1
|
Subramanian DL, Miller AMP, Smith DM. A comparison of hippocampal and retrosplenial cortical spatial and contextual firing patterns. Hippocampus 2024; 34:357-377. [PMID: 38770779 DOI: 10.1002/hipo.23610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 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.
Collapse
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
| |
Collapse
|
2
|
Jedrasiak-Cape I, Rybicki-Kler C, Brooks I, Ghosh M, Brennan EK, Kailasa S, Ekins TG, Rupp A, Ahmed OJ. Cell-type-specific cholinergic control of granular retrosplenial cortex with implications for angular velocity coding across brain states. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597341. [PMID: 38895393 PMCID: PMC11185600 DOI: 10.1101/2024.06.04.597341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Cholinergic receptor activation enables the persistent firing of cortical pyramidal neurons, providing a key cellular basis for theories of spatial navigation involving working memory, path integration, and head direction encoding. The granular retrosplenial cortex (RSG) is important for spatially-guided behaviors, but how acetylcholine impacts RSG neurons is unknown. Here, we show that a transcriptomically, morphologically, and biophysically distinct RSG cell-type - the low-rheobase (LR) neuron - has a very distinct expression profile of cholinergic muscarinic receptors compared to all other neighboring excitatory neuronal subtypes. LR neurons do not fire persistently in response to cholinergic agonists, in stark contrast to all other principal neuronal subtypes examined within the RSG and across midline cortex. This lack of persistence allows LR neuron models to rapidly compute angular head velocity (AHV), independent of cholinergic changes seen during navigation. Thus, LR neurons can consistently compute AHV across brain states, highlighting the specialized RSG neural codes supporting navigation.
Collapse
Affiliation(s)
| | - Chloe Rybicki-Kler
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109
| | - Isla Brooks
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
| | - Megha Ghosh
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
| | - Ellen K.W. Brennan
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109
| | - Sameer Kailasa
- Dept. of Mathematics, University of Michigan, Ann Arbor, MI 48109
| | - Tyler G. Ekins
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
| | - Alan Rupp
- Dept. of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Omar J. Ahmed
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109
- Kresge Hearing Research Institute, University of Michigan, Ann Arbor, MI 48109
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
| |
Collapse
|
3
|
Mizuno H, Ikegaya Y. Late-spiking retrosplenial cortical neurons are not synchronized with neocortical slow waves in anesthetized mice. Neurosci Res 2024; 203:51-56. [PMID: 38224839 DOI: 10.1016/j.neures.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/29/2023] [Accepted: 01/08/2024] [Indexed: 01/17/2024]
Abstract
Neocortical slow waves are critical for memory consolidation. The retrosplenial cortex is thought to facilitate the slow wave propagation to regions beyond the neocortex. However, it remains unclear which population is responsible for the slow wave propagation. To address this issue, we performed in vivo whole-cell recordings to identify neurons that were synchronous and asynchronous with slow waves. By quantifying their intrinsic membrane properties, we observed that the former exhibited regular spiking, whereas the latter exhibited late spiking. Thus, these two cell types transmit information in different directions between the neocortex and subcortical regions.
Collapse
Affiliation(s)
- Hiroyuki Mizuno
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan; Institute for AI and Beyond, The University of Tokyo, Tokyo 113-0033, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City, Osaka 565-0871, Japan.
