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Subramanian DL, Miller AMP, Smith DM. A comparison of hippocampal and retrosplenial cortical spatial and contextual firing patterns. Hippocampus 2024. [PMID: 38770779 DOI: 10.1002/hipo.23610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 03/22/2024] [Accepted: 05/07/2024] [Indexed: 05/22/2024]
Abstract
The hippocampus (HPC) and retrosplenial cortex (RSC) are key components of the brain's memory and navigation systems. Lesions of either region produce profound deficits in spatial cognition and HPC neurons exhibit well-known spatial firing patterns (place fields). Recent studies have also identified an array of navigation-related firing patterns in the RSC. However, there has been little work comparing the response properties and information coding mechanisms of these two brain regions. In the present study, we examined the firing patterns of HPC and RSC neurons in two tasks which are commonly used to study spatial cognition in rodents, open field foraging with an environmental context manipulation and continuous T-maze alternation. We found striking similarities in the kinds of spatial and contextual information encoded by these two brain regions. Neurons in both regions carried information about the rat's current spatial location, trajectories and goal locations, and both regions reliably differentiated the contexts. However, we also found several key differences. For example, information about head direction was a prominent component of RSC representations but was only weakly encoded in the HPC. The two regions also used different coding schemes, even when they encoded the same kind of information. As expected, the HPC employed a sparse coding scheme characterized by compact, high contrast place fields, and information about spatial location was the dominant component of HPC representations. RSC firing patterns were more consistent with a distributed coding scheme. Instead of compact place fields, RSC neurons exhibited broad, but reliable, spatial and directional tuning, and they typically carried information about multiple navigational variables. The observed similarities highlight the closely related functions of the HPC and RSC, whereas the differences in information types and coding schemes suggest that these two regions likely make somewhat different contributions to spatial cognition.
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Affiliation(s)
| | - Adam M P Miller
- Department of Psychology, Cornell University, Ithaca, New York, USA
| | - David M Smith
- Department of Psychology, Cornell University, Ithaca, New York, USA
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2
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Arndt KC, Gilbert ET, Klaver LMF, Kim J, Buhler CM, Basso JC, McKenzie S, English DF. Granular retrosplenial cortex layer 2/3 generates high-frequency oscillations dynamically coupled with hippocampal rhythms across brain states. Cell Rep 2024; 43:113910. [PMID: 38461414 DOI: 10.1016/j.celrep.2024.113910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 12/20/2023] [Accepted: 02/17/2024] [Indexed: 03/12/2024] Open
Abstract
The granular retrosplenial cortex (gRSC) exhibits high-frequency oscillations (HFOs; ∼150 Hz), which can be driven by a hippocampus-subiculum pathway. How the cellular-synaptic and laminar organization of gRSC facilitates HFOs is unknown. Here, we probe gRSC HFO generation and coupling with hippocampal rhythms using focal optogenetics and silicon-probe recordings in behaving mice. ChR2-mediated excitation of CaMKII-expressing cells in L2/3 or L5 induces HFOs, but spontaneous HFOs are found only in L2/3, where HFO power is highest. HFOs couple to CA1 sharp wave-ripples (SPW-Rs) during rest and the descending phase of theta. gRSC HFO current sources and sinks are the same for events during both SPW-Rs and theta oscillations. Independent component analysis shows that high gamma (50-100 Hz) in CA1 stratum lacunosum moleculare is comodulated with HFO power. HFOs may thus facilitate interregional communication of a multisynaptic loop between the gRSC, hippocampus, and medial entorhinal cortex during distinct brain and behavioral states.
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Affiliation(s)
- Kaiser C Arndt
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24060, USA
| | - Earl T Gilbert
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24060, USA
| | | | - Jongwoon Kim
- The Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, VA 24060, USA
| | - Chelsea M Buhler
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24060, USA
| | - Julia C Basso
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24060, USA; Department of Human Nutrition, Foods, and Exercise, Virginia Tech, Blacksburg, VA 24060, USA; Center for Health Behaviors Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Sam McKenzie
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.
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Subramanian DL, Smith DM. Time Cells in the Retrosplenial Cortex. bioRxiv 2024:2024.03.01.583039. [PMID: 38464235 PMCID: PMC10925311 DOI: 10.1101/2024.03.01.583039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
The retrosplenial cortex (RSC) is a key component of the brain's memory systems, with anatomical connections to the hippocampus, anterior thalamus, and entorhinal cortex. This circuit has been implicated in episodic memory and many of these structures have been shown to encode temporal information, which is critical for episodic memory. For example, hippocampal time cells reliably fire during specific segments of time during a delay period. Although RSC lesions are known to disrupt temporal memory, time cells have not been observed there. In the present study, we examined the firing patterns of RSC neurons during the intertrial delay period of two behavioral tasks, a blocked alternation task and a cued T-maze task. For the blocked alternation task, rats were required to approach the east or west arm of a plus maze for reward during different blocks of trials. Because the reward locations were not cued, the rat had to remember the goal location for each trial. In the cued T-maze task, the reward location was explicitly cued with a light and the rats simply had to approach the light for reward, so there was no requirement to hold a memory during the intertrial delay. Time cells were prevalent in the blocked alternation task, and most time cells clearly differentiated the east and west trials. We also found that RSC neurons could exhibit off-response time fields, periods of reliably inhibited firing. Time cells were also observed in the cued T-maze, but they were less prevalent and they did not differentiate left and right trials as well as in the blocked alternation task, suggesting that RSC time cells are sensitive to the memory demands of the task. These results suggest that temporal coding is a prominent feature of RSC firing patterns, consistent with an RSC role in episodic memory.
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Affiliation(s)
| | - David M. Smith
- Department of Psychology, Cornell University, Ithaca, NY 14853
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4
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Das D, Shaw ME, Hämäläinen MS, Dykstra AR, Doll L, Gutschalk A. A role for retro-splenial cortex in the task-related P3 network. Clin Neurophysiol 2024; 157:96-109. [PMID: 38091872 DOI: 10.1016/j.clinph.2023.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 10/12/2023] [Accepted: 11/19/2023] [Indexed: 12/26/2023]
Abstract
OBJECTIVE The P3 is an event-related response observed in relation to task-relevant sensory events. Despite its ubiquitous presence, the neural generators of the P3 are controversial and not well identified. METHODS We compared source analysis of combined magneto- and electroencephalography (M/EEG) data with functional magnetic resonance imaging (fMRI) and simulation studies to better understand the sources of the P3 in an auditory oddball paradigm. RESULTS Our results suggest that the dominant source of the classical, postero-central P3 lies in the retro-splenial cortex of the ventral cingulate gyrus. A second P3 source in the anterior insular cortex contributes little to the postero-central maximum. Multiple other sources in the auditory, somatosensory, and anterior midcingulate cortex are active in an overlapping time window but can be functionally dissociated based on their activation time courses. CONCLUSIONS The retro-splenial cortex is a dominant source of the parietal P3 maximum in EEG. SIGNIFICANCE These results provide a new perspective for the interpretation of the extensive research based on the P3 response.
