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Seger SE, Kriegel JLS, Lega BC, Ekstrom AD. Memory-related processing is the primary driver of human hippocampal theta oscillations. Neuron 2023; 111:3119-3130.e4. [PMID: 37467749 PMCID: PMC10685603 DOI: 10.1016/j.neuron.2023.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 05/01/2023] [Accepted: 06/21/2023] [Indexed: 07/21/2023]
Abstract
Decades of work in rodents suggest that movement is a powerful driver of hippocampal low-frequency "theta" oscillations. Puzzlingly, such movement-related theta increases in primates are less sustained and of lower frequency, leading to questions about their functional relevance. Verbal memory encoding and retrieval lead to robust increases in low-frequency oscillations in humans, and one possibility is that memory might be a stronger driver of hippocampal theta oscillations in humans than navigation. Here, neurosurgical patients navigated routes and then immediately mentally simulated the same routes while undergoing intracranial recordings. We found that mentally simulating the same route that was just navigated elicited oscillations that were of greater power, higher frequency, and longer duration than those involving navigation. Our findings suggest that memory is a more potent driver of human hippocampal theta oscillations than navigation, supporting models of internally generated theta oscillations in the human hippocampus.
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Affiliation(s)
- Sarah E Seger
- Neuroscience Interdisciplinary Program, University of Arizona, 1503 E. University Blvd., Tucson, AZ 85719, USA
| | - Jennifer L S Kriegel
- Department of Neurosurgery, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Brad C Lega
- Department of Neurosurgery, University of Texas Southwestern Medical School, Dallas, TX, USA
| | - Arne D Ekstrom
- Neuroscience Interdisciplinary Program, University of Arizona, 1503 E. University Blvd., Tucson, AZ 85719, USA; Psychology Department, University of Arizona, 1503 E. University Blvd., Tucson, AZ 85719, USA; Evelyn McKnight Brain Institute, University of Arizona, 1503 E. University Blvd., Tucson, AZ 85719, USA.
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2
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Ohara S, Rannap M, Tsutsui KI, Draguhn A, Egorov AV, Witter MP. Hippocampal-medial entorhinal circuit is differently organized along the dorsoventral axis in rodents. Cell Rep 2023; 42:112001. [PMID: 36680772 DOI: 10.1016/j.celrep.2023.112001] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 10/14/2022] [Accepted: 12/31/2022] [Indexed: 01/21/2023] Open
Abstract
The general understanding of hippocampal circuits is that the hippocampus and the entorhinal cortex (EC) are topographically connected through parallel identical circuits along the dorsoventral axis. Our anterograde tracing and in vitro electrophysiology data, however, show a markedly different dorsoventral organization of the hippocampal projection to the medial EC (MEC). While dorsal hippocampal projections are confined to the dorsal MEC, ventral hippocampal projections innervate both dorsal and ventral MEC. Further, whereas the dorsal hippocampus preferentially targets layer Vb (LVb) neurons, the ventral hippocampus mainly targets cells in layer Va (LVa). This connectivity scheme differs from hippocampal projections to the lateral EC, which are topographically organized along the dorsoventral axis. As LVa neurons project to telencephalic structures, our findings indicate that the ventral hippocampus regulates LVa-mediated entorhinal-neocortical output from both dorsal and ventral MEC. Overall, the marked dorsoventral differences in hippocampal-entorhinal connectivity impose important constraints on signal flow in hippocampal-neocortical circuits.
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Affiliation(s)
- Shinya Ohara
- Laboratory of Systems Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan; Kavli Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway; PRESTO, Japan Science and Technology Agency (JST), Tokyo, Japan
| | - Märt Rannap
- Institute of Physiology and Pathophysiology, Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Ken-Ichiro Tsutsui
- Laboratory of Systems Neuroscience, Tohoku University Graduate School of Life Sciences, Sendai, Japan
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Alexei V Egorov
- Institute of Physiology and Pathophysiology, Medical Faculty, Heidelberg University, Heidelberg, Germany.
| | - Menno P Witter
- Kavli Institute for Systems Neuroscience, Center for Computational Neuroscience, Egil and Pauline Braathen and Fred Kavli Center for Cortical Microcircuits, NTNU Norwegian University of Science and Technology, Trondheim, Norway.
