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Rudoler JH, Bruska JP, Chang W, Dougherty MR, Katerman BS, Halpern DJ, Diamond NB, Kahana MJ. Decoding EEG for optimizing naturalistic memory. J Neurosci Methods 2024; 410:110220. [PMID: 39033965 DOI: 10.1016/j.jneumeth.2024.110220] [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: 02/16/2024] [Revised: 06/26/2024] [Accepted: 07/17/2024] [Indexed: 07/23/2024]
Abstract
BACKGROUND Spectral features of human electroencephalographic (EEG) recordings during learning predict subsequent recall variability. NEW METHOD Capitalizing on these fluctuating neural features, we develop a non-invasive closed-loop (NICL) system for real-time optimization of human learning. Participants play a virtual navigation-and-memory game; recording multi-session data across days allowed us to build participant-specific classification models of recall success. In subsequent closed-loop sessions, our platform manipulated the timing of memory encoding, selectively presenting items during periods of predicted good or poor memory function based on EEG features decoded in real time. RESULTS The induced memory effect (the difference between recall rates when presenting items during predicted good vs. poor learning periods) increased with the accuracy of neural decoding. COMPARISON WITH EXISTING METHODS This study demonstrates greater-than-chance memory decoding from EEG recordings in a naturalistic virtual navigation task with greater real-world validity than basic word-list recall paradigms. Here we modulate memory by timing stimulus presentation based on noninvasive scalp EEG recordings, whereas prior closed-loop studies for memory improvement involved intracranial recordings and direct electrical stimulation. Other noninvasive studies have investigated the use of neurofeedback or remedial study for memory improvement. CONCLUSIONS These findings present a proof-of-concept for using non-invasive closed-loop technology to optimize human learning and memory through principled stimulus timing, but only in those participants for whom classifiers reliably predict out-of-sample memory function.
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2
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Lu JJ, Ma J, Wu JJ, Zhen XM, Xiang YT, Lu HY, Zheng MX, Hua XY, Xu JG. Tongue coating-dependent superior temporal sulcus remodeling in amnestic mild cognitive impairment. Brain Res Bull 2024; 214:110995. [PMID: 38844172 DOI: 10.1016/j.brainresbull.2024.110995] [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: 03/29/2024] [Revised: 04/23/2024] [Accepted: 06/01/2024] [Indexed: 06/10/2024]
Abstract
Tongue coating affects cognition, and cognitive decline at early stage also showed relations to functional and structural remodeling of superior temporal sulcus (STS) in amnestic mild cognitive impairment (aMCI). The potential correlation between disparate cognitive manifestations in aMCI patients with different tongue coatings, and corresponding mechanisms of STS remodeling remains uncharted. In this case-control study, aMCI patients were divided into thin coating (n = 18) and thick coating (n = 21) groups. All participants underwent neuropsychological evaluations and multimodal magnetic resonance imaging. Group comparisons were conducted in clinical assessments and neuroimaging measures of banks of the STS (bankssts). Generalized linear models were constructed to explore relationships between neuroimaging measures and cognition. aMCI patients in the thick coating group exhibited significantly poorer immediate and delayed recall and slower information processing speed (IPS) (P < 0.05), and decreased functional connectivity (FC) of bilateral bankssts with frontoparietal cortices (P < 0.05, AlphaSim corrected) compared to the thin coating group. It was found notable correlations between cognition encompassing recall and IPS, and FC of bilateral bankssts with frontoparietal cortices (P < 0.05, Bonferroni's correction), as well as interaction effects of group × regional homogeneity (ReHo) of right bankssts on the first immediate recall (P < 0.05, Bonferroni's correction). aMCI patients with thick coating exhibited poor cognitive performance, which might be attributed to decreased FC seeding from bankssts. Our findings strengthen the understanding of brain reorganization of STS via which tongue coating status impacts cognition in patients with aMCI.
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Affiliation(s)
- Juan-Juan Lu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jie Ma
- Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jia-Jia Wu
- Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xiao-Min Zhen
- Department of Neurology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yun-Ting Xiang
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hao-Yu Lu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Mou-Xiong Zheng
- Department of Traumatology and Orthopedics, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Xu-Yun Hua
- Department of Traumatology and Orthopedics, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Jian-Guang Xu
- School of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China; Department of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China; Engineering Research Center of Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai, China.
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3
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Li Y, Pazdera JK, Kahana MJ. EEG decoders track memory dynamics. Nat Commun 2024; 15:2981. [PMID: 38582783 PMCID: PMC10998865 DOI: 10.1038/s41467-024-46926-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 03/14/2024] [Indexed: 04/08/2024] Open
Abstract
Encoding- and retrieval-related neural activity jointly determine mnemonic success. We ask whether electroencephalographic activity can reliably predict encoding and retrieval success on individual trials. Each of 98 participants performed a delayed recall task on 576 lists across 24 experimental sessions. Logistic regression classifiers trained on spectral features measured immediately preceding spoken recall of individual words successfully predict whether or not those words belonged to the target list. Classifiers trained on features measured during word encoding also reliably predict whether those words will be subsequently recalled and further predict the temporal and semantic organization of the recalled items. These findings link neural variability predictive of successful memory with item-to-context binding, a key cognitive process thought to underlie episodic memory function.
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Affiliation(s)
- Yuxuan Li
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychology, Stanford University, Stanford, CA, USA
| | - Jesse K Pazdera
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychology, Neuroscience & Behaviour, McMaster University, Hamilton, ON, Canada
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA.
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Fu Y, Zhang J, Cao Y, Ye L, Zheng R, Li Q, Shen B, Shi Y, Cao J, Fang J. Recognition memory deficits detected through eye-tracking in well-controlled children with self-limited epilepsy with centrotemporal spikes. Epilepsia 2024; 65:1128-1140. [PMID: 38299621 DOI: 10.1111/epi.17902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 01/15/2024] [Accepted: 01/16/2024] [Indexed: 02/02/2024]
Abstract
OBJECTIVE Children with self-limited epilepsy characterized by centrotemporal spikes (SeLECTS) exhibit cognitive deficits in memory during the active phase, but there is currently a lack of studies and techniques to assess their memory development after well-controlled seizures. In this study, we employed eye-tracking techniques to investigate visual memory and its association with clinical factors and global intellectual ability, aiming to identify potential risk factors by examining encoding and recognition processes. METHODS A total of 26 recruited patients diagnosed with SeLECTS who had been seizure-free for at least 2 years, along with 24 control subjects, underwent Wechsler cognitive assessment and an eye-movement-based memory task while video-electroencephalographic (EEG) data were recorded. Fixation and pupil data related to eye movements were utilized to detect distinct memory processes and subsequently to compare the cognitive performance of patients exhibiting different regression patterns on EEG. RESULTS The findings revealed persistent impairments in visual memory among children with SeLECTS after being well controlled, primarily observed in the recognition stage rather than the encoding phase. Furthermore, the age at onset, frequency of seizures, and interictal epileptiform discharges exhibited significant correlations with eye movement data. SIGNIFICANCE Children with SeLECTS exhibit persistent recognition memory impairment after being well controlled for the disease. Controlling the frequency of seizures and reducing prolonged epileptiform activity may improve memory cognitive development. The application of the eye-tracking technique may provide novel insights into exploring memory cognition as well as underlying mechanisms associated with pediatric epilepsy.
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Affiliation(s)
- Yanlu Fu
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Jingxin Zhang
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Yina Cao
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Linmei Ye
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Runze Zheng
- Artificial Intelligence Institute, Hangzhou Dianzi University School of Automation, Hangzhou, Zhejiang, China
| | - Qiwei Li
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Beibei Shen
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Yi Shi
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
| | - Jiuwen Cao
- Artificial Intelligence Institute, Hangzhou Dianzi University School of Automation, Hangzhou, Zhejiang, China
| | - Jiajia Fang
- Department of Neurology, Fourth Affiliated Hospital Zhejiang University School of Medicine, Yiwu, Zhejiang, China
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5
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Moore IL, Long NM. Semantic associations restore neural encoding mechanisms. Learn Mem 2024; 31:a053996. [PMID: 38503491 PMCID: PMC11000581 DOI: 10.1101/lm.053996.124] [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] [Received: 01/29/2024] [Accepted: 02/19/2024] [Indexed: 03/21/2024]
Abstract
Lapses in attention can negatively impact later memory of an experience. Attention and encoding resources are thought to decline as more experiences are encountered in succession, accounting for the primacy effect in which memory is better for items encountered early compared to late in a study list. However, accessing prior knowledge during study can facilitate subsequent memory, suggesting a potential avenue to counteract this decline. Here, we investigated the extent to which semantic associations-shared meaning between experiences-can counteract declines in encoding resources. Our hypothesis is that semantic associations restore neural encoding mechanisms, which in turn improves memory. We recorded scalp electroencephalography (EEG) while male and female human participants performed a delayed free recall task. Half of the items from late in each study list were semantically associated with an item presented earlier in the list. We find that semantic associations improve memory specifically for late list items and selectively modulate the neural signals engaged during the study of late list items. Relative to other recalled items, late list items that are subsequently semantically clustered-recalled consecutively with their semantic associate-elicit increased high-frequency activity and decreased low-frequency activity, a hallmark of successful encoding. Our findings demonstrate that semantic associations restore neural encoding mechanisms and improve later memory. More broadly, these findings suggest that prior knowledge modulates the orientation of attention to influence encoding mechanisms.
