1
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McNaughton N, Bannerman D. The homogenous hippocampus: How hippocampal cells process available and potential goals. Prog Neurobiol 2024; 240:102653. [PMID: 38960002 DOI: 10.1016/j.pneurobio.2024.102653] [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: 01/04/2024] [Revised: 04/25/2024] [Accepted: 06/24/2024] [Indexed: 07/05/2024]
Abstract
We present here a view of the firing patterns of hippocampal cells that is contrary, both functionally and anatomically, to conventional wisdom. We argue that the hippocampus responds to efference copies of goals encoded elsewhere; and that it uses these to detect and resolve conflict or interference between goals in general. While goals can involve space, hippocampal cells do not encode spatial (or other special types of) memory, as such. We also argue that the transverse circuits of the hippocampus operate in an essentially homogeneous way along its length. The apparently different functions of different parts (e.g. memory retrieval versus anxiety) result from the different (situational/motivational) inputs on which those parts perform the same fundamental computational operations. On this view, the key role of the hippocampus is the iterative adjustment, via Papez-like circuits, of synaptic weights in cell assemblies elsewhere.
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Affiliation(s)
- Neil McNaughton
- Department of Psychology and Brain Health Research Centre, University of Otago, POB56, Dunedin 9054, New Zealand.
| | - David Bannerman
- Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford, England, UK
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2
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Low IIC, Giocomo LM, Williams AH. Remapping in a recurrent neural network model of navigation and context inference. eLife 2023; 12:RP86943. [PMID: 37410093 PMCID: PMC10328512 DOI: 10.7554/elife.86943] [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] [Indexed: 07/07/2023] Open
Abstract
Neurons in navigational brain regions provide information about position, orientation, and speed relative to environmental landmarks. These cells also change their firing patterns ('remap') in response to changing contextual factors such as environmental cues, task conditions, and behavioral states, which influence neural activity throughout the brain. How can navigational circuits preserve their local computations while responding to global context changes? To investigate this question, we trained recurrent neural network models to track position in simple environments while at the same time reporting transiently-cued context changes. We show that these combined task constraints (navigation and context inference) produce activity patterns that are qualitatively similar to population-wide remapping in the entorhinal cortex, a navigational brain region. Furthermore, the models identify a solution that generalizes to more complex navigation and inference tasks. We thus provide a simple, general, and experimentally-grounded model of remapping as one neural circuit performing both navigation and context inference.
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Affiliation(s)
- Isabel IC Low
- Zuckerman Mind Brain Behavior Institute, Columbia UniversityNew YorkUnited States
| | - Lisa M Giocomo
- Department of Neurobiology, Stanford UniversityStanfordUnited States
| | - Alex H Williams
- Center for Computational Neuroscience, Flatiron InstituteNew YorkUnited States
- Center for Neural Science, New York UniversityNew YorkUnited States
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3
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Miller AMP, Jacob AD, Ramsaran AI, De Snoo ML, Josselyn SA, Frankland PW. Emergence of a predictive model in the hippocampus. Neuron 2023; 111:1952-1965.e5. [PMID: 37015224 PMCID: PMC10293047 DOI: 10.1016/j.neuron.2023.03.011] [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: 09/08/2022] [Revised: 01/23/2023] [Accepted: 03/08/2023] [Indexed: 04/05/2023]
Abstract
The brain organizes experiences into memories that guide future behavior. Hippocampal CA1 population activity is hypothesized to reflect predictive models that contain information about future events, but little is known about how they develop. We trained mice on a series of problems with or without a common statistical structure to observe how memories are formed and updated. Mice that learned structured problems integrated their experiences into a predictive model that contained the solutions to upcoming novel problems. Retrieving the model during learning improved discrimination accuracy and facilitated learning. Using calcium imaging to track CA1 activity during learning, we found that hippocampal ensemble activity became more stable as mice formed a predictive model. The hippocampal ensemble was reactivated during training and incorporated new activity patterns from each training problem. These results show how hippocampal activity supports building predictive models by organizing new information with respect to existing memories.
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Affiliation(s)
- Adam M P Miller
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Alex D Jacob
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Adam I Ramsaran
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada
| | - Mitchell L De Snoo
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
| | - Sheena A Josselyn
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada; Brain, Mind, & Consciousness Program, Canadian Institute for Advanced Research, Toronto, ON, Canada
| | - Paul W Frankland
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada; Department of Psychology, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada; Child & Brain Development Program, Canadian Institute for Advanced Research, Toronto, ON, Canada.
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4
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Low II, Giocomo LM, Williams AH. Remapping in a recurrent neural network model of navigation and context inference. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.25.525596. [PMID: 36747825 PMCID: PMC9900889 DOI: 10.1101/2023.01.25.525596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Neurons in navigational brain regions provide information about position, orientation, and speed relative to environmental landmarks. These cells also change their firing patterns ("remap") in response to changing contextual factors such as environmental cues, task conditions, and behavioral state, which influence neural activity throughout the brain. How can navigational circuits preserve their local computations while responding to global context changes? To investigate this question, we trained recurrent neural network models to track position in simple environments while at the same time reporting transiently-cued context changes. We show that these combined task constraints (navigation and context inference) produce activity patterns that are qualitatively similar to population-wide remapping in the entorhinal cortex, a navigational brain region. Furthermore, the models identify a solution that generalizes to more complex navigation and inference tasks. We thus provide a simple, general, and experimentally-grounded model of remapping as one neural circuit performing both navigation and context inference.