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3
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Scleidorovich P, Fellous JM, Weitzenfeld A. Adapting hippocampus multi-scale place field distributions in cluttered environments optimizes spatial navigation and learning. Front Comput Neurosci 2022; 16:1039822. [PMID: 36578316 PMCID: PMC9792172 DOI: 10.3389/fncom.2022.1039822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/21/2022] [Indexed: 12/14/2022] Open
Abstract
Extensive studies in rodents show that place cells in the hippocampus have firing patterns that are highly correlated with the animal's location in the environment and are organized in layers of increasing field sizes or scales along its dorsoventral axis. In this study, we use a spatial cognition model to show that different field sizes could be exploited to adapt the place cell representation to different environments according to their size and complexity. Specifically, we provide an in-depth analysis of how to distribute place cell fields according to the obstacles in cluttered environments to optimize learning time and path optimality during goal-oriented spatial navigation tasks. The analysis uses a reinforcement learning (RL) model that assumes that place cells allow encoding the state. While previous studies have suggested exploiting different field sizes to represent areas requiring different spatial resolutions, our work analyzes specific distributions that adapt the representation to the environment, activating larger fields in open areas and smaller fields near goals and subgoals (e.g., obstacle corners). In addition to assessing how the multi-scale representation may be exploited in spatial navigation tasks, our analysis and results suggest place cell representations that can impact the robotics field by reducing the total number of cells for path planning without compromising the quality of the paths learned.
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Affiliation(s)
- Pablo Scleidorovich
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL, United States
| | - Jean-Marc Fellous
- Department of Psychology and Biomedical Engineering, University of Arizona, Tucson, AZ, United States
| | - Alfredo Weitzenfeld
- Department of Computer Science and Engineering, University of South Florida, Tampa, FL, United States
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4
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Goyal A, Miller J, Qasim SE, Watrous AJ, Zhang H, Stein JM, Inman CS, Gross RE, Willie JT, Lega B, Lin JJ, Sharan A, Wu C, Sperling MR, Sheth SA, McKhann GM, Smith EH, Schevon C, Jacobs J. Functionally distinct high and low theta oscillations in the human hippocampus. Nat Commun 2020; 11:2469. [PMID: 32424312 PMCID: PMC7235253 DOI: 10.1038/s41467-020-15670-6] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/23/2020] [Indexed: 11/08/2022] Open
Abstract
Based on rodent models, researchers have theorized that the hippocampus supports episodic memory and navigation via the theta oscillation, a ~4-10 Hz rhythm that coordinates brain-wide neural activity. However, recordings from humans have indicated that hippocampal theta oscillations are lower in frequency and less prevalent than in rodents, suggesting interspecies differences in theta's function. To characterize human hippocampal theta, we examine the properties of theta oscillations throughout the anterior-posterior length of the hippocampus as neurosurgical subjects performed a virtual spatial navigation task. During virtual movement, we observe hippocampal oscillations at multiple frequencies from 2 to 14 Hz. The posterior hippocampus prominently displays oscillations at ~8-Hz and the precise frequency of these oscillations correlates with the speed of movement, implicating these signals in spatial navigation. We also observe slower ~3 Hz oscillations, but these signals are more prevalent in the anterior hippocampus and their frequency does not vary with movement speed. Our results converge with recent findings to suggest an updated view of human hippocampal electrophysiology. Rather than one hippocampal theta oscillation with a single general role, high- and low-frequency theta oscillations, respectively, may reflect spatial and non-spatial cognitive processes.
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Affiliation(s)
- Abhinav Goyal
- Mayo Clinic Medical Scientist Training Program, Mayo Clinic College of Medicine and Science, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jonathan Miller
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - Salman E Qasim
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | | | - Honghui Zhang
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA
| | - Joel M Stein
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Cory S Inman
- Department of Neurosurgery, Emory University, Atlanta, GA, 30322, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University, Atlanta, GA, 30322, USA
| | - Jon T Willie
- Department of Neurosurgery, Emory University, Atlanta, GA, 30322, USA
| | - Bradley Lega
- Department of Neurological Surgery, University of Texas Southwestern, Dallas, TX, 75390, USA
| | - Jui-Jui Lin
- Department of Neurological Surgery, University of Texas Southwestern, Dallas, TX, 75390, USA
| | - Ashwini Sharan
- Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA, 9107, USA
- Jefferson Comprehensive Epilepsy Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Chengyuan Wu
- Department of Neurological Surgery, Thomas Jefferson University, Philadelphia, PA, 9107, USA
| | - Michael R Sperling
- Jefferson Comprehensive Epilepsy Center, Thomas Jefferson University, Philadelphia, PA, USA
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - Sameer A Sheth
- Department of Neurological Surgery, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Guy M McKhann
- Department of Neurosurgery, Columbia University Medical Center, New York, NY, 10032, USA
| | - Elliot H Smith
- Department of Neurosurgery, University of Utah, Salt Lake City, UT, USA
| | - Catherine Schevon
- Department of Neurology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Joshua Jacobs
- Department of Biomedical Engineering, Columbia University, New York, NY, 10027, USA.