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Affiliation(s)
- Isabelle L Moore
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Nicole M Long
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904, USA
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6
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Roeder BM, She X, Dakos AS, Moore B, Wicks RT, Witcher MR, Couture DE, Laxton AW, Clary HM, Popli G, Liu C, Lee B, Heck C, Nune G, Gong H, Shaw S, Marmarelis VZ, Berger TW, Deadwyler SA, Song D, Hampson RE. Developing a hippocampal neural prosthetic to facilitate human memory encoding and recall of stimulus features and categories. Front Comput Neurosci 2024; 18:1263311. [PMID: 38390007 PMCID: PMC10881797 DOI: 10.3389/fncom.2024.1263311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 01/19/2024] [Indexed: 02/24/2024] Open
Abstract
Objective Here, we demonstrate the first successful use of static neural stimulation patterns for specific information content. These static patterns were derived by a model that was applied to a subject's own hippocampal spatiotemporal neural codes for memory. Approach We constructed a new model of processes by which the hippocampus encodes specific memory items via spatiotemporal firing of neural ensembles that underlie the successful encoding of targeted content into short-term memory. A memory decoding model (MDM) of hippocampal CA3 and CA1 neural firing was computed which derives a stimulation pattern for CA1 and CA3 neurons to be applied during the encoding (sample) phase of a delayed match-to-sample (DMS) human short-term memory task. Main results MDM electrical stimulation delivered to the CA1 and CA3 locations in the hippocampus during the sample phase of DMS trials facilitated memory of images from the DMS task during a delayed recognition (DR) task that also included control images that were not from the DMS task. Across all subjects, the stimulated trials exhibited significant changes in performance in 22.4% of patient and category combinations. Changes in performance were a combination of both increased memory performance and decreased memory performance, with increases in performance occurring at almost 2 to 1 relative to decreases in performance. Across patients with impaired memory that received bilateral stimulation, significant changes in over 37.9% of patient and category combinations was seen with the changes in memory performance show a ratio of increased to decreased performance of over 4 to 1. Modification of memory performance was dependent on whether memory function was intact or impaired, and if stimulation was applied bilaterally or unilaterally, with nearly all increase in performance seen in subjects with impaired memory receiving bilateral stimulation. Significance These results demonstrate that memory encoding in patients with impaired memory function can be facilitated for specific memory content, which offers a stimulation method for a future implantable neural prosthetic to improve human memory.
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Affiliation(s)
- Brent M Roeder
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Xiwei She
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Alexander S Dakos
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Bryan Moore
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Robert T Wicks
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
- Johns Hopkins Children's Center, Baltimore, MD, United States
| | - Mark R Witcher
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
- Virginia Tech Carilion School of Medicine and Research Institute, Roanoke, VA, United States
| | - Daniel E Couture
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Adrian W Laxton
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | | | - Gautam Popli
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Charles Liu
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - Brian Lee
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - Christianne Heck
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - George Nune
- USC Keck Memorial Hospital, Los Angeles, CA, United States
| | - Hui Gong
- Rancho Los Amigos National Rehabilitation Hospital, Los Angeles, CA, United States
| | - Susan Shaw
- Rancho Los Amigos National Rehabilitation Hospital, Los Angeles, CA, United States
| | - Vasilis Z Marmarelis
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Theodore W Berger
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Sam A Deadwyler
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
| | - Dong Song
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Robert E Hampson
- Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
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7
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Ezzyat Y, Kragel JE, Solomon EA, Lega BC, Aronson JP, Jobst BC, Gross RE, Sperling MR, Worrell GA, Sheth SA, Wanda PA, Rizzuto DS, Kahana MJ. Functional and anatomical connectivity predict brain stimulation's mnemonic effects. Cereb Cortex 2024; 34:bhad427. [PMID: 38041253 PMCID: PMC10793570 DOI: 10.1093/cercor/bhad427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 12/03/2023] Open
Abstract
Closed-loop direct brain stimulation is a promising tool for modulating neural activity and behavior. However, it remains unclear how to optimally target stimulation to modulate brain activity in particular brain networks that underlie particular cognitive functions. Here, we test the hypothesis that stimulation's behavioral and physiological effects depend on the stimulation target's anatomical and functional network properties. We delivered closed-loop stimulation as 47 neurosurgical patients studied and recalled word lists. Multivariate classifiers, trained to predict momentary lapses in memory function, triggered the stimulation of the lateral temporal cortex (LTC) during the study phase of the task. We found that LTC stimulation specifically improved memory when delivered to targets near white matter pathways. Memory improvement was largest for targets near white matter that also showed high functional connectivity to the brain's memory network. These targets also reduced low-frequency activity in this network, an established marker of successful memory encoding. These data reveal how anatomical and functional networks mediate stimulation's behavioral and physiological effects, provide further evidence that closed-loop LTC stimulation can improve episodic memory, and suggest a method for optimizing neuromodulation through improved stimulation targeting.
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Affiliation(s)
- Youssef Ezzyat
- Dept. of Psychology, Wesleyan University, Middletown, CT 06459, USA
| | - James E Kragel
- Dept. of Neurology, University of Chicago, Chicago, IL 60637, USA
| | - Ethan A Solomon
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bradley C Lega
- Dept. of Neurosurgery, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Joshua P Aronson
- Dept. of Neurosurgery, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA
| | - Barbara C Jobst
- Dept. of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Robert E Gross
- Dept. of Neurosurgery, Emory University Hospital, Atlanta, GA 30322, USA
| | - Michael R Sperling
- Dept. of Neurology, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | - Sameer A Sheth
- Dept. of Neurosurgery, Baylor College of Medicine, Houston, TX 77030, USA
| | - Paul A Wanda
- Dept. of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Daniel S Rizzuto
- Dept. of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael J Kahana
- Dept. of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
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8
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Koizumi K, Kunii N, Ueda K, Takabatake K, Nagata K, Fujitani S, Shimada S, Nakao M. Intracranial Neurofeedback Modulating Neural Activity in the Mesial Temporal Lobe During Memory Encoding: A Pilot Study. Appl Psychophysiol Biofeedback 2023; 48:439-451. [PMID: 37405548 PMCID: PMC10581957 DOI: 10.1007/s10484-023-09595-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/24/2023] [Indexed: 07/06/2023]
Abstract
Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent at least five sessions of memory NF training to increase the theta power in the MTL. There was an increase in theta power and a decrease in fast beta and gamma powers in one of the patients in the late stage of memory NF sessions. NF signals were not correlated with memory function. Despite its limitations as a pilot study, to our best knowledge, this study is the first to report that intracranial NF may modulate neural activity in the MTL, which is involved in memory encoding. The findings provide important insights into the future development of NF systems for the artificial reorganization of memory functions.
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Affiliation(s)
- Koji Koizumi
- Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
| | - Naoto Kunii
- Department of Neurosurgery, The University of Tokyo, Tokyo, Japan
| | - Kazutaka Ueda
- Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
| | | | - Keisuke Nagata
- Department of Neurosurgery, The University of Tokyo, Tokyo, Japan
| | - Shigeta Fujitani
- Department of Neurosurgery, The University of Tokyo, Tokyo, Japan
| | - Seijiro Shimada
- Department of Neurosurgery, The University of Tokyo, Tokyo, Japan
| | - Masayuki Nakao
- Department of Mechanical Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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9
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Herz N, Bukala BR, Kragel JE, Kahana MJ. Hippocampal activity predicts contextual misattribution of false memories. Proc Natl Acad Sci U S A 2023; 120:e2305292120. [PMID: 37751551 PMCID: PMC10556612 DOI: 10.1073/pnas.2305292120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 08/02/2023] [Indexed: 09/28/2023] Open
Abstract
Failure of contextual retrieval can lead to false recall, wherein people retrieve an item or experience that occurred in a different context or did not occur at all. Whereas the hippocampus is thought to play a crucial role in memory retrieval, we lack understanding of how the hippocampus supports retrieval of items related to a target context while disregarding related but irrelevant information. Using direct electrical recordings from the human hippocampus, we investigate the neural process underlying contextual misattribution of false memories. In two large datasets, we characterize key physiological differences between correct and false recalls that emerge immediately prior to vocalization. By differentiating between false recalls that share high or low contextual similarity with the target context, we show that low-frequency activity (6 to 18 Hz) in the hippocampus tracks similarity between the current and retrieved context. Applying multivariate decoding methods, we were able to reliably predict the contextual source of the to-be-recalled item. Our findings elucidate one of the hallmark features of episodic memory: our ability to distinguish between memories that were formed on different occasions.
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Affiliation(s)
- Noa Herz
- Department of Psychology, University of Pennsylvania, Philadelphia, PA19104
| | - Bernard R. Bukala
- Department of Psychology, University of Pennsylvania, Philadelphia, PA19104
| | - James E. Kragel
- Department of Neurology, University of Chicago, Chicago, IL60637
| | - Michael J. Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA19104
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10
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Sandhaeger F, Siegel M. Testing the generalization of neural representations. Neuroimage 2023; 278:120258. [PMID: 37429371 PMCID: PMC10443234 DOI: 10.1016/j.neuroimage.2023.120258] [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: 12/14/2022] [Revised: 05/27/2023] [Accepted: 06/28/2023] [Indexed: 07/12/2023] Open
Abstract
Multivariate analysis methods are widely used in neuroscience to investigate the presence and structure of neural representations. Representational similarities across time or contexts are often investigated using pattern generalization, e.g. by training and testing multivariate decoders in different contexts, or by comparable pattern-based encoding methods. It is however unclear what conclusions can be validly drawn on the underlying neural representations when significant pattern generalization is found in mass signals such as LFP, EEG, MEG, or fMRI. Using simulations, we show how signal mixing and dependencies between measurements can drive significant pattern generalization even though the true underlying representations are orthogonal. We suggest that, using an accurate estimate of the expected pattern generalization given identical representations, it is nonetheless possible to test meaningful hypotheses about the generalization of neural representations. We offer such an estimate of the expected magnitude of pattern generalization and demonstrate how this measure can be used to assess the similarity and differences of neural representations across time and contexts.
