippocampal CA3 and CA1 neural circuit activity was assessed using the Arc/Homer1a cellular analysis of temporal activity by fluorescence in situ hybridization imaging method. Whereas the saline-treated subjects discriminated and had low overlap of hippocampal ensembles activated in the two contexts, LPS-treated subjects did not discriminate and had greater ensemble overlap (i.e., reduced orthogonalization). Additionally, retrieval of standard contextual fear conditioning, which does not require context discrimination, was not affected by pretesting LPS administration. Together, the behavioral and circuit analyses data provide compelling evidence that LPS administration impairs context discrimination memory by disrupting cellular pattern separation processes within the hippocampus, thus linking acute neuroinflammation to disruption of specific neural circuit functions and cognitive impairment.
Collapse
|
8
|
Gulbrandsen TL, Sutherland RJ. Temporary inactivation of the rodent hippocampus: An evaluation of the current methodology. J Neurosci Methods 2014; 225:120-8. [DOI: 10.1016/j.jneumeth.2014.01.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 01/14/2014] [Accepted: 01/16/2014] [Indexed: 11/24/2022]
|
9
|
Cox D, Czerniawski J, Ree F, Otto T. Time course of dorsal and ventral hippocampal involvement in the expression of trace fear conditioning. Neurobiol Learn Mem 2013; 106:316-23. [PMID: 23747568 DOI: 10.1016/j.nlm.2013.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 05/21/2013] [Accepted: 05/24/2013] [Indexed: 11/25/2022]
Abstract
While a number of early studies demonstrated that hippocampal damage attenuates the expression of recent, but not remotely trained tasks, an emerging body of evidence has shown that damage to, or inactivation of, the hippocampus often impairs recall across a wide range of training-testing intervals. Collectively, these data suggest that the time course of hippocampal involvement in the storage or recall of previously-acquired memories may differ according to hippocampal subregion and the particular learning task under consideration. The present study examined the contributions of dorsal (DH) and ventral (VH) hippocampus to the expression of previously-acquired trace fear conditioning, a form of Pavlovian conditioning in which the offset of an initially neutral cue or cues and the onset of an aversive stimulus is separated by a temporal (trace) interval. Specifically, either saline or the GABA-A agonist muscimol was infused into DH or VH prior to testing either 1, 7, 28, or 42 days after trace fear conditioning. The results revealed a marked dissociation: pre-testing inactivation of DH failed to impair performance at any time-point, while pre-testing inactivation of VH impaired performance at all time-points. Importantly, pre-testing inactivation of VH had no effect on the performance of previously-acquired delay conditioning, suggesting that the deficits observed in trace conditioning cannot be attributed to a deficit in performance of the freezing response. Collectively, these data suggest that VH, but not DH, remains a neuroanatomical locus critical to the recall or expression of trace fear conditioning over an extended period of time.
Collapse
Affiliation(s)
- David Cox
- Program in Behavioral and Systems Neuroscience, Department of Psychology, Rutgers University, 152 Frelinghuysen Rd., Piscataway, NJ 08854, USA.
| | | | | | | |
Collapse
|
10
|
Wheeler DS, Chang SE, Holland PC. Odor-mediated taste learning requires dorsal hippocampus, but not basolateral amygdala activity. Neurobiol Learn Mem 2013; 101:1-7. [PMID: 23274135 PMCID: PMC3602369 DOI: 10.1016/j.nlm.2012.12.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 12/17/2012] [Accepted: 12/18/2012] [Indexed: 10/27/2022]
Abstract
Mediated learning is a unique cognitive phenomenon in which mental representations of physically absent stimuli enter into associations with directly-activated representations of physically present stimuli. Three experiments investigated the functional physiology of mediated learning involving the use of odor-taste associations. In Experiments 1a and 1b, basolateral amygdala lesions failed to attenuate mediated taste aversion learning. In Experiment 2, dorsal hippocampus inactivation impaired mediated learning, but left direct learning intact. Considered with past studies, the results implicate the dorsal hippocampus in mediated learning generally, and suggest a limit on the importance of the basolateral amygdala.