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5
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Hernández-Pérez JJ, Cooper KW, Newman EL. Medial entorhinal cortex activates in a traveling wave in the rat. eLife 2020; 9:52289. [PMID: 32057292 PMCID: PMC7046467 DOI: 10.7554/elife.52289] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 02/04/2020] [Indexed: 12/12/2022] Open
Abstract
Traveling waves are hypothesized to support the long-range coordination of anatomically distributed circuits. Whether separate strongly interacting circuits exhibit traveling waves remains unknown. The hippocampus exhibits traveling ‘theta’ waves and interacts strongly with the medial entorhinal cortex (MEC). To determine whether the MEC also activates in a traveling wave, we performed extracellular recordings of local field potentials (LFP) and multi-unit activity along the MEC. These recordings revealed progressive phase shifts in activity, indicating that the MEC also activates in a traveling wave. Variation in theta waveform along the region, generated by gradients in local physiology, contributed to the observed phase shifts. Removing waveform-related phase shifts left significant residual phase shifts. The residual phase shifts covaried with theta frequency in a manner consistent with those generated by weakly coupled oscillators. These results show that the coordination of anatomically distributed circuits could be enabled by traveling waves but reveal heterogeneity in the mechanisms generating those waves.
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Affiliation(s)
- J Jesús Hernández-Pérez
- Department of Psychological and Brain Sciences, Indiana University Bloomington, Bloomington, United States
| | - Keiland W Cooper
- Department of Psychological and Brain Sciences, Indiana University Bloomington, Bloomington, United States
| | - Ehren L Newman
- Department of Psychological and Brain Sciences, Indiana University Bloomington, Bloomington, United States
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6
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Chauvière L. Update on temporal lobe‐dependent information processing, in health and disease. Eur J Neurosci 2019; 51:2159-2204. [DOI: 10.1111/ejn.14594] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/06/2019] [Accepted: 09/27/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Laëtitia Chauvière
- INSERM U1266 Institut de Psychiatrie et de Neurosciences de Paris (IPNP) Paris France
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7
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Lee SL(T, Lew D, Wickenheisser V, Markus EJ. Interdependence between dorsal and ventral hippocampus during spatial navigation. Brain Behav 2019; 9:e01410. [PMID: 31571397 PMCID: PMC6790314 DOI: 10.1002/brb3.1410] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 08/15/2019] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION The hippocampus is linked to the formation and retrieval of episodic memories and spatial navigation. In rats, it is an elongated structure divided into dorsal (septal) and ventral (temporal) regions paralleling the respective division in the posterior and anterior hippocampus in humans. The dorsal hippocampus has been suggested to be more important for spatial processing and the ventral to processing anxiety-based behaviors. Far less is known regarding the degree to which these different regions interact during information processing. The anatomical connectivity suggests a flow of information between the dorsal and ventral regions; conversely, there are also commissural connections to the contralateral hippocampus. The current study examined the extent to which information from the dorsal hippocampus interacts with processing in the ipsilateral and contralateral ventral hippocampus following the acquisition of a spatial task. METHODS Rats were well-trained on a spatial reference version of the water maze, followed by muscimol inactivation of different hippocampal subregions in a within-animal repeated design. Various combinations of bilateral, ipsilateral, and contralateral infusions were used. RESULTS Combined dorsal and ventral inactivation produced a severe impairment in spatial performance. Inactivation of only the dorsal or ventral regions resulted in intermediate impairment with performance levels falling between controls and combined inactivation. Performance was impaired during contralateral inactivation and was almost equivalent to bilateral dorsal and ventral hippocampus inactivation, while ipsilateral inactivation resulted in little impairment. CONCLUSIONS Taken together, results indicate that for spatial processing, the hippocampus functions as a single integrated structure along the longitudinal axis.
