1
|
Sheynikhovich D, Otani S, Bai J, Arleo A. Long-term memory, synaptic plasticity and dopamine in rodent medial prefrontal cortex: Role in executive functions. Front Behav Neurosci 2023; 16:1068271. [PMID: 36710953 PMCID: PMC9875091 DOI: 10.3389/fnbeh.2022.1068271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/26/2022] [Indexed: 01/12/2023] Open
Abstract
Mnemonic functions, supporting rodent behavior in complex tasks, include both long-term and (short-term) working memory components. While working memory is thought to rely on persistent activity states in an active neural network, long-term memory and synaptic plasticity contribute to the formation of the underlying synaptic structure, determining the range of possible states. Whereas, the implication of working memory in executive functions, mediated by the prefrontal cortex (PFC) in primates and rodents, has been extensively studied, the contribution of long-term memory component to these tasks received little attention. This review summarizes available experimental data and theoretical work concerning cellular mechanisms of synaptic plasticity in the medial region of rodent PFC and the link between plasticity, memory and behavior in PFC-dependent tasks. A special attention is devoted to unique properties of dopaminergic modulation of prefrontal synaptic plasticity and its contribution to executive functions.
Collapse
Affiliation(s)
- Denis Sheynikhovich
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France,*Correspondence: Denis Sheynikhovich ✉
| | - Satoru Otani
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jing Bai
- Institute of Psychiatry and Neuroscience of Paris, INSERM U1266, Paris, France
| | - Angelo Arleo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| |
Collapse
|
2
|
Liu J, Zheng L, Fang T, Li R, Ma X, Sun Y, Wang L, Tian H, Jiang D, Zhuo C. Exploration of the cortical pathophysiology underlying visual disturbances in schizophrenia comorbid with depressive disorder-An evidence from mouse model. Brain Behav 2021; 11:e02113. [PMID: 33729680 PMCID: PMC8119859 DOI: 10.1002/brb3.2113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/01/2021] [Accepted: 03/01/2021] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION Patients with schizophrenia frequently present with visual disturbances including hallucination, and this symptom is particularly prevalent in individuals with comorbid depressive disorders. Currently, little is known about the neurobiological mechanisms of such psychiatric symptoms, and few explanations for the co-occurrence of schizophrenia, depression, and visual disturbances are available. METHODS In this study, we generated a mouse schizophrenia model in which depressive symptoms were also induced. We adopted in vivo two-photon calcium imaging and ex vivo electrophysiological recording of the primary visual cortex to reveal the synaptic transmission and neural activity in the mouse schizophrenia model. RESULTS In vivo two-photon calcium imaging and ex vivo electrophysiological recording of the primary visual cortex revealed impaired synaptic transmission and abnormal neural activity in the schizophrenia model, but not in the depression model. These functional deficits were most prominent in the combined schizophrenia and depression model. CONCLUSION Overall, our data support a mechanism by which the visual cortex plays a role in visual disturbances in schizophrenia.
