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Ku SP, Nakamura NH, Maingret N, Mahnke L, Yoshida M, Sauvage MM. Regional Specific Evidence for Memory-Load Dependent Activity in the Dorsal Subiculum and the Lateral Entorhinal Cortex. Front Syst Neurosci 2017; 11:51. [PMID: 28790897 PMCID: PMC5524887 DOI: 10.3389/fnsys.2017.00051] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 07/03/2017] [Indexed: 11/13/2022] Open
Abstract
The subiculum and the lateral entorhinal cortex (LEC) are the main output areas of the hippocampus which contribute to spatial and non-spatial memory. The proximal part of the subiculum (bordering CA1) receives heavy projections from the perirhinal cortex and the distal part of CA1 (bordering the subiculum), both known for their ties to object recognition memory. However, the extent to which the proximal subiculum contributes to non-spatial memory is still unclear. Comparatively, the involvement of the LEC in non-spatial information processing is quite well known. However, very few studies have investigated its role within the frame of memory function. Thus, it is not known whether its contribution depends on memory load. In addition, the deep layers of the EC have been shown to be predictive of subsequent memory performance, but not its superficial layers. Hence, here we tested the extent to which the proximal part of the subiculum and the superficial and deep layers of the LEC contribute to non-spatial memory, and whether this contribution depends on the memory load of the task. To do so, we imaged brain activity at cellular resolution in these areas in rats performing a delayed nonmatch to sample task based on odors with two different memory loads (5 or 10 odors). This imaging technique is based on the detection of the RNA of the immediate-early gene Arc, which is especially tied to synaptic plasticity and behavioral demands, and is commonly used to map activity in the medial temporal lobe. We report for the first time that the proximal part of the subiculum is recruited in a memory-load dependent manner and the deep layers of the LEC engaged under high memory load conditions during the retrieval of non-spatial memory, thus shedding light on the specific networks contributing to non-spatial memory retrieval.
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Affiliation(s)
- Shih-Pi Ku
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany
| | - Nozomu H Nakamura
- Department of Physiology, Hyogo College of MedicineNishinomiya, Japan.,Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany
| | - Nicolas Maingret
- Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany
| | - Liv Mahnke
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany.,Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany.,Faculty of Natural Science, Otto von Guericke UniversityMagdeburg, Germany
| | - Motoharu Yoshida
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE), Cognitive Neurophysiology LaboratoryMagdeburg, Germany
| | - Magdalena M Sauvage
- Department of Functional Architecture of Memory, Leibniz-Institute for NeurobiologyMagdeburg, Germany.,Mercator Research Group, Functional Architecture of Memory Unit, Ruhr-UniversityBochum, Germany.,Medical Faculty, Department of Functional Neuroplasticity, Otto von Guericke UniversityMagdeburg, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke UniversityMagdeburg, Germany
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52
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Pilkiw M, Insel N, Cui Y, Finney C, Morrissey MD, Takehara-Nishiuchi K. Phasic and tonic neuron ensemble codes for stimulus-environment conjunctions in the lateral entorhinal cortex. eLife 2017; 6. [PMID: 28682237 PMCID: PMC5536943 DOI: 10.7554/elife.28611] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 07/05/2017] [Indexed: 02/06/2023] Open
Abstract
The lateral entorhinal cortex (LEC) is thought to bind sensory events with the environment where they took place. To compare the relative influence of transient events and temporally stable environmental stimuli on the firing of LEC cells, we recorded neuron spiking patterns in the region during blocks of a trace eyeblink conditioning paradigm performed in two environments and with different conditioning stimuli. Firing rates of some neurons were phasically selective for conditioned stimuli in a way that depended on which room the rat was in; nearly all neurons were tonically selective for environments in a way that depended on which stimuli had been presented in those environments. As rats moved from one environment to another, tonic neuron ensemble activity exhibited prospective information about the conditioned stimulus associated with the environment. Thus, the LEC formed phasic and tonic codes for event-environment associations, thereby accurately differentiating multiple experiences with overlapping features. DOI:http://dx.doi.org/10.7554/eLife.28611.001 The context in which an event occurs plays a large role in how the brain understands and responds to the event. While a key part of context is where we are, contexts can also change within the same space: different meetings are held at different times and with different people in the same room, and a grassy field can be a place of intense competition or a place to relax and gaze at clouds. However, we have little understanding of how the brain sets up and maintains a sense of context. A region of the brain called the lateral entorhinal cortex (LEC) responds to events as they happen, but may also maintain a record of past experiences, and helps us to learn new associations between events. To find out how LEC neurons might represent context, Pilkiw et al. measured the activity of individual LEC neurons in rats as they experienced different combinations of events and environments. In each trial, the rats were placed in one of two different rooms and exposed to one of two sensory cues (sound or light) six times, either alone or, to test learning, paired moments later with a mild stimulation to the eyelid. The gaps between the cues lasted from 20 to 40 seconds. As expected, some LEC neurons responded to the sensory cues, and varied their responses to cues depending on whether or not they were paired with eyelid stimulation. What was much more striking is that almost all cells in the LEC behaved very differently in different contexts, both in response to the cues and also during the long gaps between the cues. This suggests that the LEC provides the brain with information about the circumstances of an event, and may be the reason we expect different events under different circumstances – even if we are in the same place. We tend to underestimate how much we rely on context to remember events and to guide our behavior. Many disabling health conditions, including addiction, post-traumatic stress disorder and obsessive-compulsive disorder, are affected by context. For example, people who are trying to overcome drug addiction can often reduce their cravings by avoiding places and situations in which they previously used the drug in question. Understanding how the LEC represents context may therefore help us to develop treatments that target this brain region in order to alter harmful behaviors. DOI:http://dx.doi.org/10.7554/eLife.28611.002
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Affiliation(s)
- Maryna Pilkiw
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Nathan Insel
- Department of Psychology, University of Toronto, Toronto, Canada.,Department of Psychology, University of Montana, Missoula, United States
| | - Younghua Cui
- Department of Psychology, University of Toronto, Toronto, Canada
| | - Caitlin Finney
- Department of Psychology, University of Toronto, Toronto, Canada
| | - Mark D Morrissey
- Department of Psychology, University of Toronto, Toronto, Canada.,Neuroscience Program, University of Toronto, Toronto, Canada
| | - Kaori Takehara-Nishiuchi
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Psychology, University of Toronto, Toronto, Canada.,Neuroscience Program, University of Toronto, Toronto, Canada
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53
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Scaplen KM, Ramesh RN, Nadvar N, Ahmed OJ, Burwell RD. Inactivation of the Lateral Entorhinal Area Increases the Influence of Visual Cues on Hippocampal Place Cell Activity. Front Syst Neurosci 2017; 11:40. [PMID: 28611603 PMCID: PMC5447019 DOI: 10.3389/fnsys.2017.00040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/11/2017] [Indexed: 01/17/2023] Open
Abstract
The hippocampus is important for both navigation and associative learning. We previously showed that the hippocampus processes two-dimensional (2D) landmarks and objects differently. Our findings suggested that landmarks are more likely to be used for orientation and navigation, whereas objects are more likely to be used for associative learning. The process by which cues are recognized as relevant for navigation or associative learning, however, is an open question. Presumably both spatial and nonspatial information are necessary for classifying cues as landmarks or objects. The lateral entorhinal area (LEA) is a good candidate for participating in this process as it is implicated in the processing of three-dimensional (3D) objects and object location. Because the LEA is one synapse upstream of the hippocampus and processes both spatial and nonspatial information, it is reasonable to hypothesize that the LEA modulates how the hippocampus uses 2D landmarks and objects. To test this hypothesis, we temporarily inactivated the LEA ipsilateral to the dorsal hippocampal recording site using fluorophore-conjugated muscimol (FCM) 30 min prior to three foraging sessions in which either the 2D landmark or the 2D object was back-projected to the floor of an open field. Prior to the second session we rotated the 2D cue by 90°. Cues were returned to the original configuration for the third session. Compared to the Saline treatment, FCM inactivation increased the percentage of rotation responses to manipulations of the landmark cue, but had no effect on information content of place fields. In contrast, FCM inactivation increased information content of place fields in the presence of the object cue, but had no effect on rotation responses to the object cue. Thus, LEA inactivation increased the influence of visual cues on hippocampal activity, but the impact was qualitatively different for cues that are useful for navigation vs. cues that may not be useful for navigation. FCM inactivation also led to reductions in both frequency and power of hippocampal theta rhythms, indicative of the loss of functionally important LEA inputs to hippocampus. These data provide evidence that the LEA is involved in modulating how the dorsal hippocampus utilizes visual environmental cues.