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Affiliation(s)
- Florian Sandhaeger
- Department of Neural Dynamics and Magnetoencephalography, Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; Centre for Integrative Neuroscience, University of Tübingen, Germany; MEG Center, University of Tübingen, Germany; IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, Germany.
| | - Markus Siegel
- Department of Neural Dynamics and Magnetoencephalography, Hertie Institute for Clinical Brain Research, University of Tübingen, Germany; Centre for Integrative Neuroscience, University of Tübingen, Germany; MEG Center, University of Tübingen, Germany.
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11
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Koizumi K, Kunii N, Ueda K, Nagata K, Fujitani S, Shimada S, Nakao M. Paving the Way for Memory Enhancement: Development and Examination of a Neurofeedback System Targeting the Medial Temporal Lobe. Biomedicines 2023; 11:2262. [PMID: 37626758 PMCID: PMC10452721 DOI: 10.3390/biomedicines11082262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal lobe (MTL) still needs to be studied. Therefore, we aimed to develop an NF system for the memory function of the MTL and examine neural activity changes and memory task score changes through NF training. We created a memory NF system using intracranial electrodes to acquire and visualise the neural activity of the MTL during memory encoding. Twenty trials of a tug-of-war game per session were employed for NF and designed to control neural activity bidirectionally (Up/Down condition). NF training was conducted with three patients with drug-resistant epilepsy, and we observed an increasing difference in NF signal between conditions (Up-Down) as NF training progressed. Similarities and negative correlation tendencies between the transition of neural activity and the transition of memory function were also observed. Our findings demonstrate NF's potential to modulate MTL activity and memory encoding. Future research needs further improvements to the NF system to validate its effects on memory functions. Nonetheless, this study represents a crucial step in understanding NF's application to memory and provides valuable insights into developing more efficient memory enhancement strategies.
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Affiliation(s)
- Koji Koizumi
- Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan; (K.U.); (M.N.)
| | - Naoto Kunii
- Department of Neurosurgery, The University of Tokyo, Tokyo 113-8655, Japan; (N.K.); (K.N.); (S.F.); (S.S.)
| | - Kazutaka Ueda
- Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan; (K.U.); (M.N.)
| | - Keisuke Nagata
- Department of Neurosurgery, The University of Tokyo, Tokyo 113-8655, Japan; (N.K.); (K.N.); (S.F.); (S.S.)
| | - Shigeta Fujitani
- Department of Neurosurgery, The University of Tokyo, Tokyo 113-8655, Japan; (N.K.); (K.N.); (S.F.); (S.S.)
| | - Seijiro Shimada
- Department of Neurosurgery, The University of Tokyo, Tokyo 113-8655, Japan; (N.K.); (K.N.); (S.F.); (S.S.)
| | - Masayuki Nakao
- Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan; (K.U.); (M.N.)
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12
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Ezzyat Y, Kragel JE, Solomon EA, Lega BC, Aronson JP, Jobst BC, Gross RE, Sperling MR, Worrell GA, Sheth SA, Wanda PA, Rizzuto DS, Kahana MJ. Functional and anatomical connectivity predict brain stimulation's mnemonic effects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.27.550851. [PMID: 37609181 PMCID: PMC10441352 DOI: 10.1101/2023.07.27.550851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Closed-loop direct brain stimulation is a promising tool for modulating neural activity and behavior. However, it remains unclear how to optimally target stimulation to modulate brain activity in particular brain networks that underlie particular cognitive functions. Here, we test the hypothesis that stimulation's behavioral and physiological effects depend on the stimulation target's anatomical and functional network properties. We delivered closed-loop stimulation as 47 neurosurgical patients studied and recalled word lists. Multivariate classifiers, trained to predict momentary lapses in memory function, triggered stimulation of the lateral temporal cortex (LTC) during the study phase of the task. We found that LTC stimulation specifically improved memory when delivered to targets near white matter pathways. Memory improvement was largest for targets near white matter that also showed high functional connectivity to the brain's memory network. These targets also reduced low-frequency activity in this network, an established marker of successful memory encoding. These data reveal how anatomical and functional networks mediate stimulation's behavioral and physiological effects, provide further evidence that closed-loop LTC stimulation can improve episodic memory, and suggest a method for optimizing neuromodulation through improved stimulation targeting.
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Affiliation(s)
- Youssef Ezzyat
- Dept. of Psychology, Wesleyan University, Middletown CT 06459
| | | | - Ethan A. Solomon
- Perelman School of Medicine, University of Pennsylvania, Philadelphia PA 19104
| | - Bradley C. Lega
- Dept. of Neurosurgery, University of Texas Southwestern, Dallas TX 75390
| | - Joshua P. Aronson
- Dept. of Neurosurgery, Dartmouth-Hitchcock Medical Center, Lebanon NH 03756
| | - Barbara C. Jobst
- Dept. of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon NH 03756
| | - Robert E. Gross
- Dept. of Neurosurgery, Emory University Hospital, Atlanta GA 30322
| | - Michael R. Sperling
- Dept. of Neurology, Thomas Jefferson University Hospital, Philadelphia PA 19107
| | | | - Sameer A. Sheth
- Dept. of Neurosurgery, Columbia University Medical Center, New York, NY 10032
| | - Paul A. Wanda
- Dept. of Psychology, University of Pennsylvania, Philadelphia PA 19104
| | - Daniel S. Rizzuto
- Dept. of Psychology, University of Pennsylvania, Philadelphia PA 19104
| | - Michael J. Kahana
- Dept. of Psychology, University of Pennsylvania, Philadelphia PA 19104
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13
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Kahana MJ, Ezzyat Y, Wanda PA, Solomon EA, Adamovich-Zeitlin R, Lega BC, Jobst BC, Gross RE, Ding K, Diaz-Arrastia RR. Biomarker-guided neuromodulation aids memory in traumatic brain injury. Brain Stimul 2023; 16:1086-1093. [PMID: 37414370 DOI: 10.1016/j.brs.2023.07.002] [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: 09/02/2022] [Revised: 06/15/2023] [Accepted: 07/01/2023] [Indexed: 07/08/2023] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of cognitive disability in adults, often characterized by marked deficits in episodic memory and executive function. Prior studies have found that direct electrical stimulation of the temporal cortex yielded improved memory in epilepsy patients, but it is not clear if these results generalize to patients with a specific history of TBI. Here we asked whether applying closed-loop, direct electrical stimulation to lateral temporal cortex could reliably improve memory in a TBI cohort. Among a larger group of patients undergoing neurosurgical evaluation for refractory epilepsy, we recruited a subset of patients with a history of moderate-to-severe TBI. By analyzing neural data from indwelling electrodes as patients studied and recalled lists of words, we trained personalized machine-learning classifiers to predict momentary fluctuations in mnemonic function in each patient. We subsequently used these classifiers to trigger high-frequency stimulation of the lateral temporal cortex (LTC) at moments when memory was predicted to fail. This strategy yielded a 19% boost in recall performance on stimulated as compared with non-stimulated lists (P = 0.012). These results provide a proof-of-concept for using closed-loop stimulation of the brain in treatment of TBI-related memory impairment.
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Affiliation(s)
- Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Youssef Ezzyat
- Department of Psychology, Wesleyan University, Middletown, CT, 06459, USA
| | - Paul A Wanda
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Ethan A Solomon
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern, Dallas, TX, 75390, USA
| | - Barbara C Jobst
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, 03766, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University, Atlanta, GA, 30322, USA
| | - Kan Ding
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern, Dallas, TX, 75390, USA
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14
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Argiris G, Stern Y, Habeck C. Neural similarity across task load relates to cognitive reserve and brain maintenance measures on the Letter Sternberg task: a longitudinal study. Brain Imaging Behav 2023; 17:100-113. [PMID: 36484923 PMCID: PMC9925407 DOI: 10.1007/s11682-022-00746-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2022] [Indexed: 12/13/2022]
Abstract
The aging process is characterized by change across several measures that index cognitive status and brain integrity. In the present study, 54 cognitively-healthy younger and older adults, were analyzed, longitudinally, on a verbal working memory task to investigate the effect of brain maintenance (i.e., cortical thickness) and cognitive reserve (i.e., NART IQ as proxy) factors on a derived measure of neural efficiency. Participants were scanned using fMRI while presented with the Letter Sternberg task, a verbal working memory task consisting of encoding, maintenance and retrieval phases, where cognitive load is manipulated by varying the number of presented items (i.e., between one and six letters). Via correlation analysis, we looked at region-level and whole-brain relationships between load levels within each phase and then computed a global task measure, what we term phase specificity, to analyze how similar neural responses were across load levels within each phase compared to between each phase. We found that longitudinal change in phase specificity was positively related to longitudinal change in cortical thickness, at both the whole-brain and regional level. Additionally, baseline NART IQ was positively related to longitudinal change in phase specificity over time. Furthermore, we found a longitudinal effect of sex on change in phase specificity, such that females displayed higher phase specificity over time. Cross-sectional findings aligned with longitudinal findings, with the notable exception of behavioral performance being positively linked to phase specificity cross-sectionally at baseline. Taken together, our findings suggest that phase specificity positively relates to brain maintenance and reserve factors and should be better investigated as a measure of neural efficiency.