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Affiliation(s)
- Diptyajit Das
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Marnie E Shaw
- College of Engineering & Computer Science, Australian National University, Canberra, Australia
| | - Matti S Hämäläinen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, USA; Harvard, MIT Division of Health Science and Technology, USA; Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Finland
| | - Andrew R Dykstra
- Department of Biomedical Engineering, University of Miami, Coral Gables, USA
| | - Laura Doll
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Alexander Gutschalk
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
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Aggleton JP, Vann SD, O'Mara SM. Converging diencephalic and hippocampal supports for episodic memory. Neuropsychologia 2023; 191:108728. [PMID: 37939875 DOI: 10.1016/j.neuropsychologia.2023.108728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/25/2023] [Accepted: 11/03/2023] [Indexed: 11/10/2023]
Abstract
To understand the neural basis of episodic memory it is necessary to appreciate the significance of the fornix. This pathway creates a direct link between those temporal lobe and medial diencephalic sites responsible for anterograde amnesia. A collaboration with Andrew Mayes made it possible to recruit and scan 38 patients with colloid cysts in the third ventricle, a condition associated with variable fornix damage. Complete fornix loss was seen in three patients, who suffered chronic long-term memory problems. Volumetric analyses involving all 38 patients then revealed a highly consistent relationship between mammillary body volume and the recall of episodic memory. That relationship was not seen for working memory or tests of recognition memory. Three different methods all supported a dissociation between recollective-based recognition (impaired) and familiarity-based recognition (spared). This dissociation helped to show how the mammillary body-anterior thalamic nuclei axis, as well as the hippocampus, is vital for episodic memory yet is not required for familiarity-based recognition. These findings set the scene for a reformulation of temporal lobe and diencephalic amnesia. In this revised model, these two regions converge on overlapping cortical areas, including retrosplenial cortex. The united actions of the hippocampal formation and the anterior thalamic nuclei on these cortical areas enable episodic memory encoding and consolidation, impacting on subsequent recall.
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Affiliation(s)
- John P Aggleton
- School of Psychology, Cardiff University, Cardiff, CF10 3AT, Wales, United Kingdom.
| | - Seralynne D Vann
- School of Psychology, Cardiff University, Cardiff, CF10 3AT, Wales, United Kingdom
| | - Shane M O'Mara
- School of Psychology and Trinity College Institute of Neuroscience, Trinity College, Dublin - the University of Dublin, Dublin, D02 PN40, Ireland.
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Das D, Shaw ME, Hämäläinen MS, Dykstra AR, Doll L, Gutschalk A. A role for retro-splenial cortex in the task-related P3 network. bioRxiv 2023:2023.03.03.530970. [PMID: 36945516 PMCID: PMC10028840 DOI: 10.1101/2023.03.03.530970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Objective The P3 is an event-related response observed in relation to task-relevant sensory events. Despite its ubiquitous presence, the neural generators of the P3 are controversial and not well identified. Methods We compared source analysis of combined magneto- and electroencephalography (M/EEG) data with functional magnetic resonance imaging (fMRI) and simulation studies to better understand the sources of the P3 in an auditory oddball paradigm. Results Our results suggest that the dominant source of the classical, postero-central P3 lies in the retro-splenial cortex of the ventral cingulate gyrus. A second P3 source in the anterior insular cortex contributes little to the postero-central maximum. Multiple other sources in the auditory, somatosensory, and anterior midcingulate cortex are active in an overlapping time window but can be functionally dissociated based on their activation time courses. Conclusion The retro-splenial cortex is a dominant source of the parietal P3 maximum in EEG. Significance These results provide a new perspective for the interpretation of the extensive research based on the P3 response.
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Affiliation(s)
- Diptyajit Das
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Marnie E. Shaw
- College of Engineering & Computer Science, Australian National University, Canberra, Australia
| | - Matti S. Hämäläinen
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, USA
- Harvard, MIT Division of Health Science and Technology, USA
- Department of Neuroscience and Biomedical Engineering, Aalto University school of Science, Finland
| | - Andrew R. Dykstra
- Department of Biomedical Engineering, University of Miami, Coral Gables, USA
| | - Laura Doll
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Alexander Gutschalk
- Department of Neurology, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
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Feliciano-Ramos PA, Galazo M, Penagos H, Wilson M. Hippocampal memory reactivation during sleep is correlated with specific cortical states of the retrosplenial and prefrontal cortices. Learn Mem 2023; 30:221-236. [PMID: 37758288 PMCID: PMC10547389 DOI: 10.1101/lm.053834.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/25/2023] [Indexed: 10/03/2023]
Abstract
Episodic memories are thought to be stabilized through the coordination of cortico-hippocampal activity during sleep. However, the timing and mechanism of this coordination remain unknown. To investigate this, we studied the relationship between hippocampal reactivation and slow-wave sleep up and down states of the retrosplenial cortex (RTC) and prefrontal cortex (PFC). We found that hippocampal reactivations are strongly correlated with specific cortical states. Reactivation occurred during sustained cortical Up states or during the transition from up to down state. Interestingly, the most prevalent interaction with memory reactivation in the hippocampus occurred during sustained up states of the PFC and RTC, while hippocampal reactivation and cortical up-to-down state transition in the RTC showed the strongest coordination. Reactivation usually occurred within 150-200 msec of a cortical Up state onset, indicating that a buildup of excitation during cortical Up state activity influences the probability of memory reactivation in CA1. Conversely, CA1 reactivation occurred 30-50 msec before the onset of a cortical down state, suggesting that memory reactivation affects down state initiation in the RTC and PFC, but the effect in the RTC was more robust. Our findings provide evidence that supports and highlights the complexity of bidirectional communication between cortical regions and the hippocampus during sleep.
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Affiliation(s)
- Pedro A Feliciano-Ramos
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Maria Galazo
- Neuroscience Program, Tulane Brain Institute, Tulane University, New Orleans, Louisana 70118, USA
- Department of Cell and Molecular Biology, Tulane Brain Institute, Tulane University, New Orleans, Louisana 70118, USA
| | - Hector Penagos
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Center for Brains, Minds, and Machines, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Matthew Wilson
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
- Center for Brains, Minds, and Machines, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Robinson JC, Wilmot JH, Hasselmo ME. Septo-hippocampal dynamics and the encoding of space and time. Trends Neurosci 2023; 46:712-725. [PMID: 37479632 PMCID: PMC10538955 DOI: 10.1016/j.tins.2023.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 05/12/2023] [Accepted: 06/27/2023] [Indexed: 07/23/2023]
Abstract
Encoding an event in memory requires neural activity to represent multiple dimensions of behavioral experience in space and time. Recent experiments have explored the influence of neural dynamics regulated by the medial septum on the functional encoding of space and time by neurons in the hippocampus and associated structures. This review addresses these dynamics, focusing on the role of theta rhythm, the differential effects of septal inactivation and activation on the functional coding of space and time by individual neurons, and the influence on phase coding that appears as phase precession. We also discuss data indicating that theta rhythm plays a role in timing the internal dynamics of memory encoding and retrieval, as well as the behavioral influences of these neuronal manipulations with regard to memory function.
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Affiliation(s)
- Jennifer C Robinson
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, MA 02215, USA.
| | - Jacob H Wilmot
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, MA 02215, USA.
| | - Michael E Hasselmo
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, MA 02215, USA.
