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Ai S. STN-PFC circuit related to attentional fluctuations during non-movement decision-making. Neuroscience 2024; 553:110-120. [PMID: 38972448 DOI: 10.1016/j.neuroscience.2024.06.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 06/06/2024] [Accepted: 06/27/2024] [Indexed: 07/09/2024]
Abstract
Decision-making is a cognitive process, in which participants need to attend to relevant information and ignore the irrelevant information. Previous studies have described a set of cortical areas important for attention. It is unclear whether subcortical areas also serve a role. The subthalamic nucleus (STN), a part of basal ganglia, is traditionally considered a critical node in the cortico-basal ganglia-thalamus-cortico network. Given the location of the STN and its widespread connections with cortical and subcortical brain regions, the STN plays an important role in motor and non-motor cognitive processing. We would like to know if STN is also related to fluctuations in attentional task performance, and how the STN interacts with prefrontal cortical regions during the process. We examined neural activities within STN covaried with lapses of attention (defined as behavior error). We found that decreased neural activities in STN were associated with sustained attention. By examining connectivity across STN and various sub-regions of the prefrontal cortex (PFC), we found that decreased connectivity across areas was associated with sustained attention. Our results indicated that decreased STN activities were associated with sustained attention, and the STN-PFC circuit supported this process.
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Affiliation(s)
- Shengnan Ai
- Department of Automation, Tsinghua University, Beijing 100084, China; Institute for Brain and Cognitive Sciences, Tsinghua University, Beijing 100084, China.
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2
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Diamond JM, Chapeton JI, Xie W, Jackson SN, Inati SK, Zaghloul KA. Focal seizures induce spatiotemporally organized spiking activity in the human cortex. Nat Commun 2024; 15:7075. [PMID: 39152115 PMCID: PMC11329741 DOI: 10.1038/s41467-024-51338-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 08/05/2024] [Indexed: 08/19/2024] Open
Abstract
Epileptic seizures are debilitating because of the clinical symptoms they produce. These symptoms, in turn, may stem directly from disruptions in neural coding. Recent evidence has suggested that the specific temporal order, or sequence, of spiking across a population of cortical neurons may encode information. Here, we investigate how seizures disrupt neuronal spiking sequences in the human brain by recording multi-unit activity from the cerebral cortex in five male participants undergoing monitoring for seizures. We find that pathological discharges during seizures are associated with bursts of spiking activity across a population of cortical neurons. These bursts are organized into highly consistent and stereotyped temporal sequences. As the seizure evolves, spiking sequences diverge from the sequences observed at baseline and become more spatially organized. The direction of this spatial organization matches the direction of the ictal discharges, which spread over the cortex as traveling waves. Our data therefore suggest that seizures can entrain cortical spiking sequences by changing the spatial organization of neuronal firing, providing a possible mechanism by which seizures create symptoms.
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Affiliation(s)
- Joshua M Diamond
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Julio I Chapeton
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Weizhen Xie
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA
- Department of Psychology, University of Maryland, College Park, MD, 20742, USA
| | - Samantha N Jackson
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sara K Inati
- Clinical Epilepsy Section, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA.
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3
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Ding R, Ten Oever S, Martin AE. Delta-band Activity Underlies Referential Meaning Representation during Pronoun Resolution. J Cogn Neurosci 2024; 36:1472-1492. [PMID: 38652108 DOI: 10.1162/jocn_a_02163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Human language offers a variety of ways to create meaning, one of which is referring to entities, objects, or events in the world. One such meaning maker is understanding to whom or to what a pronoun in a discourse refers to. To understand a pronoun, the brain must access matching entities or concepts that have been encoded in memory from previous linguistic context. Models of language processing propose that internally stored linguistic concepts, accessed via exogenous cues such as phonological input of a word, are represented as (a)synchronous activities across a population of neurons active at specific frequency bands. Converging evidence suggests that delta band activity (1-3 Hz) is involved in temporal and representational integration during sentence processing. Moreover, recent advances in the neurobiology of memory suggest that recollection engages neural dynamics similar to those which occurred during memory encoding. Integrating from these two research lines, we here tested the hypothesis that neural dynamic patterns, especially in delta frequency range, underlying referential meaning representation, would be reinstated during pronoun resolution. By leveraging neural decoding techniques (i.e., representational similarity analysis) on a magnetoencephalogram data set acquired during a naturalistic story-listening task, we provide evidence that delta-band activity underlies referential meaning representation. Our findings suggest that, during spoken language comprehension, endogenous linguistic representations such as referential concepts may be proactively retrieved and represented via activation of their underlying dynamic neural patterns.
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Affiliation(s)
- Rong Ding
- Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Sanne Ten Oever
- Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Radboud University Donders Centre for Cognitive Neuroimaging, Nijmegen, The Netherlands
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Andrea E Martin
- Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Radboud University Donders Centre for Cognitive Neuroimaging, Nijmegen, The Netherlands
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4
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Fetterhoff D, Costa M, Hellerstedt R, Johannessen R, Imbach L, Sarnthein J, Strange BA. Neuronal population representation of human emotional memory. Cell Rep 2024; 43:114071. [PMID: 38592973 PMCID: PMC11063625 DOI: 10.1016/j.celrep.2024.114071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 03/07/2024] [Accepted: 03/21/2024] [Indexed: 04/11/2024] Open
Abstract
Understanding how emotional processing modulates learning and memory is crucial for the treatment of neuropsychiatric disorders characterized by emotional memory dysfunction. We investigate how human medial temporal lobe (MTL) neurons support emotional memory by recording spiking activity from the hippocampus, amygdala, and entorhinal cortex during encoding and recognition sessions of an emotional memory task in patients with pharmaco-resistant epilepsy. Our findings reveal distinct representations for both remembered compared to forgotten and emotional compared to neutral scenes in single units and MTL population spiking activity. Additionally, we demonstrate that a distributed network of human MTL neurons exhibiting mixed selectivity on a single-unit level collectively processes emotion and memory as a network, with a small percentage of neurons responding conjointly to emotion and memory. Analyzing spiking activity enables a detailed understanding of the neurophysiological mechanisms underlying emotional memory and could provide insights into how emotion alters memory during healthy and maladaptive learning.
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Affiliation(s)
- Dustin Fetterhoff
- Laboratory for Clinical Neuroscience, Center for Biomedical Technology, Universidad Politécnica de Madrid, IdISSC, Madrid, Spain.
| | - Manuela Costa
- Laboratory for Clinical Neuroscience, Center for Biomedical Technology, Universidad Politécnica de Madrid, IdISSC, Madrid, Spain
| | - Robin Hellerstedt
- Laboratory for Clinical Neuroscience, Center for Biomedical Technology, Universidad Politécnica de Madrid, IdISSC, Madrid, Spain
| | - Rebecca Johannessen
- Swiss Epilepsy Center, Klinik Lengg, Zurich, Switzerland; Department of Psychology, University of Zurich, Switzerland
| | - Lukas Imbach
- Swiss Epilepsy Center, Klinik Lengg, Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Johannes Sarnthein
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland; Department of Neurosurgery, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Bryan A Strange
- Laboratory for Clinical Neuroscience, Center for Biomedical Technology, Universidad Politécnica de Madrid, IdISSC, Madrid, Spain; Reina Sofia Centre for Alzheimer's Research, Madrid, Spain
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5
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Khanna AR, Muñoz W, Kim YJ, Kfir Y, Paulk AC, Jamali M, Cai J, Mustroph ML, Caprara I, Hardstone R, Mejdell M, Meszéna D, Zuckerman A, Schweitzer J, Cash S, Williams ZM. Single-neuronal elements of speech production in humans. Nature 2024; 626:603-610. [PMID: 38297120 PMCID: PMC10866697 DOI: 10.1038/s41586-023-06982-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 12/14/2023] [Indexed: 02/02/2024]
Abstract
Humans are capable of generating extraordinarily diverse articulatory movement combinations to produce meaningful speech. This ability to orchestrate specific phonetic sequences, and their syllabification and inflection over subsecond timescales allows us to produce thousands of word sounds and is a core component of language1,2. The fundamental cellular units and constructs by which we plan and produce words during speech, however, remain largely unknown. Here, using acute ultrahigh-density Neuropixels recordings capable of sampling across the cortical column in humans, we discover neurons in the language-dominant prefrontal cortex that encoded detailed information about the phonetic arrangement and composition of planned words during the production of natural speech. These neurons represented the specific order and structure of articulatory events before utterance and reflected the segmentation of phonetic sequences into distinct syllables. They also accurately predicted the phonetic, syllabic and morphological components of upcoming words and showed a temporally ordered dynamic. Collectively, we show how these mixtures of cells are broadly organized along the cortical column and how their activity patterns transition from articulation planning to production. We also demonstrate how these cells reliably track the detailed composition of consonant and vowel sounds during perception and how they distinguish processes specifically related to speaking from those related to listening. Together, these findings reveal a remarkably structured organization and encoding cascade of phonetic representations by prefrontal neurons in humans and demonstrate a cellular process that can support the production of speech.
