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Longo A, Houot M, Herlin B, Méré M, Denos M, Samson S, Dupont S. Distinctive neuropsychological profiles of lateral temporal lobe epilepsy. Epilepsy Behav 2021; 125:108411. [PMID: 34794011 DOI: 10.1016/j.yebeh.2021.108411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/07/2021] [Accepted: 10/25/2021] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Lateral temporal lobe epilepsies (LTLE) are poorly characterized heterogeneous epilepsies. As the lateral temporal lobe supports distinct functions, we hypothesized that neuropsychological profiles could differ according to the localization of the seizure focus within the lateral temporal lobe. METHODS We retrospectively examined the neuropsychological characteristics of 74 consecutive patients with refractory LTLE assessed in the context of a presurgical investigation at the Pitié-Salpêtrière Hospital in Paris between 1998 and 2018. Precise localization of the epileptic focus was correlated with scores on tests of intelligence (Global, Verbal and Performance IQ), working memory, episodic memory (verbal and visual learning and forgetting), executive functions, and language abilities. RESULTS We demonstrated an impact of the localization of the epileptic focus within the lateral temporal lobe with worse learning and/or executive performances depicted in the infero-basal and pure pole LTLE groups and greater language difficulties in the posterior LTLE group, Antiepileptic drugs had a greater effect than parameters related to the epilepsy itself as the lesion or the disease duration, and finally as in medial TLE, the age, education, and sex influenced some cognitive performances. CONCLUSION Our findings show that the lateral temporal neocortex is also part of the neural substrate for memory processing and executive functions and suggest that this involvement could be related to functions devoted to specific subregions of the temporal lobe (i.e., temporal pole, inferior and basal regions) that support language and semantic processing.
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Affiliation(s)
- Alessia Longo
- Rehabilitation Unit, AP-HP, Pitié-Salpêtrière Hospital, Paris, France; Neurosciences Department, Area Del Farmaco E Salute Del Bambino, Firenze, Italy
| | - Marion Houot
- Clinical Investigation Centre, Institut du Cerveau et de la Moelle épinière (ICM), Pitié-Salpêtrière Hospital Paris, France; Institute of Memory and Alzheimer's Disease (IM2A), Department of Neurology, AP-HP, Pitié-Salpêtrière Hospital, Paris, France; Centre of Excellence of Neurodegenerative Disease (CoEN), AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Bastien Herlin
- Rehabilitation Unit, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Marie Méré
- Epilepsy Unit, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Marisa Denos
- Rehabilitation Unit, AP-HP, Pitié-Salpêtrière Hospital, Paris, France
| | - Séverine Samson
- Epilepsy Unit, AP-HP, Pitié-Salpêtrière Hospital, Paris, France; Univ. Lille, ULR 4072 - PSITEC - Psychologie : Interactions Temps Émotions Cognition, F-59000 Lille, France
| | - Sophie Dupont
- Rehabilitation Unit, AP-HP, Pitié-Salpêtrière Hospital, Paris, France; Epilepsy Unit, AP-HP, Pitié-Salpêtrière Hospital, Paris, France; Université Paris Sorbonne, Paris, France; Centre de recherche de l'Institut du cerveau et de la moelle épinière (ICM), UMPC-UMR 7225 CNRS-UMRS 975 Inserm, Paris, France.