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Zhu W, Ou L, Zhang L, Clark IH, Zhang Y, Zhu XH, Whitley CB, Hackett PB, Low WC, Chen W. Mapping brain networks in MPS I mice and their restoration following gene therapy. Sci Rep 2023; 13:12716. [PMID: 37543633 PMCID: PMC10404260 DOI: 10.1038/s41598-023-39939-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 08/02/2023] [Indexed: 08/07/2023] Open
Abstract
Mucopolysaccharidosis type I (MPS I) is an inherited lysosomal disorder that causes syndromes characterized by physiological dysfunction in many organs and tissues. Despite the recognizable morphological and behavioral deficits associated with MPS I, neither the underlying alterations in functional neural connectivity nor its restoration following gene therapy have been shown. By employing high-resolution resting-state fMRI (rs-fMRI), we found significant reductions in functional neural connectivity in the limbic areas of the brain that play key roles in learning and memory in MPS I mice, and that adeno-associated virus (AAV)-mediated gene therapy can reestablish most brain connectivity. Using logistic regression in MPS I and treated animals, we identified functional networks with the most alterations. The rs-fMRI and statistical methods should be translatable into clinical evaluation of humans with neurological disorders.
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Affiliation(s)
- Wei Zhu
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, 55455, USA
- Department of Radiology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Li Ou
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, 55455, USA
- Genemagic Biosciences, Media, PA, 19063, USA
| | - Lin Zhang
- Division of Biostatistics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Isaac H Clark
- Biomedical Engineering Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Ying Zhang
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Xiao-Hong Zhu
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, 55455, USA
- Department of Radiology, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Chester B Whitley
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Perry B Hackett
- Department of Genetics, Cell Biology Development, University of Minnesota, Minneapolis, MN, 55455, USA
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Walter C Low
- Biomedical Engineering Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA.
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Neurosurgery, University of Minnesota, Minneapolis, MN, 55455, USA.
- Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.
| | - Wei Chen
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Radiology, University of Minnesota, Minneapolis, MN, 55455, USA.
- Biomedical Engineering Graduate Program, University of Minnesota, Minneapolis, MN, 55455, USA.
- Stem Cell Institute, University of Minnesota, Minneapolis, MN, 55455, USA.
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Arndt KC, Gilbert ET, Klaver LMF, Kim J, Buhler CM, Basso JC, McKenzie S, English DF. Granular retrosplenial cortex layer 2/3 generates high-frequency oscillations coupled with hippocampal theta and gamma in online states or sharp-wave ripples in offline states. bioRxiv 2023:2023.07.10.547981. [PMID: 37502984 PMCID: PMC10369913 DOI: 10.1101/2023.07.10.547981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Neuronal oscillations support information transfer by temporally aligning the activity of anatomically distributed 'writer' and 'reader' cell assemblies. High-frequency oscillations (HFOs) such as hippocampal CA1 sharp-wave ripples (SWRs; 100-250 Hz) are sufficiently fast to initiate synaptic plasticity between assemblies and are required for memory consolidation. HFOs are observed in parietal and midline cortices including granular retrosplenial cortex (gRSC). In 'offline' brain states (e.g. quiet wakefulness) gRSC HFOs co-occur with CA1 SWRs, while in 'online' states (e.g. ambulation) HFOs persist with the emergence of theta oscillations. The mechanisms of gRSC HFO oscillations, specifically whether the gRSC can intrinsically generate HFOs, and which layers support HFOs across states, remain unclear. We addressed these issues in behaving mice using optogenetic excitation in individual layers of the gRSC and high density silicon-probe recordings across gRSC layers and hippocampus CA1. Optogenetically induced HFOs (iHFOs) could be elicited by depolarizing excitatory neurons with 100 ms half-sine wave pulses in layer 2/3 (L2/3) or layer 5 (L5) though L5 iHFOs were of lower power than in L2/3. Critically, spontaneous HFOs were only observed in L2/3 and never in L5. Intra-laminar monosynaptic connectivity between excitatory and inhibitory neurons was similar across layers, suggesting other factors restrict HFOs to L2/3. To compare HFOs in online versus offline states we analyzed, separately, HFOs that did or did not co-occur with CA1 SWRs. Using current-source density analysis we found uniform synaptic inputs to L2/3 during all gRSC HFOs, suggesting layer-specific inputs may dictate the localization of HFOs to L2/3. HFOs occurring without SWRs were aligned with the descending phase of both gRSC and CA1 theta oscillations and were coherent with CA1 high frequency gamma oscillations (50-80 Hz). These results demonstrate that gRSC can internally generate HFOs without rhythmic inputs and that HFOs occur exclusively in L2/3, coupled to distinct hippocampal oscillations in online versus offline states.
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Harvey RE, Robinson HL, Liu C, Oliva A, Fernandez-Ruiz A. Hippocampo-cortical circuits for selective memory encoding, routing, and replay. Neuron 2023; 111:2076-2090.e9. [PMID: 37196658 DOI: 10.1016/j.neuron.2023.04.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 03/15/2023] [Accepted: 04/12/2023] [Indexed: 05/19/2023]
Abstract
Traditionally considered a homogeneous cell type, hippocampal pyramidal cells have been recently shown to be highly diverse. However, how this cellular diversity relates to the different hippocampal network computations that support memory-guided behavior is not yet known. We show that the anatomical identity of pyramidal cells is a major organizing principle of CA1 assembly dynamics, the emergence of memory replay, and cortical projection patterns in rats. Segregated pyramidal cell subpopulations encoded trajectory and choice-specific information or tracked changes in reward configuration respectively, and their activity was selectively read out by different cortical targets. Furthermore, distinct hippocampo-cortical assemblies coordinated the reactivation of complementary memory representations. These findings reveal the existence of specialized hippocampo-cortical subcircuits and provide a cellular mechanism that supports the computational flexibility and memory capacities of these structures.
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Affiliation(s)
- Ryan E Harvey
- Department of Neurobiology & Behavior, Cornell University, Ithaca, NY, USA
| | - Heath L Robinson
- Department of Neurobiology & Behavior, Cornell University, Ithaca, NY, USA
| | - Can Liu
- Department of Neurobiology & Behavior, Cornell University, Ithaca, NY, USA
| | - Azahara Oliva
- Department of Neurobiology & Behavior, Cornell University, Ithaca, NY, USA.
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Alexander AS, Robinson JC, Stern CE, Hasselmo ME. Gated transformations from egocentric to allocentric reference frames involving retrosplenial cortex, entorhinal cortex, and hippocampus. Hippocampus 2023; 33:465-487. [PMID: 36861201 PMCID: PMC10403145 DOI: 10.1002/hipo.23513] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 01/22/2023] [Accepted: 01/25/2023] [Indexed: 03/03/2023]
Abstract
This paper reviews the recent experimental finding that neurons in behaving rodents show egocentric coding of the environment in a number of structures associated with the hippocampus. Many animals generating behavior on the basis of sensory input must deal with the transformation of coordinates from the egocentric position of sensory input relative to the animal, into an allocentric framework concerning the position of multiple goals and objects relative to each other in the environment. Neurons in retrosplenial cortex show egocentric coding of the position of boundaries in relation to an animal. These neuronal responses are discussed in relation to existing models of the transformation from egocentric to allocentric coordinates using gain fields and a new model proposing transformations of phase coding that differ from current models. The same type of transformations could allow hierarchical representations of complex scenes. The responses in rodents are also discussed in comparison to work on coordinate transformations in humans and non-human primates.