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Affiliation(s)
- Arjun R Khanna
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - William Muñoz
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Yoav Kfir
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Angelique C Paulk
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Mohsen Jamali
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jing Cai
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Martina L Mustroph
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Irene Caprara
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Richard Hardstone
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Mackenna Mejdell
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Domokos Meszéna
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Jeffrey Schweitzer
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Sydney Cash
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ziv M Williams
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Harvard-MIT Division of Health Sciences and Technology, Boston, MA, USA.
- Harvard Medical School, Program in Neuroscience, Boston, MA, USA.
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6
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Zhang S, Zhang L, Ma L, Wu H, Liu L, He X, Gao M, Li R. Neuropsychological, plasma marker, and functional connectivity changes in Alzheimer's disease patients infected with COVID-19. Front Aging Neurosci 2023; 15:1302281. [PMID: 38187359 PMCID: PMC10766841 DOI: 10.3389/fnagi.2023.1302281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/05/2023] [Indexed: 01/09/2024] Open
Abstract
Introduction Patients with COVID-19 may experience various neurological conditions, including cognitive impairment, encephalitis, and stroke. This is particularly significant in individuals who already have Alzheimer's disease (AD), as the cognitive impairments can be more pronounced in these cases. However, the extent and underlying mechanisms of cognitive impairments in COVID-19-infected AD patients have yet to be fully investigated through clinical and neurophysiological approaches. Methods This study included a total of 77 AD patients. Cognitive functions were assessed using neuropsychiatric scales for all participants, and plasma biomarkers of amyloid protein and tau protein were measured in a subset of 25 participants. To investigate the changes in functional brain connectivity induced by COVID-19 infection, a cross-sectional neuroimaging design was conducted involving a subset of 37 AD patients, including a control group of 18 AD participants without COVID-19 infection and a COVID-19 group consisting of 19 AD participants. Results For the 77 AD patients between the stages of pre and post COVID-19 infection, there were significant differences in cognitive function and psychobehavioral symptoms on the Montreal Scale (MoCA), the neuropsychiatric inventory (NPI), the clinician's global impression of change (CIBIC-Plus), and the activity of daily living scale (ADL). The COVID-19 infection significantly decreased the plasma biomarker level of Aβ42 and increased the plasma p-tau181 level in AD patients. The COVID-19-infected AD patients show decreased local coherence (LCOR) in the anterior middle temporal gyrus and decreased global correlation (GCOR) in the precuneus and the medial prefrontal cortex. Conclusion The findings suggest clinical, cognitive, and neural alterations following COVID-19 infection in AD patients and emphasize the need for close monitoring of symptoms in AD patients who have had COVID-19 and further exploration of the underlying mechanisms.
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Affiliation(s)
- Shouzi Zhang
- Department of Psychiatry, Beijing Geriatric Hospital, Beijing, China
| | - Li Zhang
- Department of Psychiatry, Beijing Geriatric Hospital, Beijing, China
| | - Li Ma
- Department of Psychiatry, Beijing Geriatric Hospital, Beijing, China
| | - Haiyan Wu
- Department of Psychiatry, Beijing Geriatric Hospital, Beijing, China
| | - Lixin Liu
- Department of Psychiatry, Beijing Geriatric Hospital, Beijing, China
| | - Xuelin He
- Department of Psychiatry, Beijing Geriatric Hospital, Beijing, China
| | - Maolong Gao
- Department of Science and Technology, Beijing Geriatric Hospital, Beijing, China
| | - Rui Li
- CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
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Vaz AP, Wittig JH, Inati SK, Zaghloul KA. Backbone spiking sequence as a basis for preplay, replay, and default states in human cortex. Nat Commun 2023; 14:4723. [PMID: 37550285 PMCID: PMC10406814 DOI: 10.1038/s41467-023-40440-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 07/27/2023] [Indexed: 08/09/2023] Open
Abstract
Sequences of spiking activity have been heavily implicated as potential substrates of memory formation and retrieval across many species. A parallel line of recent evidence also asserts that sequential activity may arise from and be constrained by pre-existing network structure. Here we reconcile these two lines of research in the human brain by measuring single unit spiking sequences in the temporal lobe cortex as participants perform an episodic memory task. We find the presence of an average backbone spiking sequence identified during pre-task rest that is stable over time and different cognitive states. We further demonstrate that these backbone sequences are composed of both rigid and flexible sequence elements, and that flexible elements within these sequences serve to promote memory specificity when forming and retrieving new memories. These results support the hypothesis that pre-existing network dynamics serve as a scaffold for ongoing neural activity in the human cortex.
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Affiliation(s)
- Alex P Vaz
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - John H Wittig
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sara K Inati
- Office of the Clinical Director, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, 20892, USA.
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8
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Markowitsch HJ, Staniloiu A. Behavioral, neurological, and psychiatric frailty of autobiographical memory. WILEY INTERDISCIPLINARY REVIEWS. COGNITIVE SCIENCE 2023; 14:e1617. [PMID: 35970754 DOI: 10.1002/wcs.1617] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 07/01/2022] [Accepted: 07/03/2022] [Indexed: 05/20/2023]
Abstract
Autobiographical-episodic memory is considered to be the most complex of the five long-term memory systems. It is autonoetic, which means, self-reflective, relies on emotional colorization, and needs the features of place and time; it allows mental time traveling. Compared to the other four long-term memory systems-procedural memory, priming, perceptual, and semantic memory-it develops the latest in phylogeny and ontogeny, and is the most vulnerable of the five systems, being easily impaired by brain damage and psychiatric disorders. Furthermore, it is characterized by its fragility and proneness to distortion due to environmental influences and subsequent information. On the brain level, a distinction has to be made between memory encoding and consolidating, memory storage, and memory retrieval. For encoding, structures of the limbic system, with the hippocampus in its center, are crucial, for storage of widespread cortical networks, and for retrieval again a distributed recollection network, in which the prefrontal cortex plays a crucial role, is engaged. Brain damage and psychiatric diseases can lead to what is called "focal retrograde amnesia." In this context, the clinical picture of dissociative or functional or psychogenic amnesia is central, as it may result in autobiographical-emotional amnesia of the total past with the consequence of an impairment of the self as well. The social environment therefore can have a major impact on the brain and on autobiographical-episodic memory processing. This article is categorized under: Psychology > Memory.