Collapse
Affiliation(s)
- Jian Liu
- Laboratory of Psychiatric-Neuroimaging-Genetic and Cor-morbidity (PNGC_Lab), Tianjin Anding Hospital, Mental Health Centre of Tianjin, Affiliated Teaching Hospital of Tianjin Medical University, Tianjin, China
| | - Lidan Zheng
- Department of Psychiatry, Wenzhou Seventh Peoples Hospital, Wenzhou, China
| | - Tao Fang
- Key Laboratory of Real-Time Tracing of Brain Circuits of Neurology and Psychiatry (RTBNB_Lab), Tianjin Fourth Centre Hospital, Tianjin Medical University Affiliated Tianjin Fourth Centre Hospital, Nankai University Affiliated Fourth Hospital, Tianjin, China
| | - Ranli Li
- Laboratory of Psychiatric-Neuroimaging-Genetic and Cor-morbidity (PNGC_Lab), Tianjin Anding Hospital, Mental Health Centre of Tianjin, Affiliated Teaching Hospital of Tianjin Medical University, Tianjin, China
| | - Xiaoyan Ma
- Laboratory of Psychiatric-Neuroimaging-Genetic and Cor-morbidity (PNGC_Lab), Tianjin Anding Hospital, Mental Health Centre of Tianjin, Affiliated Teaching Hospital of Tianjin Medical University, Tianjin, China
| | - Yun Sun
- Laboratory of Psychiatric-Neuroimaging-Genetic and Cor-morbidity (PNGC_Lab), Tianjin Anding Hospital, Mental Health Centre of Tianjin, Affiliated Teaching Hospital of Tianjin Medical University, Tianjin, China
| | - Lina Wang
- Laboratory of Psychiatric-Neuroimaging-Genetic and Cor-morbidity (PNGC_Lab), Tianjin Anding Hospital, Mental Health Centre of Tianjin, Affiliated Teaching Hospital of Tianjin Medical University, Tianjin, China
| | - Hongjun Tian
- Key Laboratory of Real-Time Tracing of Brain Circuits of Neurology and Psychiatry (RTBNB_Lab), Tianjin Fourth Centre Hospital, Tianjin Medical University Affiliated Tianjin Fourth Centre Hospital, Nankai University Affiliated Fourth Hospital, Tianjin, China
| | - Deguo Jiang
- Department of Psychiatry, Wenzhou Seventh Peoples Hospital, Wenzhou, China
| | - Chuanjun Zhuo
- Laboratory of Psychiatric-Neuroimaging-Genetic and Cor-morbidity (PNGC_Lab), Tianjin Anding Hospital, Mental Health Centre of Tianjin, Affiliated Teaching Hospital of Tianjin Medical University, Tianjin, China.,Department of Psychiatry, Wenzhou Seventh Peoples Hospital, Wenzhou, China.,Key Laboratory of Real-Time Tracing of Brain Circuits of Neurology and Psychiatry (RTBNB_Lab), Tianjin Fourth Centre Hospital, Tianjin Medical University Affiliated Tianjin Fourth Centre Hospital, Nankai University Affiliated Fourth Hospital, Tianjin, China
| |
Collapse
|
3
|
Gilmore CS, Camchong J, Davenport ND, Nelson NW, Kardon RH, Lim KO, Sponheim SR. Deficits in Visual System Functional Connectivity after Blast-Related Mild TBI are Associated with Injury Severity and Executive Dysfunction. Brain Behav 2016; 6:e00454. [PMID: 27257516 PMCID: PMC4873652 DOI: 10.1002/brb3.454] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 02/12/2016] [Accepted: 02/15/2016] [Indexed: 01/12/2023] Open
Abstract
INTRODUCTION Approximately, 275,000 American service members deployed to Iraq or Afghanistan have sustained a mild traumatic brain injury (mTBI), with 75% of these incidents involving an explosive blast. Visual processing problems and cognitive dysfunction are common complaints following blast-related mTBI. METHODS In 127 veterans, we examined resting fMRI functional connectivity (FC) of four key nodes within the visual system: lateral geniculate nucleus (LGN), primary visual cortex (V1), lateral occipital gyrus (LO), and fusiform gyrus (FG). Regression analyses were performed (i) to obtain correlations between time-series from each seed and all voxels in the brain, and (ii) to identify brain regions in which FC variability was related to blast mTBI severity. Blast-related mTBI severity was quantified as the sum of the severity scores assigned to each of the three most significant blast-related injuries self-reported by subjects. Correlations between FC and performance on executive functioning tasks were performed across participants with available behavioral data (n = 94). RESULTS Greater blast mTBI severity scores were associated with lower FC between: (A) LGN seed and (i) medial frontal gyrus, (ii) lingual gyrus, and (iii) right ventral anterior nucleus of thalamus; (B) V1 seed and precuneus; (C) LO seed and middle and superior frontal gyri; (D) FG seed and (i) superior and medial frontal gyrus, and (ii) left middle frontal gyrus. Finally, lower FC between visual network regions and frontal cortical regions predicted worse performance on the WAIS digit-symbol coding task. CONCLUSION These are the first published results that directly illustrate the relationship between blast-related mTBI severity, visual pathway neural networks, and executive dysfunction - results that highlight the detrimental relationship between blast-related brain injury and the integration of visual sensory input and executive processes.