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Ruis C. Monitoring cognition during awake brain surgery in adults: A systematic review. J Clin Exp Neuropsychol 2018; 40:1081-1104. [DOI: 10.1080/13803395.2018.1469602] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Carla Ruis
- Department of Neurology and Neurosurgery, University Medical Center Utrecht, Utrecht, The Netherlands
- Experimental Psychology, Utrecht University, Utrecht, The Netherlands
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Zamora L, Corina D, Ojemann G. Human temporal cortical single neuron activity during working memory maintenance. Neuropsychologia 2016; 86:1-12. [PMID: 27059210 PMCID: PMC4899132 DOI: 10.1016/j.neuropsychologia.2016.04.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 03/23/2016] [Accepted: 04/03/2016] [Indexed: 11/19/2022]
Abstract
The Working Memory model of human memory, first introduced by Baddeley and Hitch (1974), has been one of the most influential psychological constructs in cognitive psychology and human neuroscience. However the neuronal correlates of core components of this model have yet to be fully elucidated. Here we present data from two studies where human temporal cortical single neuron activity was recorded during tasks differentially affecting the maintenance component of verbal working memory. In Study One we vary the presence or absence of distracting items for the entire period of memory storage. In Study Two we vary the duration of storage so that distractors filled all, or only one-third of the time the memory was stored. Extracellular single neuron recordings were obtained from 36 subjects undergoing awake temporal lobe resections for epilepsy, 25 in Study one, 11 in Study two. Recordings were obtained from a total of 166 lateral temporal cortex neurons during performance of one of these two tasks, 86 study one, 80 study two. Significant changes in activity with distractor manipulation were present in 74 of these neurons (45%), 38 Study one, 36 Study two. In 48 (65%) of those there was increased activity during the period when distracting items were absent, 26 Study One, 22 Study Two. The magnitude of this increase was greater for Study One, 47.6%, than Study Two, 8.1%, paralleling the reduction in memory errors in the absence of distracters, for Study One of 70.3%, Study Two 26.3% These findings establish that human lateral temporal cortex is part of the neural system for working memory, with activity during maintenance of that memory that parallels performance, suggesting it represents active rehearsal. In 31 of these neurons (65%) this activity was an extension of that during working memory encoding that differed significantly from the neural processes recorded during overt and silent language tasks without a recent memory component, 17 Study one, 14 Study two. Contrary to the Baddeley model, that activity during verbal working memory maintenance often represented activity specific to working memory rather than speech or language.
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Affiliation(s)
- Leona Zamora
- Departments of Psychology University of Washington, Seattle, WA 98195
| | - David Corina
- Departments of Psychology University of Washington, Seattle, WA 98195
| | - George Ojemann
- Department of Neurological Surgery, University of Washington, Harborview Hospital, 325 9 Ave. Box 359924, Seattle, WA 98104
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Brent BK, Rosso IM, Thermenos HW, Holt DJ, Faraone SV, Makris N, Tsuang MT, Seidman LJ. Alterations of lateral temporal cortical gray matter and facial memory as vulnerability indicators for schizophrenia: An MRI study in youth at familial high-risk for schizophrenia. Schizophr Res 2016; 170:123-9. [PMID: 26621001 PMCID: PMC4707114 DOI: 10.1016/j.schres.2015.11.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 11/11/2015] [Accepted: 11/14/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND Structural alterations of the lateral temporal cortex (LTC) in association with memory impairments have been reported in schizophrenia. This study investigated whether alterations of LTC structure were linked with impaired facial and/or verbal memory in young first-degree relatives of people with schizophrenia and, thus, may be indicators of vulnerability to the illness. METHODS Subjects included 27 non-psychotic, first-degree relatives of schizophrenia patients, and 48 healthy controls, between the ages of 13 and 28. Participants underwent high-resolution magnetic resonance imaging (MRI) at 1.5Tesla. The LTC was parcellated into superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, and temporal pole. Total cerebral and LTC volumes were measured using semi-automated morphometry. The Wechsler Memory Scale - Third Edition and the Children's Memory Scale - Third Edition assessed facial and verbal memory. General linear models tested for associations among LTC subregion volumes, familial risk and memory. RESULTS Compared with controls, relatives had significantly smaller bilateral middle temporal gyri. Moreover, right middle temporal gyral volume showed a significant positive association with delayed facial memory in relatives. CONCLUSION These results support the hypothesis that smaller middle temporal gyri are related to the genetic liability to schizophrenia and may be linked with reduced facial memory in persons at genetic risk for the illness. The findings add to the growing evidence that children at risk for schizophrenia on the basis of positive family history have cortical and subcortical structural brain abnormalities well before psychotic illness occurs.