Collapse
Affiliation(s)
- Daniel S Wheeler
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
| | | | | |
Collapse
|
11
|
Kranjac D, McLinden KA, Deodati LE, Papini MR, Chumley MJ, Boehm GW. Peripheral bacterial endotoxin administration triggers both memory consolidation and reconsolidation deficits in mice. Brain Behav Immun 2012; 26:109-21. [PMID: 21889586 DOI: 10.1016/j.bbi.2011.08.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/18/2011] [Accepted: 08/18/2011] [Indexed: 10/17/2022] Open
Abstract
Peripherally administered inflammatory stimuli, such as lipopolysaccharide (LPS), induce the synthesis and release of proinflammatory cytokines and chemokines in the periphery and the central nervous system, and trigger a variety of neurobiological responses. Indeed, prior reports indicate that peripheral LPS administration in rats disrupts contextual fear memory consolidation processes, potentially due to elevated cytokine expression. We used a similar, but partially olfaction-based, contextual fear conditioning paradigm to examine the effects of LPS on memory consolidation and reconsolidation in mice. Additionally, interleukin-1β (IL-1β), brain-derived neurotrophic factor (BDNF), and zinc finger (Zif)-268 mRNA expression in the hippocampus and the cortex, along with peripheral cytokines and chemokines, were assessed. As hypothesized, LPS administered immediately or 2 h, but not 12 h, post-training impaired memory consolidation processes that support the storage of the conditioned contextual fear memory. Additionally, as hypothesized, LPS administered immediately following the fear memory trace reactivation session impaired memory reconsolidation processes. Four hours post-injection, both central cytokine and peripheral cytokine and chemokine levels were heightened in LPS-treated animals, with a simultaneous decrease in BDNF, but not Zif-268, mRNA. Collectively, these data reinforce prior work showing LPS- and cytokine-related effects on memory consolidation, and extend this work to memory reconsolidation.
Collapse
Affiliation(s)
- Dinko Kranjac
- Department of Psychology, Texas Christian University, Fort Worth, TX 76129, USA
| | | | | | | | | | | |
Collapse
|
12
|
Krasne FB, Fanselow MS, Zelikowsky M. Design of a neurally plausible model of fear learning. Front Behav Neurosci 2011; 5:41. [PMID: 21845175 PMCID: PMC3145244 DOI: 10.3389/fnbeh.2011.00041] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/07/2011] [Indexed: 01/07/2023] Open
Abstract
A neurally oriented conceptual and computational model of fear conditioning manifested by freezing behavior (FRAT), which accounts for many aspects of delay and context conditioning, has been constructed. Conditioning and extinction are the result of neuromodulation-controlled LTP at synapses of thalamic, cortical, and hippocampal afferents on principal cells and inhibitory interneurons of lateral and basal amygdala. The phenomena accounted for by the model (and simulated by the computational version) include conditioning, secondary reinforcement, blocking, the immediate shock deficit, extinction, renewal, and a range of empirically valid effects of pre- and post-training ablation or inactivation of hippocampus or amygdala nuclei.
Collapse
Affiliation(s)
- Franklin B Krasne
- Department of Psychology, University of California Los Angeles Los Angeles, CA, USA
| | | | | |
Collapse
|
13
|
Time-limited involvement of dorsal hippocampus in unimodal discriminative contextual conditioning. Neurobiol Learn Mem 2010; 94:481-7. [PMID: 20816992 DOI: 10.1016/j.nlm.2010.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2010] [Revised: 08/23/2010] [Accepted: 08/26/2010] [Indexed: 11/21/2022]
Abstract
Converging evidence examining the effects of post-training manipulations of the hippocampus suggests that the hippocampus may play a time-limited role in the maintenance of a variety of forms of memory. In particular, either lesions or inactivation of the dorsal hippocampus results in many cases in a time-limited retrograde impairment in nondiscriminative contextual conditioning paradigms. However, the extent to which hippocampal manipulations result in a time-limited retrograde amnesia for a variety of forms of learning has recently been called into question (reviewed in Sutherland, Sparks, & Lehmann (2010)). The present study examined the effect of inactivation of the dorsal hippocampus either 7, 28, or 42 days following training in an explicitly nonspatial, discriminative contextual conditioning paradigm (Otto & Poon, 2006; Parsons & Otto, 2008). Inactivation of the dorsal hippocampus resulted in a significant deficit in the expression of contextual conditioning at 7 and 28 days, but not 42 days, following training. Importantly, inactivation of the hippocampus did not affect either baseline freezing levels or conditioning to an explicit CS. Together with previous data exploring hippocampal contributions to discriminative unimodal contextual conditioning, these data suggest that the hippocampus may play a particularly prominent role in the temporary maintenance of memory in discriminative contextual paradigms.
Collapse
|
14
|
Salehi A, Faizi M, Colas D, Valletta J, Laguna J, Takimoto-Kimura R, Kleschevnikov A, Wagner SL, Aisen P, Shamloo M, Mobley WC. Restoration of Norepinephrine-Modulated Contextual Memory in a Mouse Model of Down Syndrome. Sci Transl Med 2009; 1. [DOI: 10.1126/scitranslmed.3000258] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Cognitive deficits in mice with a Down syndrome–like genetic defect can be reversed with precursors to the neurotransmitter norepinephrine.