Collapse
Affiliation(s)
- Casey S. Gilmore
- Defense and Veterans Brain Injury CenterMinneapolisMinnesota
- Minneapolis Veterans Affairs Health Care SystemMinneapolisMinnesota
| | - Jazmin Camchong
- Department of PsychiatryUniversity of MinnesotaMinneapolisMinnesota
| | - Nicholas D. Davenport
- Minneapolis Veterans Affairs Health Care SystemMinneapolisMinnesota
- Department of PsychiatryUniversity of MinnesotaMinneapolisMinnesota
| | - Nathaniel W. Nelson
- Minneapolis Veterans Affairs Health Care SystemMinneapolisMinnesota
- Univ. of St. ThomasGraduate School of Professional PsychologyMinneapolisMinnesota
| | - Randy H. Kardon
- Department of Ophthalmology & Visual ScienceUniversity of IowaIowa CityIowa
- Iowa City Veterans Affairs Health Care SystemIowa CityIowa
| | - Kelvin O. Lim
- Defense and Veterans Brain Injury CenterMinneapolisMinnesota
- Minneapolis Veterans Affairs Health Care SystemMinneapolisMinnesota
- Department of PsychiatryUniversity of MinnesotaMinneapolisMinnesota
| | - Scott R. Sponheim
- Minneapolis Veterans Affairs Health Care SystemMinneapolisMinnesota
- Department of PsychiatryUniversity of MinnesotaMinneapolisMinnesota
| |
Collapse
|
4
|
Banks PJ, Bashir ZI, Brown MW. Recognition memory and synaptic plasticity in the perirhinal and prefrontal cortices. Hippocampus 2013; 22:2012-31. [PMID: 22987679 DOI: 10.1002/hipo.22067] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Work is reviewed that relates recognition memory to studies of synaptic plasticity mechanisms in perirhinal and prefrontal cortices. The aim is to consider evidence that perirhinal cortex and medial prefrontal cortex store rather than merely transmit information necessary for recognition memory and, if so, to consider what mechanisms are potentially available within these cortices for producing such storage through synaptic change. Interventions with known actions on plasticity mechanisms are reviewed in relation to their effects on recognition memory processes. These interventions importantly include those involving antagonism of glutamatergic and cholinergic receptors but also inhibition of plasticity consolidation and expression mechanisms. It is concluded that there is strong evidence that perirhinal cortex is involved in information storage necessary for object recognition memory and, moreover, that such storage involves synaptic weakening mechanisms including the removal of AMPA glutamate receptors from synapses. There is good evidence that medial prefrontal cortex is necessary for associative and temporal order recognition memory and that this cortex expresses plasticity mechanisms that potentially allow the storage of information. However, the case for medial prefrontal cortex acting as a store requires further support.