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Affiliation(s)
- Andrew S Alexander
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
| | - Jennifer C Robinson
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
| | - Chantal E Stern
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
| | - Michael E Hasselmo
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts, USA
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Alexander AS, Place R, Starrett MJ, Chrastil ER, Nitz DA. Rethinking retrosplenial cortex: Perspectives and predictions. Neuron 2023; 111:150-175. [PMID: 36460006 DOI: 10.1016/j.neuron.2022.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 08/09/2022] [Accepted: 11/06/2022] [Indexed: 12/03/2022]
Abstract
The last decade has produced exciting new ideas about retrosplenial cortex (RSC) and its role in integrating diverse inputs. Here, we review the diversity in forms of spatial and directional tuning of RSC activity, temporal organization of RSC activity, and features of RSC interconnectivity with other brain structures. We find that RSC anatomy and dynamics are more consistent with roles in multiple sensorimotor and cognitive processes than with any isolated function. However, two more generalized categories of function may best characterize roles for RSC in complex cognitive processes: (1) shifting and relating perspectives for spatial cognition and (2) prediction and error correction for current sensory states with internal representations of the environment. Both functions likely take advantage of RSC's capacity to encode conjunctions among sensory, motor, and spatial mapping information streams. Together, these functions provide the scaffold for intelligent actions, such as navigation, perspective taking, interaction with others, and error detection.
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Affiliation(s)
- Andrew S Alexander
- Department of Psychological and Brain Sciences, Boston University, Boston, MA 02215, USA
| | - Ryan Place
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA 92093, USA
| | - Michael J Starrett
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Elizabeth R Chrastil
- Department of Neurobiology & Behavior, University of California, Irvine, Irvine, CA 92697, USA; Department of Cognitive Sciences, University of California, Irvine, Irvine, CA 92697, USA.
| | - Douglas A Nitz
- Department of Cognitive Science, University of California, San Diego, La Jolla, CA 92093, USA.
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14
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Karimi Abadchi J, Rezaei Z, Knöpfel T, McNaughton BL, Mohajerani MH. Inhibition is a prevalent mode of activity in the neocortex around awake hippocampal ripples in mice. eLife 2023; 12:79513. [PMID: 36645126 PMCID: PMC9876570 DOI: 10.7554/elife.79513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 01/06/2023] [Indexed: 01/17/2023] Open
Abstract
Coordinated peri-ripple activity in the hippocampal-neocortical network is essential for mnemonic information processing in the brain. Hippocampal ripples likely serve different functions in sleep and awake states. Thus, the corresponding neocortical activity patterns may differ in important ways. We addressed this possibility by conducting voltage and glutamate wide-field imaging of the neocortex with concurrent hippocampal electrophysiology in awake mice. Contrary to our previously published sleep results, deactivation and activation were dominant in post-ripple neocortical voltage and glutamate activity, respectively, especially in the agranular retrosplenial cortex (aRSC). Additionally, the spiking activity of aRSC neurons, estimated by two-photon calcium imaging, revealed the existence of two subpopulations of excitatory neurons with opposite peri-ripple modulation patterns: one increases and the other decreases firing rate. These differences in peri-ripple spatiotemporal patterns of neocortical activity in sleep versus awake states might underlie the reported differences in the function of sleep versus awake ripples.
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Affiliation(s)
- Javad Karimi Abadchi
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
| | - Zahra Rezaei
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
| | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Imperial College LondonLondonUnited Kingdom
- Department of Physics, Hong Kong Baptist UniversityKowloon TongHong Kong
| | - Bruce L McNaughton
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
- Department of Neurobiology and Behavior, University of CaliforniaIrvineUnited States
| | - Majid H Mohajerani
- Canadian Centre for Behavioral Neuroscience, University of LethbridgeLethbridgeCanada
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15
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Hussin AT, Abbaspoor S, Hoffman KL. Retrosplenial and Hippocampal Synchrony during Retrieval of Old Memories in Macaques. J Neurosci 2022; 42:7947-7956. [PMID: 36261267 PMCID: PMC9617609 DOI: 10.1523/jneurosci.0001-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Revised: 06/05/2022] [Accepted: 07/11/2022] [Indexed: 11/21/2022] Open
Abstract
Memory for events from the distant past relies on multiple brain regions, but little is known about the underlying neural dynamics that give rise to such abilities. We recorded neural activity in the hippocampus and retrosplenial cortex of two female rhesus macaques as they visually selected targets in year-old and newly acquired object-scene associations. Whereas hippocampal activity was unchanging with memory age, the retrosplenial cortex responded with greater magnitude alpha oscillations (10-15 Hz) and greater phase locking to memory-guided eye movements during retrieval of old events. A similar old-memory enhancement was observed in the anterior cingulate cortex but in a beta2/gamma band (28-35 Hz). In contrast, remote retrieval was associated with decreased gamma-band synchrony between the hippocampus and each neocortical area. The increasing retrosplenial alpha oscillation and decreasing hippocampocortical synchrony with memory age may signify a shift in frank memory allocation or, alternatively, changes in selection among distributed memory representations in the primate brain.SIGNIFICANCE STATEMENT Memory depends on multiple brain regions, whose involvement is thought to change with time. Here, we recorded neuronal population activity from the hippocampus and retrosplenial cortex as nonhuman primates searched for objects embedded in scenes. These memoranda were either newly presented or a year old. Remembering old material drove stronger oscillations in the retrosplenial cortex and led to a greater locking of neural activity to search movements. Remembering new material revealed stronger oscillatory synchrony between the hippocampus and retrosplenial cortex. These results suggest that with age, memories may come to rely more exclusively on neocortical oscillations for retrieval and search guidance and less on long-range coupling with the hippocampus.
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Affiliation(s)
- Ahmed T Hussin
- Department of Biology, Centre for Vision Research, York University, Toronto Ontario M3J 1P3, Canada
| | | | - Kari L Hoffman
- Department of Biology, Centre for Vision Research, York University, Toronto Ontario M3J 1P3, Canada
- Departments of Psychology
- Biomedical Engineering, Vanderbilt Vision Research Center, Vanderbilt Brain Institute, Vanderbilt University, Nashville, Tennessee 37240
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16
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Chambers AR, Berge CN, Vervaeke K. Cell-type-specific silence in thalamocortical circuits precedes hippocampal sharp-wave ripples. Cell Rep 2022; 40:111132. [PMID: 35905724 DOI: 10.1016/j.celrep.2022.111132] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/21/2021] [Accepted: 07/01/2022] [Indexed: 11/03/2022] Open
Abstract
Evidence suggests that the hippocampus conveys memory-related neural patterns across distributed cortical circuits during high-frequency oscillations called sharp-wave ripples (SWRs). We investigate how circuit activity in the retrosplenial cortex (RSC), a primary hippocampal target, could aid in processing SWR-related input. Using patch-clamp recordings from awake mice, we find that SWR-aligned membrane potential modulation is widespread but weak, and that spiking responses are sparse. However, using cell-type-specific two-photon Ca2+ imaging and optogenetics, we show that, 1-2 s before SWRs, superficial inhibition and thalamocortical input in RSC is reduced. We propose that pyramidal dendrites experience decreased local inhibition and subcortical interference in a seconds-long time window preceding SWRs. This may aid communication of weak and sparse SWR-aligned excitation between the hippocampus and neocortex and promote the strengthening of memory-related connections.