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Affiliation(s)
- Shang Lin (Tommy) Lee
- Behavioral Neuroscience DivisionDepartment of Psychological SciencesUniversity of ConnecticutStorrsCTUSA
| | - Dana Lew
- Behavioral Neuroscience DivisionDepartment of Psychological SciencesUniversity of ConnecticutStorrsCTUSA
| | - Victoria Wickenheisser
- Behavioral Neuroscience DivisionDepartment of Psychological SciencesUniversity of ConnecticutStorrsCTUSA
| | - Etan J. Markus
- Behavioral Neuroscience DivisionDepartment of Psychological SciencesUniversity of ConnecticutStorrsCTUSA
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8
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Michaels TI, Long LL, Stevenson IH, Chrobak JJ, Chen CMA. Effects of chronic ketamine on hippocampal cross-frequency coupling: implications for schizophrenia pathophysiology. Eur J Neurosci 2018; 48:2903-2914. [PMID: 29359413 DOI: 10.1111/ejn.13822] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 01/04/2018] [Accepted: 01/11/2018] [Indexed: 11/27/2022]
Abstract
Disrupted neuronal oscillations have been identified as a potentially important biomarker for the perceptual and cognitive symptoms of schizophrenia. Emerging evidences suggest that interactions between different frequency bands, cross-frequency coupling (CFC), serve an important role in integrating sensory and cognitive information and may contribute to disease pathophysiology. In this study, we investigated the effects of 14-day consecutive administration of ketamine (30 mg/kg i.p.) vs. saline on alterations in amplitude and changes in the coupling of low-frequency (0-30 Hz) phase and high-frequency (30-115 Hz) amplitude in the CA1 hippocampus of Long Evans rats. Intracranial electrode recordings were conducted pre- and post-injection while the animals performed a foraging task on a four-arm rectangular maze. Permutation analysis of frequency band-specific change in amplitudes revealed between-group differences in theta (6-12 Hz) and slow gamma (25-50 Hz) but not fast gamma (65-100 Hz) bands at both slow and fast speeds. Chronic ketamine challenge resulted in decreased coupling (pre to post) at slow speeds but increased coupling at faster speeds, compared to either no or modest increased coupling in the saline group. These results demonstrate that chronic ketamine administration alters the interaction of low-frequency phase and high-frequency oscillations chronically and that such coupling varies as a function of locomotive speed. These findings provide evidence for the potential relevance of CFC to the pathophysiology of schizophrenia.
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Affiliation(s)
- Timothy I Michaels
- Psychological Sciences Department, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT, 06269, USA
| | - Lauren L Long
- Psychological Sciences Department, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT, 06269, USA
| | - Ian H Stevenson
- Psychological Sciences Department, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT, 06269, USA
| | - James J Chrobak
- Psychological Sciences Department, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT, 06269, USA
| | - Chi-Ming A Chen
- Psychological Sciences Department, University of Connecticut, 406 Babbidge Road, Unit 1020, Storrs, CT, 06269, USA
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9
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Joshi A, Salib M, Viney TJ, Dupret D, Somogyi P. Behavior-Dependent Activity and Synaptic Organization of Septo-hippocampal GABAergic Neurons Selectively Targeting the Hippocampal CA3 Area. Neuron 2017; 96:1342-1357.e5. [PMID: 29198757 PMCID: PMC5746169 DOI: 10.1016/j.neuron.2017.10.033] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/23/2017] [Accepted: 10/25/2017] [Indexed: 12/12/2022]
Abstract
Rhythmic medial septal (MS) GABAergic input coordinates cortical theta oscillations. However, the rules of innervation of cortical cells and regions by diverse septal neurons are unknown. We report a specialized population of septal GABAergic neurons, the Teevra cells, selectively innervating the hippocampal CA3 area bypassing CA1, CA2, and the dentate gyrus. Parvalbumin-immunopositive Teevra cells show the highest rhythmicity among MS neurons and fire with short burst duration (median, 38 ms) preferentially at the trough of both CA1 theta and slow irregular oscillations, coincident with highest hippocampal excitability. Teevra cells synaptically target GABAergic axo-axonic and some CCK interneurons in restricted septo-temporal CA3 segments. The rhythmicity of their firing decreases from septal to temporal termination of individual axons. We hypothesize that Teevra neurons coordinate oscillatory activity across the septo-temporal axis, phasing the firing of specific CA3 interneurons, thereby contributing to the selection of pyramidal cell assemblies at the theta trough via disinhibition. VIDEO ABSTRACT.