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Affiliation(s)
- Georgette Argiris
- Cognitive Neuroscience Division, Columbia University, New York, NY, USA
- Taub Institute, Columbia University, New York, NY, USA
- Columbia University Irving Medical Center, Neurological Institute, 710 West 168th Street, 3rd floor, NY, 10032, New York, USA
| | - Yaakov Stern
- Cognitive Neuroscience Division, Columbia University, New York, NY, USA
- Taub Institute, Columbia University, New York, NY, USA
- Columbia University Irving Medical Center, Neurological Institute, 710 West 168th Street, 3rd floor, NY, 10032, New York, USA
| | - Christian Habeck
- Cognitive Neuroscience Division, Columbia University, New York, NY, USA.
- Taub Institute, Columbia University, New York, NY, USA.
- Columbia University Irving Medical Center, Neurological Institute, 710 West 168th Street, 3rd floor, NY, 10032, New York, USA.
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15
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Topçu Ç, Marks VS, Saboo KV, Lech M, Nejedly P, Kremen V, Worrell GA, Kucewicz MT. Hotspot of human verbal memory encoding in the left anterior prefrontal cortex. EBioMedicine 2022; 82:104135. [PMID: 35785617 PMCID: PMC9254338 DOI: 10.1016/j.ebiom.2022.104135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 05/31/2022] [Accepted: 06/14/2022] [Indexed: 11/23/2022] Open
Abstract
Background Treating memory and cognitive deficits requires knowledge about anatomical sites and neural activities to be targeted with particular therapies. Emerging technologies for local brain stimulation offer attractive therapeutic options but need to be applied to target specific neural activities, at distinct times, and in specific brain regions that are critical for memory formation. Methods The areas that are critical for successful encoding of verbal memory as well as the underlying neural activities were determined directly in the human brain with intracranial electrophysiological recordings in epilepsy patients. We recorded a broad range of spectral activities across the cortex of 135 patients as they memorised word lists for subsequent free recall. Findings The greatest differences in the spectral power between encoding subsequently recalled and forgotten words were found in low theta frequency (3–5 Hz) activities of the left anterior prefrontal cortex. This subsequent memory effect was proportionally greater in the lower frequency bands and in the more anterior cortical regions. We found the peak of this memory signal in a distinct part of the prefrontal cortex at the junction between the Broca's area and the frontal pole. The memory effect in this confined area was significantly higher (Tukey–Kramer test, p<0.05) than in other anatomically distinct areas. Interpretation Our results suggest a focal hotspot of human verbal memory encoding located in the higher-order processing region of the prefrontal cortex, which presents a prospective target for modulating cognitive functions in the human patients. The memory effect provides an electrophysiological biomarker of low frequency neural activities, at distinct times of memory encoding, and in one hotspot location in the human brain. Funding Open-access datasets were originally collected as part of a BRAIN Initiative project called Restoring Active Memory (RAM) funded by the Defence Advanced Research Project Agency (DARPA). CT, ML, MTK and this research were supported from the First Team grant of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund.
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16
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Mirchi N, Warsi NM, Zhang F, Wong SM, Suresh H, Mithani K, Erdman L, Ibrahim GM. Decoding Intracranial EEG With Machine Learning: A Systematic Review. Front Hum Neurosci 2022; 16:913777. [PMID: 35832872 PMCID: PMC9271576 DOI: 10.3389/fnhum.2022.913777] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/31/2022] [Indexed: 11/13/2022] Open
Abstract
Advances in intracranial electroencephalography (iEEG) and neurophysiology have enabled the study of previously inaccessible brain regions with high fidelity temporal and spatial resolution. Studies of iEEG have revealed a rich neural code subserving healthy brain function and which fails in disease states. Machine learning (ML), a form of artificial intelligence, is a modern tool that may be able to better decode complex neural signals and enhance interpretation of these data. To date, a number of publications have applied ML to iEEG, but clinician awareness of these techniques and their relevance to neurosurgery, has been limited. The present work presents a review of existing applications of ML techniques in iEEG data, discusses the relative merits and limitations of the various approaches, and examines potential avenues for clinical translation in neurosurgery. One-hundred-seven articles examining artificial intelligence applications to iEEG were identified from 3 databases. Clinical applications of ML from these articles were categorized into 4 domains: i) seizure analysis, ii) motor tasks, iii) cognitive assessment, and iv) sleep staging. The review revealed that supervised algorithms were most commonly used across studies and often leveraged publicly available timeseries datasets. We conclude with recommendations for future work and potential clinical applications.
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Affiliation(s)
- Nykan Mirchi
- Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Nebras M. Warsi
- Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Frederick Zhang
- Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Simeon M. Wong
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, ON, Canada
| | - Hrishikesh Suresh
- Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Karim Mithani
- Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Lauren Erdman
- Vector Institute for Artificial Intelligence, MaRS Centre, Toronto, ON, Canada
- Department of Computer Science, University of Toronto, Toronto, ON, Canada
- Hospital for Sick Children, Toronto, ON, Canada
| | - George M. Ibrahim
- Division of Neurosurgery, Hospital for Sick Children, Department of Surgery, University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Program in Neuroscience and Mental Health, Hospital for Sick Children Research Institute, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
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17
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Camarillo-Rodriguez L, Leenen I, Waldman Z, Serruya M, Wanda PA, Herweg NA, Kahana MJ, Rubinstein D, Orosz I, Lega B, Podkorytova I, Gross RE, Worrell G, Davis KA, Jobst BC, Sheth SA, Weiss SA, Sperling MR. Temporal lobe interictal spikes disrupt encoding and retrieval of verbal memory: A subregion analysis. Epilepsia 2022; 63:2325-2337. [PMID: 35708911 DOI: 10.1111/epi.17334] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The medial temporal lobe (MTL) encodes and recalls memories and can be a predominant site for interictal spikes (IS) in patients with focal epilepsy. It is unclear whether memory deficits are due to IS in the MTL producing a transient decline. Here, we investigated whether IS in the MTL subregions and lateral temporal cortex impact episodic memory encoding and recall. METHODS Seventy-eight participants undergoing presurgical evaluation for medically refractory focal epilepsy with depth electrodes placed in the temporal lobe participated in a verbal free recall task. IS were manually annotated during the pre-encoding, encoding, and recall epochs. We examined the effect of IS on word recall using mixed-effects logistic regression. RESULTS IS in the left hippocampus (odds ratio [OR] = .73, 95% confidence interval [CI] = .63-.84, p < .001) and left middle temporal gyrus (OR = .46, 95% CI = .27-.78, p < .05) during word encoding decreased subsequent recall performance. Within the left hippocampus, this effect was specific for area CA1 (OR = .76, 95% CI = .66-.88, p < .01) and dentate gyrus (OR = .74, 95% CI = .62-.89, p < .05). IS in other MTL subregions or inferior and superior temporal gyrus and IS occurring during the prestimulus window did not affect word encoding (p > .05). IS during retrieval in right hippocampal (OR = .22, 95% CI = .08-.63, p = .01) and parahippocampal regions (OR = .24, 95% CI = .07-.8, p < .05) reduced the probability of recalling a word. SIGNIFICANCE IS in medial and lateral temporal cortex contribute to transient memory decline during verbal episodic memory.
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Affiliation(s)
| | - Iwin Leenen
- Faculty of Psychology, National Autonomous University of Mexico, Mexico City, Mexico
| | - Zachary Waldman
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Mijail Serruya
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paul A Wanda
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nora A Herweg
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Daniel Rubinstein
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Iren Orosz
- Department of Neurology, University of California, Los Angeles, Los Angeles, California, USA
| | | | | | - Robert E Gross
- Department of Neurosurgery, Emory University, Atlanta, Georgia, USA
| | | | - Kathryn A Davis
- Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Barbara C Jobst
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Sameer A Sheth
- Department of Neurological Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Shennan A Weiss
- Department of Neurology, State University of New York Downstate Medical Center, Brooklyn, New York, USA.,Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, Brooklyn, New York, USA.,Departments of Neurology, New York City Health + Hospitals/Kings County, Brooklyn, New York, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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18
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Johnson EL, Yin Q, O'Hara NB, Tang L, Jeong JW, Asano E, Ofen N. Dissociable oscillatory theta signatures of memory formation in the developing brain. Curr Biol 2022; 32:1457-1469.e4. [PMID: 35172128 PMCID: PMC9007830 DOI: 10.1016/j.cub.2022.01.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/15/2021] [Accepted: 01/19/2022] [Indexed: 11/16/2022]
Abstract
Understanding complex human brain functions is critically informed by studying such functions during development. Here, we addressed a major gap in models of human memory by leveraging rare direct electrophysiological recordings from children and adolescents. Specifically, memory relies on interactions between the medial temporal lobe (MTL) and prefrontal cortex (PFC), and the maturation of these interactions is posited to play a key role in supporting memory development. To understand the nature of MTL-PFC interactions, we examined subdural recordings from MTL and PFC in 21 neurosurgical patients aged 5.9-20.5 years as they performed an established scene memory task. We determined signatures of memory formation by comparing the study of subsequently recognized to forgotten scenes in single trials. Results establish that MTL and PFC interact via two distinct theta mechanisms, an ∼3-Hz oscillation that supports amplitude coupling and slows down with age and an ∼7-Hz oscillation that supports phase coupling and speeds up with age. Slow and fast theta interactions immediately preceding scene onset further explained age-related differences in recognition performance. Last, with additional diffusion imaging data, we linked both functional mechanisms to the structural maturation of the cingulum tract. Our findings establish system-level dynamics of memory formation and suggest that MTL and PFC interact via increasingly dissociable mechanisms as memory improves across development.