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Affiliation(s)
- Hans J Markowitsch
- Department of Physiological Psychology, University of Bielefeld, Bielefeld, Germany
| | - Angelica Staniloiu
- Department of Physiological Psychology, University of Bielefeld, Bielefeld, Germany
- Oberberg Clinic, Hornberg, Germany
- Department of Psychology, University of Bucharest, Bucharest, Romania
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Chen ZS, Wilson MA. How our understanding of memory replay evolves. J Neurophysiol 2023; 129:552-580. [PMID: 36752404 PMCID: PMC9988534 DOI: 10.1152/jn.00454.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 02/09/2023] Open
Abstract
Memory reactivations and replay, widely reported in the hippocampus and cortex across species, have been implicated in memory consolidation, planning, and spatial and skill learning. Technological advances in electrophysiology, calcium imaging, and human neuroimaging techniques have enabled neuroscientists to measure large-scale neural activity with increasing spatiotemporal resolution and have provided opportunities for developing robust analytic methods to identify memory replay. In this article, we first review a large body of historically important and representative memory replay studies from the animal and human literature. We then discuss our current understanding of memory replay functions in learning, planning, and memory consolidation and further discuss the progress in computational modeling that has contributed to these improvements. Next, we review past and present analytic methods for replay analyses and discuss their limitations and challenges. Finally, looking ahead, we discuss some promising analytic methods for detecting nonstereotypical, behaviorally nondecodable structures from large-scale neural recordings. We argue that seamless integration of multisite recordings, real-time replay decoding, and closed-loop manipulation experiments will be essential for delineating the role of memory replay in a wide range of cognitive and motor functions.
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Affiliation(s)
- Zhe Sage Chen
- Department of Psychiatry, New York University Grossman School of Medicine, New York, New York, United States
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, New York, United States
- Neuroscience Institute, New York University Grossman School of Medicine, New York, New York, United States
- Department of Biomedical Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States
| | - Matthew A Wilson
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
- Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States
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10
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Sherif MA, Khalil MZ, Shukla R, Brown JC, Carpenter LL. Synapses, predictions, and prediction errors: A neocortical computational study of MDD using the temporal memory algorithm of HTM. Front Psychiatry 2023; 14:976921. [PMID: 36911109 PMCID: PMC9995817 DOI: 10.3389/fpsyt.2023.976921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 01/16/2023] [Indexed: 02/25/2023] Open
Abstract
INTRODUCTION Synapses and spines play a significant role in major depressive disorder (MDD) pathophysiology, recently highlighted by the rapid antidepressant effect of ketamine and psilocybin. According to the Bayesian brain and interoception perspectives, MDD is formalized as being stuck in affective states constantly predicting negative energy balance. To understand how spines and synapses relate to the predictive function of the neocortex and thus to symptoms, we used the temporal memory (TM), an unsupervised machine-learning algorithm. TM models a single neocortical layer, learns in real-time, and extracts and predicts temporal sequences. TM exhibits neocortical biological features such as sparse firing and continuous online learning using local Hebbian-learning rules. METHODS We trained a TM model on random sequences of upper-case alphabetical letters, representing sequences of affective states. To model depression, we progressively destroyed synapses in the TM model and examined how that affected the predictive capacity of the network. We found that the number of predictions decreased non-linearly. RESULTS Destroying 50% of the synapses slightly reduced the number of predictions, followed by a marked drop with further destruction. However, reducing the synapses by 25% distinctly dropped the confidence in the predictions. Therefore, even though the network was making accurate predictions, the network was no longer confident about these predictions. DISCUSSION These findings explain how interoceptive cortices could be stuck in limited affective states with high prediction error. Connecting ketamine and psilocybin's proposed mechanism of action to depression pathophysiology, the growth of new synapses would allow representing more futuristic predictions with higher confidence. To our knowledge, this is the first study to use the TM model to connect changes happening at synaptic levels to the Bayesian formulation of psychiatric symptomatology. Linking neurobiological abnormalities to symptoms will allow us to understand the mechanisms of treatments and possibly, develop new ones.
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Affiliation(s)
- Mohamed A Sherif
- Lifespan Physician Group, Department of Psychiatry and Human Behavior, The Warren Alpert Medical School of Brown University, Carney Institute for Brain Science, Norman Prince Neurosciences Institute, Providence, RI, United States
| | - Mostafa Z Khalil
- Department of Psychiatry and Behavioral Health, Penn State Milton S. Hershey Medical Center, Penn State College of Medicine, Hershey, PA, United States
| | - Rammohan Shukla
- Department of Neurosciences, The University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Joshua C Brown
- Department of Psychiatry and Human Behavior, The Warren Alpert Medical School of Brown University, Butler Hospital, Providence, RI, United States
| | - Linda L Carpenter
- Department of Psychiatry and Human Behavior, The Warren Alpert Medical School of Brown University, Butler Hospital, Providence, RI, United States
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11
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Chapeton JI, Wittig JH, Inati SK, Zaghloul KA. Micro-scale functional modules in the human temporal lobe. Nat Commun 2022; 13:6263. [PMID: 36271010 PMCID: PMC9587217 DOI: 10.1038/s41467-022-34018-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 10/11/2022] [Indexed: 12/25/2022] Open
Abstract
The sensory cortices of many mammals are often organized into modules in the form of cortical columns, yet whether modular organization at this spatial scale is a general property of the human neocortex is unknown. The strongest evidence for modularity arises when measures of connectivity, structure, and function converge. Here we use microelectrode recordings in humans to examine functional connectivity and neuronal spiking responses in order to assess modularity in submillimeter scale networks. We find that the human temporal lobe consists of temporally persistent spatially compact modules approximately 1.3mm in diameter. Functionally, the information coded by single neurons during an image categorization task is more similar for neurons belonging to the same module than for neurons from different modules. The geometry, connectivity, and spiking responses of these local cortical networks provide converging evidence that the human temporal lobe is organized into functional modules at the micro scale.
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Affiliation(s)
- Julio I. Chapeton
- grid.416870.c0000 0001 2177 357XSurgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892 USA
| | - John H. Wittig
- grid.416870.c0000 0001 2177 357XSurgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892 USA
| | - Sara K. Inati
- grid.416870.c0000 0001 2177 357XSurgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892 USA
| | - Kareem A. Zaghloul
- grid.416870.c0000 0001 2177 357XSurgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892 USA
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12
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Kang J, Kang W, Lee SH. Stronger memory representation after memory reinstatement during retrieval in the human hippocampus. Neuroimage 2022; 260:119493. [PMID: 35868616 DOI: 10.1016/j.neuroimage.2022.119493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/19/2022] Open
Abstract
Memory retrieval allows us to reinstate previously encoded information but is also considered to contribute to memory enhancement. Retrieval-induced enhancement may involve processing to strengthen memory traces, but neural processing beyond reinstatement during retrieval remains elusive. Here, we show that hippocampal processing, different from memory reinstatement, exists during retrieval in the human brain. By tracking changes in the response patterns in the selected hippocampal and cortical regions over time during retrieval based on functional MRI, we found that the representation of associative memory in CA3/DG became stronger even after cortical memory reinstatement, while CA1 showed significant memory representation at retrieval onset with the cortical reinstatement, but not afterwards. This tendency was not observed in the condition without active retrieval. Moreover, subsequent long-term memory performance depended on the delayed CA3/DG representation during retrieval. These findings suggest that CA3/DG contributes to neural processing beyond memory reinstatement during retrieval, which may lead to memory enhancement.
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Affiliation(s)
- Joonyoung Kang
- Department of Bio and Brain Engineering, College of Engineering, Korea Advanced Institute of Science and Technology (KAIST); Program of Brain and Cognitive Engineering, College of Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-Ro, Yuseong-Gu, Daejeon 34141 Republic of Korea
| | - Wonjun Kang
- Department of Bio and Brain Engineering, College of Engineering, Korea Advanced Institute of Science and Technology (KAIST)
| | - Sue-Hyun Lee
- Department of Bio and Brain Engineering, College of Engineering, Korea Advanced Institute of Science and Technology (KAIST); Program of Brain and Cognitive Engineering, College of Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-Ro, Yuseong-Gu, Daejeon 34141 Republic of Korea.