| |
Collapse
|
4
|
McElroy DL, Sabir H, Glass AE, Greba Q, Howland JG. The anterior retrosplenial cortex is required for short-term object in place recognition memory retrieval: Role of ionotropic glutamate receptors in male and female Long-Evans rats. Eur J Neurosci 2024; 59:2260-2275. [PMID: 38411499 DOI: 10.1111/ejn.16284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 01/24/2024] [Accepted: 02/01/2024] [Indexed: 02/28/2024]
Abstract
The anterior retrosplenial cortex (aRSC) integrates multimodal sensory information into cohesive associative recognition memories. Little is known about how information is integrated during different learning phases (i.e., encoding and retrieval). Additionally, sex differences are observed in performance of some visuospatial memory tasks; however, inconsistent findings warrant more research. We conducted three experiments using the 1-h delay object-in-place (1-h OiP) test to assess recognition memory retrieval in male and female Long-Evans rats. (i) We found both sexes performed equally in three repeated 1-h OiP test sessions. (ii) We showed infusions of a mixture of muscimol/baclofen (GABAA/B receptor agonists) into the aRSC ~15-min prior to the test phase disrupted 1-h OiP in both sexes. (iii) We assessed the role of aRSC ionotropic glutamate receptors in 1-h OiP retrieval using another squad of cannulated rats and confirmed that infusions of either the competitive AMPA/Kainate receptor antagonist CNQX (3 mM) or competitive NMDA receptor antagonist AP-5 (30 mM) (volumes = 0.50 uL/side) significantly impaired 1-h OiP retrieval in both sexes compared to controls. Taken together, findings challenge reported sex differences and clearly establish a role for aRSC ionotropic glutamate receptors in short-term visuospatial recognition memory retrieval. Thus, modulating neural activity in the aRSC may alleviate some memory processing impairments in related disorders.
Collapse
Affiliation(s)
- Dan L McElroy
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Hassaan Sabir
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Aiden E Glass
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Quentin Greba
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - John G Howland
- Department of Anatomy, Physiology, and Pharmacology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| |
Collapse
|
5
|
Tian J, Bavencoffe AG, Zhu MX, Walters ET. Readiness of nociceptor cell bodies to generate spontaneous activity results from background activity of diverse ion channels and high input resistance. Pain 2024; 165:893-907. [PMID: 37862056 PMCID: PMC10950548 DOI: 10.1097/j.pain.0000000000003091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 08/09/2023] [Indexed: 10/21/2023]
Abstract
ABSTRACT Nociceptor cell bodies generate "spontaneous" discharge that can promote ongoing pain in persistent pain conditions. Little is known about the underlying mechanisms. Recordings from nociceptor cell bodies (somata) dissociated from rodent and human dorsal root ganglia have shown that previous pain in vivo is associated with low-frequency discharge controlled by irregular depolarizing spontaneous fluctuations of membrane potential (DSFs), likely produced by transient inward currents across the somal input resistance. Using mouse nociceptors, we show that DSFs are associated with high somal input resistance over a wide range of membrane potentials, including depolarized levels where DSFs approach action potential (AP) threshold. Input resistance and both the amplitude and frequency of DSFs were increased in neurons exhibiting spontaneous activity. Ion substitution experiments indicated that the depolarizing phase of DSFs is generated by spontaneous opening of channels permeable to Na + or Ca 2+ and that Ca 2+ -permeable channels are especially important for larger DSFs. Partial reduction of the amplitude or frequency of DSFs by perfusion of pharmacological inhibitors indicated small but significant contributions from Nav1.7, Nav1.8, TRPV1, TRPA1, TRPM4, and N-type Ca 2+ channels. Less specific blockers suggested a contribution from NALCN channels, and global knockout suggested a role for Nav1.9. The combination of high somal input resistance plus background activity of diverse ion channels permeable to Na + or Ca 2+ produces DSFs that are poised to reach AP threshold if resting membrane potential depolarizes, AP threshold decreases, or DSFs become enhanced-all of which can occur under painful neuropathic and inflammatory conditions.
Collapse
Affiliation(s)
- Jinbin Tian
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Alexis G. Bavencoffe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Michael X. Zhu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| | - Edgar T. Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston
| |
Collapse
|
6
|
Subramanian DL, Smith DM. Time Cells in the Retrosplenial Cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 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] [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.