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Affiliation(s)
- Benjamin K. Brent
- Harvard Medical School, Department of Psychiatry at Massachusetts General Hospital, Boston, MA 02114,Harvard Medical School, Massachusetts Mental Health Center Public Psychiatry Division of the Beth Israel Deaconess Medical Center, Boston, MA 02115, United States
| | - Isabelle M. Rosso
- Harvard Medical School Department of Psychiatry at McLean Hospital, Belmont, MA 02478, United States
| | - Heidi W. Thermenos
- Harvard Medical School, Massachusetts Mental Health Center Public Psychiatry Division of the Beth Israel Deaconess Medical Center, Boston, MA 02115, United States,The HST-MIT Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA 02129, United States
| | - Daphne J. Holt
- Harvard Medical School, Department of Psychiatry at Massachusetts General Hospital, Boston, MA 02114,The HST-MIT Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA 02129, United States
| | - Stephen V. Faraone
- Departments of Psychiatry and Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, United States; K.G. Jebsen Centre for Psychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Nikos Makris
- Harvard Medical School, Department of Psychiatry at Massachusetts General Hospital, Boston, MA 02114,The HST-MIT Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA 02129, United States,Harvard Medical School Department of Neurology and Radiology Services, Center for Morphometric Analysis, Massachusetts General Hospital, Boston, MA 02120, United States
| | - Ming T. Tsuang
- Center for Behavioral Genomics, Department of Psychiatry; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, United States
| | - Larry J. Seidman
- Harvard Medical School, Department of Psychiatry at Massachusetts General Hospital, Boston, MA 02114,Harvard Medical School, Massachusetts Mental Health Center Public Psychiatry Division of the Beth Israel Deaconess Medical Center, Boston, MA 02115, United States,The HST-MIT Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA 02129, United States
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Human Temporal Cortical Single Neuron Activity during Language: A Review. Brain Sci 2013; 3:627-41. [PMID: 24961418 PMCID: PMC4061841 DOI: 10.3390/brainsci3020627] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 04/08/2013] [Indexed: 11/17/2022] Open
Abstract
Findings from recordings of human temporal cortical single neuron activity during several measures of language, including object naming and word reading are reviewed and related to changes in activity in the same neurons during recent verbal memory and verbal associative learning measures, in studies conducted during awake neurosurgery for the treatment of epilepsy. The proportion of neurons changing activity with language tasks was similar in either hemisphere. Dominant hemisphere activity was characterized by relative inhibition, some of which occurred during overt speech, possibly to block perception of one’s own voice. However, the majority seems to represent a dynamic network becoming active with verbal memory encoding and especially verbal learning, but inhibited during performance of overlearned language tasks. Individual neurons are involved in different networks for different aspects of language, including naming or reading and naming in different languages. The majority of the changes in activity were tonic sustained shifts in firing. Patterned phasic activity for specific language items was very infrequently recorded. Human single neuron recordings provide a unique perspective on the biologic substrate for language, for these findings are in contrast to many of the findings from other techniques for investigating this.
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Ojemann GA, Corina DP, Corrigan N, Schoenfield-McNeill J, Poliakov A, Zamora L, Zanos S. Neuronal correlates of functional magnetic resonance imaging in human temporal cortex. Brain 2010; 133:46-59. [PMID: 19773355 PMCID: PMC2801320 DOI: 10.1093/brain/awp227] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 07/15/2009] [Accepted: 07/19/2009] [Indexed: 11/12/2022] Open
Abstract
The relationship between changes in functional magnetic resonance imaging and neuronal activity remains controversial. Data collected during awake neurosurgical procedures for the treatment of epilepsy provided a rare opportunity to examine this relationship in human temporal association cortex. We obtained functional magnetic resonance imaging blood oxygen dependent signals, single neuronal activity and local field potentials from 8 to 300 Hz at 13 temporal cortical sites, from nine subjects, during paired associate learning and control measures. The relation between the functional magnetic resonance imaging signal and the electrophysiologic parameters was assessed in two ways: colocalization between significant changes in these signals on the same paired associate-control comparisons and multiple linear regressions of the electrophysiologic measures on the functional magnetic resonance imaging signal, across all tasks. Significant colocalization was present between increased functional magnetic resonance imaging signals and increased local field potentials power in the 50-250 Hz range. Local field potentials power greater than 100 Hz was also a significant regressor for the functional magnetic resonance imaging signal, establishing this local field potentials frequency range as a neuronal correlate of the functional magnetic resonance imaging signal. There was a trend for a relation between power in some low frequency local field potentials frequencies and the functional magnetic resonance imaging signal, for 8-15 Hz increases in the colocalization analysis and 16-23 Hz in the multiple linear regression analysis. Neither analysis provided evidence for an independent relation to frequency of single neuron activity.
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Affiliation(s)
- George A Ojemann
- Department of Neurological Surgery, Campus Box 356470, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA.