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Affiliation(s)
- Kristin M Scaplen
- Department of Neuroscience, Brown UniversityProvidence, RI, United States
| | - Rohan N Ramesh
- Department of Neuroscience, Brown UniversityProvidence, RI, United States
| | - Negin Nadvar
- Department of Biomedical Engineering, University of MichiganAnn Arbor, MI, United States
| | - Omar J Ahmed
- Department of Biomedical Engineering, University of MichiganAnn Arbor, MI, United States.,Department of Psychology, University of MichiganAnn Arbor, MI, United States
| | - Rebecca D Burwell
- Department of Neuroscience, Brown UniversityProvidence, RI, United States.,Department of Cognitive, Linguistics and Psychological Science, Brown UniversityProvidence, RI, United States
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54
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Bos JJ, Vinck M, van Mourik-Donga LA, Jackson JC, Witter MP, Pennartz CMA. Perirhinal firing patterns are sustained across large spatial segments of the task environment. Nat Commun 2017; 8:15602. [PMID: 28548084 PMCID: PMC5458559 DOI: 10.1038/ncomms15602] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 03/27/2017] [Indexed: 11/16/2022] Open
Abstract
Spatial navigation and memory depend on the neural coding of an organism's location. Fine-grained coding of location is thought to depend on the hippocampus. Likewise, animals benefit from knowledge parsing their environment into larger spatial segments, which are relevant for task performance. Here we investigate how such knowledge may be coded, and whether this occurs in structures in the temporal lobe, supplying cortical inputs to the hippocampus. We found that neurons in the perirhinal cortex of rats generate sustained firing patterns that discriminate large segments of the task environment. This contrasted to transient firing in hippocampus and sensory neocortex. These spatially extended patterns were not explained by task variables or temporally discrete sensory stimuli. Previously it has been suggested that the perirhinal cortex is part of a pathway processing object, but not spatial information. Our results indicate a greater complexity of neural coding than captured by this dichotomy.
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Affiliation(s)
- Jeroen J. Bos
- Swammerdam Institute for Life Sciences, Center for Neuroscience, Faculty of Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Research Priority Program Brain and Cognition, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Martin Vinck
- Swammerdam Institute for Life Sciences, Center for Neuroscience, Faculty of Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Deutschordenstraße 46, 60528 Frankfurt, Germany
| | - Laura A. van Mourik-Donga
- Swammerdam Institute for Life Sciences, Center for Neuroscience, Faculty of Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Research Priority Program Brain and Cognition, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Jadin C. Jackson
- Swammerdam Institute for Life Sciences, Center for Neuroscience, Faculty of Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Medtronic, 7000 Central Avenue NE, Minneapolis, Minnesota 55432, USA
| | - Menno P. Witter
- Kavli Institute for Systems Neuroscience, Centre for Neural Computation, Norwegian University of Science and Technology, DMF, NTNU PO Box 8905, NO-7491 Trondheim, Norway
| | - Cyriel M. A. Pennartz
- Swammerdam Institute for Life Sciences, Center for Neuroscience, Faculty of Science, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
- Research Priority Program Brain and Cognition, University of Amsterdam, 1098 XH Amsterdam, The Netherlands
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55
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Kuruvilla MV, Ainge JA. Lateral Entorhinal Cortex Lesions Impair Local Spatial Frameworks. Front Syst Neurosci 2017; 11:30. [PMID: 28567006 PMCID: PMC5434111 DOI: 10.3389/fnsys.2017.00030] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 04/28/2017] [Indexed: 11/14/2022] Open
Abstract
A prominent theory in the neurobiology of memory processing is that episodic memory is supported by contextually gated spatial representations in the hippocampus formed by combining spatial information from medial entorhinal cortex (MEC) with non-spatial information from lateral entorhinal cortex (LEC). However, there is a growing body of evidence from lesion and single-unit recording studies in rodents suggesting that LEC might have a role in encoding space, particularly the current and previous locations of objects within the local environment. Landmarks, both local and global, have been shown to control the spatial representations hypothesized to underlie cognitive maps. Consequently, it has recently been suggested that information processing within this network might be organized with reference to spatial scale with LEC and MEC providing information about local and global spatial frameworks respectively. In the present study, we trained animals to search for food using either a local or global spatial framework. Animals were re-tested on both tasks after receiving excitotoxic lesions of either the MEC or LEC. LEC lesioned animals were impaired in their ability to learn a local spatial framework task. LEC lesioned animals were also impaired on an object recognition (OR) task involving multiple local features but unimpaired at recognizing a single familiar object. Together, this suggests that LEC is involved in associating features of the local environment. However, neither LEC nor MEC lesions impaired performance on the global spatial framework task.
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Affiliation(s)
| | - James A. Ainge
- School of Psychology and Neuroscience, University of St AndrewsSt Andrews, UK
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56
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Anterolateral Entorhinal Cortex Volume Predicted by Altered Intra-Item Configural Processing. J Neurosci 2017; 37:5527-5538. [PMID: 28473640 DOI: 10.1523/jneurosci.3664-16.2017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/20/2017] [Accepted: 04/25/2017] [Indexed: 01/03/2023] Open
Abstract
Recent functional imaging studies have proposed that the human entorhinal cortex (ERC) is subdivided into functionally distinct anterolateral (alERC) and posteromedial (pmERC) subregions. The alERC overlaps with regions that are affected earliest by Alzheimer's disease pathology, yet its cognitive function remains poorly understood. Previous human fMRI studies have focused on its role in object memory, but rodent studies on the putatively homologous lateral entorhinal cortex suggest that it also plays an important role in representing spatial properties of objects. To investigate the cognitive effects of human alERC volume differences, we developed an eye-tracking-based task to evaluate intra-item configural processing (i.e., processing the arrangement of an object's features) and used manual segmentation based on a recently developed protocol to delineate the alERC/pmERC and other medial temporal lobe (MTL) subregions. In a group of older adult men and women at varying stages of brain atrophy and cognitive decline, we found that intra-item configural processing, regardless of an object's novelty, was strongly predicted by alERC volume, but not by the volume of any other MTL subregion. These results provide the first evidence that the human alERC plays a role in supporting a distinct aspect of object processing, namely attending to the arrangement of an object's component features.SIGNIFICANCE STATEMENT Alzheimer's disease pathology appears earliest in brain regions that overlap with the anterolateral entorhinal cortex (alERC). However, the cognitive role of the alERC is poorly understood. Previous human studies treat the alERC as an extension of the neighboring perirhinal cortex, supporting object memory. Animal studies suggest that the alERC may support the spatial properties of objects. In a group of older adult humans at the earliest stages of cognitive decline, we show here that alERC volume selectively predicted configural processing (attention to the spatial arrangement of an object's parts). This is the first study to demonstrate a cognitive role related to alERC volume in humans. This task can be adapted to serve as an early detection method for Alzheimer's disease pathology.
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57
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Kinnavane L, Amin E, Olarte-Sánchez CM, Aggleton JP. Medial temporal pathways for contextual learning: Network c- fos mapping in rats with or without perirhinal cortex lesions. Brain Neurosci Adv 2017; 1:2398212817694167. [PMID: 28685167 PMCID: PMC5496664 DOI: 10.1177/2398212817694167] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 01/25/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND In the rat brain, context information is thought to engage network interactions between the postrhinal cortex, medial entorhinal cortex, and the hippocampus. In contrast, object information is thought to be more reliant on perirhinal cortex and lateral entorhinal cortex interactions with the hippocampus. METHOD The 'context network' was explored by mapping expression of the immediate-early gene, c-fos, after exposure to a new spatial environment. RESULTS Structural equation modelling of Fos counts produced networks of good fit that closely matched prior predictions based on anatomically-grounded functional models. These same models did not, however, fit the Fos data from home-cage controls nor did they fit the corresponding data from a previous study exploring object recognition. These additional analyses highlight the specificity of the context network. The home-cage controls, meanwhile, showed raised levels of inter-area Fos correlations between the many sites examined, i.e., their changes in Fos levels lacked anatomical specificity. Two additional groups of rats received perirhinal cortex lesions. While the loss of perirhinal cortex reduced lateral entorhinal c-fos activity, it did not affect mean levels of hippocampal c-fos expression. Similarly, overall c-fos expression in the prelimbic cortex, retrosplenial cortex and nucleus reuniens of the thalamus appeared unaffected by the perirhinal cortex lesions. CONCLUSION The perirhinal cortex lesions disrupted network interactions involving the medial entorhinal cortex and the hippocampus, highlighting ways in which perirhinal cortex might affect specific aspects of context learning.
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Affiliation(s)
| | - Eman Amin
- School of Psychology, Cardiff University, Cardiff, UK
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58
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Yoder WM, Gaynor LS, Burke SN, Setlow B, Smith DW, Bizon JL. Interaction between age and perceptual similarity in olfactory discrimination learning in F344 rats: relationships with spatial learning. Neurobiol Aging 2017; 53:122-137. [PMID: 28259065 DOI: 10.1016/j.neurobiolaging.2017.01.023] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 01/22/2017] [Accepted: 01/28/2017] [Indexed: 11/28/2022]
Abstract
Emerging evidence suggests that aging is associated with a reduced ability to distinguish perceptually similar stimuli in one's environment. As the ability to accurately perceive and encode sensory information is foundational for explicit memory, understanding the neurobiological underpinnings of discrimination impairments that emerge with advancing age could help elucidate the mechanisms of mnemonic decline. To this end, there is a need for preclinical approaches that robustly and reliably model age-associated perceptual discrimination deficits. Taking advantage of rodents' exceptional olfactory abilities, the present study applied rigorous psychophysical techniques to the evaluation of discrimination learning in young and aged F344 rats. Aging did not influence odor detection thresholds or the ability to discriminate between perceptually distinct odorants. In contrast, aged rats were disproportionately impaired relative to young on problems that required discriminations between perceptually similar olfactory stimuli. Importantly, these disproportionate impairments in discrimination learning did not simply reflect a global learning impairment in aged rats, as they performed other types of difficult discriminations on par with young rats. Among aged rats, discrimination deficits were strongly associated with spatial learning deficits. These findings reveal a new, sensitive behavioral approach for elucidating the neural mechanisms of cognitive decline associated with normal aging.