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Affiliation(s)
- Isabel I.C. Low
- Zuckerman Mind Brain Behavior Institute, Columbia University,Center for Computational Neuroscience, Flatiron Institute,Correspondence to: ,
| | | | - Alex H. Williams
- Center for Computational Neuroscience, Flatiron Institute,Center for Neural Science, New York University,Correspondence to: ,
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5
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Duvelle É, Grieves RM, van der Meer MAA. Temporal context and latent state inference in the hippocampal splitter signal. eLife 2023; 12:e82357. [PMID: 36622350 PMCID: PMC9829411 DOI: 10.7554/elife.82357] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/06/2022] [Indexed: 01/10/2023] Open
Abstract
The hippocampus is thought to enable the encoding and retrieval of ongoing experience, the organization of that experience into structured representations like contexts, maps, and schemas, and the use of these structures to plan for the future. A central goal is to understand what the core computations supporting these functions are, and how these computations are realized in the collective action of single neurons. A potential access point into this issue is provided by 'splitter cells', hippocampal neurons that fire differentially on the overlapping segment of trajectories that differ in their past and/or future. However, the literature on splitter cells has been fragmented and confusing, owing to differences in terminology, behavioral tasks, and analysis methods across studies. In this review, we synthesize consistent findings from this literature, establish a common set of terms, and translate between single-cell and ensemble perspectives. Most importantly, we examine the combined findings through the lens of two major theoretical ideas about hippocampal function: representation of temporal context and latent state inference. We find that unique signature properties of each of these models are necessary to account for the data, but neither theory, by itself, explains all of its features. Specifically, the temporal gradedness of the splitter signal is strong support for temporal context, but is hard to explain using state models, while its flexibility and task-dependence is naturally accounted for using state inference, but poses a challenge otherwise. These theories suggest a number of avenues for future work, and we believe their application to splitter cells is a timely and informative domain for testing and refining theoretical ideas about hippocampal function.
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Affiliation(s)
- Éléonore Duvelle
- Department of Psychological and Brain Sciences, Dartmouth CollegeHanoverUnited States
| | - Roddy M Grieves
- Department of Psychological and Brain Sciences, Dartmouth CollegeHanoverUnited States
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6
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Non-spatial similarity can bias spatial distances in a cognitive map. Cognition 2022; 229:105251. [PMID: 36152528 DOI: 10.1016/j.cognition.2022.105251] [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: 08/25/2021] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 11/23/2022]
Abstract
The cognitive map theory suggests the hippocampal-entorhinal system has a representation of space that encodes geometric properties. There is also evidence that the hippocampus plays a critical role in supporting declarative memory, and recent theories have hypothesized the mechanism for encoding space is the same as that for processing memory. If space is not represented independently, it might be influenced by non-spatial properties. This study tested whether connections between non-spatial properties can distort judgments about spatial distance. In virtual reality, subjects navigated through an environment to learn the locations of target houses, and then were tested on their ability to judge the pairwise distances between houses and reconstruct a map of the environment. The environment was constructed to have pairs of houses with the same spatial distance but either the same or different color. If memory for spatial and non-spatial properties interact, similar houses would be expected to be judged as closer. In Experiment 1, the similar pairs all had the same color, while in Experiment 2, each pair had a different color to make the pairs more distinctive. We observed that similar houses were drawn closer on reconstructed maps in both experiments, and pairwise distance judgments were smaller for similar houses in Experiment 2. Biases from color similarity are difficult to reconcile with independent representation of space. Our results support theories that space is represented with other properties, and the mechanisms for encoding space in the hippocampal-entorhinal system have a broader function.
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7
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Stoianov I, Maisto D, Pezzulo G. The hippocampal formation as a hierarchical generative model supporting generative replay and continual learning. Prog Neurobiol 2022; 217:102329. [PMID: 35870678 DOI: 10.1016/j.pneurobio.2022.102329] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 11/28/2022]
Abstract
We advance a novel computational theory of the hippocampal formation as a hierarchical generative model that organizes sequential experiences, such as rodent trajectories during spatial navigation, into coherent spatiotemporal contexts. We propose that the hippocampal generative model is endowed with inductive biases to identify individual items of experience (first hierarchical layer), organize them into sequences (second layer) and cluster them into maps (third layer). This theory entails a novel characterization of hippocampal reactivations as generative replay: the offline resampling of fictive sequences from the generative model, which supports the continual learning of multiple sequential experiences. We show that the model learns and efficiently retains multiple spatial navigation trajectories, by organizing them into spatial maps. Furthermore, the model reproduces flexible and prospective aspects of hippocampal dynamics that are challenging to explain within existing frameworks. This theory reconciles multiple roles of the hippocampal formation in map-based navigation, episodic memory and imagination.
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Affiliation(s)
- Ivilin Stoianov
- Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| | - Domenico Maisto
- Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| | - Giovanni Pezzulo
- Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy.
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8
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Eckstein MK, Master SL, Dahl RE, Wilbrecht L, Collins AGE. Reinforcement learning and Bayesian inference provide complementary models for the unique advantage of adolescents in stochastic reversal. Dev Cogn Neurosci 2022; 55:101106. [PMID: 35537273 PMCID: PMC9108470 DOI: 10.1016/j.dcn.2022.101106] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 03/01/2022] [Accepted: 03/25/2022] [Indexed: 12/02/2022] Open
Abstract
During adolescence, youth venture out, explore the wider world, and are challenged to learn how to navigate novel and uncertain environments. We investigated how performance changes across adolescent development in a stochastic, volatile reversal-learning task that uniquely taxes the balance of persistence and flexibility. In a sample of 291 participants aged 8-30, we found that in the mid-teen years, adolescents outperformed both younger and older participants. We developed two independent cognitive models, based on Reinforcement learning (RL) and Bayesian inference (BI). The RL parameter for learning from negative outcomes and the BI parameters specifying participants' mental models were closest to optimal in mid-teen adolescents, suggesting a central role in adolescent cognitive processing. By contrast, persistence and noise parameters improved monotonically with age. We distilled the insights of RL and BI using principal component analysis and found that three shared components interacted to form the adolescent performance peak: adult-like behavioral quality, child-like time scales, and developmentally-unique processing of positive feedback. This research highlights adolescence as a neurodevelopmental window that can create performance advantages in volatile and uncertain environments. It also shows how detailed insights can be gleaned by using cognitive models in new ways.