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Affiliation(s)
- Anna R Chambers
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
| | - Christoffer Nerland Berge
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Koen Vervaeke
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.
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17
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Ghosh M, Yang FC, Rice SP, Hetrick V, Gonzalez AL, Siu D, Brennan EKW, John TT, Ahrens AM, Ahmed OJ. Running speed and REM sleep control two distinct modes of rapid interhemispheric communication. Cell Rep 2022; 40:111028. [PMID: 35793619 PMCID: PMC9291430 DOI: 10.1016/j.celrep.2022.111028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 04/08/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022] Open
Abstract
Rhythmic gamma-band communication within and across cortical hemispheres is critical for optimal perception, navigation, and memory. Here, using multisite recordings in both rats and mice, we show that even faster ~140 Hz rhythms are robustly anti-phase across cortical hemispheres, visually resembling splines, the interlocking teeth on mechanical gears. Splines are strongest in superficial granular retrosplenial cortex, a region important for spatial navigation and memory. Spline-frequency interhemispheric communication becomes more coherent and more precisely anti-phase at faster running speeds. Anti-phase splines also demarcate high-activity frames during REM sleep. While splines and associated neuronal spiking are anti-phase across retrosplenial hemispheres during navigation and REM sleep, gamma-rhythmic interhemispheric communication is precisely in-phase. Gamma and splines occur at distinct points of a theta cycle and thus highlight the ability of interhemispheric cortical communication to rapidly switch between in-phase (gamma) and anti-phase (spline) modes within individual theta cycles during both navigation and REM sleep. Gamma-rhythmic communication within and across cortical hemispheres is critical for optimal perception, navigation, and memory. Here, Ghosh et al. identify even faster ~140 Hz rhythms, named splines, that reflect anti-phase neuronal synchrony across hemispheres. The balance of anti-phase spline and in-phase gamma communication is dynamically controlled by behavior and sleep.
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Affiliation(s)
- Megha Ghosh
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Fang-Chi Yang
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sharena P Rice
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vaughn Hetrick
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Alcides Lorenzo Gonzalez
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Danny Siu
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ellen K W Brennan
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Tibin T John
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Allison M Ahrens
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Omar J Ahmed
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA; Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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18
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Smith DM, Yang YY, Subramanian DL, Miller AMP, Bulkin DA, Law LM. The limbic memory circuit and the neural basis of contextual memory. Neurobiol Learn Mem 2022; 187:107557. [PMID: 34808337 PMCID: PMC8755583 DOI: 10.1016/j.nlm.2021.107557] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 01/03/2023]
Abstract
The hippocampus, retrosplenial cortex and anterior thalamus are key components of a neural circuit known to be involved in a variety of memory functions, including spatial, contextual and episodic memory. In this review, we focus on the role of this circuit in contextual memory processes. The background environment, or context, is a powerful cue for memory retrieval, and neural representations of the context provide a mechanism for efficiently retrieving relevant memories while avoiding interference from memories that belong to other contexts. Data from experimental lesions and neural manipulation techniques indicate that each of these regions is critical for contextual memory. Neurophysiological evidence from the hippocampus and retrosplenial cortex suggest that contextual information is represented within this circuit by population-level neural firing patterns that reliably differentiate each context a subject encounters. These findings indicate that encoding contextual information to support context-dependent memory retrieval is a key function of this circuit.
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Affiliation(s)
- David M Smith
- Department of Psychology, Cornell University, Ithaca, NY, United States.
| | - Yan Yu Yang
- Department of Psychology, Cornell University, Ithaca, NY, United States
| | | | - Adam M P Miller
- Department of Psychology, Cornell University, Ithaca, NY, United States
| | - David A Bulkin
- Department of Psychology, Cornell University, Ithaca, NY, United States
| | - L Matthew Law
- Department of Psychology, Cornell University, Ithaca, NY, United States
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19
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Lomi E, Mathiasen ML, Cheng HY, Zhang N, Aggleton JP, Mitchell AS, Jeffery KJ. Evidence for two distinct thalamocortical circuits in retrosplenial cortex. Neurobiol Learn Mem 2021; 185:107525. [PMID: 34555510 DOI: 10.1016/j.nlm.2021.107525] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/20/2021] [Accepted: 09/15/2021] [Indexed: 01/04/2023]
Abstract
Retrosplenial cortex (RSC) lies at the interface between sensory and cognitive networks in the brain and mediates between these, although it is not yet known how. It has two distinct subregions, granular (gRSC) and dysgranular (dRSC). The present study investigated how these subregions differ with respect to their electrophysiology and thalamic connectivity, as a step towards understanding their functions. The gRSC is more closely connected to the hippocampal formation, in which theta-band local field potential oscillations are prominent. We, therefore, compared theta-rhythmic single-unit activity between the two RSC subregions and found, mostly in gRSC, a subpopulation of non-directional cells with spiking activity strongly entrained by theta oscillations, suggesting a stronger coupling of gRSC to the hippocampal system. We then used retrograde tracers to test for differential inputs to RSC from the anteroventral thalamus (AV). We found that gRSC and dRSC differ in their afferents from two AV subfields: dorsomedial (AVDM) and ventrolateral (AVVL). Specifically: (1) as a whole AV projects more strongly to gRSC; (2) AVVL targets both gRSC and dRSC, while AVDM provides a selective projection to gRSC, (3) the gRSC projection is layer-specific: AVDM targets specifically gRSC superficial layers. These same AV projections are topographically organized with ventral AV neurons innervating rostral RSC and dorsal AV neurons innervating caudal RSC. These combined results suggest the existence of two distinct but interacting RSC subcircuits: one connecting AVDM to gRSC that may comprise part of the cognitive hippocampal system, and the other connecting AVVL to both RSC regions that may link hippocampal and perceptual regions. We suggest that these subcircuits are distinct to allow for differential weighting during integration of converging sensory and cognitive computations: an integration that may take place in thalamus, RSC, or both.