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Affiliation(s)
- Wendy M Yoder
- Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Florida, Gainesville, FL, USA
| | - Leslie S Gaynor
- Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA
| | - Sara N Burke
- Department of Neuroscience, University of Florida, Gainesville, FL, USA
| | - Barry Setlow
- Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Florida, Gainesville, FL, USA; Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA
| | - David W Smith
- Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Florida, Gainesville, FL, USA; Center for Smell and Taste, University of Florida, Gainesville, FL, USA
| | - Jennifer L Bizon
- Department of Neuroscience, University of Florida, Gainesville, FL, USA; Department of Psychiatry, University of Florida, Gainesville, FL, USA; Center for Smell and Taste, University of Florida, Gainesville, FL, USA.
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59
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Grieves RM, Jeffery KJ. The representation of space in the brain. Behav Processes 2017; 135:113-131. [DOI: 10.1016/j.beproc.2016.12.012] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 12/09/2016] [Accepted: 12/19/2016] [Indexed: 11/16/2022]
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60
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Perirhinal cortex involvement in allocentric spatial learning in the rat: Evidence from doubly marked tasks. Hippocampus 2017; 27:507-517. [DOI: 10.1002/hipo.22707] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 12/17/2016] [Accepted: 01/06/2017] [Indexed: 02/05/2023]
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61
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Hernandez AR, Reasor JE, Truckenbrod LM, Lubke KN, Johnson SA, Bizon JL, Maurer AP, Burke SN. Medial prefrontal-perirhinal cortical communication is necessary for flexible response selection. Neurobiol Learn Mem 2016; 137:36-47. [PMID: 27815215 DOI: 10.1016/j.nlm.2016.10.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/20/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
Abstract
The ability to use information from the physical world to update behavioral strategies is critical for survival across species. The prefrontal cortex (PFC) supports behavioral flexibility; however, exactly how this brain structure interacts with sensory association cortical areas to facilitate the adaptation of response selection remains unknown. Given the role of the perirhinal cortex (PER) in higher-order perception and associative memory, the current study evaluated whether PFC-PER circuits are critical for the ability to perform biconditional object discriminations when the rule for selecting the rewarded object shifted depending on the animal's spatial location in a 2-arm maze. Following acquisition to criterion performance on an object-place paired association task, pharmacological blockade of communication between the PFC and PER significantly disrupted performance. Specifically, the PFC-PER disconnection caused rats to regress to a response bias of selecting an object on a particular side regardless of its identity. Importantly, the PFC-PER disconnection did not interfere with the capacity to perform object-only or location-only discriminations, which do not require the animal to update a response rule across trials. These findings are consistent with a critical role for PFC-PER circuits in rule shifting and the effective updating of a response rule across spatial locations.
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Affiliation(s)
- Abbi R Hernandez
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States
| | - Jordan E Reasor
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States
| | - Leah M Truckenbrod
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States
| | - Katelyn N Lubke
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States; Department of Biomedical Engineering, University of Florida, United States
| | - Sarah A Johnson
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States
| | - Jennifer L Bizon
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States
| | - Andrew P Maurer
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States; Department of Biomedical Engineering, University of Florida, United States
| | - Sara N Burke
- McKnight Brain Institute, Department of Neuroscience, University of Florida, United States; Institute on Aging, University of Florida, United States
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62
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Fu H, Hussaini SA, Wegmann S, Profaci C, Daniels JD, Herman M, Emrani S, Figueroa HY, Hyman BT, Davies P, Duff KE. 3D Visualization of the Temporal and Spatial Spread of Tau Pathology Reveals Extensive Sites of Tau Accumulation Associated with Neuronal Loss and Recognition Memory Deficit in Aged Tau Transgenic Mice. PLoS One 2016; 11:e0159463. [PMID: 27466814 PMCID: PMC4965059 DOI: 10.1371/journal.pone.0159463] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 07/01/2016] [Indexed: 11/19/2022] Open
Abstract
3D volume imaging using iDISCO+ was applied to observe the spatial and temporal progression of tau pathology in deep structures of the brain of a mouse model that recapitulates the earliest stages of Alzheimer’s disease (AD). Tau pathology was compared at four timepoints, up to 34 months as it spread through the hippocampal formation and out into the neocortex along an anatomically connected route. Tau pathology was associated with significant gliosis. No evidence for uptake and accumulation of tau by glia was observed. Neuronal cells did appear to have internalized tau, including in extrahippocampal areas as a small proportion of cells that had accumulated human tau protein did not express detectible levels of human tau mRNA. At the oldest timepoint, mature tau pathology in the entorhinal cortex (EC) was associated with significant cell loss. As in human AD, mature tau pathology in the EC and the presence of tau pathology in the neocortex correlated with cognitive impairment. 3D volume imaging is an ideal technique to easily monitor the spread of pathology over time in models of disease progression.
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Affiliation(s)
- Hongjun Fu
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - S. Abid Hussaini
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Susanne Wegmann
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Caterina Profaci
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Jacob D. Daniels
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Mathieu Herman
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Sheina Emrani
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Helen Y. Figueroa
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
| | - Bradley T. Hyman
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, United States of America
| | - Peter Davies
- Litwin-Zucker Center for Research in Alzheimer's Disease, Feinstein Institute for Medical Research, North Shore/LIJ Health System, Manhasset, New York, United States of America
| | - Karen E. Duff
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, United States of America
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States of America
- * E-mail:
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Kinnavane L, Amin E, Olarte-Sánchez CM, Aggleton JP. Detecting and discriminating novel objects: The impact of perirhinal cortex disconnection on hippocampal activity patterns. Hippocampus 2016; 26:1393-1413. [PMID: 27398938 PMCID: PMC5082501 DOI: 10.1002/hipo.22615] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2016] [Indexed: 12/11/2022]
Abstract
Perirhinal cortex provides object‐based information and novelty/familiarity information for the hippocampus. The necessity of these inputs was tested by comparing hippocampal c‐fos expression in rats with or without perirhinal lesions. These rats either discriminated novel from familiar objects (Novel‐Familiar) or explored pairs of novel objects (Novel‐Novel). Despite impairing Novel‐Familiar discriminations, the perirhinal lesions did not affect novelty detection, as measured by overall object exploration levels (Novel‐Novel condition). The perirhinal lesions also largely spared a characteristic network of linked c‐fos expression associated with novel stimuli (entorhinal cortex→CA3→distal CA1→proximal subiculum). The findings show: I) that perirhinal lesions preserve behavioral sensitivity to novelty, whilst still impairing the spontaneous ability to discriminate novel from familiar objects, II) that the distinctive patterns of hippocampal c‐fos activity promoted by novel stimuli do not require perirhinal inputs, III) that entorhinal Fos counts (layers II and III) increase for novelty discriminations, IV) that hippocampal c‐fos networks reflect proximal‐distal connectivity differences, and V) that discriminating novelty creates different pathway interactions from merely detecting novelty, pointing to top‐down effects that help guide object selection. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Lisa Kinnavane
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, Wales, CF10 3AT, United Kingdom.