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13
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Zheng J, Schjetnan AGP, Yebra M, Gomes BA, Mosher CP, Kalia SK, Valiante TA, Mamelak AN, Kreiman G, Rutishauser U. Neurons detect cognitive boundaries to structure episodic memories in humans. Nat Neurosci 2022; 25:358-368. [PMID: 35260859 PMCID: PMC8966433 DOI: 10.1038/s41593-022-01020-w] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 01/19/2022] [Indexed: 11/11/2022]
Abstract
While experience is continuous, memories are organized as discrete events. Cognitive boundaries are thought to segment experience and structure memory, but how this process is implemented remains unclear. We recorded the activity of single neurons in the human medial temporal lobe during the formation and retrieval of memories with complex narratives. Here we show that neurons responded to abstract cognitive boundaries between different episodes. Boundary-induced neural state changes during encoding predicted subsequent recognition accuracy but impaired event order memory, mirroring a fundamental behavioral tradeoff between content and time memory. Furthermore, the neural state following boundaries was reinstated during both successful retrieval and false memories. These findings reveal a neuronal substrate for detecting cognitive boundaries that transform experience into mnemonic episodes and structure mental time travel during retrieval.
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Affiliation(s)
- Jie Zheng
- Department of Ophthalmology, Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Andrea G P Schjetnan
- Krembil Brain Institute and Division of Neurosurgery, University Health Network (UHN), University of Toronto, Toronto, Ontario, Canada
| | - Mar Yebra
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Bernard A Gomes
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Clayton P Mosher
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Suneil K Kalia
- Krembil Brain Institute and Division of Neurosurgery, University Health Network (UHN), University of Toronto, Toronto, Ontario, Canada
| | - Taufik A Valiante
- Krembil Brain Institute and Division of Neurosurgery, University Health Network (UHN), University of Toronto, Toronto, Ontario, Canada.,Department of Surgery (Neurosurgery), Institute of Biomedical Engineering, and Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.,Max Planck-University of Toronto Center for Neural Science and Technology, University of Toronto, Toronto, Ontario, Canada.,Center for Advancing Neurotechnological Innovation to Application, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Adam N Mamelak
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Gabriel Kreiman
- Department of Ophthalmology, Children's Hospital, Harvard Medical School, Boston, MA, USA. .,Center for Brains, Minds and Machines, Cambridge, MA, USA.
| | - Ueli Rutishauser
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA. .,Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA. .,Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA. .,Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
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14
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Tong APS, Vaz AP, Wittig JH, Inati SK, Zaghloul KA. Ripples reflect a spectrum of synchronous spiking activity in human anterior temporal lobe. eLife 2021; 10:68401. [PMID: 34779398 PMCID: PMC8716101 DOI: 10.7554/elife.68401] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 11/13/2021] [Indexed: 11/13/2022] Open
Abstract
Direct brain recordings have provided important insights into how high-frequency activity captured through intracranial EEG (iEEG) supports human memory retrieval. The extent to which such activity is comprised of transient fluctuations that reflect the dynamic coordination of underlying neurons, however, remains unclear. Here, we simultaneously record iEEG, local field potential (LFP), and single unit activity in the human temporal cortex. We demonstrate that fast oscillations within the previously identified 80-120 Hz ripple band contribute to broadband high-frequency activity in the human cortex. These ripple oscillations exhibit a spectrum of amplitudes and durations related to the amount of underlying neuronal spiking. Ripples in the macro-scale iEEG are related to the number and synchrony of ripples in the micro-scale LFP, which in turn are related to the synchrony of neuronal spiking. Our data suggest that neural activity in the human temporal lobe is organized into transient bouts of ripple oscillations that reflect underlying bursts of spiking activity.
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Affiliation(s)
- Ai Phuong S Tong
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Alex P Vaz
- Medical Scientist Training Program, Duke University School of Medicine, Durham, United States
| | - John H Wittig
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Sara K Inati
- Office of the Clinical Director, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kareem A Zaghloul
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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15
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Ten Oever S, Sack AT, Oehrn CR, Axmacher N. An engram of intentionally forgotten information. Nat Commun 2021; 12:6443. [PMID: 34750407 PMCID: PMC8575985 DOI: 10.1038/s41467-021-26713-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/12/2021] [Indexed: 12/20/2022] Open
Abstract
Successful forgetting of unwanted memories is crucial for goal-directed behavior and mental wellbeing. While memory retention strengthens memory traces, it is unclear what happens to memory traces of events that are actively forgotten. Using intracranial EEG recordings from lateral temporal cortex, we find that memory traces for actively forgotten information are partially preserved and exhibit unique neural signatures. Memory traces of successfully remembered items show stronger encoding-retrieval similarity in gamma frequency patterns. By contrast, encoding-retrieval similarity of item-specific memory traces of actively forgotten items depend on activity at alpha/beta frequencies commonly associated with functional inhibition. Additional analyses revealed selective modification of item-specific patterns of connectivity and top-down information flow from dorsolateral prefrontal cortex to lateral temporal cortex in memory traces of intentionally forgotten items. These results suggest that intentional forgetting relies more on inhibitory top-down connections than intentional remembering, resulting in inhibitory memory traces with unique neural signatures and representational formats.
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Affiliation(s)
- Sanne Ten Oever
- Max Planck Institute for Psycholinguistics, Wundtlaan 1, 6525XD, Nijmegen, The Netherlands.
- Donders Centre for Cognitive Neuroimaging, Radboud University, Kapittelweg 29, 6525EN, Nijmegen, The Netherlands.
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Oxfordlaan 55, 6229EV, Maastricht, The Netherlands.
| | - Alexander T Sack
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Oxfordlaan 55, 6229EV, Maastricht, The Netherlands
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNs), Brain and Nerve Centre, Maastricht University Medical Centre+ (MUMC+), Debyelaan 25, 6229HX, Maastricht, The Netherlands
| | - Carina R Oehrn
- Department of Neurology, Philipps-University of Marburg, Biegenstraße 10, 35037, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), Philipps-University Marburg, Biegenstraße 10, 35037, Marburg, Germany
| | - Nikolai Axmacher
- Department of Neuropsychology, Faculty of Psychology, Institute of Cognitive Neuroscience, Ruhr University Bochum, Universitätsstraße 150, 44801, Bochum, Germany.
- State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, 19 Xinjiekou Outer St, Beijing, 100875, China.
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16
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Quon RJ, Camp EJ, Meisenhelter S, Song Y, Steimel SA, Testorf ME, Andrew AS, Gross RE, Lega BC, Sperling MR, Kahana MJ, Jobst BC. Features of intracranial interictal epileptiform discharges associated with memory encoding. Epilepsia 2021; 62:2615-2626. [PMID: 34486107 DOI: 10.1111/epi.17060] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 08/23/2021] [Accepted: 08/23/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Interictal epileptiform discharges (IEDs) were shown to be associated with cognitive impairment in persons with epilepsy. Previous studies indicated that IED rate, location, timing, and spatial relation to the seizure onset zone could predict an IED's impact on memory encoding and retrieval if they occurred in lateral temporal, mesial temporal, or parietal regions. In this study, we explore the influence that other IED properties (e.g., amplitude, duration, white matter classification) have on memory performance. We were specifically interested in investigating the influence that lateral temporal IEDs have on memory encoding. METHODS Two hundred sixty-one subjects with medication-refractory epilepsy undergoing intracranial electroencephalographic monitoring performed multiple sessions of a delayed free-recall task (n = 671). Generalized linear mixed models were utilized to examine the relationship between IED properties and memory performance. RESULTS We found that increased IED rate, IEDs propagating in white matter, and IEDs localized to the left middle temporal region were associated with poorer memory performance. For lateral temporal IEDs, we observed a significant interaction between IED white matter categorization and amplitude, where IEDs with an increased amplitude and white matter propagation were associated with reduced memory performance. Additionally, changes in alpha power after an IED showed a significant positive correlation with memory performance. SIGNIFICANCE Our results suggest that IED properties may be useful for predicting the impact an IED has on memory encoding. We provide an essential step toward understanding pathological versus potentially beneficial interictal epileptiform activity.