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Affiliation(s)
- Elizabeth L Johnson
- Life-Span Cognitive Neuroscience Program, Institute of Gerontology and Merrill Palmer Skillman Institute, Wayne State University, Detroit, MI 48202, USA; Departments of Medical Social Sciences and Pediatrics, Northwestern University, Chicago, IL 60611, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Qin Yin
- Life-Span Cognitive Neuroscience Program, Institute of Gerontology and Merrill Palmer Skillman Institute, Wayne State University, Detroit, MI 48202, USA; Department of Psychology, Wayne State University, Detroit, MI 48202, USA
| | - Nolan B O'Hara
- Translational Neuroscience Program, Wayne State University, Detroit, MI 48201, USA
| | - Lingfei Tang
- Life-Span Cognitive Neuroscience Program, Institute of Gerontology and Merrill Palmer Skillman Institute, Wayne State University, Detroit, MI 48202, USA; Department of Psychology, Wayne State University, Detroit, MI 48202, USA
| | - Jeong-Won Jeong
- Translational Neuroscience Program, Wayne State University, Detroit, MI 48201, USA; Departments of Pediatrics and Neurology, Children's Hospital of Michigan, Wayne State University, Detroit, MI 48201, USA
| | - Eishi Asano
- Translational Neuroscience Program, Wayne State University, Detroit, MI 48201, USA; Departments of Pediatrics and Neurology, Children's Hospital of Michigan, Wayne State University, Detroit, MI 48201, USA
| | - Noa Ofen
- Life-Span Cognitive Neuroscience Program, Institute of Gerontology and Merrill Palmer Skillman Institute, Wayne State University, Detroit, MI 48202, USA; Department of Psychology, Wayne State University, Detroit, MI 48202, USA; Translational Neuroscience Program, Wayne State University, Detroit, MI 48201, USA.
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19
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Kragel JE, Voss JL. Looking for the neural basis of memory. Trends Cogn Sci 2022; 26:53-65. [PMID: 34836769 PMCID: PMC8678329 DOI: 10.1016/j.tics.2021.10.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 01/03/2023]
Abstract
Memory neuroscientists often measure neural activity during task trials designed to recruit specific memory processes. Behavior is championed as crucial for deciphering brain-memory linkages but is impoverished in typical experiments that rely on summary judgments. We criticize this approach as being blind to the multiple cognitive, neural, and behavioral processes that occur rapidly within a trial to support memory. Instead, time-resolved behaviors such as eye movements occur at the speed of cognition and neural activity. We highlight successes using eye-movement tracking with in vivo electrophysiology to link rapid hippocampal oscillations to encoding and retrieval processes that interact over hundreds of milliseconds. This approach will improve research on the neural basis of memory because it pinpoints discrete moments of brain-behavior-cognition correspondence.
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Affiliation(s)
- James E Kragel
- Department of Neurology, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA.
| | - Joel L Voss
- Department of Neurology, The University of Chicago, 5841 South Maryland Avenue, Chicago, IL 60637, USA
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20
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Ye Q, Chen H, Liu R, Qin R, Luo C, Li M, Xu Y, Zhao H, Bai F. Lateralized Contributions of Medial Prefrontal Cortex Network to Episodic Memory Deficits in Subjects With Amnestic Mild Cognitive Impairment. Front Aging Neurosci 2021; 13:756241. [PMID: 34867283 PMCID: PMC8635729 DOI: 10.3389/fnagi.2021.756241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 10/27/2021] [Indexed: 11/13/2022] Open
Abstract
Both episodic memory and executive function are impaired in amnestic mild cognitive impairment (aMCI) subjects, but it is unclear if these impairments are independent or interactive. The present study aimed to explore the relationship between episodic memory deficits and executive function deficits, and the underlying functional mechanisms in aMCI subjects. Thirty-one aMCI subjects and 27 healthy subjects underwent neuropsychological tests and multimodal magnetic resonance imaging (MRI) scans. Hippocampal networks and medial prefrontal cortex (MPFC) networks were identified based on resting-sate functional MRI (fMRI) data. AMCI subjects displayed lower episodic memory scores and executive function scores than control subjects, and the episodic memory scores were positively correlated with the executive function scores in aMCI subjects. Brain network analyses showed an interaction between the hippocampal networks and the MPFC networks, and the interaction was significantly associated with the episodic memory scores and the executive function scores. Notably, aMCI subjects displayed higher functional connectivity (FC) of the right hippocampal network with the right prefrontal cortex than did control subjects, but this difference disappeared when controlling for the MPFC networks. Furthermore, the effects of the MPFC networks on the hippocampal networks were significantly associated with the episodic memory scores in aMCI subjects. The present findings suggested that the episodic memory deficits in aMCI subjects could be partially underpinned by the modulation of the MPFC networks on the hippocampal networks.
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Affiliation(s)
- Qing Ye
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Haifeng Chen
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Renyuan Liu
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,Department of Radiology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China
| | - Ruomeng Qin
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Caimei Luo
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Mengchun Li
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Hui Zhao
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Feng Bai
- Department of Neurology, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing, China.,The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
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21
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Kragel JE, Ezzyat Y, Lega BC, Sperling MR, Worrell GA, Gross RE, Jobst BC, Sheth SA, Zaghloul KA, Stein JM, Kahana MJ. Distinct cortical systems reinstate the content and context of episodic memories. Nat Commun 2021; 12:4444. [PMID: 34290240 PMCID: PMC8295370 DOI: 10.1038/s41467-021-24393-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/07/2021] [Indexed: 02/06/2023] Open
Abstract
Episodic recall depends upon the reinstatement of cortical activity present during the formation of a memory. Evidence from functional neuroimaging and invasive recordings in humans suggest that reinstatement organizes our memories by time or content, yet the neural systems involved in reinstating these unique types of information remain unclear. Here, combining computational modeling and intracranial recordings from 69 epilepsy patients, we show that two cortical systems uniquely reinstate the semantic content and temporal context of previously studied items during free recall. Examining either the posterior medial or anterior temporal networks, we find that forward encoding models trained on the brain's response to the temporal and semantic attributes of items can predict the serial position and semantic category of unseen items. During memory recall, these models uniquely link reinstatement of temporal context and semantic content to these posterior and anterior networks, respectively. These findings demonstrate how specialized cortical systems enable the human brain to target specific memories.
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Affiliation(s)
- James E. Kragel
- grid.25879.310000 0004 1936 8972Department of Psychology, University of Pennsylvania, Philadelphia, PA USA
| | - Youssef Ezzyat
- grid.25879.310000 0004 1936 8972Department of Psychology, University of Pennsylvania, Philadelphia, PA USA
| | - Bradley C. Lega
- grid.267313.20000 0000 9482 7121Department of Neurosurgery, University of Texas Southwestern, Dallas, TX USA
| | - Michael R. Sperling
- grid.265008.90000 0001 2166 5843Department of Neurology, Thomas Jefferson University, Philadelphia, PA USA
| | - Gregory A. Worrell
- grid.66875.3a0000 0004 0459 167XDepartment of Neurology, Mayo Clinic, Rochester, MN USA
| | - Robert E. Gross
- grid.189967.80000 0001 0941 6502Department of Neurosurgery, Emory School of Medicine, Atlanta, GA USA
| | - Barbara C. Jobst
- grid.413480.a0000 0004 0440 749XDepartment of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH USA
| | - Sameer A. Sheth
- grid.239585.00000 0001 2285 2675Department of Neurosurgery, Columbia University Medical Center, New York, NY USA
| | - Kareem A. Zaghloul
- grid.94365.3d0000 0001 2297 5165Surgical Neurology Branch, National Institutes of Health, Bethesda, MD USA
| | - Joel M. Stein
- grid.411115.10000 0004 0435 0884Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA USA
| | - Michael J. Kahana
- grid.25879.310000 0004 1936 8972Department of Psychology, University of Pennsylvania, Philadelphia, PA USA
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22
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Jobst BC, Conner KR, Coulter D, Fried I, Guilfoyle S, Hirsch LJ, Hogan RE, Hopp JL, Naritoku D, Plueger M, Schevon C, Smith G, Valencia I, Gaillard WD. Highlights From AES2020, a Virtual American Epilepsy Society Experience. Epilepsy Curr 2021; 21:15357597211018219. [PMID: 33998298 PMCID: PMC8512915 DOI: 10.1177/15357597211018219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Due to COVID-19 a live, in-person meeting was not possible for the American Epilepsy Society in 2020. An alternative, virtual event, the AES2020, was held instead. AES2020 was a great success with 4679 attendees from 70 countries. The educational content was outstanding and spanned the causes, treatments, and outcomes from epileptic encephalopathy to the iatrogenicity of epilepsy interventions to neurocognitive disabilities to the approach to neocortical epilepsies. New gene therapy approaches such as antisense oligonucleotide treatment for Dravet syndrome were introduced and neuromodulation devices were discussed. There were many other topics discussed in special interest groups and investigators' workshops. A highlight was having a Nobel prize winner speak about memory processing. Human intracranial electrophysiology contributes insights into memory processing and complements animal work. In a special COVID symposium, the impact of COVID on patients with epilepsy was reviewed. Telehealth has been expanded rapidly and may be well suited for some parts of epilepsy care. In summary, the epilepsy community was alive and engaged despite being limited to a virtual platform.