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Affiliation(s)
- Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK; MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, UK.
| | - Minas Salib
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Tim James Viney
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - David Dupret
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK; MRC Brain Network Dynamics Unit, Department of Pharmacology, University of Oxford, Oxford OX1 3TH, UK
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK; Center for Brain Research, Medical University of Vienna, Vienna 1090, Austria.
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10
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Gianelli S, Harland B, Fellous JM. A new rat-compatible robotic framework for spatial navigation behavioral experiments. J Neurosci Methods 2017; 294:40-50. [PMID: 29113794 DOI: 10.1016/j.jneumeth.2017.10.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 10/23/2017] [Accepted: 10/23/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND Understanding the neural substrate of information encoding and processing requires a precise control of the animal's behavior. Most of what has been learned from the rodent navigational system results from relatively simple tasks in which the movements of the animal is controlled by corridors or walkways, passive movements, treadmills or virtual reality environments. While a lot has been and continues to be learned from these types of experiments, recent evidence has shown that such artificial constraints may have significant consequences on the functioning of the neural circuits of spatial navigation. NEW METHODS We present a novel and alternative approach for effectively controlling the precise direction and speed of movement of the animal in an ethologically realistic environment, using a small robot (Sphero). RESULTS We describe the robotic framework and demonstrate its use in replicating pre-programmed or rat-recorded paths. We show that the robot can control the movement of a rat in order to produce specific trajectories and speeds. We demonstrate that the robot can be used to aid the rat in learning a spatial memory task in a large and complex environment. We show that dorsal hippocampal CA1 place cells do not remap when the rat is following the robot. Comparison with existing method(s): Our framework only involves positive motivation and has been tested together with wireless electrophysiology in large and complex environments. CONCLUSIONS Our robotic framework can be used to design novel tasks and experiments in which electrophysiological recordings would be largely devoid of maze or task-dependent artifacts.
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Affiliation(s)
- Sam Gianelli
- Computational and Experimental Neuroscience Laboratory, University of Arizona, United States
| | - Bruce Harland
- Computational and Experimental Neuroscience Laboratory, University of Arizona, United States; Psychology Department, University of Arizona, United States
| | - Jean-Marc Fellous
- Psychology Department, University of Arizona, United States; Program in Applied Mathematics University of Arizona, Tucson, AZ, United States.
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11
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Morton NW, Sherrill KR, Preston AR. Memory integration constructs maps of space, time, and concepts. Curr Opin Behav Sci 2017; 17:161-168. [PMID: 28924579 DOI: 10.1016/j.cobeha.2017.08.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Recent evidence demonstrates that new events are learned in the context of their relationships to existing memories. Within the hippocampus and medial prefrontal cortex, related memories are represented by integrated codes that connect events experienced at different times and places. Integrated codes form the basis of spatial, temporal, and conceptual maps of experience. These maps represent information that goes beyond direct experience and support generalization behaviors that require knowledge be used in new ways. The degree to which an individual memory is integrated into a coherent map is determined by its spatial, temporal, and conceptual proximity to existing knowledge. Integration is observed over a wide range of scales, suggesting that memories contain information about both broad and fine-grained contexts.