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Affiliation(s)
- Eleonora Lomi
- Department of Experimental Psychology, University of Oxford, The Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK.
| | | | - Han Y Cheng
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire, USA
| | - Ningyu Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | | | - Anna S Mitchell
- Department of Experimental Psychology, University of Oxford, The Tinsley Building, Mansfield Road, Oxford OX1 3SR, UK
| | - Kate J Jeffery
- Institute of Behavioural Neuroscience, Division of Psychology and Language Sciences, University College London, London WC1E 6BT, UK
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20
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de Almeida-Filho DG, Koike BDV, Billwiller F, Farias KS, de Sales IRP, Luppi PH, Ribeiro S, Queiroz CM. Hippocampus-retrosplenial cortex interaction is increased during phasic REM and contributes to memory consolidation. Sci Rep 2021; 11:13078. [PMID: 34158548 DOI: 10.1038/s41598-021-91659-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/20/2021] [Indexed: 11/23/2022] Open
Abstract
Hippocampal (HPC) theta oscillation during post-training rapid eye movement (REM) sleep supports spatial learning. Theta also modulates neuronal and oscillatory activity in the retrosplenial cortex (RSC) during REM sleep. To investigate the relevance of theta-driven interaction between these two regions to memory consolidation, we computed the Granger causality within theta range on electrophysiological data recorded in freely behaving rats during REM sleep, both before and after contextual fear conditioning. We found a training-induced modulation of causality between HPC and RSC that was correlated with memory retrieval 24 h later. Retrieval was proportional to the change in the relative influence RSC exerted upon HPC theta oscillation. Importantly, causality peaked during theta acceleration, in synchrony with phasic REM sleep. Altogether, these results support a role for phasic REM sleep in hippocampo-cortical memory consolidation and suggest that causality modulation between RSC and HPC during REM sleep plays a functional role in that phenomenon.
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21
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Shelley LE, Nitz DA. Locomotor action sequences impact the scale of representation in hippocampus and posterior parietal cortex. Hippocampus 2021; 31:677-689. [DOI: 10.1002/hipo.23339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 04/23/2021] [Accepted: 05/02/2021] [Indexed: 11/10/2022]
Affiliation(s)
- Laura E. Shelley
- Department of Cognitive Science University of California San Diego California USA
| | - Douglas A. Nitz
- Department of Cognitive Science University of California San Diego California USA
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22
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Brennan EKW, Sudhakar SK, Jedrasiak-Cape I, John TT, Ahmed OJ. Hyperexcitable Neurons Enable Precise and Persistent Information Encoding in the Superficial Retrosplenial Cortex. Cell Rep 2021; 30:1598-1612.e8. [PMID: 32023472 DOI: 10.1016/j.celrep.2019.12.093] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 10/25/2019] [Accepted: 12/27/2019] [Indexed: 11/29/2022] Open
Abstract
The retrosplenial cortex (RSC) is essential for memory and navigation, but the neural codes underlying these functions remain largely unknown. Here, we show that the most prominent cell type in layers 2/3 (L2/3) of the mouse granular RSC is a hyperexcitable, small pyramidal cell. These cells have a low rheobase (LR), high input resistance, lack of spike frequency adaptation, and spike widths intermediate to those of neighboring fast-spiking (FS) inhibitory neurons and regular-spiking (RS) excitatory neurons. LR cells are excitatory but rarely synapse onto neighboring neurons. Instead, L2/3 is a feedforward, not feedback, inhibition-dominated network with dense connectivity between FS cells and from FS to LR neurons. Biophysical models of LR but not RS cells precisely and continuously encode sustained input from afferent postsubicular head-direction cells. Thus, the distinct intrinsic properties of LR neurons can support both the precision and persistence necessary to encode information over multiple timescales in the RSC.
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Affiliation(s)
- Ellen K W Brennan
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | | | | | - Tibin T John
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Omar J Ahmed
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Center for Integrative Research in Critical Care, University of Michigan, Ann Arbor, MI 48109, USA; Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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23
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Kitanishi T, Umaba R, Mizuseki K. Robust information routing by dorsal subiculum neurons. Sci Adv 2021; 7:7/11/eabf1913. [PMID: 33692111 PMCID: PMC7946376 DOI: 10.1126/sciadv.abf1913] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 01/25/2021] [Indexed: 05/27/2023]
Abstract
The dorsal hippocampus conveys various information associated with spatial navigation; however, how the information is distributed to multiple downstream areas remains unknown. We investigated this by identifying axonal projections using optogenetics during large-scale recordings from the rat subiculum, the major hippocampal output structure. Subicular neurons demonstrated a noise-resistant representation of place, speed, and trajectory, which was as accurate as or even more accurate than that of hippocampal CA1 neurons. Speed- and trajectory-dependent firings were most prominent in neurons projecting to the retrosplenial cortex and nucleus accumbens, respectively. Place-related firing was uniformly observed in neurons targeting the retrosplenial cortex, nucleus accumbens, anteroventral thalamus, and medial mammillary body. Theta oscillations and sharp-wave/ripples tightly controlled the firing of projection neurons in a target region-specific manner. In conclusion, the dorsal subiculum robustly routes diverse navigation-associated information to downstream areas.
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Affiliation(s)
- Takuma Kitanishi
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan.
- PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Saitama 332-0012, Japan
| | - Ryoko Umaba
- Department of Neurosurgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan
| | - Kenji Mizuseki
- Department of Physiology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan.
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24
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Opalka AN, Huang WQ, Liu J, Liang H, Wang DV. Hippocampal Ripple Coordinates Retrosplenial Inhibitory Neurons during Slow-Wave Sleep. Cell Rep 2021; 30:432-441.e3. [PMID: 31940487 PMCID: PMC7007963 DOI: 10.1016/j.celrep.2019.12.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/01/2019] [Accepted: 12/12/2019] [Indexed: 12/20/2022] Open
Abstract
The hippocampus and retrosplenial cortex (RSC) play indispensable roles in memory formation, and importantly, a hippocampal oscillation known as ripple is key to consolidation of new memories. However, it remains unclear how the hippocampus and RSC communicate and the role of ripple oscillation in coordinating the activity between these two brain regions. Here, we record from the dorsal hippocampus and RSC simultaneously in freely behaving mice during sleep and reveal that the RSC displays a pre-ripple activation associated with slow and fast oscillations. Immediately after ripples, a subpopulation of RSC putative inhibitory neurons increases firing activity, while most RSC putative excitatory neurons decrease activity. Consistently, optogenetic stimulation of this hippocampus-RSC pathway activates and suppresses RSC putative inhibitory and excitatory neurons, respectively. These results suggest that the dorsal hippocampus mainly inhibits RSC activity via its direct innervation of RSC inhibitory neurons, which overshadows the RSC in supporting learning and memory functions. Converging evidence suggests that hippocampal ripple oscillations and their interaction with the neocortex are critical for memory consolidation. By combining electrophysiology and optogenetic techniques in freely behaving mice, Opalka et al. provide direct evidence that hippocampal ripples communicate with retrosplenial cortex (RSC) interneurons and inhibit RSC population activity during sleep-associated memory consolidation.
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Affiliation(s)
- Ashley N Opalka
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Wen-Qiang Huang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Jun Liu
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Hualou Liang
- School of Biomedical Engineering, Drexel University, Philadelphia, PA 19104, USA
| | - Dong V Wang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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25
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Abstract
While memories are often thought of as flashbacks to a previous experience, they do not simply conserve veridical representations of the past but must continually integrate new information to ensure survival in dynamic environments. Therefore, 'drift' in neural firing patterns, typically construed as disruptive 'instability' or an undesirable consequence of noise, may actually be useful for updating memories. In our view, continual modifications in memory representations reconcile classical theories of stable memory traces with neural drift. Here we review how memory representations are updated through dynamic recruitment of neuronal ensembles on the basis of excitability and functional connectivity at the time of learning. Overall, we emphasize the importance of considering memories not as static entities, but instead as flexible network states that reactivate and evolve across time and experience.