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Affiliation(s)
| | | | - Ronald E Dahl
- Institute of Human Development, 2121 Berkeley Way West, USA
| | - Linda Wilbrecht
- Department of Psychology, 2121 Berkeley Way West, USA; Helen Wills Neuroscience Institute, 175 Li Ka Shing Center, Berkeley, CA 94720, USA
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9
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Abstract
Active inference is a first principle account of how autonomous agents operate in dynamic, nonstationary environments. This problem is also considered in reinforcement learning, but limited work exists on comparing the two approaches on the same discrete-state environments. In this letter, we provide (1) an accessible overview of the discrete-state formulation of active inference, highlighting natural behaviors in active inference that are generally engineered in reinforcement learning, and (2) an explicit discrete-state comparison between active inference and reinforcement learning on an OpenAI gym baseline. We begin by providing a condensed overview of the active inference literature, in particular viewing the various natural behaviors of active inference agents through the lens of reinforcement learning. We show that by operating in a pure belief-based setting, active inference agents can carry out epistemic exploration-and account for uncertainty about their environment-in a Bayes-optimal fashion. Furthermore, we show that the reliance on an explicit reward signal in reinforcement learning is removed in active inference, where reward can simply be treated as another observation we have a preference over; even in the total absence of rewards, agent behaviors are learned through preference learning. We make these properties explicit by showing two scenarios in which active inference agents can infer behaviors in reward-free environments compared to both Q-learning and Bayesian model-based reinforcement learning agents and by placing zero prior preferences over rewards and learning the prior preferences over the observations corresponding to reward. We conclude by noting that this formalism can be applied to more complex settings (e.g., robotic arm movement, Atari games) if appropriate generative models can be formulated. In short, we aim to demystify the behavior of active inference agents by presenting an accessible discrete state-space and time formulation and demonstrate these behaviors in a OpenAI gym environment, alongside reinforcement learning agents.
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Affiliation(s)
- Noor Sajid
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, WC1N 3AR, U.K.
| | - Philip J Ball
- Machine Learning Research Group, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, U.K.
| | - Thomas Parr
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, WC1N 3AR, U.K.
| | - Karl J Friston
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, London, WC1N 3AR, U.K.
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10
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Sanders H, Wilson MA, Gershman SJ. Hippocampal remapping as hidden state inference. eLife 2020; 9:51140. [PMID: 32515352 PMCID: PMC7282808 DOI: 10.7554/elife.51140] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 05/09/2020] [Indexed: 11/13/2022] Open
Abstract
Cells in the hippocampus tuned to spatial location (place cells) typically change their tuning when an animal changes context, a phenomenon known as remapping. A fundamental challenge to understanding remapping is the fact that what counts as a ‘‘context change’’ has never been precisely defined. Furthermore, different remapping phenomena have been classified on the basis of how much the tuning changes after different types and degrees of context change, but the relationship between these variables is not clear. We address these ambiguities by formalizing remapping in terms of hidden state inference. According to this view, remapping does not directly reflect objective, observable properties of the environment, but rather subjective beliefs about the hidden state of the environment. We show how the hidden state framework can resolve a number of puzzles about the nature of remapping.
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Affiliation(s)
- Honi Sanders
- Center for Brains Minds and Machines, Harvard University, Cambridge, United States.,Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Matthew A Wilson
- Center for Brains Minds and Machines, Harvard University, Cambridge, United States.,Picower Institute for Learning and Memory and Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Samuel J Gershman
- Center for Brains Minds and Machines, Harvard University, Cambridge, United States.,Department of Psychology, Harvard University, Cambridge, United States
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11
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Baradaran R, Khoshdel‐Sarkarizi H, Kargozar S, Hami J, Mohammadipour A, Sadr‐Nabavi A, Peyvandi Karizbodagh M, Kheradmand H, Haghir H. Developmental regulation and lateralisation of the α7 and α4 subunits of nicotinic acetylcholine receptors in developing rat hippocampus. Int J Dev Neurosci 2020; 80:303-318. [DOI: 10.1002/jdn.10026] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 12/25/2022] Open
Affiliation(s)
- Raheleh Baradaran
- Department of Anatomy and Cell Biology School of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | - Hoda Khoshdel‐Sarkarizi
- Department of Anatomy and Cell Biology School of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | - Saeid Kargozar
- Tissue Engineering Research Group (TERG) Department of Anatomy and Cell Biology School of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | - Javad Hami
- Department of Anatomical Sciences School of Medicine Birjand University of Medical Sciences Birjand Iran
| | - Abbas Mohammadipour
- Department of Anatomy and Cell Biology School of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | - Ariane Sadr‐Nabavi
- Department of Medical Genetics School of Medicine Mashhad University of Medical Sciences Mashhad Iran
- Medical Genetic Research Center (MGRC) School of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | | | - Hamed Kheradmand
- Hazrat Rasoul Hospital Tehran University of Medical Sciences Tehran Iran
| | - Hossein Haghir
- Department of Anatomy and Cell Biology School of Medicine Mashhad University of Medical Sciences Mashhad Iran
- Medical Genetic Research Center (MGRC) School of Medicine Mashhad University of Medical Sciences Mashhad Iran
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12
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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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13
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Abstract
Midbrain dopamine signals are widely thought to report reward prediction errors that drive learning in the basal ganglia. However, dopamine has also been implicated in various probabilistic computations, such as encoding uncertainty and controlling exploration. Here, we show how these different facets of dopamine signalling can be brought together under a common reinforcement learning framework. The key idea is that multiple sources of uncertainty impinge on reinforcement learning computations: uncertainty about the state of the environment, the parameters of the value function and the optimal action policy. Each of these sources plays a distinct role in the prefrontal cortex-basal ganglia circuit for reinforcement learning and is ultimately reflected in dopamine activity. The view that dopamine plays a central role in the encoding and updating of beliefs brings the classical prediction error theory into alignment with more recent theories of Bayesian reinforcement learning.