Collapse
Affiliation(s)
| | - David M. Smith
- Department of Psychology, Cornell University, Ithaca, NY 14853
| |
Collapse
|
7
|
Jiang S, Liu B, Lin K, Li L, Li R, Tan S, Zhang X, Jiang L, Ni H, Wang Y, Ding H, Hu J, Qian H, Ge R. Impacted spike frequency adaptation associated with reduction of KCNQ2/3 exacerbates seizure activity in temporal lobe epilepsy. Hippocampus 2024; 34:58-72. [PMID: 38049972 DOI: 10.1002/hipo.23587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 09/21/2023] [Accepted: 10/28/2023] [Indexed: 12/06/2023]
Abstract
Numerous epilepsy-related genes have been identified in recent decades by unbiased genome-wide screens. However, the available druggable targets for temporal lobe epilepsy (TLE) remain limited. Furthermore, a substantial pool of candidate genes potentially applicable to TLE therapy awaits further validation. In this study, we reveal the significant role of KCNQ2 and KCNQ3, two M-type potassium channel genes, in the onset of seizures in TLE. Our investigation began with a quantitative analysis of two publicly available TLE patient databases to establish a correlation between seizure onset and the downregulated expression of KCNQ2/3. We then replicated these pathological changes in a pilocarpine seizure mouse model and observed a decrease in spike frequency adaptation due to the affected M-currents in dentate gyrus granule neurons. In addition, we performed a small-scale simulation of the dentate gyrus network and confirmed that the impaired spike frequency adaptation of granule cells facilitated epileptiform activity throughout the network. This, in turn, resulted in prolonged seizure duration and reduced interictal intervals. Our findings shed light on an underlying mechanism contributing to ictogenesis in the TLE hippocampus and suggest a promising target for the development of antiepileptic drugs.
Collapse
Affiliation(s)
- Shicheng Jiang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Bei Liu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Kaiwen Lin
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Lianjun Li
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Rongrong Li
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Shuo Tan
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Xinyu Zhang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Lei Jiang
- Department of General Surgery, The Second Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, China
| | - Hong Ni
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Yuanyuan Wang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Haihu Ding
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Bengbu Medical College, Bengbu, Anhui, China
| | - Jing Hu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Hao Qian
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Rongjing Ge
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
- Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Bengbu Medical College, Bengbu, Anhui, China
| |
Collapse
|
8
|
Ekins TG, Brooks I, Kailasa S, Rybicki-Kler C, Jedrasiak-Cape I, Donoho E, Mashour GA, Rech J, Ahmed OJ. Cellular rules underlying psychedelic control of prefrontal pyramidal neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.20.563334. [PMID: 37961554 PMCID: PMC10634703 DOI: 10.1101/2023.10.20.563334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Classical psychedelic drugs are thought to increase excitability of pyramidal cells in prefrontal cortex via activation of serotonin 2A receptors (5-HT2ARs). Here, we instead find that multiple classes of psychedelics dose-dependently suppress intrinsic excitability of pyramidal neurons, and that extracellular delivery of psychedelics decreases excitability significantly more than intracellular delivery. A previously unknown mechanism underlies this psychedelic drug action: enhancement of ubiquitously expressed potassium "M-current" channels that is independent of 5-HT2R activation. Using machine-learning-based data assimilation models, we show that M-current activation interacts with previously described mechanisms to dramatically reduce intrinsic excitability and shorten working memory timespan. Thus, psychedelic drugs suppress intrinsic excitability by modulating ion channels that are expressed throughout the brain, potentially triggering homeostatic adjustments that can contribute to widespread therapeutic benefits.
Collapse
Affiliation(s)
- Tyler G Ekins
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109
| | - Isla Brooks
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
| | - Sameer Kailasa
- Dept. of Mathematics, University of Michigan, Ann Arbor, MI 48109
| | - Chloe Rybicki-Kler
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109
| | | | - Ethan Donoho
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
| | - George A. Mashour
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109
| | - Jason Rech
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109
| | - Omar J Ahmed
- Dept. of Psychology, University of Michigan, Ann Arbor, MI 48109
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, MI 48109
- Dept. of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
| |
Collapse
|
9
|
Sullivan KE, Kraus L, Kapustina M, Wang L, Stach TR, Lemire AL, Clements J, Cembrowski MS. Sharp cell-type-identity changes differentiate the retrosplenial cortex from the neocortex. Cell Rep 2023; 42:112206. [PMID: 36881508 DOI: 10.1016/j.celrep.2023.112206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/22/2022] [Accepted: 02/15/2023] [Indexed: 03/08/2023] Open
Abstract
The laminae of the neocortex are fundamental processing layers of the mammalian brain. Notably, such laminae are believed to be relatively stereotyped across short spatial scales such that shared laminae between nearby brain regions exhibit similar constituent cells. Here, we consider a potential exception to this rule by studying the retrosplenial cortex (RSC), a brain region known for sharp cytoarchitectonic differences across its granular-dysgranular border. Using a variety of transcriptomics techniques, we identify, spatially map, and interpret the excitatory cell-type landscape of the mouse RSC. In doing so, we uncover that RSC gene expression and cell types change sharply at the granular-dysgranular border. Additionally, supposedly homologous laminae between the RSC and the neocortex are effectively wholly distinct in their cell-type composition. In collection, the RSC exhibits a variety of intrinsic cell-type specializations and embodies an organizational principle wherein cell-type identities can vary sharply within and between brain regions.