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Affiliation(s)
- William Mau
- Neuroscience Department, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | | | - Denise J Cai
- Neuroscience Department, Icahn School of Medicine at Mount SinaiNew YorkUnited States
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26
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Botterill JJ, Lu YL, LaFrancois JJ, Bernstein HL, Alcantara-Gonzalez D, Jain S, Leary P, Scharfman HE. An Excitatory and Epileptogenic Effect of Dentate Gyrus Mossy Cells in a Mouse Model of Epilepsy. Cell Rep 2020; 29:2875-2889.e6. [PMID: 31775052 PMCID: PMC6905501 DOI: 10.1016/j.celrep.2019.10.100] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/25/2019] [Accepted: 10/24/2019] [Indexed: 12/20/2022] Open
Abstract
The sparse activity of hippocampal dentate gyrus (DG) granule cells (GCs) is thought to be critical for cognition and behavior, whereas excessive DG activity may contribute to disorders such as temporal lobe epilepsy (TLE). Glutamatergic mossy cells (MCs) of the DG are potentially critical to normal and pathological functions of the DG because they can regulate GC activity through innervation of GCs or indirectly through GABAergic neurons. Here, we test the hypothesis that MC excitation of GCs is normally weak, but under pathological conditions, MC excitation of GCs is dramatically strengthened. We show that selectively inhibiting MCs during severe seizures reduced manifestations of those seizures, hippocampal injury, and chronic epilepsy. In contrast, selectively activating MCs was pro-convulsant. Mechanistic in vitro studies using optogenetics further demonstrated the unanticipated ability of MC axons to excite GCs under pathological conditions. These results demonstrate an excitatory and epileptogenic effect of MCs in the DG.
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Affiliation(s)
- Justin J Botterill
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Yi-Ling Lu
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - John J LaFrancois
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Hannah L Bernstein
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Neuroscience & Physiology, New York University Langone Health, New York, NY 10016, USA
| | - David Alcantara-Gonzalez
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Swati Jain
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Paige Leary
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Helen E Scharfman
- Center for Dementia Research, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Neuroscience & Physiology, New York University Langone Health, New York, NY 10016, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA.
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27
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Pernia AM, Zorzo C, Prieto MJ, Martinez JA, Higarza SG, Mendez M, Arias JL. Equipment for Repetitive Transcranial Magnetic Stimulation. IEEE Trans Biomed Circuits Syst 2020; 14:525-534. [PMID: 32175874 DOI: 10.1109/tbcas.2020.2981012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique used for the treatment of a great variety of neurological disorders. The technique involves applying a magnetic field in certain areas of the cerebral cortex in order to modify neuronal excitability outside the skull. However, the exact brain mechanisms underlying rTMS effects are not completely elucidated. For that purpose, and in order to generate a pulsed magnetic field, a half-bridge converter controlled by a microcontroller has been designed to apply rTMS in small animals. Moreover, the small size of the rodent head makes it necessary to design a magnetic transducer, with the aim of focusing the magnetic field on selected brain areas using a specific and a small magnetic head. Using such devices, our purpose was to compare the effects of five different rTMS dosages on rat brain metabolic activity. The experimental results showed that one day of stimulation leads to an enhancement of brain metabolic activity in cortical areas, meanwhile with three days of stimulation it is possible to also modify subcortical zones, results that were not found when extending the number of rTMS applications up to seven days. In consequence, the number of pulses delivered might be an important parameter in rTMS protocols, highlighting its importance in rTMS impact.
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28
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Nitzan N, McKenzie S, Beed P, English DF, Oldani S, Tukker JJ, Buzsáki G, Schmitz D. Propagation of hippocampal ripples to the neocortex by way of a subiculum-retrosplenial pathway. Nat Commun 2020; 11:1947. [PMID: 32327634 PMCID: PMC7181800 DOI: 10.1038/s41467-020-15787-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Accepted: 03/27/2020] [Indexed: 02/07/2023] Open
Abstract
Bouts of high frequency activity known as sharp wave ripples (SPW-Rs) facilitate communication between the hippocampus and neocortex. However, the paths and mechanisms by which SPW-Rs broadcast their content are not well understood. Due to its anatomical positioning, the granular retrosplenial cortex (gRSC) may be a bridge for this hippocampo-cortical dialogue. Using silicon probe recordings in awake, head-fixed mice, we show the existence of SPW-R analogues in gRSC and demonstrate their coupling to hippocampal SPW-Rs. gRSC neurons reliably distinguished different subclasses of hippocampal SPW-Rs according to ensemble activity patterns in CA1. We demonstrate that this coupling is brain state-dependent, and delineate a topographically-organized anatomical pathway via VGlut2-expressing, bursty neurons in the subiculum. Optogenetic stimulation or inhibition of bursty subicular cells induced or reduced responses in superficial gRSC, respectively. These results identify a specific path and underlying mechanisms by which the hippocampus can convey neuronal content to the neocortex during SPW-Rs.
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Affiliation(s)
- Noam Nitzan
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
| | - Sam McKenzie
- Neuroscience Institute and Department of Neurology New York University Langone Medical Center, New York, NY, 10016, USA
| | - Prateep Beed
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
| | - Daniel Fine English
- Neuroscience Institute and Department of Neurology New York University Langone Medical Center, New York, NY, 10016, USA
- School of Neuroscience, College of Science, Virginia Tech, VA, 24061, USA
| | - Silvia Oldani
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
- Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - John J Tukker
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany
- Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - György Buzsáki
- Neuroscience Institute and Department of Neurology New York University Langone Medical Center, New York, NY, 10016, USA.
- Center for Neural Science, New York University, New York, NY, 10016, USA.
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Neuroscience Research Center, Berlin, Germany.
- Center for Neurodegenerative Diseases (DZNE), Berlin, Germany.
- Cluster of Excellence NeuroCure, Berlin, Germany.
- Einstein Center for Neurosciences, Berlin, Germany.
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29
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Karimi Abadchi J, Nazari-Ahangarkolaee M, Gattas S, Bermudez-Contreras E, Luczak A, McNaughton BL, Mohajerani MH. Spatiotemporal patterns of neocortical activity around hippocampal sharp-wave ripples. eLife 2020; 9:51972. [PMID: 32167467 PMCID: PMC7096182 DOI: 10.7554/elife.51972] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 03/11/2020] [Indexed: 01/06/2023] Open
Abstract
A prevalent model is that sharp-wave ripples (SWR) arise ‘spontaneously’ in CA3 and propagate recent memory traces outward to the neocortex to facilitate memory consolidation there. Using voltage and extracellular glutamate transient recording over widespread regions of mice dorsal neocortex in relation to CA1 multiunit activity (MUA) and SWR, we find that the largest SWR-related modulation occurs in retrosplenial cortex; however, contrary to the unidirectional hypothesis, neocortical activation exhibited a continuum of activation timings relative to SWRs, varying from leading to lagging. Thus, contrary to the model in which SWRs arise ‘spontaneously’ in the hippocampus, neocortical activation often precedes SWRs and may thus constitute a trigger event in which neocortical information seeds associative reactivation of hippocampal ‘indices’. This timing continuum is consistent with a dynamics in which older, more consolidated memories may in fact initiate the hippocampal-neocortical dialog, whereas reactivation of newer memories may be initiated predominantly in the hippocampus.