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Affiliation(s)
- Samuel J Gershman
- Department of Psychology, Center for Brain Science, Harvard University, Cambridge, MA, USA.
| | - Naoshige Uchida
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA
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14
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Cox KM, Fiez JA. Abstract inference of unchosen option values. Eur J Neurosci 2019; 51:909-921. [PMID: 31518460 DOI: 10.1111/ejn.14577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 08/09/2019] [Accepted: 08/30/2019] [Indexed: 11/27/2022]
Abstract
Reinforcement learning research has pursued a persistent question: Does reward feedback prompt inferences that transcend simple associations? Reversal learning data suggest an affirmative answer: When the positive stimulus (S+) becomes the negative stimulus (S-), trained humans rapidly switch to choosing the former S-. The operations supporting such inferences remain ambiguous. Do participants identify transitions between stimulus-specific contexts (i.e., A+B- and A-B+), or deduce values by learning the abstract contingency structure? Across two experiments, we probed humans' use of abstract rules to infer the values of unchosen alternatives. In Experiment 1, 37 participants attempted a task that originally demonstrated monkeys' difficulty with this form of inference. We presented modified discrimination problems in which the initially chosen stimulus (abstract inference group) or unchosen stimulus (control group) was replaced with a novel stimulus of identical status on Trial 2. In the abstract inference condition, accurate performance can be achieved by applying the consistent contingency structure (but not memory of stimulus-specific reward associations) to infer to the unchosen stimulus' value. The abstract inference group learned to make accurate choices, but only after committing substantially more errors than were observed among control participants-suggesting that unchosen value inferences are infrequently drawn in standard discrimination scenarios. In Experiment 2, 17 participants completed abstract inference problems that had been modified to be suitable for fMRI investigations. Behavioral results both corroborated the Experiment 1 trends and further revealed marked individual differences in explicit awareness of the novel stimulus values.
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Affiliation(s)
- Karin M Cox
- University of Pittsburgh, Pittsburgh, PA, USA
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15
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Hasz BM, Redish AD. Deliberation and Procedural Automation on a Two-Step Task for Rats. Front Integr Neurosci 2018; 12:30. [PMID: 30123115 PMCID: PMC6085996 DOI: 10.3389/fnint.2018.00030] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 07/02/2018] [Indexed: 11/25/2022] Open
Abstract
Current theories suggest that decision-making arises from multiple, competing action-selection systems. Rodent studies dissociate deliberation and procedural behavior, and find a transition from procedural to deliberative behavior with experience. However, it remains unknown how this transition from deliberative to procedural control evolves within single trials, or within blocks of repeated choices. We adapted for rats a two-step task which has been used to dissociate model-based from model-free decisions in humans. We found that a mixture of model-based and model-free algorithms was more likely to explain rat choice strategies on the task than either model-based or model-free algorithms alone. This task contained two choices per trial, which provides a more complex and non-discrete per-trial choice structure. This task structure enabled us to evaluate how deliberative and procedural behavior evolved within-trial and within blocks of repeated choice sequences. We found that vicarious trial and error (VTE), a behavioral correlate of deliberation in rodents, was correlated between the two choice points on a given lap. We also found that behavioral stereotypy, a correlate of procedural automation, increased with the number of repeated choices. While VTE at the first choice point decreased [corrected] with the number of repeated choices, VTE at the second choice point did not, and only increased after unexpected transitions within the task. This suggests that deliberation at the beginning of trials may correspond to changes in choice patterns, while mid-trial deliberation may correspond to an interruption of a procedural process.
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Affiliation(s)
- Brendan M. Hasz
- Graduate Program in Neuroscience, University of Minnesota Twin CitiesMinneapolis, MN, United States
| | - A. David Redish
- Department of Neuroscience, University of Minnesota Twin CitiesMinneapolis, MN, United States
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16
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Babayan BM, Uchida N, Gershman SJ. Belief state representation in the dopamine system. Nat Commun 2018; 9:1891. [PMID: 29760401 PMCID: PMC5951832 DOI: 10.1038/s41467-018-04397-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 04/26/2018] [Indexed: 12/19/2022] Open
Abstract
Learning to predict future outcomes is critical for driving appropriate behaviors. Reinforcement learning (RL) models have successfully accounted for such learning, relying on reward prediction errors (RPEs) signaled by midbrain dopamine neurons. It has been proposed that when sensory data provide only ambiguous information about which state an animal is in, it can predict reward based on a set of probabilities assigned to hypothetical states (called the belief state). Here we examine how dopamine RPEs and subsequent learning are regulated under state uncertainty. Mice are first trained in a task with two potential states defined by different reward amounts. During testing, intermediate-sized rewards are given in rare trials. Dopamine activity is a non-monotonic function of reward size, consistent with RL models operating on belief states. Furthermore, the magnitude of dopamine responses quantitatively predicts changes in behavior. These results establish the critical role of state inference in RL.