Collapse
Affiliation(s)
- Kaitlin E Sullivan
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Boulevard, Vancouver, BC, Canada
| | - Larissa Kraus
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Boulevard, Vancouver, BC, Canada
| | - Margarita Kapustina
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Boulevard, Vancouver, BC, Canada
| | - Lihua Wang
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, Canada
| | - Tara R Stach
- School of Biomedical Engineering, Biomedical Research Centre, University of British Columbia, 2222 Health Sciences Mall, Vancouver, BC, Canada
| | - Andrew L Lemire
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, Canada
| | - Jody Clements
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, Canada
| | - Mark S Cembrowski
- Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Boulevard, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, Canada; Janelia Research Campus, HHMI, 19700 Helix Dr, Ashburn, VA, USA.
| |
Collapse
|
10
|
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] [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.
Collapse
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.
| |
Collapse
|
11
|
Environment Symmetry Drives a Multidirectional Code in Rat Retrosplenial Cortex. J Neurosci 2022; 42:9227-9241. [PMID: 36302638 PMCID: PMC9761682 DOI: 10.1523/jneurosci.0619-22.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 09/19/2022] [Accepted: 09/23/2022] [Indexed: 02/02/2023] Open
Abstract
We investigated how environment symmetry shapes the neural processing of direction by recording directionally tuned retrosplenial neurons in male Lister hooded rats exploring multicompartment environments that had different levels of global rotational symmetry. Our hypothesis built on prior observations of twofold symmetry in the directional tuning curves of rats in a globally twofold-symmetric environment. To test whether environment symmetry was the relevant factor shaping the directional responses, here we deployed the same apparatus (two connected rectangular boxes) plus one with fourfold symmetry (a 2 × 2 array of connected square boxes) and one with onefold symmetry (a circular open-field arena). Consistent with our hypothesis we found many neurons with tuning curve symmetries that mirrored these environment symmetries, having twofold, fourfold, or onefold symmetric tuning, respectively. Some cells expressed this pattern only globally (across the whole environment), maintaining singular tuning curves in each subcompartment. However, others also expressed it locally within each subcompartment. Because multidirectionality has not been reported in naive rats in single environmental compartments, this suggests an experience-dependent effect of global environment symmetry on local firing symmetry. An intermingled population of directional neurons were classic head direction cells with globally referenced directional tuning. These cells were electrophysiologically distinct, with narrower tuning curves and a burstier firing pattern. Thus, retrosplenial directional neurons can simultaneously encode overall head direction and local head direction (relative to compartment layout). Furthermore, they can learn about global environment symmetry and express this locally. This may be important for the encoding of environment structure beyond immediate perceptual reach.SIGNIFICANCE STATEMENT We investigated how environment symmetry shapes the neural code for space by recording directionally tuned neurons from the retrosplenial cortex of rats exploring single- or multicompartment environments having onefold, twofold, or fourfold rotational symmetry. We found that many cells expressed a symmetry in their head direction tuning curves that matched the corresponding global environment symmetry, indicating plasticity of their directional tuning. They were also electrophysiologically distinct from canonical head directional cells. Notably, following exploration of the global space, many multidirectionally tuned neurons encoded global environment symmetry, even in local subcompartments. Our results suggest that multidirectional head direction codes contribute to the cognitive mapping of the complex structure of multicompartmented spaces.
Collapse
|
12
|
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] [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.