Collapse
Affiliation(s)
- A. Salehi
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA 94305, USA
| | - M. Faizi
- Behavioral and Functional Neuroscience Laboratory, Stanford Medical School, Stanford, CA 94305, USA
| | - D. Colas
- Department of Biology, Stanford Medical School, Stanford, CA 94305, USA
| | - J. Valletta
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA 94305, USA
| | - J. Laguna
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA 94305, USA
| | - R. Takimoto-Kimura
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA 94305, USA
| | - A. Kleschevnikov
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA 94305, USA
| | - S. L. Wagner
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - P. Aisen
- Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - M. Shamloo
- Behavioral and Functional Neuroscience Laboratory, Stanford Medical School, Stanford, CA 94305, USA
| | - W. C. Mobley
- Department of Neurology and Neurological Sciences, Stanford Medical School, Stanford, CA 94305, USA
| |
Collapse
|
15
|
Walker DL, Miles LA, Davis M. Selective participation of the bed nucleus of the stria terminalis and CRF in sustained anxiety-like versus phasic fear-like responses. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:1291-308. [PMID: 19595731 PMCID: PMC2783512 DOI: 10.1016/j.pnpbp.2009.06.022] [Citation(s) in RCA: 258] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2009] [Revised: 06/26/2009] [Accepted: 06/29/2009] [Indexed: 01/09/2023]
Abstract
The medial division of the central nucleus of the amygdala (CeA(M)) and the lateral division of the bed nucleus of the stria terminalis (BNST(L)) are closely related. Both receive projections from the basolateral amygdala (BLA) and both project to brain areas that mediate fear-influenced behaviors. In contrast to CeA(M) however, initial attempts to implicate the BNST in conditioned fear responses were largely unsuccessful. More recent studies have shown that the BNST does participate in some types of anxiety and stress responses. Here, we review evidence suggesting that the CeA(M) and BNST(L) are functionally complementary, with CeA(M) mediating short- but not long-duration threat responses (i.e., phasic fear) and BNST(L) mediating long- but not short-duration responses (sustained fear or 'anxiety'). We also review findings implicating the stress-related peptide corticotropin-releasing factor (CRF) in sustained but not phasic threat responses, and attempt to integrate these findings into a neural circuit model which accounts for these and related observations.
Collapse
Affiliation(s)
- D. L. Walker
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA, USA,Correspondence should be addressed to: David L. Walker, Emory University School of Medicine, 954 Gatewood Road NE, Yerkes Neurosci Bldg – Rm 5214, Atlanta, GA 30329, Ph: (404) 727-3587, Fax: (404) 727-8070,
| | | | - M. Davis
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, GA, USA,The Center for Behavior Neurosci, Emory University, Atlanta, GA, USA
| |
Collapse
|
16
|
Czerniawski J, Yoon T, Otto T. Dissociating space and trace in dorsal and ventral hippocampus. Hippocampus 2009; 19:20-32. [PMID: 18651617 DOI: 10.1002/hipo.20469] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Emerging evidence suggests that the hippocampus can be anatomically and functionally dissociated along its septotemporal axis into dorsal and ventral subregions. With respect to function, we have recently demonstrated that pre-training excitotoxic lesions of ventral, but not dorsal, hippocampus impair the acquisition of trace fear conditioning, whereas post-training lesions of either dorsal or ventral hippocampus impair the subsequent expression of trace fear conditioning (Yoon and Otto (2007) Neurobiol Learn Mem 87:464-475). In addition to trace fear conditioning, dorsal and ventral hippocampus appear to be differentially involved in a number of spatial memory tasks. The present study examined the effects of temporary inactivation of dorsal or ventral hippocampus on the acquisition and expression of trace fear conditioning and on performance of a spatial delayed reinforced alternation task. The findings demonstrate a double dissociation of dorsal and ventral hippocampal function: inactivation of ventral, but not dorsal, hippocampus attenuated the acquisition and expression of trace fear conditioning, whereas inactivation of dorsal, but not ventral, hippocampus dramatically impaired performance in the delayed reinforced alternation task. These data further support the notion that dorsal and ventral hippocampus contribute differentially to performance in a variety of paradigms.
Collapse
|
17
|
Welinder PE, Burak Y, Fiete IR. Grid cells: the position code, neural network models of activity, and the problem of learning. Hippocampus 2009; 18:1283-300. [PMID: 19021263 DOI: 10.1002/hipo.20519] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We review progress on the modeling and theoretical fronts in the quest to unravel the computational properties of the grid cell code and to explain the mechanisms underlying grid cell dynamics. The goals of the review are to outline a coherent framework for understanding the dynamics of grid cells and their representation of space; to critically present and draw contrasts between recurrent network models of grid cells based on continuous attractor dynamics and independent-neuron models based on temporal interference; and to suggest open questions for experiment and theory.
Collapse
Affiliation(s)
- Peter E Welinder
- Computation and Neural Systems, California Institute of Technology, Pasadena, California, USA
| | | | | |
Collapse
|