Collapse
|
5
|
Zhang ZW, Kang JI, Vaucher E. Axonal varicosity density as an index of local neuronal interactions. PLoS One 2011; 6:e22543. [PMID: 21811630 PMCID: PMC3141066 DOI: 10.1371/journal.pone.0022543] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 06/29/2011] [Indexed: 01/09/2023] Open
Abstract
Diffuse transmission is an important non-synaptic communication mode in the cerebral neocortex, in which neurotransmitters released from en passant varicosities interact with surrounding cells. In a previous study we have shown that the cholinergic axonal segments which were in the microproximity with dopaminergic fibers possessed a greater density of en passant varicosities compared to more distant segments, suggesting an activity-dependent level of en passant varicosities in the axonal zone of interaction. To further evaluate this plastic relationship, the density of cholinergic varicosities was quantified on fiber segments within the microproximity of activated or non-activated pyramidal cells of the prefrontal cortex (mPFC). Repetitive 14 days patterned visual stimulation paired with an electrical stimulation of the cholinergic fibers projecting to the mPFC from the HDB was performed to induce persistent axonal plastic changes. The c-Fos early gene immunoreactivity was used as a neuronal activity marker of layer V pyramidal cells, labelled with anti-glutamate transporter EAAC1. Cholinergic fibers were labeled with anti-ChAT (choline acetyltransferase) immunostaining. The density of ChAT+ varicosities on and the length of fiber segments within the 3 µm microproximity of c-Fos positive/negative pyramidal cells were evaluated on confocal images. More than 50% of the pyramidal cells in the mPFC were c-Fos immunoreactive. Density of ChAT+ varicosities was significantly increased within 3 µm vicinity of activated pyramidal cells (0.50±0.01 per µm of ChAT+ fiber length) compared to non-activated cells in this group (0.34±0.001; p≤0.05) or control rats (0.32±0.02; p≤0.05). Different types of stimulation (visual, HDB or visual/HDB) induced similar increase of the density of ChAT+ varicosities within microproximity of activated pyramidal cells. This study demonstrated at the subcellular level an activity-dependent enrichment of ChAT+ varicosities in the axonal zone of interaction with other neuronal elements.
Collapse
Affiliation(s)
- Zi-Wei Zhang
- School of Optometry, Université de Montréal, Montréal, Quebec, Canada
- Department of Physiology, Université de Montréal, Montréal, Quebec, Canada
| | - Jun Il Kang
- School of Optometry, Université de Montréal, Montréal, Quebec, Canada
- Department of Physiology, Université de Montréal, Montréal, Quebec, Canada
| | - Elvire Vaucher
- School of Optometry, Université de Montréal, Montréal, Quebec, Canada
- * E-mail:
| |
Collapse
|
6
|
Goto Y, Yang CR, Otani S. Functional and dysfunctional synaptic plasticity in prefrontal cortex: roles in psychiatric disorders. Biol Psychiatry 2010; 67:199-207. [PMID: 19833323 DOI: 10.1016/j.biopsych.2009.08.026] [Citation(s) in RCA: 227] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Revised: 08/19/2009] [Accepted: 08/20/2009] [Indexed: 12/12/2022]
Abstract
Prefrontal cortex (PFC) mediates an assortment of cognitive functions including working memory, behavioral flexibility, attention, and future planning. Unlike the hippocampus, where induction of synaptic plasticity in the network is well-documented in relation to long-term memory, cognitive functions mediated by the PFC have been thought to be independent of long-lasting neuronal adaptation of the network. Nonetheless, accumulating evidence suggests that prefrontal cortical neurons possess the cellular machinery of synaptic plasticity and exhibit lasting changes of neural activity associated with various cognitive processes. Moreover, deficits in the mechanisms of synaptic plasticity induction in the PFC might be involved in the pathophysiology of psychiatric and neurological disorders such as schizophrenia, drug addiction, mood disorders, and Alzheimer's disease.
Collapse
Affiliation(s)
- Yukiori Goto
- Department of Psychiatry, McGill University, Montreal, Quebec H3A 1A1, Canada.
| | | | | |
Collapse
|
7
|
Abstract
Neuropsychological and neuroimaging studies in humans have shown that the prefrontal cortex (PFC) is involved in long-term memory functioning. In general, the participation of the PFC in long-term memory has been attributed to its role in executive control rather than information storage. Accumulating data from recent animal studies, however, suggest the possible role of the PFC in the storage of long-term memory. In support of this view, there is evidence that various projection systems in the PFC support long-term synaptic plasticity. Recording studies have further demonstrated neural correlates of learning in various animal species. Lastly, behavioral and physiological studies indicate that the PFC is critically involved in memory consolidation, retrieval and extinction processes. These studies then suggest that the PFC is an integral part of the neural network where long-term memory trace is stored and retrieved. Though decisive evidence is still lacking at present, we propose here to assign a term 'control memory' (i.e., memory for top-down control processes) as a new type of memory function for the PFC. This new principle of PFC-long-term memory can help organize existing data and provide novel insights into future empirical studies.