Collapse
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.
| |
Collapse
|
13
|
Stacho M, Manahan-Vaughan D. Mechanistic flexibility of the retrosplenial cortex enables its contribution to spatial cognition. Trends Neurosci 2022; 45:284-296. [DOI: 10.1016/j.tins.2022.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/17/2021] [Accepted: 01/27/2022] [Indexed: 12/20/2022]
|
14
|
Cholinergic systems, attentional-motor integration, and cognitive control in Parkinson's disease. PROGRESS IN BRAIN RESEARCH 2022; 269:345-371. [PMID: 35248201 PMCID: PMC8957710 DOI: 10.1016/bs.pbr.2022.01.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Dysfunction and degeneration of CNS cholinergic systems is a significant component of multi-system pathology in Parkinson's disease (PD). We review the basic architecture of human CNS cholinergic systems and the tools available for studying changes in human cholinergic systems. Earlier post-mortem studies implicated abnormalities of basal forebrain corticopetal cholinergic (BFCC) and pedunculopontine-laterodorsal tegmental (PPN-LDT) cholinergic projections in cognitive deficits and gait-balance deficits, respectively. Recent application of imaging methods, particularly molecular imaging, allowed more sophisticated correlation of clinical features with regional cholinergic deficits. BFCC projection deficits correlate with general and domain specific cognitive deficits, particularly for attentional and executive functions. Detailed analyses suggest that cholinergic deficits within the salience and cingulo-opercular task control networks, including both neocortical, thalamic, and striatal nodes, are a significant component of cognitive deficits in non-demented PD subjects. Both BFCC and PPN-LDT cholinergic projection systems, and striatal cholinergic interneuron (SChI), abnormalities are implicated in PD gait-balance disorders. In the context of experimental studies, these results indicate that disrupted attentional functions of BFCC and PPN-LDT cholinergic systems underlie impaired gait-balance functions. SChI dysfunction likely impairs intra-striatal integration of attentional and motor information. Thalamic and entorhinal cortex cholinergic deficits may impair multi-sensory integration. Overt degeneration of CNS systems may be preceded by increased activity of cholinergic neurons compensating for nigrostriatal dopaminergic deficits. Subsequent dysfunction and degeneration of cholinergic systems unmasks and exacerbates functional deficits secondary to dopaminergic denervation. Research on CNS cholinergic systems dysfunctions in PD requires a systems-level approach to understanding PD pathophysiology.
Collapse
|
15
|
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] [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.
Collapse
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
| |
Collapse
|
16
|
Piette C, Vandecasteele M, Bosch-Bouju C, Goubard V, Paillé V, Cui Y, Mendes A, Perez S, Valtcheva S, Xu H, Pouget P, Venance L. Intracellular Properties of Deep-Layer Pyramidal Neurons in Frontal Eye Field of Macaque Monkeys. Front Synaptic Neurosci 2021; 13:725880. [PMID: 34621162 PMCID: PMC8490863 DOI: 10.3389/fnsyn.2021.725880] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/24/2021] [Indexed: 11/13/2022] Open
Abstract
Although many details remain unknown, several positive statements can be made about the laminar distribution of primate frontal eye field (FEF) neurons with different physiological properties. Most certainly, pyramidal neurons in the deep layer of FEF that project to the brainstem carry movement and fixation signals but clear evidence also support that at least some deep-layer pyramidal neurons projecting to the superior colliculus carry visual responses. Thus, deep-layer neurons in FEF are functionally heterogeneous. Despite the useful functional distinctions between neuronal responses in vivo, the underlying existence of distinct cell types remain uncertain, mostly due to methodological limitations of extracellular recordings in awake behaving primates. To substantiate the functionally defined cell types encountered in the deep layer of FEF, we measured the biophysical properties of pyramidal neurons recorded intracellularly in brain slices issued from macaque monkey biopsies. Here, we found that biophysical properties recorded in vitro permit us to distinguish two main subtypes of regular-spiking neurons, with, respectively, low-resistance and low excitability vs. high-resistance and strong excitability. These results provide useful constraints for cognitive models of visual attention and saccade production by indicating that at least two distinct populations of deep-layer neurons exist.