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Affiliation(s)
- Neal W Morton
- Center for Learning & Memory, The University of Texas at Austin
| | | | - Alison R Preston
- Center for Learning & Memory, The University of Texas at Austin.,Department of Psychology, The University of Texas at Austin.,Department of Neuroscience, The University of Texas at Austin
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12
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Prominent differences in sharp waves, ripples and complex spike bursts between the dorsal and the ventral rat hippocampus. Neuroscience 2017; 352:131-143. [DOI: 10.1016/j.neuroscience.2017.03.050] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/27/2017] [Accepted: 03/27/2017] [Indexed: 12/17/2022]
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13
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Altmann GTM. Abstraction and generalization in statistical learning: implications for the relationship between semantic types and episodic tokens. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160060. [PMID: 27872378 PMCID: PMC5124085 DOI: 10.1098/rstb.2016.0060] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2016] [Indexed: 12/19/2022] Open
Abstract
Statistical approaches to emergent knowledge have tended to focus on the process by which experience of individual episodes accumulates into generalizable experience across episodes. However, there is a seemingly opposite, but equally critical, process that such experience affords: the process by which, from a space of types (e.g. onions-a semantic class that develops through exposure to individual episodes involving individual onions), we can perceive or create, on-the-fly, a specific token (a specific onion, perhaps one that is chopped) in the absence of any prior perceptual experience with that specific token. This article reviews a selection of statistical learning studies that lead to the speculation that this process-the generation, on the basis of semantic memory, of a novel episodic representation-is itself an instance of a statistical, in fact associative, process. The article concludes that the same processes that enable statistical abstraction across individual episodes to form semantic memories also enable the generation, from those semantic memories, of representations that correspond to individual tokens, and of novel episodic facts about those tokens. Statistical learning is a window onto these deeper processes that underpin cognition.This article is part of the themed issue 'New frontiers for statistical learning in the cognitive sciences'.
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Affiliation(s)
- Gerry T M Altmann
- Department of Psychological Sciences, Institute for the Brain and Cognitive Sciences, University of Connecticut, 406 Babbidge Road, Storrs, CT 06269-1020, USA
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14
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Chadwick A, van Rossum MC, Nolan MF. Flexible theta sequence compression mediated via phase precessing interneurons. eLife 2016; 5. [PMID: 27929374 PMCID: PMC5245972 DOI: 10.7554/elife.20349] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 12/07/2016] [Indexed: 01/15/2023] Open
Abstract
Encoding of behavioral episodes as spike sequences during hippocampal theta oscillations provides a neural substrate for computations on events extended across time and space. However, the mechanisms underlying the numerous and diverse experimentally observed properties of theta sequences remain poorly understood. Here we account for theta sequences using a novel model constrained by the septo-hippocampal circuitry. We show that when spontaneously active interneurons integrate spatial signals and theta frequency pacemaker inputs, they generate phase precessing action potentials that can coordinate theta sequences in place cell populations. We reveal novel constraints on sequence generation, predict cellular properties and neural dynamics that characterize sequence compression, identify circuit organization principles for high capacity sequential representation, and show that theta sequences can be used as substrates for association of conditioned stimuli with recent and upcoming events. Our results suggest mechanisms for flexible sequence compression that are suited to associative learning across an animal’s lifespan. DOI:http://dx.doi.org/10.7554/eLife.20349.001 Nerve cells in the brain exchange information via electrical impulses. In a given brain area, the electrical impulses at any particular moment can be thought of as forming a code that represents an aspect of the outside world. For example, groups of nerve cells in the hippocampus generate a type of code called a theta sequence, which represents a series of recent and upcoming events. The specific timing of electrical impulses within a theta sequence is crucial in creating certain types of memory. There are two major classes of nerve cell in the brain: excitatory cells activate impulses in neighbouring cells, while inhibitory cells act to temporarily block impulses from other nerve cells. Many groups, or “circuits”, of nerve cells contain combinations of both cell types to control how and when they communicate. Previous studies show that both types of cell are active within theta sequences, but it is not known precisely how they contribute to creating the sequences. Chadwick et al. developed a new mathematical model that simulates how theta sequences can emerge from circuits of both excitatory and inhibitory nerve cells. The connections between these simulated cells are based on experimental data from real nerve cells in the hippocampus. The model predicts that inhibitory cells play an important role in generating theta sequences by interacting with groups of excitatory cells to coordinate the timing of electrical impulses. Furthermore, the model shows how memory capacity depends on these connections. The next step following on from this work is to carry out experiments to test the model’s predictions. This will include monitoring the same group of nerve cells in multiple different situations to find out how their theta sequences change, and recording electrical events in individual nerve cells during theta sequences. If the theory’s predictions are confirmed this would lead to a deeper understanding of how our brains remember sequences of events. DOI:http://dx.doi.org/10.7554/eLife.20349.002