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Affiliation(s)
- Robert J Quon
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Edward J Camp
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Stephen Meisenhelter
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Yinchen Song
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Sarah A Steimel
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Markus E Testorf
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.,Thayer School of Engineering at Dartmouth College, Hanover, New Hampshire, USA
| | - Angeline S Andrew
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA.,Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University, Atlanta, Georgia, USA
| | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern, Dallas, Texas, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Barbara C Jobst
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA.,Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, USA
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17
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Li J, Pylkkänen L. Disentangling Semantic Composition and Semantic Association in the Left Temporal Lobe. J Neurosci 2021; 41:6526-6538. [PMID: 34131034 PMCID: PMC8318083 DOI: 10.1523/jneurosci.2317-20.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 05/04/2021] [Accepted: 05/05/2021] [Indexed: 11/21/2022] Open
Abstract
Although composing two words into a complex representation (e.g., "coffee cake") is conceptually different from forming associations between a pair of words (e.g., "coffee, cake"), the brain regions supporting semantic composition have also been implicated for associative encoding. Here, we adopted a two-word magnetoencephalography (MEG) paradigm which varies compositionality ("French/Korean cheese" vs "France/Korea cheese") and strength of association ("France/French cheese" vs "Korea/Korean cheese") between the two words. We collected MEG data while 42 English speakers (24 females) viewed the two words successively in the scanner, and we applied both univariate regression analyses and multivariate pattern classification to the source estimates of the two words. We show that the left anterior temporal lobe (LATL) and left middle temporal lobe (LMTL) are distinctively modulated by semantic composition and semantic association. Specifically, the LATL is mostly sensitive to high-association compositional phrases, while the LMTL responds more to low-association compositional phrases. Pattern-based directed connectivity analyses further revealed a continuous information flow from the anterior to the middle temporal region, suggesting that the integration of adjective and noun properties originated earlier in the LATL is consistently delivered to the LMTL when the complex meaning is newly encountered. Taken together, our findings shed light into a functional dissociation within the left temporal lobe for compositional and distributional semantic processing.SIGNIFICANCE STATEMENT Prior studies on semantic composition and associative encoding have been conducted independently within the subfields of language and memory, and they typically adopt similar two-word experimental paradigms. However, no direct comparison has been made on the neural substrates of the two processes. The current study relates the two streams of literature, and appeals to audiences in both subfields within cognitive neuroscience. Disentangling the neural computations for semantic composition and association also offers insight into modeling compositional and distributional semantics, which has been the subject of much discussion in natural language processing and cognitive science.
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Affiliation(s)
- Jixing Li
- NYUAD Institute, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
| | - Liina Pylkkänen
- NYUAD Institute, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
- Department of Linguistics, New York University, New York, New York 10003
- Department of Psychology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
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18
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Henin S, Shankar A, Borges H, Flinker A, Doyle W, Friedman D, Devinsky O, Buzsáki G, Liu A. Spatiotemporal dynamics between interictal epileptiform discharges and ripples during associative memory processing. Brain 2021; 144:1590-1602. [PMID: 33889945 DOI: 10.1093/brain/awab044] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 11/16/2020] [Accepted: 12/06/2020] [Indexed: 12/13/2022] Open
Abstract
We describe the spatiotemporal course of cortical high-gamma activity, hippocampal ripple activity and interictal epileptiform discharges during an associative memory task in 15 epilepsy patients undergoing invasive EEG. Successful encoding trials manifested significantly greater high-gamma activity in hippocampus and frontal regions. Successful cued recall trials manifested sustained high-gamma activity in hippocampus compared to failed responses. Hippocampal ripple rates were greater during successful encoding and retrieval trials. Interictal epileptiform discharges during encoding were associated with 15% decreased odds of remembering in hippocampus (95% confidence interval 6-23%). Hippocampal interictal epileptiform discharges during retrieval predicted 25% decreased odds of remembering (15-33%). Odds of remembering were reduced by 25-52% if interictal epileptiform discharges occurred during the 500-2000 ms window of encoding or by 41% during retrieval. During encoding and retrieval, hippocampal interictal epileptiform discharges were followed by a transient decrease in ripple rate. We hypothesize that interictal epileptiform discharges impair associative memory in a regionally and temporally specific manner by decreasing physiological hippocampal ripples necessary for effective encoding and recall. Because dynamic memory impairment arises from pathological interictal epileptiform discharge events competing with physiological ripples, interictal epileptiform discharges represent a promising therapeutic target for memory remediation in patients with epilepsy.
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Affiliation(s)
- Simon Henin
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA
| | - Anita Shankar
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA
| | - Helen Borges
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA
| | - Adeen Flinker
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA
| | - Werner Doyle
- NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA.,NYU Langone Health, Department of Neurosurgery, New York, NY 10016, USA
| | - Daniel Friedman
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA
| | - Orrin Devinsky
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA
| | - György Buzsáki
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,New York University, Neuroscience Institute, New York, NY 10016, USA
| | - Anli Liu
- NYU Langone Health, Department of Neurology, New York, NY 10017, USA.,NYU Langone Health, Comprehensive Epilepsy Center, New York, NY 10016, USA.,New York University, Neuroscience Institute, New York, NY 10016, USA
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19
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The Architecture of Human Memory: Insights from Human Single-Neuron Recordings. J Neurosci 2020; 41:883-890. [PMID: 33257323 DOI: 10.1523/jneurosci.1648-20.2020] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/24/2020] [Accepted: 09/27/2020] [Indexed: 02/08/2023] Open
Abstract
Deciphering the mechanisms of human memory is a central goal of neuroscience, both from the point of view of the fundamental biology of memory and for its translational relevance. Here, we review some contributions that recordings from neurons in humans implanted with electrodes for clinical purposes have made toward this goal. Recordings from the medial temporal lobe, including the hippocampus, reveal the existence of two classes of cells: those encoding highly selective and invariant representations of abstract concepts, and memory-selective cells whose activity is related to familiarity and episodic retrieval. Insights derived from observing these cells in behaving humans include that semantic representations are activated before episodic representations, that memory content and memory strength are segregated, and that the activity of both types of cells is related to subjective awareness as expected from a substrate for declarative memory. Visually selective cells can remain persistently active for several seconds, thereby revealing a cellular substrate for working memory in humans. An overarching insight is that the neural code of human memory is interpretable at the single-neuron level. Jointly, intracranial recording studies are starting to reveal aspects of the building blocks of human memory at the single-cell level. This work establishes a bridge to cellular-level work in animals on the one hand, and the extensive literature on noninvasive imaging in humans on the other hand. More broadly, this work is a step toward a detailed mechanistic understanding of human memory that is needed to develop therapies for human memory disorders.
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20
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Feedforward prediction error signals during episodic memory retrieval. Nat Commun 2020; 11:6075. [PMID: 33247100 PMCID: PMC7699639 DOI: 10.1038/s41467-020-19828-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/28/2020] [Indexed: 12/14/2022] Open
Abstract
Our memories enable us to form expectations for our future experiences, yet the precise neural mechanisms underlying how we compare any experience to our memory remain unknown. Here, using intracranial EEG recordings, we show that episodic memories formed after a single visual experience establish expectations for future experience within neocortical-medial temporal lobe circuits. When subsequent experiences violate these expectations, we find a 80-120 Hz prediction error signal that emerges in both visual association areas and the medial temporal lobe. Critically, this error signal emerges in visual association areas first and then propagates to the medial temporal lobe. This error signal is accompanied by alpha coherence between the two regions. Our data therefore suggest that internal models formed from episodic memories are generated throughout the visual hierarchy after just a single exposure, and that these internal models are then used for comparison with future experiences.