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Affiliation(s)
| | | | | | | | - Shanna Guilfoyle
- Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
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23
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Adamovich-Zeitlin R, Wanda PA, Solomon E, Phan T, Lega B, Jobst BC, Gross RE, Ding K, Diaz-Arrastia R, Kahana MJ. Biomarkers of memory variability in traumatic brain injury. Brain Commun 2021; 3:fcaa202. [PMID: 33543140 PMCID: PMC7850041 DOI: 10.1093/braincomms/fcaa202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/08/2020] [Accepted: 10/05/2020] [Indexed: 11/18/2022] Open
Abstract
Traumatic brain injury is a leading cause of cognitive disability and is often associated with significant impairment in episodic memory. In traumatic brain injury survivors, as in healthy controls, there is marked variability between individuals in memory ability. Using recordings from indwelling electrodes, we characterized and compared the oscillatory biomarkers of mnemonic variability in two cohorts of epilepsy patients: a group with a history of moderate-to-severe traumatic brain injury (n = 37) and a group of controls without traumatic brain injury (n = 111) closely matched for demographics and electrode coverage. Analysis of these recordings demonstrated that increased high-frequency power and decreased theta power across a broad set of brain regions mark periods of successful memory formation in both groups. As features in a logistic-regression classifier, spectral power biomarkers effectively predicted recall probability, with little difference between traumatic brain injury patients and controls. The two groups also displayed similar patterns of theta-frequency connectivity during successful encoding periods. These biomarkers of successful memory, highly conserved between traumatic brain injury patients and controls, could serve as the basis for novel therapies that target disordered memory across diverse forms of neurological disease.
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Affiliation(s)
| | - Paul A Wanda
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ethan Solomon
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tung Phan
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bradley Lega
- Department of Neurosurgery, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Barbara C Jobst
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Hanover, NH 03766, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University, Atlanta, GA 30322, USA
| | - Kan Ding
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Ramon Diaz-Arrastia
- Department of Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
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24
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Johnson EL, Kam JWY, Tzovara A, Knight RT. Insights into human cognition from intracranial EEG: A review of audition, memory, internal cognition, and causality. J Neural Eng 2020; 17:051001. [PMID: 32916678 PMCID: PMC7731730 DOI: 10.1088/1741-2552/abb7a5] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
By recording neural activity directly from the human brain, researchers gain unprecedented insight into how neurocognitive processes unfold in real time. We first briefly discuss how intracranial electroencephalography (iEEG) recordings, performed for clinical practice, are used to study human cognition with the spatiotemporal and single-trial precision traditionally limited to non-human animal research. We then delineate how studies using iEEG have informed our understanding of issues fundamental to human cognition: auditory prediction, working and episodic memory, and internal cognition. We also discuss the potential of iEEG to infer causality through the manipulation or 'engineering' of neurocognitive processes via spatiotemporally precise electrical stimulation. We close by highlighting limitations of iEEG, potential of burgeoning techniques to further increase spatiotemporal precision, and implications for future research using intracranial approaches to understand, restore, and enhance human cognition.
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Affiliation(s)
- Elizabeth L Johnson
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Life-Span Cognitive Neuroscience Program, Institute of Gerontology, Wayne State University, United States of America
| | - Julia W Y Kam
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Department of Psychology, University of Calgary, Canada
- Hotchkiss Brain Institute, University of Calgary, Canada
| | - Athina Tzovara
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Institute for Computer Science, University of Bern, Switzerland
- Sleep Wake Epilepsy Center | NeuroTec, Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Robert T Knight
- Helen Wills Neuroscience Institute, University of California, Berkeley, United States of America
- Department of Psychology, University of California, Berkeley, United States of America
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25
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Owen LLW, Muntianu TA, Heusser AC, Daly PM, Scangos KW, Manning JR. A Gaussian Process Model of Human Electrocorticographic Data. Cereb Cortex 2020; 30:5333-5345. [PMID: 32495832 PMCID: PMC7472198 DOI: 10.1093/cercor/bhaa115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 12/17/2022] Open
Abstract
We present a model-based method for inferring full-brain neural activity at millimeter-scale spatial resolutions and millisecond-scale temporal resolutions using standard human intracranial recordings. Our approach makes the simplifying assumptions that different people's brains exhibit similar correlational structure, and that activity and correlation patterns vary smoothly over space. One can then ask, for an arbitrary individual's brain: given recordings from a limited set of locations in that individual's brain, along with the observed spatial correlations learned from other people's recordings, how much can be inferred about ongoing activity at other locations throughout that individual's brain? We show that our approach generalizes across people and tasks, thereby providing a person- and task-general means of inferring high spatiotemporal resolution full-brain neural dynamics from standard low-density intracranial recordings.
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Affiliation(s)
- Lucy L W Owen
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Tudor A Muntianu
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA
| | - Andrew C Heusser
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA
- Akili Interactive, Boston, MA 02110, USA
| | - Patrick M Daly
- Department of Psychiatry, University of California, San Francisco, CA 94143, USA
| | - Katherine W Scangos
- Department of Psychiatry, University of California, San Francisco, CA 94143, USA
| | - Jeremy R Manning
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA
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26
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Lu Z, Bassett DS. Invertible generalized synchronization: A putative mechanism for implicit learning in neural systems. CHAOS (WOODBURY, N.Y.) 2020; 30:063133. [PMID: 32611103 DOI: 10.1063/5.0004344] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 05/25/2020] [Indexed: 06/11/2023]
Abstract
Regardless of the marked differences between biological and artificial neural systems, one fundamental similarity is that they are essentially dynamical systems that can learn to imitate other dynamical systems whose governing equations are unknown. The brain is able to learn the dynamic nature of the physical world via experience; analogously, artificial neural systems such as reservoir computing networks (RCNs) can learn the long-term behavior of complex dynamical systems from data. Recent work has shown that the mechanism of such learning in RCNs is invertible generalized synchronization (IGS). Yet, whether IGS is also the mechanism of learning in biological systems remains unclear. To shed light on this question, we draw inspiration from features of the human brain to propose a general and biologically feasible learning framework that utilizes IGS. To evaluate the framework's relevance, we construct several distinct neural network models as instantiations of the proposed framework. Regardless of their particularities, these neural network models can consistently learn to imitate other dynamical processes with a biologically feasible adaptation rule that modulates the strength of synapses. Further, we observe and theoretically explain the spontaneous emergence of four distinct phenomena reminiscent of cognitive functions: (i) learning multiple dynamics; (ii) switching among the imitations of multiple dynamical systems, either spontaneously or driven by external cues; (iii) filling-in missing variables from incomplete observations; and (iv) deciphering superimposed input from different dynamical systems. Collectively, our findings support the notion that biological neural networks can learn the dynamic nature of their environment through the mechanism of IGS.
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Affiliation(s)
- Zhixin Lu
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Danielle S Bassett
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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27
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Herweg NA, Solomon EA, Kahana MJ. Theta Oscillations in Human Memory. Trends Cogn Sci 2020; 24:208-227. [PMID: 32029359 PMCID: PMC8310425 DOI: 10.1016/j.tics.2019.12.006] [Citation(s) in RCA: 203] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 11/21/2022]
Abstract
Theta frequency (4-8 Hz) fluctuations of the local field potential have long been implicated in learning and memory. Human studies of episodic memory, however, have provided mixed evidence for theta's role in successful learning and remembering. Re-evaluating these conflicting findings leads us to conclude that: (i) successful memory is associated both with increased narrow-band theta oscillations and a broad-band tilt of the power spectrum; (ii) theta oscillations specifically support associative memory, whereas the spectral tilt reflects a general index of activation; and (iii) different cognitive contrasts (generalized versus specific to memory), recording techniques (invasive versus noninvasive), and referencing schemes (local versus global) alter the balance between the two phenomena to make one or the other more easily detectable.
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Affiliation(s)
- Nora A Herweg
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ethan A Solomon
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA.
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28
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Reactivated Spatial Context Guides Episodic Recall. J Neurosci 2020; 40:2119-2128. [PMID: 31974207 DOI: 10.1523/jneurosci.1640-19.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 11/21/2019] [Accepted: 11/23/2019] [Indexed: 01/01/2023] Open
Abstract
The medial temporal lobe (MTL) is known as the locus of spatial coding and episodic memory, but the interaction between these cognitive domains as well as the extent to which they rely on common neurophysiological mechanisms is poorly understood. Here, we use intracranial electroencephalography and a hybrid spatial-episodic memory task (29 subjects, 15 female) to determine how spatial information is dynamically reactivated in subregions of the human MTL and how this reactivation guides recall of episodic information. Our results implicate theta oscillations across the MTL as a common neurophysiological substrate for spatial coding in navigation and episodic recall. We further show that our index of retrieved spatial context is high in the hippocampus (HC) in an early time window preceding recall. Closer to recall, it decreases in the HC and increases in the parahippocampal gyrus. Finally, we demonstrate that hippocampal theta phase modulates parahippocampal gamma amplitude during retrieval of spatial context, suggesting a role for cross-frequency coupling in coding and transmitting retrieved spatial information.SIGNIFICANCE STATEMENT By recording from the human medial temporal lobe (MTL) while subjects recall items experienced in a virtual environment, we establish a direct relation between the strength of theta activity during memory search and the extent to which memories are organized by their spatial locations. We thereby pinpoint a role for theta oscillations in accessing the "cognitive map" during episodic retrieval and further highlight the dynamic interplay of hippocampus and extrahippocampal MTL in representing retrieved spatial context. Our results provide an important step toward a unified theory of MTL function encompassing its role in spatial navigation and episodic memory.