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Affiliation(s)
- Angus Chadwick
- Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, Scotland, United Kingdom.,Neuroinformatics Doctoral Training Centre, School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
| | - Mark Cw van Rossum
- Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, Scotland, United Kingdom
| | - Matthew F Nolan
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
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Movement Enhances the Nonlinearity of Hippocampal Theta. J Neurosci 2016; 36:4218-30. [PMID: 27076421 DOI: 10.1523/jneurosci.3564-15.2016] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 03/02/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The nonlinear, metastable dynamics of the brain are essential for large-scale integration of smaller components and for the rapid organization of neurons in support of behavior. Therefore, understanding the nonlinearity of the brain is paramount for understanding the relationship between brain dynamics and behavior. Explicit quantitative descriptions of the properties and consequences of nonlinear neural networks, however, are rare. Because the local field potential (LFP) reflects the total activity across a population of neurons, nonlinearites of the nervous system should be quantifiable by examining oscillatory structure. We used high-order spectral analysis of LFP recorded from the dorsal and intermediate regions of the rat hippocampus to show that the nonlinear character of the hippocampal theta rhythm is directly related to movement speed of the animal. In the time domain, nonlinearity is expressed as the development of skewness and asymmetry in the theta shape. In the spectral domain, nonlinear dynamics manifest as the development of a chain of harmonics statistically phase coupled to the theta oscillation. This evolution was modulated across hippocampal regions, being stronger in the dorsal CA1 relative to more intermediate areas. The intensity and timing of the spiking activity of pyramidal cells and interneurons was strongly correlated to theta nonlinearity. Because theta is known to propagate from dorsal to ventral regions of the hippocampus, these data suggest that the nonlinear character of theta decreases as it travels and supports a hypothesis that activity dissipates along the longitudinal axis of the hippocampus. SIGNIFICANCE STATEMENT We describe the first explicit quantification regarding how behavior enhances the nonlinearity of the nervous system. Our findings demonstrate uniquely how theta changes with increasing speed due to the altered underlying neuronal dynamics and open new directions of research on the relationship between single-neuron activity and propagation of theta through the hippocampus. This work is significant because it will encourage others to consider the nonlinear nature of the nervous system and higher-order spectral analyses when examining oscillatory interactions.
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Roth FC, Beyer KM, Both M, Draguhn A, Egorov AV. Downstream effects of hippocampal sharp wave ripple oscillations on medial entorhinal cortex layer V neurons in vitro. Hippocampus 2016; 26:1493-1508. [DOI: 10.1002/hipo.22623] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/29/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Fabian C. Roth
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University; Heidelberg D-69120 Germany
| | - Katinka M. Beyer
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University; Heidelberg D-69120 Germany
| | - Martin Both
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University; Heidelberg D-69120 Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University; Heidelberg D-69120 Germany
| | - Alexei V. Egorov
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University; Heidelberg D-69120 Germany
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Zhao R, Grunke SD, Keralapurath MM, Yetman MJ, Lam A, Lee TC, Sousounis K, Jiang Y, Swing DA, Tessarollo L, Ji D, Jankowsky JL. Impaired Recall of Positional Memory following Chemogenetic Disruption of Place Field Stability. Cell Rep 2016; 16:793-804. [PMID: 27373150 PMCID: PMC4956499 DOI: 10.1016/j.celrep.2016.06.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/03/2016] [Accepted: 06/03/2016] [Indexed: 11/06/2022] Open
Abstract
The neural network of the temporal lobe is thought to provide a cognitive map of our surroundings. Functional analysis of this network has been hampered by coarse tools that often result in collateral damage to other circuits. We developed a chemogenetic system to temporally control electrical input into the hippocampus. When entorhinal input to the perforant path was acutely silenced, hippocampal firing patterns became destabilized and underwent extensive remapping. We also found that spatial memory acquired prior to neural silencing was impaired by loss of input through the perforant path. Together, our experiments show that manipulation of entorhinal activity destabilizes spatial coding and disrupts spatial memory. Moreover, we introduce a chemogenetic model for non-invasive neuronal silencing that offers multiple advantages over existing strategies in this setting.
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Affiliation(s)
- Rong Zhao
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stacy D Grunke
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Michael J Yetman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Alexander Lam
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Cognitive Science, Rice University, Houston, TX 77251, USA
| | - Tang-Cheng Lee
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Yongying Jiang
- Institute for Applied Cancer Science, The University of Texas MD Anderson Cancer Center, Houston, TX 77054, USA
| | - Deborah A Swing
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Lino Tessarollo
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Daoyun Ji
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Joanna L Jankowsky
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA; Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA.