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21
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Tan RJ, Rugg MD, Lega BC. Direct brain recordings identify hippocampal and cortical networks that distinguish successful versus failed episodic memory retrieval. Neuropsychologia 2020; 147:107595. [PMID: 32871132 PMCID: PMC7554101 DOI: 10.1016/j.neuropsychologia.2020.107595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 08/06/2020] [Accepted: 08/26/2020] [Indexed: 12/14/2022]
Abstract
Human data collected using noninvasive imaging techniques have established the importance of parietal regions towards episodic memory retrieval, including the angular gyrus and posterior cingulate cortex. Such regions comprise part of a putative core episodic retrieval network. In free recall, comparisons between contextually appropriate and inappropriate recall events (i.e. prior list intrusions) provide the opportunity to study memory retrieval networks supporting veridical recall, and existing findings predict that differences in electrical activity in these brain regions should be identified according to the accuracy of recall. However, prior iEEG studies, utilizing principally subdural grid electrodes, have not fully characterized brain activity in parietal regions during memory retrieval and have not examined connectivity between core recollection areas and the hippocampus or prefrontal cortex. Here, we employed a data set obtained from 100 human patients implanted with stereo EEG electrodes for seizure mapping purposes as they performed a free recall task. This data set allowed us to separately analyze activity in midline versus lateral parietal brain regions, and in anterior versus posterior hippocampus, to identify areas in which retrieval-related activity predicted the recollection of a correct versus an incorrect memory. With the wide coverage afforded by the stereo EEG approach, we were also able to examine interregional connectivity. Our key findings were that differences in gamma band activity in the angular gyrus, precuneus, posterior temporal cortex, and posterior (more than anterior) hippocampus discriminated accurate versus inaccurate recall as well as active retrieval versus memory search. The left angular gyrus exhibited a significant power decrease preceding list intrusions as well as unique phase-amplitude coupling properties, whereas the prefrontal cortex was unique in exhibiting a power increase during list intrusions. Analysis of connectivity revealed significant hemispheric asymmetry, with relatively sparse left-sided functional connections compared to the right hemisphere. One exception to this finding was elevated connectivity between the prefrontal cortex and left angular gyrus. This finding is interpreted as evidence for the engagement of prefrontal cortex in memory monitoring and mnemonic decision-making.
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Affiliation(s)
- Ryan Joseph Tan
- Department of Neurosurgery, University of Texas Southwestern, Dallas, TX 75390, USA.
| | - Michael D Rugg
- Center for Vital Longevity, University of Texas at Dallas, Dallas, TX 75390, USA
| | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern, Dallas, TX 75390, USA
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22
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Xie W, Bainbridge WA, Inati SK, Baker CI, Zaghloul KA. Memorability of words in arbitrary verbal associations modulates memory retrieval in the anterior temporal lobe. Nat Hum Behav 2020; 4:937-948. [PMID: 32601459 PMCID: PMC7501186 DOI: 10.1038/s41562-020-0901-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 05/27/2020] [Indexed: 01/08/2023]
Abstract
Despite large individual differences in memory performance, people remember certain stimuli with overwhelming consistency. This phenomenon is referred to as the memorability of an individual item. However, it remains unknown whether memorability also affects our ability to retrieve associations between items. Here, using a paired-associates verbal memory task, we combine behavioural data, computational modelling and direct recordings from the human brain to examine how memorability influences associative memory retrieval. We find that certain words are correctly retrieved across participants irrespective of the cues used to initiate memory retrieval. These words, which share greater semantic similarity with other words, are more readily available during retrieval and lead to more intrusions when retrieval fails. Successful retrieval of these memorable items, relative to less memorable ones, results in faster reinstatement of neural activity in the anterior temporal lobe. Collectively, our data reveal how the brain prioritizes certain information to facilitate memory retrieval.
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Affiliation(s)
- Weizhen Xie
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, USA.
| | - Wilma A Bainbridge
- Department of Psychology, University of Chicago, Chicago, IL, USA. .,Laboratory of Brain and Cognition, NIMH, National Institutes of Health, Bethesda, MD, USA.
| | - Sara K Inati
- Office of the Clinical Director, NINDS, National Institutes of Health, Bethesda, MD, USA
| | - Chris I Baker
- Laboratory of Brain and Cognition, NIMH, National Institutes of Health, Bethesda, MD, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, USA.
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23
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Xie S, Kaiser D, Cichy RM. Visual Imagery and Perception Share Neural Representations in the Alpha Frequency Band. Curr Biol 2020; 30:2621-2627.e5. [PMID: 32531274 PMCID: PMC7342016 DOI: 10.1016/j.cub.2020.04.074] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 04/06/2020] [Accepted: 04/27/2020] [Indexed: 11/21/2022]
Abstract
To behave adaptively with sufficient flexibility, biological organisms must cognize beyond immediate reaction to a physically present stimulus. For this, humans use visual mental imagery [1, 2], the ability to conjure up a vivid internal experience from memory that stands in for the percept of the stimulus. Visually imagined contents subjectively mimic perceived contents, suggesting that imagery and perception share common neural mechanisms. Using multivariate pattern analysis on human electroencephalography (EEG) data, we compared the oscillatory time courses of mental imagery and perception of objects. We found that representations shared between imagery and perception emerged specifically in the alpha frequency band. These representations were present in posterior, but not anterior, electrodes, suggesting an origin in parieto-occipital cortex. Comparison of the shared representations to computational models using representational similarity analysis revealed a relationship to later layers of deep neural networks trained on object representations, but not auditory or semantic models, suggesting representations of complex visual features as the basis of commonality. Together, our results identify and characterize alpha oscillations as a cortical signature of representations shared between visual mental imagery and perception. Perception and imagery share neural representations in the alpha frequency band Shared representations stem from parieto-occipital sources Modeling suggests contents of shared representations are complex visual features
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Affiliation(s)
- Siying Xie
- Department of Education and Psychology, Freie Universität Berlin, Habelschwerdter Allee 45, Berlin 14195, Germany.
| | - Daniel Kaiser
- Department of Psychology, University of York, Heslington, York YO10 5DD, UK
| | - Radoslaw M Cichy
- Department of Education and Psychology, Freie Universität Berlin, Habelschwerdter Allee 45, Berlin 14195, Germany; Berlin School of Mind and Brain, Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin 10099, Germany; Bernstein Centre for Computational Neuroscience Berlin, Humboldt-Universität zu Berlin, Unter den Linden 6, Berlin 10099, Germany.
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24
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Schreiner T, Staudigl T. Electrophysiological signatures of memory reactivation in humans. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190293. [PMID: 32248789 PMCID: PMC7209925 DOI: 10.1098/rstb.2019.0293] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The reactivation of neural activity that was present during the encoding of an event is assumed to be essential for human episodic memory retrieval and the consolidation of memories during sleep. Pioneering animal work has already established a crucial role of memory reactivation to prepare and guide behaviour. Research in humans is now delineating the neural processes involved in memory reactivation during both wakefulness and sleep as well as their functional significance. Focusing on the electrophysiological signatures of memory reactivation in humans during both memory retrieval and sleep-related consolidation, this review provides an overview of the state of the art in the field. We outline recent advances, methodological developments and open questions and specifically highlight commonalities and differences in the neuronal signatures of memory reactivation during the states of wakefulness and sleep. This article is part of the Theo Murphy meeting issue ‘Memory reactivation: replaying events past, present and future’.