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29
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Voxel-based analysis and multivariate pattern analysis of diffusion tensor imaging study in anti-NMDA receptor encephalitis. Neuroradiology 2019; 62:231-239. [PMID: 31784810 DOI: 10.1007/s00234-019-02321-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/30/2019] [Indexed: 12/25/2022]
Abstract
PURPOSE This study aimed to investigate brain white matter (WM) changes and their relationship to cognition in patients with anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis. Multivariate pattern analysis (MVPA) was used to explore brain regions that play an important role in classification. METHODS Fifteen patients and fifteen controls underwent Montreal Cognitive Assessment (MoCA) and diffusion tensor imaging. Based on fractional anisotropy (FA) and mean diffusivity (MD) for MVPA classification, the weights of each brain region were calculated. RESULTS Compared with the controls, the patients showed an FA reduction in right middle temporal gyrus, left middle cerebellar peduncle, right praecuneus, and an MD increase in left medial temporal gyrus and left frontal lobe. The MoCA score for patients was lower than controls, especially in executive function, fluency, delayed recall and visual perception items. The FA value of right praecuneus was positively correlated with total MoCA score and fluency score. The MD of left frontal lobe was negatively correlated with total MoCA score, and MD of the left medial temporal gyrus was positively correlated with delayed recall. The accuracy, sensitivity and specificity of classification based on FA were 70%, 60% and 80%, respectively. Based on MD, they were each 80%. The brain regions with large weights from FA and MD overlap in temporal lobe, cerebellum and hippocampus. CONCLUSIONS These results suggest that WM changes are associated with cognitive deficits. MVPA based on FA and MD has good classification ability. Our study may provide new insights into the pathophysiological mechanisms of residual cognitive deficits.
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30
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Chaitanya G, Hinds W, Kragel J, He X, Sideman N, Ezzyat Y, Sperling MR, Sharan A, Tracy JI. Tonic Resting State Hubness Supports High Gamma Activity Defined Verbal Memory Encoding Network in Epilepsy. Neuroscience 2019; 425:194-216. [PMID: 31786346 DOI: 10.1016/j.neuroscience.2019.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 10/25/2019] [Accepted: 11/01/2019] [Indexed: 01/06/2023]
Abstract
High gamma activity (HGA) of verbal-memory encoding using invasive-electroencephalogram has laid the foundation for numerous studies testing the integrity of memory in diseased populations. Yet, the functional connectivity characteristics of networks subserving these memory linkages remains uncertain. By integrating this electrophysiological biomarker of memory encoding from IEEG with resting-state BOLD fluctuations, we estimated the segregation and hubness of HGA-memory regions in drug-resistant epilepsy patients and matched healthy controls. HGA-memory regions express distinctly different hubness compared to neighboring regions in health and in epilepsy, and this hubness was more relevant than segregation in predicting verbal memory encoding. The HGA-memory network comprised regions from both the cognitive control and primary processing networks, validating that effective verbal-memory encoding requires integrating brain functions, and is not dominated by a central cognitive core. Our results demonstrate a tonic intrinsic set of functional connectivity, which provides the necessary conditions for effective, phasic, task-dependent memory encoding.
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Affiliation(s)
- Ganne Chaitanya
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Walter Hinds
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, United States
| | - James Kragel
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Xiaosong He
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Noah Sideman
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Youssef Ezzyat
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Ashwini Sharan
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Joseph I Tracy
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, United States.
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31
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Hill PF, King DR, Lega BC, Rugg MD. Comparison of fMRI correlates of successful episodic memory encoding in temporal lobe epilepsy patients and healthy controls. Neuroimage 2019; 207:116397. [PMID: 31770638 PMCID: PMC7238288 DOI: 10.1016/j.neuroimage.2019.116397] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2019] [Revised: 10/23/2019] [Accepted: 11/22/2019] [Indexed: 12/30/2022] Open
Abstract
Intra-cranial electroencephalographic brain recordings (iEEG) provide a powerful tool for investigating the neural processes supporting episodic memory encoding and form the basis of experimental therapies aimed at improving memory dysfunction. However, given the invasiveness of iEEG, investigations are constrained to patients with drug-resistant epilepsy for whom such recordings are clinically indicated. Particularly in the case of temporal lobe epilepsy (TLE), neuropathology and the possibility of functional reorganization are potential constraints on the generalizability of intra-cerebral findings and pose challenges to the development of therapies for memory disorders stemming from other etiologies. Here, samples of TLE (N = 16; all of whom had undergone iEEG) and age-matched healthy control (N = 19) participants underwent fMRI as they studied lists of concrete nouns. fMRI BOLDresponses elicited by the study words were segregated according to subsequent performance on tests of delayed free recall and recognition memory. Subsequent memory effects predictive of both successful recall and recognition memory were evident in several neural regions, most prominently in the left inferior frontal gyrus, and did not demonstrate any group differences. Behaviorally, the groups did not differ in overall recall performance or in the strength of temporal contiguity effects. However, group differences in serial position effects and false alarm rates were evident during the free recall and recognition memory tasks, respectively. Despite these behavioral differences, neuropathology associated with temporal lobe epilepsy was apparently insufficient to give rise to detectable differences in the functional neuroanatomy of episodic memory encoding relative to neurologically healthy controls. The findings provide reassurance that iEEG findings derived from experimental paradigms similar to those employed here generalize to the neurotypical population.
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Affiliation(s)
- Paul F Hill
- Center for Vital Longevity, University of Texas at Dallas, 1600 Viceroy Dr. #800, Dallas, TX, 75235, USA; School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA.
| | - Danielle R King
- Center for Vital Longevity, University of Texas at Dallas, 1600 Viceroy Dr. #800, Dallas, TX, 75235, USA; School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern Medical Center, 5303 Harry Hines Blvd 6th Floor Suite 108, Dallas, TX, 75390, USA
| | - Michael D Rugg
- Center for Vital Longevity, University of Texas at Dallas, 1600 Viceroy Dr. #800, Dallas, TX, 75235, USA; School of Behavioral and Brain Sciences, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, 6363 Forest Park Rd 7th Floor Suite 749, Dallas, TX, 75235, USA
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32
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Khambhati AN, Kahn AE, Costantini J, Ezzyat Y, Solomon EA, Gross RE, Jobst BC, Sheth SA, Zaghloul KA, Worrell G, Seger S, Lega BC, Weiss S, Sperling MR, Gorniak R, Das SR, Stein JM, Rizzuto DS, Kahana MJ, Lucas TH, Davis KA, Tracy JI, Bassett DS. Functional control of electrophysiological network architecture using direct neurostimulation in humans. Netw Neurosci 2019; 3:848-877. [PMID: 31410383 PMCID: PMC6663306 DOI: 10.1162/netn_a_00089] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/14/2019] [Indexed: 01/30/2023] Open
Abstract
Chronically implantable neurostimulation devices are becoming a clinically viable option for treating patients with neurological disease and psychiatric disorders. Neurostimulation offers the ability to probe and manipulate distributed networks of interacting brain areas in dysfunctional circuits. Here, we use tools from network control theory to examine the dynamic reconfiguration of functionally interacting neuronal ensembles during targeted neurostimulation of cortical and subcortical brain structures. By integrating multimodal intracranial recordings and diffusion-weighted imaging from patients with drug-resistant epilepsy, we test hypothesized structural and functional rules that predict altered patterns of synchronized local field potentials. We demonstrate the ability to predictably reconfigure functional interactions depending on stimulation strength and location. Stimulation of areas with structurally weak connections largely modulates the functional hubness of downstream areas and concurrently propels the brain towards more difficult-to-reach dynamical states. By using focal perturbations to bridge large-scale structure, function, and markers of behavior, our findings suggest that stimulation may be tuned to influence different scales of network interactions driving cognition. Brain stimulation devices capable of perturbing the physiological state of neural systems are rapidly gaining popularity for their potential to treat neurological and psychiatric disease. A root problem is that underlying dysfunction spans a large-scale network of brain regions, requiring the ability to control the complex interactions between multiple brain areas. Here, we use tools from network control theory to examine the dynamic reconfiguration of functionally interacting neuronal ensembles during targeted neurostimulation of cortical and subcortical brain structures. We demonstrate the ability to predictably reconfigure patterns of interactions between functional brain areas by modulating the strength and location of stimulation. Our findings have high significance for designing stimulation protocols capable of modulating distributed neural circuits in the human brain.
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Affiliation(s)
- Ankit N Khambhati
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Ari E Kahn
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Julia Costantini
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Youssef Ezzyat
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ethan A Solomon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert E Gross
- Department of Neurosurgery, Emory University Hospital, Atlanta, GA, USA
| | - Barbara C Jobst
- Department of Neurology, Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA
| | - Sameer A Sheth
- Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
| | - Kareem A Zaghloul
- Surgical Neurology Branch, National Institutes of Health, Bethesda, MD, USA
| | | | - Sarah Seger
- Department of Neurosurgery, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Bradley C Lega
- Department of Neurosurgery, University of Texas, Southwestern Medical Center, Dallas, TX, USA
| | - Shennan Weiss
- Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Richard Gorniak
- Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Sandhitsu R Das
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Joel M Stein
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel S Rizzuto
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Timothy H Lucas
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Kathryn A Davis
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph I Tracy
- Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Danielle S Bassett
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
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33
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Wirt RA, Hyman JM. ACC Theta Improves Hippocampal Contextual Processing during Remote Recall. Cell Rep 2019; 27:2313-2327.e4. [DOI: 10.1016/j.celrep.2019.04.080] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 03/18/2019] [Accepted: 04/17/2019] [Indexed: 12/27/2022] Open
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34
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Solomon EA, Stein JM, Das S, Gorniak R, Sperling MR, Worrell G, Inman CS, Tan RJ, Jobst BC, Rizzuto DS, Kahana MJ. Dynamic Theta Networks in the Human Medial Temporal Lobe Support Episodic Memory. Curr Biol 2019; 29:1100-1111.e4. [PMID: 30905609 DOI: 10.1016/j.cub.2019.02.020] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 01/06/2019] [Accepted: 02/06/2019] [Indexed: 12/22/2022]
Abstract
The medial temporal lobe (MTL) is a locus of episodic memory in the human brain. It is comprised of cytologically distinct subregions that, in concert, give rise to successful encoding and retrieval of context-dependent memories. However, the functional connections between these subregions are poorly understood. To determine functional connectivity among MTL subregions, we had 131 subjects fitted with indwelling electrodes perform a verbal memory task and asked how encoding or retrieval correlated with inter-regional synchronization. Using phase-based measures of connectivity, we found that synchronous theta (4-8 Hz) activity underlies successful episodic memory. During encoding, we observed a dynamic pattern of connections converging on the left entorhinal cortex, beginning with the perirhinal cortex and shifting through hippocampal subfields. Retrieval-associated networks demonstrated enhanced involvement of the subiculum and CA1, reflecting a substantial reorganization of the encoding network. We posit that coherent theta activity within the MTL marks periods of successful memory, but distinct patterns of connectivity dissociate key stages of memory processing.