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Affiliation(s)
- Benedicte M Babayan
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA
- Department of Psychology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA
| | - Naoshige Uchida
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, 16 Divinity Avenue, Cambridge, MA, 02138, USA.
| | - Samuel J Gershman
- Department of Psychology, Center for Brain Science, Harvard University, 52 Oxford Street, Cambridge, MA, 02138, USA.
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17
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Lisman J, Buzsáki G, Eichenbaum H, Nadel L, Ranganath C, Redish AD. Viewpoints: how the hippocampus contributes to memory, navigation and cognition. Nat Neurosci 2017; 20:1434-1447. [PMID: 29073641 PMCID: PMC5943637 DOI: 10.1038/nn.4661] [Citation(s) in RCA: 387] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The hippocampus serves a critical function in memory, navigation, and cognition. Nature Neuroscience asked John Lisman to lead a group of researchers in a dialog on shared and distinct viewpoints on the hippocampus. There has been a long history of studying the hippocampus, but recent work has made it possible to study the cellular and network basis of defined operations—operations that include cognitive processes that have been otherwise difficult to study (see Box 1 for useful terminology). These operations deal with the context-dependent representation of complex memories, the role of mental exploration based on imagined rather than real movements, and the use of recalled information for navigation and decision-making. The progress that has been made in understanding the hippocampus has motivated the study of other brain regions that provide hippocampal input or receive hippocampal output; the hippocampus is thus serving as a nucleating point for the larger goal of understanding the neural codes that allow inter-regional communication and more generally, understanding how memory-guided behavior is achieved by large scale integration of brain regions. In generating a discussion among experts in the study of the cognitive processes of the hippocampus, the editors and I have posed questions that probe important principles of hippocampal function. We hope that the resulting discussion will make clear to readers the progress that has been made, while also identifying issues where consensus has not yet been achieved and that should be pursued in future research. – John Lisman
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Affiliation(s)
- John Lisman
- Department of Biology at Brandeis University, Waltham, Massachusetts, USA
| | - György Buzsáki
- NYU Neuroscience Institute at New York University, New York, New York, USA
| | - Howard Eichenbaum
- Center for Memory and Brain at Boston University, Boston, Massachusetts, USA
| | - Lynn Nadel
- Department of Psychology and Cognitive Science Program at University of Arizona, Tucson, Arizona, USA
| | - Charan Ranganath
- Center for Neuroscience and Department of Psychology at the University of California, Davis, California, USA
| | - A David Redish
- Department of Neuroscience at the University of Minnesota, Minneapolis, Minnesota, USA
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Pezzulo G, Kemere C, van der Meer MAA. Internally generated hippocampal sequences as a vantage point to probe future-oriented cognition. Ann N Y Acad Sci 2017; 1396:144-165. [PMID: 28548460 DOI: 10.1111/nyas.13329] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/31/2017] [Accepted: 02/07/2017] [Indexed: 12/22/2022]
Abstract
Information processing in the rodent hippocampus is fundamentally shaped by internally generated sequences (IGSs), expressed during two different network states: theta sequences, which repeat and reset at the ∼8 Hz theta rhythm associated with active behavior, and punctate sharp wave-ripple (SWR) sequences associated with wakeful rest or slow-wave sleep. A potpourri of diverse functional roles has been proposed for these IGSs, resulting in a fragmented conceptual landscape. Here, we advance a unitary view of IGSs, proposing that they reflect an inferential process that samples a policy from the animal's generative model, supported by hippocampus-specific priors. The same inference affords different cognitive functions when the animal is in distinct dynamical modes, associated with specific functional networks. Theta sequences arise when inference is coupled to the animal's action-perception cycle, supporting online spatial decisions, predictive processing, and episode encoding. SWR sequences arise when the animal is decoupled from the action-perception cycle and may support offline cognitive processing, such as memory consolidation, the prospective simulation of spatial trajectories, and imagination. We discuss the empirical bases of this proposal in relation to rodent studies and highlight how the proposed computational principles can shed light on the mechanisms of future-oriented cognition in humans.