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Affiliation(s)
- Thomas Schreiner
- School of Psychology and Centre for Human Brain Health, University of Birmingham, Birmingham, UK.,Department of Psychology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Tobias Staudigl
- Department of Psychology, Ludwig-Maximilians-University Munich, Munich, Germany
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25
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Vaz AP, Wittig JH, Inati SK, Zaghloul KA. Replay of cortical spiking sequences during human memory retrieval. Science 2020; 367:1131-1134. [PMID: 32139543 PMCID: PMC7211396 DOI: 10.1126/science.aba0672] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/05/2020] [Indexed: 12/16/2022]
Abstract
Episodic memory retrieval is thought to rely on the replay of past experiences, yet it remains unknown how human single-unit activity is temporally organized during episodic memory encoding and retrieval. We found that ripple oscillations in the human cortex reflect underlying bursts of single-unit spiking activity that are organized into memory-specific sequences. Spiking sequences occurred repeatedly during memory formation and were replayed during successful memory retrieval, and this replay was associated with ripples in the medial temporal lobe. Together, these data demonstrate that human episodic memory is encoded by specific sequences of neural activity and that memory recall involves reinstating this temporal order of activity.
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Affiliation(s)
- Alex P Vaz
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD 20892, USA
- Medical Scientist Training Program, Duke University School of Medicine, Durham, NC 27710, USA
- Department of Neurobiology, Duke University, Durham, NC 27710, USA
| | - John H Wittig
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD 20892, USA
| | - Sara K Inati
- Office of the Clinical Director, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD 20892, USA.
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26
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A Neural Chronometry of Memory Recall. Trends Cogn Sci 2019; 23:1071-1085. [DOI: 10.1016/j.tics.2019.09.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/13/2019] [Accepted: 09/25/2019] [Indexed: 12/23/2022]
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27
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Vaz AP, Inati SK, Brunel N, Zaghloul KA. Coupled ripple oscillations between the medial temporal lobe and neocortex retrieve human memory. Science 2019; 363:975-978. [PMID: 30819961 DOI: 10.1126/science.aau8956] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 01/09/2019] [Indexed: 12/24/2022]
Abstract
Episodic memory retrieval relies on the recovery of neural representations of waking experience. This process is thought to involve a communication dynamic between the medial temporal lobe memory system and the neocortex. How this occurs is largely unknown, however, especially as it pertains to awake human memory retrieval. Using intracranial electroencephalographic recordings, we found that ripple oscillations were dynamically coupled between the human medial temporal lobe (MTL) and temporal association cortex. Coupled ripples were more pronounced during successful verbal memory retrieval and recover the cortical neural representations of remembered items. Together, these data provide direct evidence that coupled ripples between the MTL and association cortex may underlie successful memory retrieval in the human brain.
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Affiliation(s)
- Alex P Vaz
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA.,Medical Scientist Training Program, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Neurobiology, Duke University, Durham, NC 27710, USA
| | - Sara K Inati
- Office of the Clinical Director, NINDS, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nicolas Brunel
- Department of Neurobiology, Duke University, Durham, NC 27710, USA.,Department of Physics, Duke University, Durham, NC 27710, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD 20892, USA.
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28
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Jang AI, Nassar MR, Dillon DG, Frank MJ. Positive reward prediction errors during decision-making strengthen memory encoding. Nat Hum Behav 2019; 3:719-732. [PMID: 31061490 PMCID: PMC6625913 DOI: 10.1038/s41562-019-0597-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 03/27/2019] [Indexed: 01/19/2023]
Abstract
Dopamine is thought to provide reward prediction error signals to temporal lobe memory systems, but the role of these signals in episodic memory has not been fully characterized. Here we developed an incidental memory paradigm to (i) estimate the influence of reward prediction errors on the formation of episodic memories, (ii) dissociate this influence from surprise and uncertainty, (iii) characterize the role of temporal correspondence between prediction error and memoranda presentation and (iv) determine the extent to which this influence is dependent on memory consolidation. We found that people encoded incidental memoranda more strongly when they gambled for potential rewards. Moreover, the degree to which gambling strengthened encoding scaled with the reward prediction error experienced when memoranda were presented (and not before or after). This encoding enhancement was detectable within minutes and did not differ substantially after 24 h, indicating that it is not dependent on memory consolidation. These results suggest a computationally and temporally specific role for reward prediction error signalling in memory formation.
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Affiliation(s)
- Anthony I Jang
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, RI, USA
| | - Matthew R Nassar
- Department of Neuroscience, Brown University, Providence, RI, USA.
- Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, USA.
| | - Daniel G Dillon
- Center for Depression, Anxiety and Stress Research, McLean Hospital, Belmont, MA, USA
- Harvard Medical School, Boston, MA, USA
| | - Michael J Frank
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, RI, USA
- Robert J. and Nancy D. Carney Institute for Brain Science, Brown University, Providence, RI, USA
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29
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Pacheco Estefan D, Sánchez-Fibla M, Duff A, Principe A, Rocamora R, Zhang H, Axmacher N, Verschure PFMJ. Coordinated representational reinstatement in the human hippocampus and lateral temporal cortex during episodic memory retrieval. Nat Commun 2019; 10:2255. [PMID: 31113952 PMCID: PMC6529470 DOI: 10.1038/s41467-019-09569-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 03/18/2019] [Indexed: 12/29/2022] Open
Abstract
Theoretical models of episodic memory have proposed that retrieval depends on interactions between the hippocampus and neocortex, where hippocampal reinstatement of item-context associations drives neocortical reinstatement of item information. Here, we simultaneously recorded intracranial EEG from hippocampus and lateral temporal cortex (LTC) of epilepsy patients who performed a virtual reality spatial navigation task. We extracted stimulus-specific representations of both item and item-context associations from the time-frequency patterns of activity in hippocampus and LTC. Our results revealed a double dissociation of representational reinstatement across time and space: an early reinstatement of item-context associations in hippocampus preceded a later reinstatement of item information in LTC. Importantly, reinstatement levels in hippocampus and LTC were correlated across trials, and the quality of LTC reinstatement was predicted by the magnitude of phase synchronization between hippocampus and LTC. These findings confirm that episodic memory retrieval in humans relies on coordinated representational interactions within a hippocampal-neocortical network. Episodic memory retrieval is hypothesized to rely on hippocampal reinstatement of item-context associations which drives reinstatement of item information in cortex. Here, the authors confirm this sequence of events, using iEEG recordings from the human hippocampus and lateral temporal cortex.
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Affiliation(s)
- D Pacheco Estefan
- Laboratory of Synthetic Perceptive, Emotive and Cognitive Systems (SPECS), Institute for Bioengineering of Catalonia (IBEC), 08028, Barcelona, Spain.,Department of Information and Communications Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - M Sánchez-Fibla
- Department of Information and Communications Technologies, Universitat Pompeu Fabra, 08018, Barcelona, Spain
| | - A Duff
- Laboratory of Synthetic Perceptive, Emotive and Cognitive Systems (SPECS), Institute for Bioengineering of Catalonia (IBEC), 08028, Barcelona, Spain
| | - A Principe
- Epilepsy Monitoring Unit, Department of Neurology, Hospital del Mar, 08003, Barcelona, Spain.,Hospital del Mar Medical Research Institute, 08003, Barcelona, Spain
| | - R Rocamora
- Epilepsy Monitoring Unit, Department of Neurology, Hospital del Mar, 08003, Barcelona, Spain.,Hospital del Mar Medical Research Institute, 08003, Barcelona, Spain.,Faculty of Health and Life Sciences, Universitat Pompeu Fabra, 08003, Barcelona, Spain
| | - H Zhang
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, 44801, Bochum, Germany
| | - N Axmacher
- Department of Neuropsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, 44801, Bochum, Germany
| | - P F M J Verschure
- Laboratory of Synthetic Perceptive, Emotive and Cognitive Systems (SPECS), Institute for Bioengineering of Catalonia (IBEC), 08028, Barcelona, Spain. .,The Barcelona Institute of Science and Technology (BIST), 08036, Barcelona, Spain. .,ICREA, Institució Catalana de Recerca i Estudis Avançats, Passeig de Lluís Companys, 23, 08010, Barcelona, Spain.