| | - Eman Amin
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, Wales, CF10 3AT, United Kingdom
| | | | - John P Aggleton
- School of Psychology, Cardiff University, 70 Park Place, Cardiff, Wales, CF10 3AT, United Kingdom
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von Linstow Roloff E, Muller RU, Brown MW. Finding and Not Finding Rat Perirhinal Neuronal Responses to Novelty. Hippocampus 2016; 26:1021-32. [PMID: 26972751 PMCID: PMC4973686 DOI: 10.1002/hipo.22584] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2016] [Indexed: 01/12/2023]
Abstract
There is much evidence that the perirhinal cortex of both rats and monkeys is important for judging the relative familiarity of visual stimuli. In monkeys many studies have found that a proportion of perirhinal neurons respond more to novel than familiar stimuli. There are fewer studies of perirhinal neuronal responses in rats, and those studies based on exploration of objects, have raised into question the encoding of stimulus familiarity by rat perirhinal neurons. For this reason, recordings of single neuronal activity were made from the perirhinal cortex of rats so as to compare responsiveness to novel and familiar stimuli in two different behavioral situations. The first situation was based upon that used in “paired viewing” experiments that have established rat perirhinal differences in immediate early gene expression for novel and familiar visual stimuli displayed on computer monitors. The second situation was similar to that used in the spontaneous object recognition test that has been widely used to establish the involvement of rat perirhinal cortex in familiarity discrimination. In the first condition 30 (25%) of 120 perirhinal neurons were visually responsive; of these responsive neurons 19 (63%) responded significantly differently to novel and familiar stimuli. In the second condition eight (53%) of 15 perirhinal neurons changed activity significantly in the vicinity of objects (had “object fields”); however, for none (0%) of these was there a significant activity change related to the familiarity of an object, an incidence significantly lower than for the first condition. Possible reasons for the difference are discussed. It is argued that the failure to find recognition‐related neuronal responses while exploring objects is related to its detectability by the measures used, rather than the absence of all such signals in perirhinal cortex. Indeed, as shown by the results, such signals are found when a different methodology is used. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Eva von Linstow Roloff
- School of Physiology and Pharmacology, Medical Sciences Building, University of Bristol, United Kingdom
| | - Robert U Muller
- Department of Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, New York. In memoriam, Robert U. Muller (1942-2013)
| | - Malcolm W Brown
- School of Physiology and Pharmacology, Medical Sciences Building, University of Bristol, United Kingdom
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Lee CH, Ryu J, Lee SH, Kim H, Lee I. Functional cross-hemispheric shift between object-place paired associate memory and spatial memory in the human hippocampus. Hippocampus 2016; 26:1061-77. [PMID: 27009679 PMCID: PMC5074286 DOI: 10.1002/hipo.22587] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2016] [Indexed: 11/15/2022]
Abstract
The hippocampus plays critical roles in both object‐based event memory and spatial navigation, but it is largely unknown whether the left and right hippocampi play functionally equivalent roles in these cognitive domains. To examine the hemispheric symmetry of human hippocampal functions, we used an fMRI scanner to measure BOLD activity while subjects performed tasks requiring both object‐based event memory and spatial navigation in a virtual environment. Specifically, the subjects were required to form object‐place paired associate memory after visiting four buildings containing discrete objects in a virtual plus maze. The four buildings were visually identical, and the subjects used distal visual cues (i.e., scenes) to differentiate the buildings. During testing, the subjects were required to identify one of the buildings when cued with a previously associated object, and when shifted to a random place, the subject was expected to navigate to the previously chosen building. We observed that the BOLD activity foci changed from the left hippocampus to the right hippocampus as task demand changed from identifying a previously seen object (object‐cueing period) to searching for its paired‐associate place (object‐cued place recognition period). Furthermore, the efficient retrieval of object‐place paired associate memory (object‐cued place recognition period) was correlated with the BOLD response of the left hippocampus, whereas the efficient retrieval of relatively pure spatial memory (spatial memory period) was correlated with the right hippocampal BOLD response. These findings suggest that the left and right hippocampi in humans might process qualitatively different information for remembering episodic events in space. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Choong-Hee Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
| | - Jungwon Ryu
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
| | - Sang-Hun Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
| | - Hakjin Kim
- Department of Psychology, Korea University, Seoul, Korea
| | - Inah Lee
- Department of Brain and Cognitive Sciences, Seoul National University, Seoul, Korea
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66
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Keene CS, Bladon J, McKenzie S, Liu CD, O'Keefe J, Eichenbaum H. Complementary Functional Organization of Neuronal Activity Patterns in the Perirhinal, Lateral Entorhinal, and Medial Entorhinal Cortices. J Neurosci 2016; 36:3660-75. [PMID: 27030753 PMCID: PMC4812128 DOI: 10.1523/jneurosci.4368-15.2016] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Accepted: 02/16/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED It is commonly conceived that the cortical areas of the hippocampal region are functionally divided into the perirhinal cortex (PRC) and the lateral entorhinal cortex (LEC), which selectively process object information; and the medial entorhinal cortex (MEC), which selectively processes spatial information. Contrary to this notion, in rats performing a task that demands both object and spatial information processing, single neurons in PRC, LEC, and MEC, including those in both superficial and deep cortical areas and in grid, border, and head direction cells of MEC, have a highly similar range of selectivity to object and spatial dimensions of the task. By contrast, representational similarity analysis of population activity reveals a key distinction in the organization of information in these areas, such that PRC and LEC populations prioritize object over location information, whereas MEC populations prioritize location over object information. These findings bring to the hippocampal system a growing emphasis on population analyses as a powerful tool for characterizing neural representations supporting cognition and memory. SIGNIFICANCE STATEMENT Contrary to the common view that brain regions in the "what" and "where" streams distinctly process object and spatial cues, respectively, we found that both streams encode both object and spatial information but distinctly organize memories for objects and space. Specifically, perirhinal cortex and lateral entorhinal cortex represent objects and, within the object-specific representations, the locations where they occur. Conversely, medial entorhinal cortex represents relevant locations and, within those spatial representations, the objects that occupy them. Furthermore, these findings reach beyond simple notions of perirhinal cortex and lateral entorhinal cortex neurons as object detectors and MEC neurons as position detectors, and point to a more complex organization of memory representations within the medial temporal lobe system.
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Affiliation(s)
- Christopher S Keene
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - John Bladon
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - Sam McKenzie
- The Neuroscience Institute, New York University Langone Medical Center, New York, New York 10016
| | - Cindy D Liu
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - Joseph O'Keefe
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
| | - Howard Eichenbaum
- Center for Memory and Brain, Boston University, Boston, Massachusetts 02215, and
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McKenzie S, Keene CS, Farovik A, Bladon J, Place R, Komorowski R, Eichenbaum H. Representation of memories in the cortical-hippocampal system: Results from the application of population similarity analyses. Neurobiol Learn Mem 2015; 134 Pt A:178-191. [PMID: 26748022 DOI: 10.1016/j.nlm.2015.12.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Revised: 12/08/2015] [Accepted: 12/24/2015] [Indexed: 01/07/2023]
Abstract
Here we consider the value of neural population analysis as an approach to understanding how information is represented in the hippocampus and cortical areas and how these areas might interact as a brain system to support memory. We argue that models based on sparse coding of different individual features by single neurons in these areas (e.g., place cells, grid cells) are inadequate to capture the complexity of experience represented within this system. By contrast, population analyses of neurons with denser coding and mixed selectivity reveal new and important insights into the organization of memories. Furthermore, comparisons of the organization of information in interconnected areas suggest a model of hippocampal-cortical interactions that mediates the fundamental features of memory.
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Affiliation(s)
- Sam McKenzie
- The Neuroscience Institute, NYU Langone Medical Center, United States
| | | | - Anja Farovik
- Center for Memory and Brain, Boston University, United States
| | - John Bladon
- Center for Memory and Brain, Boston University, United States
| | - Ryan Place
- Center for Memory and Brain, Boston University, United States
| | - Robert Komorowski
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, United States
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Abstract
Perirhinal cortex (PER) has a well established role in the familiarity-based recognition of individual items and objects. For example, animals and humans with perirhinal damage are unable to distinguish familiar from novel objects in recognition memory tasks. In the normal brain, perirhinal neurons respond to novelty and familiarity by increasing or decreasing firing rates. Recent work also implicates oscillatory activity in the low-beta and low-gamma frequency bands in sensory detection, perception, and recognition. Using optogenetic methods in a spontaneous object exploration (SOR) task, we altered recognition memory performance in rats. In the SOR task, normal rats preferentially explore novel images over familiar ones. We modulated exploratory behavior in this task by optically stimulating channelrhodopsin-expressing perirhinal neurons at various frequencies while rats looked at novel or familiar 2D images. Stimulation at 30-40 Hz during looking caused rats to treat a familiar image as if it were novel by increasing time looking at the image. Stimulation at 30-40 Hz was not effective in increasing exploration of novel images. Stimulation at 10-15 Hz caused animals to treat a novel image as familiar by decreasing time looking at the image, but did not affect looking times for images that were already familiar. We conclude that optical stimulation of PER at different frequencies can alter visual recognition memory bidirectionally. Significance statement: Recognition of novelty and familiarity are important for learning, memory, and decision making. Perirhinal cortex (PER) has a well established role in the familiarity-based recognition of individual items and objects, but how novelty and familiarity are encoded and transmitted in the brain is not known. Perirhinal neurons respond to novelty and familiarity by changing firing rates, but recent work suggests that brain oscillations may also be important for recognition. In this study, we showed that stimulation of the PER could increase or decrease exploration of novel and familiar images depending on the frequency of stimulation. Our findings suggest that optical stimulation of PER at specific frequencies can predictably alter recognition memory.
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Schultz H, Sommer T, Peters J. The Role of the Human Entorhinal Cortex in a Representational Account of Memory. Front Hum Neurosci 2015; 9:628. [PMID: 26635581 PMCID: PMC4653609 DOI: 10.3389/fnhum.2015.00628] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/02/2015] [Indexed: 01/08/2023] Open
Abstract
Connectivity studies in animals form the basis for a representational view of medial temporal lobe (MTL) subregions. In this view, distinct subfields of the entorhinal cortex (EC) relay object-related and spatial information from the perirhinal and parahippocampal cortices (PRC, PHC) to the hippocampus (HC). Relatively recent advances in functional magnetic resonance imaging (fMRI) methodology allow examining properties of human EC subregions directly. Antero-lateral and posterior-medial EC subfields show remarkable consistency to their putative rodent and nonhuman primate homologs with regard to intra- and extra-MTL functional connectivity. Accordingly, there is now evidence for a dissociation of object-related vs. spatial processing in human EC subfields. Here, variance in localization may be integrated in the antero-lateral vs. posterior-medial distinction, but may additionally reflect process differences. Functional results in rodents further suggest material-specific representations may be more integrated in EC compared to PRC/PHC. In humans, however, evidence for such a dissociation between EC and PRC/PHC is lacking. Future research may elucidate on the unique contributions of human EC to memory, especially in light of its high degree of intrinsic and extrinsic connectivity. A thorough characterization of EC subfield function may not only advance our understanding of human memory, but also have important clinical implications.