Collapse
Affiliation(s)
- Min Whan Jung
- Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon, Korea.
| | | | | | | | | |
Collapse
|
8
|
Effects of methamphetamine on single unit activity in rat medial prefrontal cortex in vivo. Neural Plast 2008; 2007:29821. [PMID: 18288241 PMCID: PMC2220029 DOI: 10.1155/2007/29821] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Revised: 06/14/2007] [Accepted: 06/14/2007] [Indexed: 11/17/2022] Open
Abstract
To investigate how neuronal activity in the prefrontal cortex changes in an animal model of schizophrenia, we recorded single unit activity in the medial prefrontal cortex of urethane-anesthetized and awake rats following methamphetamine (MA) administration. Systemic MA injection (4 mg/kg, IP) induced inconsistent changes, that is, both enhancement and reduction, in unit discharge rate, with a subset of neurons transiently (<30 min) elevating their activities. The direction of firing rate change was poorly predicted by the mean firing rate or the degree of burst firing during the baseline period. Also, simultaneously recorded units showed opposite directions of firing rate change, indicating that recording location is a poor predictor of the direction of firing rate change. These results raise the possibility that systemic MA injection induces random bidirectional changes in prefrontal cortical unit activity, which may underlie some of MA-induced psychotic symptoms.
Collapse
|
9
|
Baeg EH, Kim YB, Kim J, Ghim JW, Kim JJ, Jung MW. Learning-induced enduring changes in functional connectivity among prefrontal cortical neurons. J Neurosci 2007; 27:909-18. [PMID: 17251433 PMCID: PMC6672909 DOI: 10.1523/jneurosci.4759-06.2007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Current thinking about how memories are stored in the brain has been profoundly influenced by Donald O. Hebb's cell assembly hypothesis, which posits that (1) learning produces a stable alteration in patterns of connectivity among repeatedly coactivated neurons, and (2) memory retrieval involves reactivation of those altered patterns of connectivity. However, learning-induced changes in connectivity that persist over long periods of time have not been clearly demonstrated. In the present study, two spatial navigation tasks and a long-term ensemble recording technique are used to describe long-lasting modifications in functional connectivity (FC) (defined as changes in synchronous firing) of prefrontal cortical neurons in behaving rats. Animals were initially trained to alternate visiting two spatial locations on a figure-8-shaped maze to obtain a reward (alternating task 1). Afterward, while continuing on task 1, animals were additionally trained to visit only one spatial location on the same maze to obtain a reward (unilateral task 2). Multiple single units were recorded while rats were undergoing acquisition, retention, and performance of both tasks. Our data indicate that correlated firing of prefrontal cortical neurons changed significantly in early phases of training when learning rate was maximal but became progressively smaller in later phases when learning reached asymptote. After animals became proficient, FC remained constant, although neuronal activities varied across two different tasks. The present finding of negatively accelerated changes in FC confirms associative learning theories and provides crucial neurophysiological evidence for Hebb's hypothesis.