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30
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Rutishauser U. Testing Models of Human Declarative Memory at the Single-Neuron Level. Trends Cogn Sci 2019; 23:510-524. [PMID: 31031021 DOI: 10.1016/j.tics.2019.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Revised: 03/15/2019] [Accepted: 03/20/2019] [Indexed: 11/19/2022]
Abstract
Deciphering the mechanisms of declarative memory is a major goal of neuroscience. While much theoretical progress has been made, it has proven difficult to experimentally verify key predictions of some foundational models of memory. Recently, single-neuron recordings in human patients have started to provide direct experimental verification of some theories, including mnemonic evidence accumulation, balance-of-evidence for confidence judgments, sparse coding, contextual reinstatement, and the ventral tegmental area (VTA)-hippocampus loop model. Here, we summarize the cell types that have been described in the medial temporal lobe and posterior parietal cortex, discuss their properties, and reflect on how these findings inform theoretical work. This body of work exemplifies the scientific power of a synergistic combination of modeling and human single-neuron recordings to advance cognitive neuroscience.
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Affiliation(s)
- Ueli Rutishauser
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Center for Neural Science and Medicine, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
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31
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Recollection in the human hippocampal-entorhinal cell circuitry. Nat Commun 2019; 10:1503. [PMID: 30944325 PMCID: PMC6447634 DOI: 10.1038/s41467-019-09558-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 03/18/2019] [Indexed: 01/23/2023] Open
Abstract
Imagine how flicking through your photo album and seeing a picture of a beach sunset brings back fond memories of a tasty cocktail you had that night. Computational models suggest that upon receiving a partial memory cue (‘beach’), neurons in the hippocampus coordinate reinstatement of associated memories (‘cocktail’) in cortical target sites. Here, using human single neuron recordings, we show that hippocampal firing rates are elevated from ~ 500–1500 ms after cue onset during successful associative retrieval. Concurrently, the retrieved target object can be decoded from population spike patterns in adjacent entorhinal cortex (EC), with hippocampal firing preceding EC spikes and predicting the fidelity of EC object reinstatement. Prior to orchestrating reinstatement, a separate population of hippocampal neurons distinguishes different scene cues (buildings vs. landscapes). These results elucidate the hippocampal-entorhinal circuit dynamics for memory recall and reconcile disparate views on the role of the hippocampus in scene processing vs. associative memory. The hippocampus is involved both in episodic memory recall and scene processing. Here, the authors show that hippocampal neurons first process scene cues before coordinating memory-guided pattern completion in adjacent entorhinal cortex.
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32
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Wittig JH, Jang AI, Cocjin JB, Inati SK, Zaghloul KA. Attention improves memory by suppressing spiking-neuron activity in the human anterior temporal lobe. Nat Neurosci 2018; 21:808-810. [PMID: 29786083 PMCID: PMC5970979 DOI: 10.1038/s41593-018-0148-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/04/2018] [Indexed: 11/09/2022]
Abstract
We identify a memory-specific attention mechanism in the human anterior temporal lobe, an area implicated in semantic processing and episodic memory formation. Spiking neuron activity is suppressed and becomes more reliable in preparation for verbal memory formation. Intracranial electroencephalography signals implicate this region as a source of executive control for attentional selection. Consistent with this interpretation, its surgical removal causes significant memory impairment for attended words relative to unattended words.
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Affiliation(s)
- John H Wittig
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, USA
| | - Anthony I Jang
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, USA
| | - John B Cocjin
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, USA
| | - Sara K Inati
- Office of the Clinical Director, NINDS, National Institutes of Health, Bethesda, MD, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, NINDS, National Institutes of Health, Bethesda, MD, USA.
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33
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Signal Complexity of Human Intracranial EEG Tracks Successful Associative-Memory Formation across Individuals. J Neurosci 2018; 38:1744-1755. [PMID: 29330327 DOI: 10.1523/jneurosci.2389-17.2017] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/22/2017] [Accepted: 12/30/2017] [Indexed: 12/26/2022] Open
Abstract
Memory performance is highly variable among individuals. Most studies examining human memory, however, have largely focused on the neural correlates of successful memory formation within individuals, rather than the differences among them. As such, what gives rise to this variability is poorly understood. Here, we examined intracranial EEG (iEEG) recordings captured from 43 participants (23 male) implanted with subdural electrodes for seizure monitoring as they performed a paired-associates verbal memory task. We identified three separate but related signatures of neural activity that tracked differences in successful memory formation across individuals. High-performing individuals consistently exhibited less broadband power, flatter power spectral density slopes, and greater complexity in their iEEG signals. Furthermore, within individuals across three separate time scales ranging from seconds to days, successful recall was positively associated with these same metrics. Our data therefore suggest that memory ability across individuals can be indexed by increased neural signal complexity.SIGNIFICANCE STATEMENT We show that participants whose intracranial EEG exhibits less low-frequency power, flatter power spectrums, and greater sample entropy overall are better able to memorize associations, and that the same metrics track fluctuations in memory performance across time within individuals. These metrics together signify greater neural signal complexity, which may index the brain's ability to flexibly engage with information and generate separable memory representations. Critically, the current set of results provides a unique window into the neural markers of individual differences in memory performance, which have hitherto been underexplored.
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34
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Sreekumar V, Wittig JH, Sheehan TC, Zaghloul KA. Principled Approaches to Direct Brain Stimulation for Cognitive Enhancement. Front Neurosci 2017; 11:650. [PMID: 29249927 PMCID: PMC5714894 DOI: 10.3389/fnins.2017.00650] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/08/2017] [Indexed: 11/13/2022] Open
Abstract
In this brief review, we identify key areas of research that inform a systematic and targeted approach for invasive brain stimulation with the goal of modulating higher cognitive functions such as memory. We outline several specific challenges that must be successfully navigated in order to achieve this goal. Specifically, using direct brain stimulation to support memory requires demonstrating that (1) there are reliable neural patterns corresponding to different events and memory states, (2) stimulation can be used to induce these target activity patterns, and (3) inducing such patterns modulates memory in the expected directions. Invasive stimulation studies typically have not taken into account intrinsic brain states and dynamics, nor have they a priori targeted specific neural patterns that have previously been identified as playing an important role in memory. Moreover, the effects of stimulation on neural activity are poorly understood and are sensitive to multiple factors including the specific stimulation parameters, the processing state of the brain at the time of stimulation, and neuroanatomy of the stimulated region. As a result, several studies have reported conflicting results regarding the use of direct stimulation for memory modulation. Here, we review the latest findings relevant to these issues and discuss how we can gain better control over the effects of direct brain stimulation for modulating human memory and cognition.
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Affiliation(s)
| | | | | | - Kareem A. Zaghloul
- Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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35
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Galetzka C. The Story So Far: How Embodied Cognition Advances Our Understanding of Meaning-Making. Front Psychol 2017; 8:1315. [PMID: 28824497 PMCID: PMC5534471 DOI: 10.3389/fpsyg.2017.01315] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/17/2017] [Indexed: 11/18/2022] Open
Abstract
Meaning-making in the brain has become one of the most intensely discussed topics in cognitive science. Traditional theories on cognition that emphasize abstract symbol manipulations often face a dead end: The symbol grounding problem. The embodiment idea tries to overcome this barrier by assuming that the mind is grounded in sensorimotor experiences. A recent surge in behavioral and brain-imaging studies has therefore focused on the role of the motor cortex in language processing. Concrete, action-related words have received convincing evidence to rely on sensorimotor activation. Abstract concepts, however, still pose a distinct challenge for embodied theories on cognition. Fully embodied abstraction mechanisms were formulated but sensorimotor activation alone seems unlikely to close the explanatory gap. In this respect, the idea of integration areas, such as convergence zones or the ‘hub and spoke’ model, do not only appear like the most promising candidates to account for the discrepancies between concrete and abstract concepts but could also help to unite the field of cognitive science again. The current review identifies milestones in cognitive science research and recent achievements that highlight fundamental challenges, key questions and directions for future research.
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Affiliation(s)
- Cedric Galetzka
- Division of Cognitive Sciences, University of PotsdamPotsdam, Germany
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