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Affiliation(s)
- Heidrun Schultz
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany ; Department of Education and Psychology, Freie Universität Berlin Berlin, Germany
| | - Tobias Sommer
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany
| | - Jan Peters
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf Hamburg, Germany
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70
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Marozzi E, Ginzberg LL, Alenda A, Jeffery KJ. Purely Translational Realignment in Grid Cell Firing Patterns Following Nonmetric Context Change. Cereb Cortex 2015; 25:4619-27. [PMID: 26048956 PMCID: PMC4816804 DOI: 10.1093/cercor/bhv120] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Grid cells in entorhinal and parahippocampal cortices contribute to a network, centered on the hippocampal place cell system, that constructs a representation of spatial context for use in navigation and memory. In doing so, they use metric cues such as the distance and direction of nearby boundaries to position and orient their firing field arrays (grids). The present study investigated whether they also use purely nonmetric "context" information such as color and odor of the environment. We found that, indeed, purely nonmetric cues--sufficiently salient to cause changes in place cell firing patterns--can regulate grid positioning; they do so independently of orientation, and thus interact with linear but not directional spatial inputs. Grid cells responded homogeneously to context changes. We suggest that the grid and place cell networks receive context information directly and also from each other; the information is used by place cells to compute the final decision of the spatial system about which context the animal is in, and by grid cells to help inform the system about where the animal is within it.
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Affiliation(s)
- Elizabeth Marozzi
- Department of Experimental Psychology, University College London, London WC1H 0AP, UK
| | - Lin Lin Ginzberg
- Department of Experimental Psychology, University College London, London WC1H 0AP, UK Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Andrea Alenda
- Department of Electrical and Electronic Engineering, Imperial College London, London SW7 2AZ, UK
| | - Kate J Jeffery
- Department of Experimental Psychology, University College London, London WC1H 0AP, UK
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71
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Abstract
The perirhinal cortex (PRC) is reportedly important for object recognition memory, with supporting physiological evidence obtained largely from primate studies. Whether neurons in the rodent PRC also exhibit similar physiological correlates of object recognition, however, remains to be determined. We recorded single units from the PRC in a PRC-dependent, object-cued spatial choice task in which, when cued by an object image, the rat chose the associated spatial target from two identical discs appearing on a touchscreen monitor. The firing rates of PRC neurons were significantly modulated by critical events in the task, such as object sampling and choice response. Neuronal firing in the PRC was correlated primarily with the conjunctive relationships between an object and its associated choice response, although some neurons also responded to the choice response alone. However, we rarely observed a PRC neuron that represented a specific object exclusively regardless of spatial response in rats, although the neurons were influenced by the perceptual ambiguity of the object at the population level. Some PRC neurons fired maximally after a choice response, and this post-choice feedback signal significantly enhanced the neuronal specificity for the choice response in the subsequent trial. Our findings suggest that neurons in the rat PRC may not participate exclusively in object recognition memory but that their activity may be more dynamically modulated in conjunction with other variables, such as choice response and its outcomes.
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72
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Mathiasen ML, Hansen L, Witter MP. Insular projections to the parahippocampal region in the rat. J Comp Neurol 2015; 523:1379-98. [PMID: 25641117 DOI: 10.1002/cne.23742] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 11/11/2022]
Abstract
The insular cortex is involved in the perception of interoceptive signals, coding of emotional and affective states, and processing information from gustatory, olfactory, auditory, somatosensory, and nociceptive modalities. This information represents an important component of episodic memory, mediated by the parahippocampal-hippocampal region. A comprehensive description of insular projections to the latter region is lacking. Previous studies reported that insular projections do not target any of the subdivisions in the hippocampal formation (the dentate gyus, the cornu ammonis [CA] fields 1, 2, and 3 and the subiculum), but, in contrast, target the parahippocampal region (perirhinal, postrhinal, lateral and medial entorhinal cortices, and pre- and parasubiculum). The present study examined the topographical and laminar organization of insular projections to the parahippocampal region in the rat with the use of anterograde tracing. Notably, our results corroborated the absence of hippocampal projections. We further showed that the perirhinal and the lateral entorhinal cortices received extensive projections from the insular cortex, primarily from its agranular areas. With the exception of a weak projection to the postrhinal cortex, projections to the remaining parahippocampal areas were either absent or very sparse. The projections to the lateral entorhinal cortex displayed a preference for the deep layers of its most lateral subdivisions, known also to receive hippocampal inputs. Projections to the perirhinal cortex primarily targeted the superficial layers with a preference for its ventral subdivision, referred to as area 35. Our findings indicate that only processed information, reflecting emotional and affective states, but not primary gustatory and viscerosensory information, has direct access to the parahippocampal-hippocampal system.
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Affiliation(s)
- Mathias L Mathiasen
- Kavli Institute for Systems Neuroscience & Centre for Neural Computation, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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73
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Hales JB, Schlesiger MI, Leutgeb JK, Squire LR, Leutgeb S, Clark RE. Medial entorhinal cortex lesions only partially disrupt hippocampal place cells and hippocampus-dependent place memory. Cell Rep 2014; 9:893-901. [PMID: 25437546 DOI: 10.1016/j.celrep.2014.10.009] [Citation(s) in RCA: 136] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 08/13/2014] [Accepted: 10/01/2014] [Indexed: 10/24/2022] Open
Abstract
The entorhinal cortex provides the primary cortical projections to the hippocampus, a brain structure critical for memory. However, it remains unclear how the precise firing patterns of medial entorhinal cortex (MEC) cells influence hippocampal physiology and hippocampus-dependent behavior. We found that complete bilateral lesions of the MEC resulted in a lower proportion of active hippocampal cells. The remaining active cells had place fields, but with decreased spatial precision and decreased long-term spatial stability. In addition, MEC rats were as impaired in the water maze as hippocampus rats, while rats with combined MEC and hippocampal lesions had an even greater deficit. However, MEC rats were not impaired on other hippocampus-dependent tasks, including those in which an object location or context was remembered. Thus, the MEC is not necessary for all types of spatial coding or for all types of hippocampus-dependent memory, but it is necessary for the normal acquisition of place memory.
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Affiliation(s)
- Jena B Hales
- Department of Psychiatry, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Magdalene I Schlesiger
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jill K Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Larry R Squire
- Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA; Department of Psychiatry, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Psychology and Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Stefan Leutgeb
- Neurobiology Section and Center for Neural Circuits and Behavior, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA; Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Robert E Clark
- Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA; Department of Psychiatry, School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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In search of a recognition memory engram. Neurosci Biobehav Rev 2014; 50:12-28. [PMID: 25280908 PMCID: PMC4382520 DOI: 10.1016/j.neubiorev.2014.09.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Revised: 09/18/2014] [Accepted: 09/22/2014] [Indexed: 01/06/2023]
Abstract
The role of the perirhinal cortex in familiarity discrimination is reviewed. Behavioural, pharmacological and electrophysiological evidence is considered. The cortex is found to be essential for memory acquisition, retrieval and storage. The evidence indicates that perirhinal synaptic weakening is critically involved.
A large body of data from human and animal studies using psychological, recording, imaging, and lesion techniques indicates that recognition memory involves at least two separable processes: familiarity discrimination and recollection. Familiarity discrimination for individual visual stimuli seems to be effected by a system centred on the perirhinal cortex of the temporal lobe. The fundamental change that encodes prior occurrence within the perirhinal cortex is a reduction in the responses of neurones when a stimulus is repeated. Neuronal network modelling indicates that a system based on such a change in responsiveness is potentially highly efficient in information theoretic terms. A review is given of findings indicating that perirhinal cortex acts as a storage site for recognition memory of objects and that such storage depends upon processes producing synaptic weakening.
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75
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Kondo H, Witter MP. Topographic organization of orbitofrontal projections to the parahippocampal region in rats. J Comp Neurol 2014; 522:772-93. [PMID: 23897637 DOI: 10.1002/cne.23442] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 07/17/2013] [Accepted: 07/18/2013] [Indexed: 11/12/2022]
Abstract
The parahippocampal region, which comprises the perirhinal, postrhinal, and entorhinal cortices, as well as the pre- and parasubiculum, receives inputs from several association cortices and provides the major cortical input to the hippocampus. This study examined the topographic organization of projections from the orbitofrontal cortex (OFC) to the parahippocampal region in rats by injecting anterograde tracers, biotinylated dextran amine (BDA) and Phaseolus vulgaris-leucoagglutinin (PHA-L), into four subdivisions of OFC. The rostral portion of the perirhinal cortex receives strong projections from the medial (MO), ventral (VO), and ventrolateral (VLO) orbitofrontal areas and the caudal portion of lateral orbitofrontal area (LO). These projections terminate in the dorsal bank and fundus of the rhinal sulcus. In contrast, the postrhinal cortex receives a strong projection specifically from VO. All four subdivisions of OFC give rise to projections to the dorsolateral parts of the lateral entorhinal cortex (LEC), preferentially distributing to more caudal levels of LEC. The medial entorhinal cortex (MEC) receives moderate input from VO and weak projections from MO, VLO, and LO. The presubiculum receives strong projections from caudal VO but only weak projections from other OFC regions. As for the laminar distribution of projections, axons originating from OFC terminate more densely in upper layers (layers I-III) than in deep layers in the parahippocampal region. These results thus show a striking topographic organization of OFC-to-parahippocampal connectivity. Whereas LO, VLO, VO, and MO interact with perirhinal-LEC circuits, the interactions with postrhinal cortex, presubiculum, and MEC are mediated predominantly through the projections of VO.