Collapse
Affiliation(s)
- Charlotte Piette
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Marie Vandecasteele
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Clémentine Bosch-Bouju
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Valérie Goubard
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Vincent Paillé
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Yihui Cui
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Alexandre Mendes
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Sylvie Perez
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Silvana Valtcheva
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Hao Xu
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| | - Pierre Pouget
- INSERM, CNRS, Institut du Cerveau, Sorbonne Université, Paris, France
| | - Laurent Venance
- Dynamics and Pathophysiology of Neuronal Networks Team, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, PSL University, Paris, France
| |
Collapse
|
17
|
Brennan EKW, Jedrasiak-Cape I, Kailasa S, Rice SP, Sudhakar SK, Ahmed OJ. Thalamus and claustrum control parallel layer 1 circuits in retrosplenial cortex. eLife 2021; 10:e62207. [PMID: 34170817 PMCID: PMC8233040 DOI: 10.7554/elife.62207] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 05/17/2021] [Indexed: 11/13/2022] Open
Abstract
The granular retrosplenial cortex (RSG) is critical for both spatial and non-spatial behaviors, but the underlying neural codes remain poorly understood. Here, we use optogenetic circuit mapping in mice to reveal a double dissociation that allows parallel circuits in superficial RSG to process disparate inputs. The anterior thalamus and dorsal subiculum, sources of spatial information, strongly and selectively recruit small low-rheobase (LR) pyramidal cells in RSG. In contrast, neighboring regular-spiking (RS) cells are preferentially controlled by claustral and anterior cingulate inputs, sources of mostly non-spatial information. Precise sublaminar axonal and dendritic arborization within RSG layer 1, in particular, permits this parallel processing. Observed thalamocortical synaptic dynamics enable computational models of LR neurons to compute the speed of head rotation, despite receiving head direction inputs that do not explicitly encode speed. Thus, parallel input streams identify a distinct principal neuronal subtype ideally positioned to support spatial orientation computations in the RSG.
Collapse
Affiliation(s)
- Ellen KW Brennan
- Department of Psychology, University of MichiganAnn ArborUnited States
- Neuroscience Graduate Program, University of MichiganAnn ArborUnited States
| | | | - Sameer Kailasa
- Department of Mathematics, University of MichiganAnn ArborUnited States
| | - Sharena P Rice
- Department of Psychology, University of MichiganAnn ArborUnited States
- Neuroscience Graduate Program, University of MichiganAnn ArborUnited States
| | | | - Omar J Ahmed
- Department of Psychology, University of MichiganAnn ArborUnited States
- Neuroscience Graduate Program, University of MichiganAnn ArborUnited States
- Michigan Center for Integrative Research in Critical Care, University of MichiganAnn ArborUnited States
- Kresge Hearing Research Institute, University of MichiganAnn ArborUnited States
- Department of Biomedical Engineering, University of MichiganAnn ArborUnited States
| |
Collapse
|
18
|
Gao M, Noguchi A, Ikegaya Y. The subiculum sensitizes retrosplenial cortex layer 2/3 pyramidal neurons. J Physiol 2021; 599:3151-3167. [PMID: 33878801 DOI: 10.1113/jp281152] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 04/13/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Neurons in the retrosplenial cortex (RSC), a cerebral region that connects synaptically with various brain regions, are known to increase neuronal activity in accordance with hippocampal sharp wave-ripples. Pyramidal cells in granular RSC (gRSC) layer 2/3, but not layer 5, exhibit slowly ramping depolarization and considerably delayed spikes in response to a step-pulse current injection. The latencies of delayed spikes in RSC layer 2/3 pyramidal neurons were shortened by a preceding current injection. This effect was mimicked by activation of axonal afferents from the subiculum, but not of neocortical afferents. The subiculum is likely to facilitate information processing and flow in the RSC. ABSTRACT The retrosplenial cortex (RSC), a cerebral region involved in diverse cognitive functions, is an anatomical hub that forms monosynaptic connections with various brain areas. Here, we report a unique form of short-term intrinsic plasticity in mouse granular RSC layer 2/3 pyramidal cells. These cells exhibited delayed spikes in response to somatic current injection, but the spike latencies were shortened by a preceding brief depolarization (priming). This priming-induced sensitization is distinct from desensitization, which is commonly observed in other cortical neurons. The facilitatory priming effect lasted for more than 3 s, providing a time window for increased sensitivity to RSC inputs. Based on in vitro and in vivo patch-clamp recordings following optogenetic stimulation of axonal fibres, we found that preactivation of subicular afferents replicated the facilitatory priming effect. The results suggest that subicular inputs to RSC layer 2/3 neurons may modulate subsequent information integration in the RSC layer 2/3 circuits.