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Affiliation(s)
- Ethan A Solomon
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Joel M Stein
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sandhitsu Das
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Richard Gorniak
- Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA
| | - Gregory Worrell
- Department of Neurology, Department of Physiology and Bioengineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Cory S Inman
- Department of Neurosurgery, Emory School of Medicine, Atlanta, GA 30322, USA
| | - Ryan J Tan
- Department of Neurosurgery, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Barbara C Jobst
- Department of Neurology, Dartmouth Medical Center, Lebanon, NH 03756, USA
| | - Daniel S Rizzuto
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Michael J Kahana
- Department of Psychology, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Hesse E, Mikulan E, Sitt JD, Garcia MDC, Silva W, Ciraolo C, Vaucheret E, Raimondo F, Baglivo F, Adolfi F, Herrera E, Bekinschtein TA, Petroni A, Lew S, Sedeno L, Garcia AM, Ibanez A. Consistent Gradient of Performance and Decoding of Stimulus Type and Valence From Local and Network Activity. IEEE Trans Neural Syst Rehabil Eng 2019; 27:619-629. [PMID: 30869625 DOI: 10.1109/tnsre.2019.2903921] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The individual differences approach focuses on the variation of behavioral and neural signatures across subjects. In this context, we searched for intracranial neural markers of performance in three individuals with distinct behavioral patterns (efficient, borderline, and inefficient) in a dual-valence task assessing facial and lexical emotion recognition. First, we performed a preliminary study to replicate well-established evoked responses in relevant brain regions. Then, we examined time series data and network connectivity, combined with multivariate pattern analyses and machine learning, to explore electrophysiological differences in resting-state versus task-related activity across subjects. Next, using the same methodological approach, we assessed the neural decoding of performance for different dimensions of the task. The classification of time series data mirrored the behavioral gradient across subjects for stimulus type but not for valence. However, network-based measures reflected the subjects' hierarchical profiles for both stimulus types and valence. Therefore, this measure serves as a sensitive marker for capturing distributed processes such as emotional valence discrimination, which relies on an extended set of regions. Network measures combined with classification methods may offer useful insights to study single subjects and understand inter-individual performance variability. Promisingly, this approach could eventually be extrapolated to other neuroscientific techniques.
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Weidemann CT, Kragel JE, Lega BC, Worrell GA, Sperling MR, Sharan AD, Jobst BC, Khadjevand F, Davis KA, Wanda PA, Kadel A, Rizzuto DS, Kahana MJ. Neural activity reveals interactions between episodic and semantic memory systems during retrieval. J Exp Psychol Gen 2019; 148:1-12. [PMID: 30596439 DOI: 10.1037/xge0000480] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Whereas numerous findings support a distinction between episodic and semantic memory, it is now widely acknowledged that these two forms of memory interact during both encoding and retrieval. The precise nature of this interaction, however, remains poorly understood. To examine the role of semantic organization during episodic encoding and retrieval, we recorded intracranial encephalographic signals as 69 neurosurgical patients studied and subsequently recalled categorized and unrelated word lists. Applying multivariate classifiers to neural recordings, we were able to reliably predict encoding success, retrieval success, and temporal and categorical clustering during recall. By assessing how these classifiers generalized across list types, we identified specific retrieval processes that predicted recall of categorized lists and distinguished between recall transitions within and between category clusters. These results particularly implicate retrieval (rather than encoding) processes in the categorical organization of episodic memories. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
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Affiliation(s)
| | | | - Bradley C Lega
- Department of Neurosurgery, University of Texas Southwestern
| | | | | | | | | | | | - Kathryn A Davis
- Department of Neurology, Hospital of the University of Pennsylvania
| | - Paul A Wanda
- Department of Psychology, University of Pennsylvania
| | - Allison Kadel
- Department of Psychology, University of Pennsylvania
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Ezzyat Y, Rizzuto DS. Direct brain stimulation during episodic memory. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2018. [DOI: 10.1016/j.cobme.2018.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Miller J, Watrous AJ, Tsitsiklis M, Lee SA, Sheth SA, Schevon CA, Smith EH, Sperling MR, Sharan A, Asadi-Pooya AA, Worrell GA, Meisenhelter S, Inman CS, Davis KA, Lega B, Wanda PA, Das SR, Stein JM, Gorniak R, Jacobs J. Lateralized hippocampal oscillations underlie distinct aspects of human spatial memory and navigation. Nat Commun 2018; 9:2423. [PMID: 29930307 PMCID: PMC6013427 DOI: 10.1038/s41467-018-04847-9] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 05/29/2018] [Indexed: 12/29/2022] Open
Abstract
The hippocampus plays a vital role in various aspects of cognition including both memory and spatial navigation. To understand electrophysiologically how the hippocampus supports these processes, we recorded intracranial electroencephalographic activity from 46 neurosurgical patients as they performed a spatial memory task. We measure signals from multiple brain regions, including both left and right hippocampi, and we use spectral analysis to identify oscillatory patterns related to memory encoding and navigation. We show that in the left but not right hippocampus, the amplitude of oscillations in the 1–3-Hz “low theta” band increases when viewing subsequently remembered object–location pairs. In contrast, in the right but not left hippocampus, low-theta activity increases during periods of navigation. The frequencies of these hippocampal signals are slower than task-related signals in the neocortex. These results suggest that the human brain includes multiple lateralized oscillatory networks that support different aspects of cognition. Theta oscillations are implicated in memory formation. Here, the authors show that low-theta oscillations in the hippocampus are differentially modulated between each hemisphere, with oscillations in the left increasing when successfully learning object–location pairs and in the right during spatial navigation.
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Affiliation(s)
- Jonathan Miller
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904, 1210 Amsterdam Avenue, New York, NY, 10027, USA
| | - Andrew J Watrous
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904, 1210 Amsterdam Avenue, New York, NY, 10027, USA
| | - Melina Tsitsiklis
- Doctoral Program in Neurobiology and Behavior, Columbia University, New York, 10027, NY, USA
| | - Sang Ah Lee
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Korea
| | - Sameer A Sheth
- Department of Neurosurgery, Baylor College of Medicine, Houston, 77030, TX, USA
| | - Catherine A Schevon
- Department of Neurology, Columbia University Medical Center, New York, 10032, NY, USA
| | - Elliot H Smith
- Department of Neurological Surgery, Columbia University Medical Center, New York, 10032, NY, USA
| | - Michael R Sperling
- Department of Neurology, Thomas Jefferson University, Philadelphia, 19107, PA, USA
| | - Ashwini Sharan
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, 19107, PA, USA
| | - Ali Akbar Asadi-Pooya
- Department of Neurology, Thomas Jefferson University, Philadelphia, 19107, PA, USA.,Shiraz Neurosciences Research Center, Shiraz University of Medical Sciences, Shiraz, 71348, Iran
| | | | - Stephen Meisenhelter
- Department of Neurology, Geisel School of Medicine at Dartmouth, Lebanon, 03756, NH, USA
| | - Cory S Inman
- Emory University School of Medicine, Atlanta, 30322, GA, USA
| | - Kathryn A Davis
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Bradley Lega
- University of Texas-Southwestern, Dallas, 75390, TX, USA
| | - Paul A Wanda
- Department of Psychology, University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Sandhitsu R Das
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Joel M Stein
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, 19104, PA, USA
| | - Richard Gorniak
- Department of Radiology, Thomas Jefferson University, Philadelphia, 19107, PA, USA
| | - Joshua Jacobs
- Department of Biomedical Engineering, Columbia University, 351 Engineering Terrace, Mail Code 8904, 1210 Amsterdam Avenue, New York, NY, 10027, USA.
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Closed-loop stimulation of temporal cortex rescues functional networks and improves memory. Nat Commun 2018; 9:365. [PMID: 29410414 PMCID: PMC5802791 DOI: 10.1038/s41467-017-02753-0] [Citation(s) in RCA: 171] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/20/2017] [Indexed: 01/12/2023] Open
Abstract
Memory failures are frustrating and often the result of ineffective encoding. One approach to improving memory outcomes is through direct modulation of brain activity with electrical stimulation. Previous efforts, however, have reported inconsistent effects when using open-loop stimulation and often target the hippocampus and medial temporal lobes. Here we use a closed-loop system to monitor and decode neural activity from direct brain recordings in humans. We apply targeted stimulation to lateral temporal cortex and report that this stimulation rescues periods of poor memory encoding. This system also improves later recall, revealing that the lateral temporal cortex is a reliable target for memory enhancement. Taken together, our results suggest that such systems may provide a therapeutic approach for treating memory dysfunction.
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