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Affiliation(s)
- Hideki Kondo
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, 7489, Trondheim, Norway
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76
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Burke SN, Barnes CA. The neural representation of 3-dimensional objects in rodent memory circuits. Behav Brain Res 2014; 285:60-6. [PMID: 25205370 DOI: 10.1016/j.bbr.2014.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/22/2014] [Accepted: 09/01/2014] [Indexed: 12/13/2022]
Abstract
Three-dimensional objects are common stimuli that rodents and other animals encounter in the natural world that contribute to the associations that are the hallmark of explicit memory. Thus, the use of 3-dimensional objects for investigating the circuits that support associative and episodic memories has a long history. In rodents, the neural representation of these types of stimuli is a polymodal process and lesion data suggest that the perirhinal cortex, an area of the medial temporal lobe that receives afferent input from all sensory modalities, is particularly important for integrating sensory information across modalities to support object recognition. Not surprisingly, recent data from in vivo electrophysiological recordings have shown that principal cells within the perirhinal cortex are activated at locations of an environment that contain 3-dimensional objects. Interestingly, it appears that neural activity patterns related to object stimuli are ubiquitous across memory circuits and have now been observed in many medial temporal lobe structures as well as in the anterior cingulate cortex. This review summarizes behavioral and neurophysiological data that examine the representation of 3-dimensional objects across brain regions that are involved in memory.
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Affiliation(s)
- Sara N Burke
- McKnight Brain Institute, United States of America; Department of Neuroscience, College of Medicine, University of Florida, Gainesville, Florida 32610, United States of America
| | - Carol A Barnes
- Evelyn F. McKnight Brain Institute, United States of America; Arizona Research Laboratories Division of Neural Systems, Memory & Aging, United States of America; Departments of Psychology, Neurology and Neuroscience, University of Arizona, Tucson, AZ 85724, United States of America.
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Westbrook SR, Brennan LE, Stanton ME. Ontogeny of object versus location recognition in the rat: acquisition and retention effects. Dev Psychobiol 2014; 56:1492-506. [PMID: 24992011 DOI: 10.1002/dev.21232] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 05/27/2014] [Indexed: 12/11/2022]
Abstract
Novel object and location recognition tasks harness the rat's natural tendency to explore novelty (Berlyne, 1950) to study incidental learning. The present study examined the ontogenetic profile of these two tasks and retention of spatial learning between postnatal day (PD) 17 and 31. Experiment 1 showed that rats ages PD17, 21, and 26 recognize novel objects, but only PD21 and PD26 rats recognize a novel location of a familiar object. These results suggest that novel object recognition develops before PD17, while object location recognition emerges between PD17 and PD21. Experiment 2 studied the ontogenetic profile of object location memory retention in PD21, 26, and 31 rats. PD26 and PD31 rats retained the object location memory for both 10-min and 24-hr delays. PD21 rats failed to retain the object location memory for the 24-hr delay, suggesting differential development of short- versus long-term memory in the ontogeny of object location memory.
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Affiliation(s)
- Sara R Westbrook
- Department of Psychology, University of Delaware, Newark, Delaware, 19716
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78
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Rennó-Costa C, Lisman JE, Verschure PFMJ. A signature of attractor dynamics in the CA3 region of the hippocampus. PLoS Comput Biol 2014; 10:e1003641. [PMID: 24854425 PMCID: PMC4031055 DOI: 10.1371/journal.pcbi.1003641] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 04/09/2014] [Indexed: 12/02/2022] Open
Abstract
The notion of attractor networks is the leading hypothesis for how associative memories are stored and recalled. A defining anatomical feature of such networks is excitatory recurrent connections. These "attract" the firing pattern of the network to a stored pattern, even when the external input is incomplete (pattern completion). The CA3 region of the hippocampus has been postulated to be such an attractor network; however, the experimental evidence has been ambiguous, leading to the suggestion that CA3 is not an attractor network. In order to resolve this controversy and to better understand how CA3 functions, we simulated CA3 and its input structures. In our simulation, we could reproduce critical experimental results and establish the criteria for identifying attractor properties. Notably, under conditions in which there is continuous input, the output should be "attracted" to a stored pattern. However, contrary to previous expectations, as a pattern is gradually "morphed" from one stored pattern to another, a sharp transition between output patterns is not expected. The observed firing patterns of CA3 meet these criteria and can be quantitatively accounted for by our model. Notably, as morphing proceeds, the activity pattern in the dentate gyrus changes; in contrast, the activity pattern in the downstream CA3 network is attracted to a stored pattern and thus undergoes little change. We furthermore show that other aspects of the observed firing patterns can be explained by learning that occurs during behavioral testing. The CA3 thus displays both the learning and recall signatures of an attractor network. These observations, taken together with existing anatomical and behavioral evidence, make the strong case that CA3 constructs associative memories based on attractor dynamics.
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Affiliation(s)
- César Rennó-Costa
- Universitat Pompeu Fabra, Synthetic, Perceptive, Emotive and Cognitive Systems group (SPECS), Barcelona, Spain
- Federal University of Rio Grande do Norte (UFRN), Brain Institute (ICe), Natal, Rio Grande do Norte, Brazil
| | - John E. Lisman
- Brandeis University, Biology Department & Volen Center for Complex Systems, Waltham, Massachusetts, United States of America
| | - Paul F. M. J. Verschure
- Universitat Pompeu Fabra, Synthetic, Perceptive, Emotive and Cognitive Systems group (SPECS), Barcelona, Spain
- Catalan Institute of Advanced Research (ICREA), Passeig Lluís Companys 23, Barcelona, Spain
- Universitat Pompeu Fabra, Center of Autonomous Systems and Neurorobotics (NRAS), Barcelona, Spain
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79
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Abstract
The perirhinal cortex (PRC) is proposed to both represent high-order sensory information and maintain those representations across delays. These cognitive processes are required for recognition memory, which declines during normal aging. Whether or not advanced age affects the ability of PRC principal cells to support these dual roles, however, is not known. The current experiment recorded PRC neurons as young and aged rats traversed a track. When objects were placed on the track, a subset of the neurons became active at discrete locations adjacent to objects. Importantly, the aged rats had a lower proportion of neurons that were activated by objects. Once PRC activity patterns in the presence of objects were established, however, both age groups maintained these representations across delays up to 2 h. These data support the hypothesis that age-associated deficits in stimulus recognition arise from impairments in high-order stimulus representation rather than difficulty in sustaining stable activity patterns over time.
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80
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Knierim JJ, Neunuebel JP, Deshmukh SS. Functional correlates of the lateral and medial entorhinal cortex: objects, path integration and local-global reference frames. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130369. [PMID: 24366146 DOI: 10.1098/rstb.2013.0369] [Citation(s) in RCA: 271] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The hippocampus receives its major cortical input from the medial entorhinal cortex (MEC) and the lateral entorhinal cortex (LEC). It is commonly believed that the MEC provides spatial input to the hippocampus, whereas the LEC provides non-spatial input. We review new data which suggest that this simple dichotomy between 'where' versus 'what' needs revision. We propose a refinement of this model, which is more complex than the simple spatial-non-spatial dichotomy. MEC is proposed to be involved in path integration computations based on a global frame of reference, primarily using internally generated, self-motion cues and external input about environmental boundaries and scenes; it provides the hippocampus with a coordinate system that underlies the spatial context of an experience. LEC is proposed to process information about individual items and locations based on a local frame of reference, primarily using external sensory input; it provides the hippocampus with information about the content of an experience.