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Affiliation(s)
- Giovanni Pezzulo
- Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| | - Caleb Kemere
- Electrical and Computer Engineering, Rice University, Houston, Texas
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19
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Ekstrom AD, Ranganath C. Space, time, and episodic memory: The hippocampus is all over the cognitive map. Hippocampus 2017; 28:680-687. [DOI: 10.1002/hipo.22750] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 06/12/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Arne D. Ekstrom
- Center for NeuroscienceUniversity of CaliforniaDavis, 1544 Newton Court, Davis California
- Department of PsychologyUniversity of CaliforniaDavis, Davis California
- Neuroscience Graduate GroupUniversity of CaliforniaDavis, Davis California
| | - Charan Ranganath
- Center for NeuroscienceUniversity of CaliforniaDavis, 1544 Newton Court, Davis California
- Department of PsychologyUniversity of CaliforniaDavis, Davis California
- Neuroscience Graduate GroupUniversity of CaliforniaDavis, Davis California
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20
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Gershman SJ, Monfils MH, Norman KA, Niv Y. The computational nature of memory modification. eLife 2017; 6. [PMID: 28294944 PMCID: PMC5391211 DOI: 10.7554/elife.23763] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Accepted: 03/13/2017] [Indexed: 11/25/2022] Open
Abstract
Retrieving a memory can modify its influence on subsequent behavior. We develop a computational theory of memory modification, according to which modification of a memory trace occurs through classical associative learning, but which memory trace is eligible for modification depends on a structure learning mechanism that discovers the units of association by segmenting the stream of experience into statistically distinct clusters (latent causes). New memories are formed when the structure learning mechanism infers that a new latent cause underlies current sensory observations. By the same token, old memories are modified when old and new sensory observations are inferred to have been generated by the same latent cause. We derive this framework from probabilistic principles, and present a computational implementation. Simulations demonstrate that our model can reproduce the major experimental findings from studies of memory modification in the Pavlovian conditioning literature. DOI:http://dx.doi.org/10.7554/eLife.23763.001 Our memories contain our expectations about the world that we can retrieve to make predictions about the future. For example, most people would expect a chocolate bar to taste good, because they have previously learned to associate chocolate with pleasure. When a surprising event occurs, such as tasting an unpalatable chocolate bar, the brain therefore faces a dilemma. Should it update the existing memory and overwrite the association between chocolate and pleasure? Or should it create an additional memory? In the latter case, the brain would form a new association between chocolate and displeasure that competes with, but does not overwrite, the original one between chocolate and pleasure. Previous studies have shown that surprising events tend to create new memories unless the existing memory is briefly reactivated before the surprising event occurs. In other words, retrieving old memories makes them more malleable. Gershman et al. have now developed a computational model for how the brain decides whether to update an old memory or create a new one. The idea at the heart of the model is that the brain will attempt to infer what caused the surprising event. The reason the chocolate bar tastes unpalatable, for example, might be because it was old and had spoiled. Every time the brain infers a new possible cause for a surprising event, it will create an additional memory to store this new set of expectations. In the future we will know that spoiled chocolate bars taste bad. However, if the brain cannot infer a new cause for the surprising event – because, for example, there appears to be nothing unusual about the unpalatable chocolate bar – it will instead opt to update the existing memory. The next time we buy a chocolate bar, we will have slightly lower expectations about how good it will taste. The dilemma of whether to update an existing memory or create a new one thus boils down to the question: is the surprising event the consequence of a new cause or an old one? This theory implies that retrieving a memory nudges the brain to infer that its associated cause is once again active and, since this is an old cause, it means that the memory will be eligible for updating. Many experiments have been performed on the topic of modifying memories, but this is the first computational model that offers a unifying explanation for the results. The next step is to work out how to apply the model, which is phrased in abstract terms, to networks of neurons that are more biologically realistic. DOI:http://dx.doi.org/10.7554/eLife.23763.002
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Affiliation(s)
- Samuel J Gershman
- Department of Psychology and Center for Brain Science, Harvard University, Cambridge, United States
| | - Marie-H Monfils
- Department of Psychology, University of Texas, Austin, United States
| | - Kenneth A Norman
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, United States
| | - Yael Niv
- Princeton Neuroscience Institute and Department of Psychology, Princeton University, Princeton, United States
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21
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Friston K, Buzsáki G. The Functional Anatomy of Time: What and When in the Brain. Trends Cogn Sci 2016; 20:500-511. [PMID: 27261057 DOI: 10.1016/j.tics.2016.05.001] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 04/24/2016] [Accepted: 05/02/2016] [Indexed: 11/17/2022]
Abstract
This Opinion article considers the implications for functional anatomy of how we represent temporal structure in our exchanges with the world. It offers a theoretical treatment that tries to make sense of the architectural principles seen in mammalian brains. Specifically, it considers a factorisation between representations of temporal succession and representations of content or, heuristically, a segregation into when and what. This segregation may explain the central role of the hippocampus in neuronal hierarchies while providing a tentative explanation for recent observations of how ordinal sequences are encoded. The implications for neuroanatomy and physiology may have something important to say about how self-organised cell assembly sequences enable the brain to exhibit purposeful behaviour that transcends the here and now.
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Affiliation(s)
- Karl Friston
- Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, UK.
| | - Gyorgy Buzsáki
- NYU Neuroscience Institute, School of Medicine, New York University, New York, NY 10016, USA; Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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22
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23
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Zucker HR, Ranganath C. Navigating the human hippocampus without a GPS. Hippocampus 2015; 25:697-703. [DOI: 10.1002/hipo.22447] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 03/17/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Halle R. Zucker
- Center for Neuroscience and Department of Psychology; University of California at Davis; California
| | - Charan Ranganath
- Center for Neuroscience and Department of Psychology; University of California at Davis; California
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24
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Hami J, Kheradmand H, Haghir H. Sex differences and laterality of insulin receptor distribution in developing rat hippocampus: an immunohistochemical study. J Mol Neurosci 2014; 54:100-8. [PMID: 24573599 DOI: 10.1007/s12031-014-0255-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 02/04/2014] [Indexed: 12/19/2022]
Abstract
This study aimed to compare the regional distribution of insulin receptor in various portions of newborn rat hippocampus on postnatal days 0 (P0), 7 (P7), and 14 (P14) between male/female and right/left hippocampi. We found that the number of insulin receptor (InsR)-immunoreactive-positive (InsR+) cells in CA1 continued to increase until P7 and remained unchanged thereafter. A marked increase in distribution of InsR+ cells in CA3 from P0 to P14 was observed, although there was a significant decline in the number of InsR+ cells in dentate gyrus (DG) at the same time. No differences between the right/left and male/female hippocampi were detected at P0 (P > 0.05). Seven-day-old female rats showed a higher number of labeled cells in the left than in the right hippocampus. Moreover, the differences between the number of InsR+ cells in area CA1 and CA3 were statistically significant between males and females (P < 0.05). At P14, the number of InsR+ cells was significantly higher in CA1 and DG of males, especially in the right one (P < 0.05). These results indicate the existence of a differential distribution pattern of InsR between the left/right and male/female hippocampi. Together with other mechanisms, these differences may underlie sexual dimorphism and left/right asymmetry in the hippocampus.