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Affiliation(s)
- J Karimi Abadchi
- Canadian Centre for Behavioral Neuroscience, University of Lethbridge, Lethbridge, Canada
| | | | - Sandra Gattas
- Department of Electrical Engineering and Computer Science, University of California, Irvine, United States.,Medical Scientist Training Program, University of California, Irvine, United States
| | | | - Artur Luczak
- Canadian Centre for Behavioral Neuroscience, University of Lethbridge, Lethbridge, Canada
| | - Bruce L McNaughton
- Canadian Centre for Behavioral Neuroscience, University of Lethbridge, Lethbridge, Canada.,Department of Neurobiology and Behavior, University of California, Irvine, United States
| | - Majid H Mohajerani
- Canadian Centre for Behavioral Neuroscience, University of Lethbridge, Lethbridge, Canada
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30
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Hasselmo ME, Alexander AS, Dannenberg H, Newman EL. Overview of computational models of hippocampus and related structures: Introduction to the special issue. Hippocampus 2020; 30:295-301. [PMID: 32119171 DOI: 10.1002/hipo.23201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Extensive computational modeling has focused on the hippocampal formation and associated cortical structures. This overview describes some of the factors that have motivated the strong focus on these structures, including major experimental findings and their impact on computational models. This overview provides a framework for describing the topics addressed by individual articles in this special issue of the journal Hippocampus.
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Affiliation(s)
- Michael E Hasselmo
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts
| | - Andrew S Alexander
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts
| | - Holger Dannenberg
- Center for Systems Neuroscience, Boston University, Boston, Massachusetts
| | - Ehren L Newman
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, Indiana
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31
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Alexander AS, Carstensen LC, Hinman JR, Raudies F, Chapman GW, Hasselmo ME. Egocentric boundary vector tuning of the retrosplenial cortex. Sci Adv 2020; 6:eaaz2322. [PMID: 32128423 PMCID: PMC7035004 DOI: 10.1126/sciadv.aaz2322] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/27/2019] [Indexed: 05/17/2023]
Abstract
The retrosplenial cortex is reciprocally connected with multiple structures implicated in spatial cognition, and damage to the region itself produces numerous spatial impairments. Here, we sought to characterize spatial correlates of neurons within the region during free exploration in two-dimensional environments. We report that a large percentage of retrosplenial cortex neurons have spatial receptive fields that are active when environmental boundaries are positioned at a specific orientation and distance relative to the animal itself. We demonstrate that this vector-based location signal is encoded in egocentric coordinates, is localized to the dysgranular retrosplenial subregion, is independent of self-motion, and is context invariant. Further, we identify a subpopulation of neurons with this response property that are synchronized with the hippocampal theta oscillation. Accordingly, the current work identifies a robust egocentric spatial code in retrosplenial cortex that can facilitate spatial coordinate system transformations and support the anchoring, generation, and utilization of allocentric representations.
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Affiliation(s)
- Andrew S. Alexander
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
- Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA
- Corresponding author.
| | - Lucas C. Carstensen
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
- Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA
- Graduate Program for Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
| | - James R. Hinman
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
| | - Florian Raudies
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
| | - G. William Chapman
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
- Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA
| | - Michael E. Hasselmo
- Center for Systems Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
- Department of Psychological and Brain Sciences, Boston University, 64 Cummington Mall, Boston, MA 02215, USA
- Graduate Program for Neuroscience, Boston University, 610 Commonwealth Ave., Boston, MA 02215, USA
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32
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Kay K, Chung JE, Sosa M, Schor JS, Karlsson MP, Larkin MC, Liu DF, Frank LM. Constant Sub-second Cycling between Representations of Possible Futures in the Hippocampus. Cell 2020; 180:552-567.e25. [PMID: 32004462 DOI: 10.1016/j.cell.2020.01.014] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/17/2019] [Accepted: 01/09/2020] [Indexed: 02/07/2023]
Abstract
Cognitive faculties such as imagination, planning, and decision-making entail the ability to represent hypothetical experience. Crucially, animal behavior in natural settings implies that the brain can represent hypothetical future experience not only quickly but also constantly over time, as external events continually unfold. To determine how this is possible, we recorded neural activity in the hippocampus of rats navigating a maze with multiple spatial paths. We found neural activity encoding two possible future scenarios (two upcoming maze paths) in constant alternation at 8 Hz: one scenario per ∼125-ms cycle. Further, we found that the underlying dynamics of cycling (both inter- and intra-cycle dynamics) generalized across qualitatively different representational correlates (location and direction). Notably, cycling occurred across moving behaviors, including during running. These findings identify a general dynamic process capable of quickly and continually representing hypothetical experience, including that of multiple possible futures.
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Affiliation(s)
- Kenneth Kay
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA.
| | - Jason E Chung
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Marielena Sosa
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jonathan S Schor
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Mattias P Karlsson
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Margaret C Larkin
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Daniel F Liu
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Loren M Frank
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Physiology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
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33
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Alexander AS, Robinson JC, Dannenberg H, Kinsky NR, Levy SJ, Mau W, Chapman GW, Sullivan DW, Hasselmo ME. Neurophysiological coding of space and time in the hippocampus, entorhinal cortex, and retrosplenial cortex. Brain Neurosci Adv 2020; 4:2398212820972871. [PMID: 33294626 PMCID: PMC7708714 DOI: 10.1177/2398212820972871] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/21/2020] [Indexed: 11/18/2022] Open
Abstract
Neurophysiological recordings in behaving rodents demonstrate neuronal response properties that may code space and time for episodic memory and goal-directed behaviour. Here, we review recordings from hippocampus, entorhinal cortex, and retrosplenial cortex to address the problem of how neurons encode multiple overlapping spatiotemporal trajectories and disambiguate these for accurate memory-guided behaviour. The solution could involve neurons in the entorhinal cortex and hippocampus that show mixed selectivity, coding both time and location. Some grid cells and place cells that code space also respond selectively as time cells, allowing differentiation of time intervals when a rat runs in the same location during a delay period. Cells in these regions also develop new representations that differentially code the context of prior or future behaviour allowing disambiguation of overlapping trajectories. Spiking activity is also modulated by running speed and head direction, supporting the coding of episodic memory not as a series of snapshots but as a trajectory that can also be distinguished on the basis of speed and direction. Recent data also address the mechanisms by which sensory input could distinguish different spatial locations. Changes in firing rate reflect running speed on long but not short time intervals, and few cells code movement direction, arguing against path integration for coding location. Instead, new evidence for neural coding of environmental boundaries in egocentric coordinates fits with a modelling framework in which egocentric coding of barriers combined with head direction generates distinct allocentric coding of location. The egocentric input can be used both for coding the location of spatiotemporal trajectories and for retrieving specific viewpoints of the environment. Overall, these different patterns of neural activity can be used for encoding and disambiguation of prior episodic spatiotemporal trajectories or for planning of future goal-directed spatiotemporal trajectories.
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Affiliation(s)
| | | | | | | | - Samuel J. Levy
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | - William Mau
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
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