Collapse
Affiliation(s)
- Mengxuan Gao
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Asako Noguchi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Yuji Ikegaya
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan.,Institute of AI and Beyond, The University of Tokyo, Tokyo, 113-0033, Japan.,Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita City, Osaka, 565-0871, Japan
| |
Collapse
|
19
|
Miller AMP, Serrichio AC, Smith DM. Dual-Factor Representation of the Environmental Context in the Retrosplenial Cortex. Cereb Cortex 2020; 31:2720-2728. [PMID: 33386396 DOI: 10.1093/cercor/bhaa386] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The retrosplenial cortex (RSC) is thought to be involved in a variety of spatial and contextual memory processes. However, we do not know how contextual information might be encoded in the RSC or whether the RSC representations may be distinct from context representations seen in other brain regions such as the hippocampus. We recorded RSC neuronal responses while rats explored different environments and discovered 2 kinds of context representations: one involving a novel rate code in which neurons reliably fire at a higher rate in the preferred context regardless of spatial location, and a second involving context-dependent spatial firing patterns similar to those seen in the hippocampus. This suggests that the RSC employs a unique dual-factor representational mechanism to support contextual memory.
Collapse
Affiliation(s)
- Adam M P Miller
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA
| | - Anna C Serrichio
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA
| | - David M Smith
- Department of Psychology, Cornell University, Ithaca, NY 14853, USA
| |
Collapse
|
20
|
Yousuf H, Nye AN, Moyer JR. Heterogeneity of neuronal firing type and morphology in retrosplenial cortex of male F344 rats. J Neurophysiol 2020; 123:1849-1863. [PMID: 32267193 DOI: 10.1152/jn.00577.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The rodent granular retrosplenial cortex (gRSC) has reciprocal connections to the hippocampus to support fear memories. Although activity-dependent plasticity occurs within the RSC during memory formation, the intrinsic and morphological properties of RSC neurons are poorly understood. The present study used whole-cell recordings to examine intrinsic neuronal firing and morphology of neurons in layer 2/3 (L2/3) and layer 5 (L5) of the gRSC in adult male rats. Five different classifications were observed: regular-spiking (RS), regular-spiking afterdepolarization (RSADP), late-spiking (LS), burst-spiking (BS), and fast-spiking (FS) neurons. RSADP neurons were the most commonly observed neuronal class, identified by their robust spike frequency adaptation and pronounced afterdepolarization (ADP) following an action potential (AP). They also had the most extensive dendritic branching compared with other cell types. LS neurons were predominantly found in L2/3 and exhibited a long delay before onset of their initial AP. They also had reduced dendritic branching compared with other cell types. BS neurons were limited to L5 and generated an initial burst of two or more APs. FS neurons demonstrated sustained firing and little frequency adaptation and were the only nonpyramidal firing type. Relative to adults, RS neurons from juvenile rats (PND 14-30) lacked an ADP and were less excitable. Bath application of group 1 mGluR blockers attenuated the ADP in adult neurons. In other fear-related brain structures, the ADP has been shown to enhance excitability and synaptic plasticity. Thus, understanding cellular mechanisms of the gRSC will provide insight regarding its precise role in memory-related processes across the lifespan.NEW & NOTEWORTHY This is the first study to demonstrate that granular retrosplenial cortical (gRSC) neurons exhibit five distinctive firing types: regular spiking (RS), regular spiking with an afterdepolarization (RSADP), late spiking (LS), burst spiking (BS), and fast spiking (FS). RSADP neurons were the most frequently observed cell type in adult gRSC neurons. Interestingly, RS neurons without an ADP were most common in gRSC neurons of juvenile rats (PND 14-30). Thus, the ADP property, which was previously shown to enhance neuronal excitability, emerges during development.
Collapse
Affiliation(s)
- Hanna Yousuf
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
| | - Andrew N Nye
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
| | - James R Moyer
- Department of Psychology, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin.,Department of Biological Sciences University of Wisconsin-Milwaukee, Milwaukee, Wisconsin
| |
Collapse
|