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Affiliation(s)
- Javad Hami
- Department of Anatomical Sciences, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran
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25
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Penny WD, Zeidman P, Burgess N. Forward and backward inference in spatial cognition. PLoS Comput Biol 2013; 9:e1003383. [PMID: 24348230 PMCID: PMC3861045 DOI: 10.1371/journal.pcbi.1003383] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Accepted: 10/23/2013] [Indexed: 12/26/2022] Open
Abstract
This paper shows that the various computations underlying spatial cognition can be implemented using statistical inference in a single probabilistic model. Inference is implemented using a common set of 'lower-level' computations involving forward and backward inference over time. For example, to estimate where you are in a known environment, forward inference is used to optimally combine location estimates from path integration with those from sensory input. To decide which way to turn to reach a goal, forward inference is used to compute the likelihood of reaching that goal under each option. To work out which environment you are in, forward inference is used to compute the likelihood of sensory observations under the different hypotheses. For reaching sensory goals that require a chaining together of decisions, forward inference can be used to compute a state trajectory that will lead to that goal, and backward inference to refine the route and estimate control signals that produce the required trajectory. We propose that these computations are reflected in recent findings of pattern replay in the mammalian brain. Specifically, that theta sequences reflect decision making, theta flickering reflects model selection, and remote replay reflects route and motor planning. We also propose a mapping of the above computational processes onto lateral and medial entorhinal cortex and hippocampus.
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Affiliation(s)
- Will D. Penny
- Wellcome Trust Centre for Neuroimaging, University College, London, London, United Kingdom
| | - Peter Zeidman
- Wellcome Trust Centre for Neuroimaging, University College, London, London, United Kingdom
| | - Neil Burgess
- Institute for Cognitive Neuroscience, University College, London, London, United Kingdom
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26
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Hami J, Kheradmand H, Haghir H. Gender differences and lateralization in the distribution pattern of insulin-like growth factor-1 receptor in developing rat hippocampus: an immunohistochemical study. Cell Mol Neurobiol 2013; 34:215-26. [PMID: 24287499 DOI: 10.1007/s10571-013-0005-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 11/06/2013] [Indexed: 12/11/2022]
Abstract
Numerous investigators have provided data supporting essential roles for insulin-like growth factor-I (IGF-I) in development of the brain. The aim of this study was to immunohistochemically determine the distinct regional distribution pattern of IGF-1 receptor (IGF-IR) expression in various portions of newborn rat hippocampus on postnatal days 0 (P0), 7 (P7), and 14 (P14), with comparison between male/female and right/left hippocampi. We found an overall significant increase in distribution of IGF-IR-positive (IGF-IR+) cells in CA1 from P0 until P14. Although, no marked changes in distribution of IGF-IR+ cells in areas CA2 and CA3 were observed; IGF-IR+ cells in DG decreased until P14. The smallest number of immunoreactive cells was present in CA2 and the highest number in DG at P0. Moreover, in CA1, CA3, and DG, the number of IGF-IR+ cells was markedly higher in both sides of the hippocampus in females. Our data also showed a higher mean number of IGF-IR+ cells in the left hippocampus of female at P7. By contrast, male pups showed a significantly higher number of IGF-IR+ cells in the DG of the right hippocampus. At P14, the mean number of immunoreactive cells in CA1, CA3, and DG areas found to be significantly increased in left side of hippocampus of males, compared to females. These results indicate the existence of a differential distribution pattern of IGF-IR between left-right and male-female hippocampi. Together with other mechanisms, these differences may underlie sexual dimorphism and left-right asymmetry in the hippocampus.
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Affiliation(s)
- Javad Hami
- Department of Anatomy, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran
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27
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Wang WC, Yonelinas AP, Ranganath C. Dissociable neural correlates of item and context retrieval in the medial temporal lobes. Behav Brain Res 2013; 254:102-7. [PMID: 23711925 DOI: 10.1016/j.bbr.2013.05.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2012] [Revised: 05/13/2013] [Accepted: 05/20/2013] [Indexed: 11/16/2022]
Abstract
Although it is generally accepted that the medial temporal lobe (MTL) is critical for episodic memory, the contributions of cortical regions in the MTL, such as the perirhinal (PRc) and parahippocampal (PHc) cortices, remain unresolved. Recent studies have asserted that the PRc supports the processing of object and face information, whereas the PHc supports the processing of scene information. These findings have been used to characterize the PRc and PHc as being important for the memory of objects and scenes, respectively. However, these results are also consistent with the idea that these MTL regions are critical for the memory of stimuli that are processed as either items or contexts. It has been difficult to differentiate between these two accounts given that in most studies, item and context are operationalized as different types of memoranda (e.g., memory for objects compared to memory for background scenes). Here, we tested the extent to which different MTL regions are involved in the retrieval of item or context information when the material type is held constant. Participants encoded pairs of fractal images and were oriented to encode one fractal as an item and the other as a context. At test, they were cued with previously studied item or context fractals and asked to retrieve the corresponding associate. Results indicated that on test trials, PRc activity was increased during recall of fractals that were encoded as items, whereas PHc activity was greater during recall of fractals that were encoded as contexts. These results provide direct evidence that, even when stimulus type is held constant, the PRc and PHc are preferentially involved in supporting memory for item and context information, respectively.
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Affiliation(s)
- Wei-Chun Wang
- Department of Psychology, University of California, Davis, United States.