Collapse
Affiliation(s)
- Eun H. Baeg
- Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Yun B. Kim
- Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Jieun Kim
- Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea
| | - Jeong-Wook Ghim
- Department of Physics, Pohang Institute of Science and Technology, Pohang 790-784, Korea, and
| | - Jeansok J. Kim
- Department of Psychology and Program in Neurobiology and Behavior, University of Washington, Seattle, Washington 98195-1525
| | - Min W. Jung
- Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon 443-721, Korea
| |
Collapse
|
10
|
Dere E, Huston JP, De Souza Silva MA. The pharmacology, neuroanatomy and neurogenetics of one-trial object recognition in rodents. Neurosci Biobehav Rev 2007; 31:673-704. [PMID: 17368764 DOI: 10.1016/j.neubiorev.2007.01.005] [Citation(s) in RCA: 524] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2006] [Revised: 01/08/2007] [Accepted: 01/18/2007] [Indexed: 01/31/2023]
Abstract
Rats and mice are attracted by novel objects. They readily approach novel objects and explore them with their vibrissae, nose and forepaws. It is assumed that such a single explorative episode leaves a lasting and complex memory trace, which includes information about the features of the object explored, as well as where and even when the object was encountered. Indeed, it has been shown that rodents are able to discriminate a novel from a familiar object (one-trial object recognition), can detect a mismatch between the past and present location of a familiar object (one-trial object-place recognition), and can discriminate different objects in terms of their relative recency (temporal order memory), i.e., which one of two objects has been encountered earlier. Since the novelty-preference paradigm is very versatile and has some advantages compared to several other memory tasks, such as the water maze, it has become a powerful tool in current neurophamacological, neuroanatomical and neurogenetical memory research using both rats and mice. This review is intended to provide a comprehensive summary on key findings delineating the brain structures, neurotransmitters, molecular mechanisms and genes involved in encoding, consolidation, storage and retrieval of different forms of one-trial object memory in rats and mice.
Collapse
Affiliation(s)
- Ekrem Dere
- Institute of Physiological Psychology, and Center for Biological and Medical Research, Heinrich-Heine-University of Düsseldorf, Düsseldorf, Germany.
| | | | | |
Collapse
|
11
|
Di Pietro NC, Black YD, Green-Jordan K, Eichenbaum HB, Kantak KM. Complementary Tasks to Measure Working Memory in Distinct Prefrontal Cortex Subregions in Rats. Behav Neurosci 2004; 118:1042-51. [PMID: 15506886 DOI: 10.1037/0735-7044.118.5.1042] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Acquisition of odor-guided or visually-guided delayed win-shift behavior was evaluated in rats after lidocaine-induced inactivation within the agranular insular area of the prefrontal cortex (PFC) or the prelimbic area of the PFC. Additional sites and tasks were used to control for neuroanatomical and behavioral specificity of lidocaine inactivation of the agranular insular and prelimbic areas. Results showed that acquisition of the odor-guided delayed win-shift task was dependent on the agranular insular area, whereas acquisition of the visually-guided version was dependent on the prelimbic area. This dissociation suggests that the stimulus modality used is critical for revealing working memory functions of different PFC subregions. The described methods provide a complementary means to study working memory in PFC subregions using a radial-arm maze.
Collapse
Affiliation(s)
- Nina C Di Pietro
- Laboratory of Behavioral Neuroscience, Department of Psychology and Program in Neuroscience, Boston University, Boston, MA 02215, USA
| | | | | | | | | |
Collapse
|
12
|
Baeg EH, Kim YB, Huh K, Mook-Jung I, Kim HT, Jung MW. Dynamics of population code for working memory in the prefrontal cortex. Neuron 2003; 40:177-88. [PMID: 14527442 DOI: 10.1016/s0896-6273(03)00597-x] [Citation(s) in RCA: 245] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Some neurons (delay cells) in the prefrontal cortex elevate their activities throughout the time period during which the animal is required to remember past events and prepare future behavior, suggesting that working memory is mediated by continuous neural activity. It is unknown, however, how working memory is represented within a population of prefrontal cortical neurons. We recorded from neuronal ensembles in the prefrontal cortex as rats learned a new delayed alternation task. Ensemble activities changed in parallel with behavioral learning so that they increasingly allowed correct decoding of previous and future goal choices. In well-trained rats, considerable decoding was possible based on only a few neurons and after removing continuously active delay cells. These results show that neural activity in the prefrontal cortex changes dynamically during new task learning so that working memory is robustly represented and that working memory can be mediated by sequential activation of different neural populations.
Collapse
Affiliation(s)
- E H Baeg
- Neuroscience Laboratory, Institute for Medical Sciences, Ajou University School of Medicine, Suwon 442-721, South Korea
| | | | | | | | | | | |
Collapse
|