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Affiliation(s)
- James J Knierim
- Solomon H. Snyder Department of Neuroscience, Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, , Baltimore, MD 21218, USA
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81
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Lee I, Park SB. Perirhinal cortical inactivation impairs object-in-place memory and disrupts task-dependent firing in hippocampal CA1, but not in CA3. Front Neural Circuits 2013; 7:134. [PMID: 23966912 PMCID: PMC3743073 DOI: 10.3389/fncir.2013.00134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/26/2013] [Indexed: 11/13/2022] Open
Abstract
Objects and their locations can associatively define an event and a conjoint representation of object-place can form an event memory. Remembering how to respond to a certain object in a spatial context is dependent on both hippocampus and perirhinal cortex (PER). However, the relative functional contributions of the two regions are largely unknown in object-place associative memory. We investigated the PER influence on hippocampal firing in a goal-directed object-place memory task by comparing the firing patterns of CA1 and CA3 of the dorsal hippocampus between conditions of PER muscimol inactivation and vehicle control infusions. Rats were required to choose one of the two objects in a specific spatial context (regardless of the object positions in the context), which was shown to be dependent on both hippocampus and PER. Inactivation of PER with muscimol (MUS) severely disrupted performance of well-trained rats, resulting in response bias (i.e., choosing any object on a particular side). MUS did not significantly alter the baseline firing rates of hippocampal neurons. We measured the similarity in firing patterns between two trial conditions in which the same target objects were chosen on opposite sides within the same arm [object-in-place (O-P) strategy] and compared the results with the similarity in firing between two trial conditions in which the rat chose any object encountered on a particular side [response-in-place (R-P) strategy]. We found that the similarity in firing patterns for O-P trials was significantly reduced with MUS compared to control conditions (CTs). Importantly, this was largely because MUS injections affected the O-P firing patterns in CA1 neurons, but not in CA3. The results suggest that PER is critical for goal-directed organization of object-place associative memory in the hippocampus presumably by influencing how object information is associated with spatial information in CA1 according to task demand.
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Affiliation(s)
- Inah Lee
- Department of Brain and Cognitive Sciences, Seoul National University Seoul, South Korea
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82
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Wilson DIG, Watanabe S, Milner H, Ainge JA. Lateral entorhinal cortex is necessary for associative but not nonassociative recognition memory. Hippocampus 2013; 23:1280-90. [PMID: 23836525 PMCID: PMC4030623 DOI: 10.1002/hipo.22165] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/20/2013] [Accepted: 06/24/2013] [Indexed: 12/28/2022]
Abstract
The lateral entorhinal cortex (LEC) provides one of the two major input pathways to the hippocampus and has been suggested to process the nonspatial contextual details of episodic memory. Combined with spatial information from the medial entorhinal cortex it is hypothesised that this contextual information is used to form an integrated spatially selective, context-specific response in the hippocampus that underlies episodic memory. Recently, we reported that the LEC is required for recognition of objects that have been experienced in a specific context (Wilson et al. (2013) Hippocampus 23:352-366). Here, we sought to extend this work to assess the role of the LEC in recognition of all associative combinations of objects, places and contexts within an episode. Unlike controls, rats with excitotoxic lesions of the LEC showed no evidence of recognizing familiar combinations of object in place, place in context, or object in place and context. However, LEC lesioned rats showed normal recognition of objects and places independently from each other (nonassociative recognition). Together with our previous findings, these data suggest that the LEC is critical for associative recognition memory and may bind together information relating to objects, places, and contexts needed for episodic memory formation.
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Affiliation(s)
- David I G Wilson
- School of Psychology and Neuroscience, University of St Andrews, St Mary's Quad, St Andrews, Fife, United Kingdom
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83
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Conflicts between local and global spatial frameworks dissociate neural representations of the lateral and medial entorhinal cortex. J Neurosci 2013; 33:9246-58. [PMID: 23719794 DOI: 10.1523/jneurosci.0946-13.2013] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Manipulation of spatial reference frames is a common experimental tool to investigate the nature of hippocampal information coding and to investigate high-order processes, such as cognitive coordination. However, it is unknown how the hippocampus afferents represent the local and global reference frames of an environment. To address these issues, single units were recorded in freely moving rats with multi-tetrode arrays targeting the superficial layers of the lateral entorhinal cortex (LEC) and medial entorhinal cortex (MEC), the two primary cortical inputs to the hippocampus. Rats ran clockwise laps around a circular track partitioned into quadrants covered by different textures (the local reference frame). The track was centered in a circular environment with distinct landmarks on the walls (the global reference frame). Here we demonstrate a novel dissociation between MEC and LEC in that the global frame controlled the MEC representation and the local frame controlled the LEC representation when the reference frames were rotated in equal, but opposite, directions. Consideration of the functional anatomy of the hippocampal circuit and popular models of attractor dynamics in CA3 suggests a mechanistic explanation of previous data showing a dissociation between the CA3 and CA1 regions in their responses to this local-global conflict. Furthermore, these results are consistent with a model of the LEC providing the hippocampus with the external sensory content of an experience and the MEC providing the spatial context, which combine to form conjunctive codes in the hippocampus that form the basis of episodic memory.
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84
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Rossato JI, Radiske A, Kohler CA, Gonzalez C, Bevilaqua LR, Medina JH, Cammarota M. Consolidation of object recognition memory requires simultaneous activation of dopamine D1/D5 receptors in the amygdala and medial prefrontal cortex but not in the hippocampus. Neurobiol Learn Mem 2013; 106:66-70. [PMID: 23891712 DOI: 10.1016/j.nlm.2013.07.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 06/26/2013] [Accepted: 07/12/2013] [Indexed: 02/07/2023]
Abstract
The mesocorticolimbic dopaminergic system includes the ventral tegmental area (VTA) and its projections to the amygdala (AMY), the hippocampus (HIP) and the medial prefrontal cortex (mPFC), among others. Object recognition (OR) long-term memory (LTM) processing requires dopaminergic activity but, although some of the brain regions mentioned above are necessary for OR LTM consolidation, their possible dopamine-mediated interplay remains to be analyzed. Using adult male Wistar rats, we found that posttraining microinjection of the dopamine D1/D5 receptor antagonist SCH23390 in mPFC or AMY, but not in HIP, impaired OR LTM. The dopamine D2 receptor agonist quinpirole had no effect on retention. VTA inactivation also hindered OR LTM, and even though this effect was unaffected by co-infusion of the dopamine D1/D5 receptor agonist SKF38393 in HIP, mPFC or AMY alone, it was reversed by simultaneous activation of D1/D5 receptors in the last two regions. Our results demonstrate that the mesocorticolimbic dopaminergic system is indeed essential for OR LTM consolidation and suggest that the role played by some of its components during this process is much more complex than previously thought.
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Affiliation(s)
- Janine I Rossato
- Memory Research Laboratory, Brain Institute (ICe), Federal University of Rio Grande do Norte (UFRN), Natal, RN 59056-450, Brazil; Laboratory of Behavioral Neurobiology, Biomedical Research Institute, Porto Alegre, RS 90610-000, Brazil
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85
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Lu L, Leutgeb JK, Tsao A, Henriksen EJ, Leutgeb S, Barnes CA, Witter MP, Moser MB, Moser EI. Impaired hippocampal rate coding after lesions of the lateral entorhinal cortex. Nat Neurosci 2013; 16:1085-93. [PMID: 23852116 DOI: 10.1038/nn.3462] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 06/10/2013] [Indexed: 11/09/2022]
Abstract
In the hippocampus, spatial and non-spatial parameters may be represented by a dual coding scheme, in which coordinates in space are expressed by the collective firing locations of place cells and the diversity of experience at these locations is encoded by orthogonal variations in firing rates. Although the spatial signal may reflect input from medial entorhinal cortex, the sources of the variations in firing rate have not been identified. We found that rate variations in rat CA3 place cells depended on inputs from the lateral entorhinal cortex (LEC). Hippocampal rate remapping, induced by changing the shape or the color configuration of the environment, was impaired by lesions in those parts of the ipsilateral LEC that provided the densest input to the hippocampal recording position. Rate remapping was not observed in LEC itself. The findings suggest that LEC inputs are important for efficient rate coding in the hippocampus.
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Affiliation(s)
- Li Lu
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway.
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86
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Burke SN, Maurer AP, Hartzell AL, Nematollahi S, Uprety A, Wallace JL, Barnes CA. Representation of three-dimensional objects by the rat perirhinal cortex. Hippocampus 2013; 22:2032-44. [PMID: 22987680 DOI: 10.1002/hipo.22060] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The perirhinal cortex (PRC) is known to play an important role in object recognition. Little is known, however, regarding the activity of PRC neurons during the presentation of stimuli that are commonly used for recognition memory tasks in rodents, that is, three-dimensional objects. Rats in the present study were exposed to three-dimensional objects while they traversed a circular track for food reward. Under some behavioral conditions, the track contained novel objects, familiar objects, or no objects. Approximately 38% of PRC neurons demonstrated "object fields" (a selective increase in firing at the location of one or more objects). Although the rats spent more time exploring the objects when they were novel compared to familiar, indicating successful recognition memory, the proportion of object fields and the firing rates of PRC neurons were not affected by the rats' previous experience with the objects. Together, these data indicate that the activity of PRC cells is powerfully affected by the presence of objects while animals navigate through an environment; but under these conditions, the firing patterns are not altered by the relative novelty of objects during successful object recognition.