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28
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Lloyd K, Leslie DS. Context-dependent decision-making: a simple Bayesian model. J R Soc Interface 2013; 10:20130069. [PMID: 23427101 PMCID: PMC3627089 DOI: 10.1098/rsif.2013.0069] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 01/29/2013] [Indexed: 11/12/2022] Open
Abstract
Many phenomena in animal learning can be explained by a context-learning process whereby an animal learns about different patterns of relationship between environmental variables. Differentiating between such environmental regimes or 'contexts' allows an animal to rapidly adapt its behaviour when context changes occur. The current work views animals as making sequential inferences about current context identity in a world assumed to be relatively stable but also capable of rapid switches to previously observed or entirely new contexts. We describe a novel decision-making model in which contexts are assumed to follow a Chinese restaurant process with inertia and full Bayesian inference is approximated by a sequential-sampling scheme in which only a single hypothesis about current context is maintained. Actions are selected via Thompson sampling, allowing uncertainty in parameters to drive exploration in a straightforward manner. The model is tested on simple two-alternative choice problems with switching reinforcement schedules and the results compared with rat behavioural data from a number of T-maze studies. The model successfully replicates a number of important behavioural effects: spontaneous recovery, the effect of partial reinforcement on extinction and reversal, the overtraining reversal effect, and serial reversal-learning effects.
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Affiliation(s)
- Kevin Lloyd
- Department of Computer Science, University of Bristol, Bristol, UK.
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29
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Penner MR, Mizumori SJY. Neural systems analysis of decision making during goal-directed navigation. Prog Neurobiol 2011; 96:96-135. [PMID: 21964237 DOI: 10.1016/j.pneurobio.2011.08.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/06/2011] [Accepted: 08/29/2011] [Indexed: 10/17/2022]
Abstract
The ability to make adaptive decisions during goal-directed navigation is a fundamental and highly evolved behavior that requires continual coordination of perceptions, learning and memory processes, and the planning of behaviors. Here, a neurobiological account for such coordination is provided by integrating current literatures on spatial context analysis and decision-making. This integration includes discussions of our current understanding of the role of the hippocampal system in experience-dependent navigation, how hippocampal information comes to impact midbrain and striatal decision making systems, and finally the role of the striatum in the implementation of behaviors based on recent decisions. These discussions extend across cellular to neural systems levels of analysis. Not only are key findings described, but also fundamental organizing principles within and across neural systems, as well as between neural systems functions and behavior, are emphasized. It is suggested that studying decision making during goal-directed navigation is a powerful model for studying interactive brain systems and their mediation of complex behaviors.
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Affiliation(s)
- Marsha R Penner
- Department of Psychology, University of Washington, Seattle, WA 98195-1525, United States
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30
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Effects of pharmacological manipulations of NMDA-receptors on deliberation in the Multiple-T task. Neurobiol Learn Mem 2011; 95:376-84. [PMID: 21296174 DOI: 10.1016/j.nlm.2011.01.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/04/2011] [Accepted: 01/25/2011] [Indexed: 11/24/2022]
Abstract
Both humans and non-human animals have the ability to navigate and make decisions within complex environments. This ability is largely dependent upon learning and memory processes, many of which are known to depend on NMDA-sensitive receptors. When humans come to difficult decisions they often pause to deliberate over their choices. Similarly, rats pause at difficult choice points. This behavior, known as vicarious trial and error (VTE), is hippocampally dependent and entails neurophysiological representations of expectations of future outcomes in hippocampus and downstream structures. In order to determine the dependence of VTE behaviors on NMDA-sensitive receptors, we tested rats on a Multiple-T choice task with a reward-delivery reversal known to elicit VTE. Rats under the influence of NMDA-receptor antagonists (CPP) showed a significant reduction in VTE, particularly at the reward reversal, implying a role for NMDA-sensitive receptors in the generation of vicarious trial and error behaviors.
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31
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Zilli EA, Hasselmo ME. The influence of Markov decision process structure on the possible strategic use of working memory and episodic memory. PLoS One 2008; 3:e2756. [PMID: 18648498 PMCID: PMC2447173 DOI: 10.1371/journal.pone.0002756] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 06/23/2008] [Indexed: 11/19/2022] Open
Abstract
Researchers use a variety of behavioral tasks to analyze the effect of biological manipulations on memory function. This research will benefit from a systematic mathematical method for analyzing memory demands in behavioral tasks. In the framework of reinforcement learning theory, these tasks can be mathematically described as partially-observable Markov decision processes. While a wealth of evidence collected over the past 15 years relates the basal ganglia to the reinforcement learning framework, only recently has much attention been paid to including psychological concepts such as working memory or episodic memory in these models. This paper presents an analysis that provides a quantitative description of memory states sufficient for correct choices at specific decision points. Using information from the mathematical structure of the task descriptions, we derive measures that indicate whether working memory (for one or more cues) or episodic memory can provide strategically useful information to an agent. In particular, the analysis determines which observed states must be maintained in or retrieved from memory to perform these specific tasks. We demonstrate the analysis on three simplified tasks as well as eight more complex memory tasks drawn from the animal and human literature (two alternation tasks, two sequence disambiguation tasks, two non-matching tasks, the 2-back task, and the 1-2-AX task). The results of these analyses agree with results from quantitative simulations of the task reported in previous publications and provide simple indications of the memory demands of the tasks which can require far less computation than a full simulation of the task. This may provide a basis for a quantitative behavioral stoichiometry of memory tasks.
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Affiliation(s)
- Eric A Zilli
- Center for Memory and Brain, Boston University, Boston, Massachusetts, United States of America.
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