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18
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Llofriu M, Tejera G, Contreras M, Pelc T, Fellous J, Weitzenfeld A. Goal-oriented robot navigation learning using a multi-scale space representation. Neural Netw 2015; 72:62-74. [DOI: 10.1016/j.neunet.2015.09.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 09/21/2015] [Accepted: 09/21/2015] [Indexed: 10/22/2022]
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Numan R. A Prefrontal-Hippocampal Comparator for Goal-Directed Behavior: The Intentional Self and Episodic Memory. Front Behav Neurosci 2015; 9:323. [PMID: 26635567 PMCID: PMC4658443 DOI: 10.3389/fnbeh.2015.00323] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/11/2015] [Indexed: 01/02/2023] Open
Abstract
The hypothesis of this article is that the interactions between the prefrontal cortex and the hippocampus play a critical role in the modulation of goal-directed self-action and the strengthening of episodic memories. We describe various theories that model a comparator function for the hippocampus, and then elaborate the empirical evidence that supports these theories. One theory which describes a prefrontal-hippocampal comparator for voluntary action is emphasized. Action plans are essential for successful goal-directed behavior, and are elaborated by the prefrontal cortex. When an action plan is initiated, the prefrontal cortex transmits an efference copy (or corollary discharge) to the hippocampus where it is stored as a working memory for the action plan (which includes the expected outcomes of the action plan). The hippocampus then serves as a response intention-response outcome working memory comparator. Hippocampal comparator function is enabled by the hippocampal theta rhythm allowing the hippocampus to compare expected action outcomes to actual action outcomes. If the expected and actual outcomes match, the hippocampus transmits a signal to prefrontal cortex which strengthens or consolidates the action plan. If a mismatch occurs, the hippocampus transmits an error signal to the prefrontal cortex which facilitates a reformulation of the action plan, fostering behavioral flexibility and memory updating. The corollary discharge provides the self-referential component to the episodic memory, affording the personal and subjective experience of what behavior was carried out, when it was carried out, and in what context (where) it occurred. Such a perspective can be applied to episodic memory in humans, and episodic-like memory in non-human animal species.
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Affiliation(s)
- Robert Numan
- Psychology Department, Santa Clara University Santa Clara, CA, USA
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Kang D, Ding M, Topchiy I, Shifflett L, Kocsis B. Theta-rhythmic drive between medial septum and hippocampus in slow-wave sleep and microarousal: a Granger causality analysis. J Neurophysiol 2015; 114:2797-803. [PMID: 26354315 DOI: 10.1152/jn.00542.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/03/2015] [Indexed: 11/22/2022] Open
Abstract
Medial septum (MS) plays a critical role in controlling the electrical activity of the hippocampus (HIPP). In particular, theta-rhythmic burst firing of MS neurons is thought to drive lasting HIPP theta oscillations in rats during waking motor activity and REM sleep. Less is known about MS-HIPP interactions in nontheta states such as non-REM sleep, in which HIPP theta oscillations are absent but theta-rhythmic burst firing in subsets of MS neurons is preserved. The present study used Granger causality (GC) to examine the interaction patterns between MS and HIPP in slow-wave sleep (SWS, a nontheta state) and during its short interruptions called microarousals (a transient theta state). We found that during SWS, while GC revealed a unidirectional MS→HIPP influence over a wide frequency band (2-12 Hz, maximum: ∼8 Hz), there was no theta peak in the hippocampal power spectra, indicating a lack of theta activity in HIPP. In contrast, during microarousals, theta peaks were seen in both MS and HIPP power spectra and were accompanied by bidirectional GC with MS→HIPP and HIPP→MS theta drives being of equal magnitude. Thus GC in a nontheta state (SWS) vs. a theta state (microarousal) primarily differed in the level of HIPP→MS. The present findings suggest a modification of our understanding of the role of MS as the theta generator in two regards. First, a MS→HIPP theta drive does not necessarily induce theta field oscillations in the hippocampus, as found in SWS. Second, HIPP theta oscillations entail bidirectional theta-rhythmic interactions between MS and HIPP.
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Affiliation(s)
- D Kang
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida; and
| | - M Ding
- J Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida; and
| | - I Topchiy
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - L Shifflett
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - B Kocsis
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
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