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Affiliation(s)
- S N Burke
- Evelyn F. McKnight Brain Institute, University of Arizona, Tucson, AZ, USA
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87
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The role of histamine receptors in the consolidation of object recognition memory. Neurobiol Learn Mem 2013; 103:64-71. [PMID: 23583502 DOI: 10.1016/j.nlm.2013.04.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 03/12/2013] [Accepted: 04/02/2013] [Indexed: 12/18/2022]
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88
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Abstract
One prominent view holds that episodic memory emerged recently in humans and lacks a "(neo)Darwinian evolution" [Tulving E (2002) Annu Rev Psychol 53:1-25]. Here, we review evidence supporting the alternative perspective that episodic memory has a long evolutionary history. We show that fundamental features of episodic memory capacity are present in mammals and birds and that the major brain regions responsible for episodic memory in humans have anatomical and functional homologs in other species. We propose that episodic memory capacity depends on a fundamental neural circuit that is similar across mammalian and avian species, suggesting that protoepisodic memory systems exist across amniotes and, possibly, all vertebrates. The implication is that episodic memory in diverse species may primarily be due to a shared underlying neural ancestry, rather than the result of evolutionary convergence. We also discuss potential advantages that episodic memory may offer, as well as species-specific divergences that have developed on top of the fundamental episodic memory architecture. We conclude by identifying possible time points for the emergence of episodic memory in evolution, to help guide further research in this area.
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89
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Lee I, Lee CH. Contextual behavior and neural circuits. Front Neural Circuits 2013; 7:84. [PMID: 23675321 PMCID: PMC3650478 DOI: 10.3389/fncir.2013.00084] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 04/14/2013] [Indexed: 11/13/2022] Open
Abstract
Animals including humans engage in goal-directed behavior flexibly in response to items and their background, which is called contextual behavior in this review. Although the concept of context has long been studied, there are differences among researchers in defining and experimenting with the concept. The current review aims to provide a categorical framework within which not only the neural mechanisms of contextual information processing but also the contextual behavior can be studied in more concrete ways. For this purpose, we categorize contextual behavior into three subcategories as follows by considering the types of interactions among context, item, and response: contextual response selection, contextual item selection, and contextual item–response selection. Contextual response selection refers to the animal emitting different types of responses to the same item depending on the context in the background. Contextual item selection occurs when there are multiple items that need to be chosen in a contextual manner. Finally, when multiple items and multiple contexts are involved, contextual item–response selection takes place whereby the animal either chooses an item or inhibits such a response depending on item–context paired association. The literature suggests that the rhinal cortical regions and the hippocampal formation play key roles in mnemonically categorizing and recognizing contextual representations and the associated items. In addition, it appears that the fronto-striatal cortical loops in connection with the contextual information-processing areas critically control the flexible deployment of adaptive action sets and motor responses for maximizing goals. We suggest that contextual information processing should be investigated in experimental settings where contextual stimuli and resulting behaviors are clearly defined and measurable, considering the dynamic top-down and bottom-up interactions among the neural systems for contextual behavior.
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Affiliation(s)
- Inah Lee
- Behavioral Neurophysiology Laboratory, Department of Brain and Cognitive Sciences, Seoul National University Seoul, South Korea
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90
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Transcription of the immediate-early gene Arc in CA1 of the hippocampus reveals activity differences along the proximodistal axis that are attenuated by advanced age. J Neurosci 2013; 33:3424-33. [PMID: 23426670 DOI: 10.1523/jneurosci.4727-12.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The CA1 region of the hippocampus receives distinct patterns of afferent input to distal (near subiculum) and proximal (near CA2) zones. Specifically, distal CA1 receives a direct projection from cells in the lateral entorhinal cortex that are sensitive to objects, whereas proximal CA1 is innervated by cells in the medial entorhinal cortex that are responsive to space. This suggests that neurons in different areas along the proximodistal axis of CA1 of the hippocampus will be functionally distinct. The current experiment investigated this possibility by monitoring behavior-induced cell activity across the CA1 axis using Arc mRNA imaging methods that compared adult and old rats in two conditions: (1) exploration of the same environment containing the same objects twice (AA) or (2) exploration of two different environments that contained identical objects (AB). The hypothesis was that CA1 place cells should show field remapping in the condition in which environments were changed, but the extent of remapping was expected to differ between proximal and distal regions and between age groups. In fact, neurons in the proximal region of CA1 in adult animals exhibited a greater degree of remapping than did distal CA1 cells when the environment changed, suggesting that cells receiving input from the medial entorhinal cortex are more sensitive to spatial context. However, in old rats, there were no differences in remapping across the proximodistal CA1 axis. Together, these data suggest that distal and proximal CA1 may be functionally distinct and differentially vulnerable to normative aging processes.
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91
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Deshmukh SS, Knierim JJ. Influence of local objects on hippocampal representations: Landmark vectors and memory. Hippocampus 2013; 23:253-67. [PMID: 23447419 DOI: 10.1002/hipo.22101] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2013] [Indexed: 11/10/2022]
Abstract
The hippocampus is thought to represent nonspatial information in the context of spatial information. An animal can derive both spatial information as well as nonspatial information from the objects (landmarks) it encounters as it moves around in an environment. In this article, correlates of both object-derived spatial as well as nonspatial information in the hippocampus of rats foraging in the presence of objects are demonstrated. A new form of CA1 place cells, called landmark-vector cells, that encode spatial locations as a vector relationship to local landmarks is described. Such landmark vector relationships can be dynamically encoded. Of the 26 CA1 neurons that developed new fields in the course of a day's recording sessions, in eight cases, the new fields were located at a similar distance and direction from a landmark as the initial field was located relative to a different landmark. In addition, object-location memory in the hippocampus is also described. When objects were removed from an environment or moved to new locations, a small number of neurons in CA1 and CA3 increased firing at the locations where the objects used to be. In some neurons, this increase occurred only in one location, indicating object + place conjunctive memory; in other neurons, the increase in firing was seen at multiple locations where an object used to be. Taken together, these results demonstrate that the spatially restricted firing of hippocampal neurons encode multiple types of information regarding the relationship between an animal's location and the location of objects in its environment.
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Affiliation(s)
- Sachin S Deshmukh
- Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218, USA.
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92
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Hunsaker MR, Chen V, Tran GT, Kesner RP. The medial and lateral entorhinal cortex both contribute to contextual and item recognition memory: A test of the binding ofitems and context model. Hippocampus 2013; 23:380-91. [DOI: 10.1002/hipo.22097] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2013] [Indexed: 11/07/2022]
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93
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Hirel J, Gaussier P, Quoy M, Banquet JP, Save E, Poucet B. The hippocampo-cortical loop: spatio-temporal learning and goal-oriented planning in navigation. Neural Netw 2013; 43:8-21. [PMID: 23500496 DOI: 10.1016/j.neunet.2013.01.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 01/30/2013] [Accepted: 01/31/2013] [Indexed: 11/25/2022]
Abstract
We present a neural network model where the spatial and temporal components of a task are merged and learned in the hippocampus as chains of associations between sensory events. The prefrontal cortex integrates this information to build a cognitive map representing the environment. The cognitive map can be used after latent learning to select optimal actions to fulfill the goals of the animal. A simulation of the architecture is made and applied to learning and solving tasks that involve both spatial and temporal knowledge. We show how this model can be used to solve the continuous place navigation task, where a rat has to navigate to an unmarked goal and wait for 2 seconds without moving to receive a reward. The results emphasize the role of the hippocampus for both spatial and timing prediction, and the prefrontal cortex in the learning of goals related to the task.
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Affiliation(s)
- J Hirel
- ETIS, ENSEA, Université de Cergy-Pontoise, CNRS F-95000 Cergy-Pontoise, France
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94
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Wilson DIG, Langston RF, Schlesiger MI, Wagner M, Watanabe S, Ainge JA. Lateral entorhinal cortex is critical for novel object-context recognition. Hippocampus 2013; 23:352-66. [PMID: 23389958 PMCID: PMC3648979 DOI: 10.1002/hipo.22095] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2013] [Indexed: 11/10/2022]
Abstract
Episodic memory incorporates information about specific events or occasions including spatial locations and the contextual features of the environment in which the event took place. It has been modeled in rats using spontaneous exploration of novel configurations of objects, their locations, and the contexts in which they are presented. While we have a detailed understanding of how spatial location is processed in the brain relatively little is known about where the nonspatial contextual components of episodic memory are processed. Initial experiments measured c-fos expression during an object-context recognition (OCR) task to examine which networks within the brain process contextual features of an event. Increased c-fos expression was found in the lateral entorhinal cortex (LEC; a major hippocampal afferent) during OCR relative to control conditions. In a subsequent experiment it was demonstrated that rats with lesions of LEC were unable to recognize object-context associations yet showed normal object recognition and normal context recognition. These data suggest that contextual features of the environment are integrated with object identity in LEC and demonstrate that recognition of such object-context associations requires the LEC. This is consistent with the suggestion that contextual features of an event are processed in LEC and that this information is combined with spatial information from medial entorhinal cortex to form episodic memory in the hippocampus. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- David I G Wilson
- School of Psychology, University of St Andrews, St Mary's Quad, St Andrews, Fife, United Kingdom
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95
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Mello-Carpes PB, Izquierdo I. The Nucleus of the Solitary Tract→Nucleus Paragigantocellularis→Locus Coeruleus→CA1 region of dorsal hippocampus pathway is important for consolidation of object recognition memory. Neurobiol Learn Mem 2013; 100:56-63. [DOI: 10.1016/j.nlm.2012.12.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/29/2012] [Accepted: 12/02/2012] [Indexed: 11/26/2022]
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