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Ojemann GA, Schoenfield-McNeill J, Corina D. The roles of human lateral temporal cortical neuronal activity in recent verbal memory encoding. Cereb Cortex 2009; 19:197-205. [PMID: 18469317 PMCID: PMC2638743 DOI: 10.1093/cercor/bhn071] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Activity of 98 single neurons in human lateral temporal cortex was measured during memory encoding for auditory words, text, or pictures and compared with identification of material of the same modality in extracellular recordings during awake neurosurgery for epilepsy. Frequency of activity was divided into early or late epochs or activity sustained throughout both; 44 neurons had significant changes in one or more categories. Polymodal and sustained changes lateralized to dominant hemisphere and late changes to nondominant. The majority of polymodal neurons shifted categories for different modalities. In dominant hemisphere, the timing and nature of changes in activity provide the basis for a model of the roles of temporal cortex in encoding. Superior temporal gyrus excitatory activity was related to the early epoch, when perception and processing occur, and middle gyrus to the late epoch, when semantic labeling occurs. The superior two-thirds of middle gyrus also demonstrated sustained inhibition. In a subset of lateral temporal neurons, memory-encoding activity reflected simultaneous convergence of sustained attentional and early perceptual inputs.
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Affiliation(s)
- George A Ojemann
- Department of Neurological Surgery, University of Washington, Seattle, WA 98195, USA
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9
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Engel AK, Moll CKE, Fried I, Ojemann GA. Invasive recordings from the human brain: clinical insights and beyond. Nat Rev Neurosci 2005; 6:35-47. [PMID: 15611725 DOI: 10.1038/nrn1585] [Citation(s) in RCA: 219] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although non-invasive methods such as functional magnetic resonance imaging, electroencephalograms and magnetoencephalograms provide most of the current data about the human brain, their resolution is insufficient to show physiological processes at the cellular level. Clinical approaches sometimes allow invasive recordings to be taken from the human brain, mainly in patients with epilepsy or with movement disorders, and such recordings can sample neural activity at spatial scales ranging from single cells to distributed cell assemblies. In addition to their clinical relevance, these recordings can provide unique insights into brain functions such as movement control, perception, memory, language and even consciousness.
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Affiliation(s)
- Andreas K Engel
- Institute of Neurophysiology and Pathophysiology, Center of Experimental Medicine, University Hospital Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany.
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10
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Ojemann GA, Schoenfield-McNeill J, Corina D. Different neurons in different regions of human temporal lobe distinguish correct from incorrect identification or memory. Neuropsychologia 2004; 42:1383-93. [PMID: 15193946 DOI: 10.1016/j.neuropsychologia.2004.01.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2003] [Revised: 01/07/2004] [Accepted: 01/14/2004] [Indexed: 11/28/2022]
Abstract
Changes in the frequency of neural activity differentiating correct from incorrect responses were identified in extracellular recordings from 113 neurons at 62 sites in temporal lobe of 26 patients undergoing awake neurosurgery, during identification and recent explicit memory for object names, text or auditory words. Activity significantly differentiating correct from incorrect performance was identified in 22 neurons at 16 sites in 12 patients. Different neurons in different regions differentiated identification or memory performance. The 13 neurons differentiating identification performance were overrepresented in medial-basal recordings, the 9 neurons differentiating memory performance in superior temporal gyrus. All memory changes occurred during encoding. For both identification and memory there was separation of neurons showing differentiation early during perception and processing from those showing differentiation late, when output should occur, perhaps reflecting response monitoring. Early differentiating neurons were located more superior-laterally within the different regions related to accuracy of identification or memory.
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Affiliation(s)
- George A Ojemann
- Department of Neurological Surgery, University of Washington, 1959 N.E. Pacific Street, Box 356470, Seattle, WA 98195, USA.
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Ojemann GA. The neurobiology of language and verbal memory: observations from awake neurosurgery. Int J Psychophysiol 2003; 48:141-6. [PMID: 12763571 DOI: 10.1016/s0167-8760(03)00051-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Neurosurgical operations under local anesthesia provide a unique opportunity to investigate the neurobiology of human cognition. We have studied the cortical organization of language and verbal memory in this setting, using two different techniques: electrical stimulation mapping and extracellular microelectrode recording of activity of individual neurons. The two techniques provide very different perspectives. Stimulation mapping identifies brain areas that are essential for a behavior, while changes in neuronal activity can occur in non-essential regions. Stimulation mapping identifies multiple discrete areas in perisylvian cortex of the dominant hemisphere as essential for a function, with separation of areas for different aspects of language including naming in two languages, different semantic classes, naming compared to reading, and language from verbal memory. There is substantial individual variation in the location of these essential areas, variability that in part relates to subjects age, gender and verbal abilities. Neurons changing activity with language or verbal memory are widely distributed, in both hemispheres. However, individual neurons usually change activity with only one function, including naming in only one of two languages, only naming or reading, or with recent verbal memory encoding but not identification of similar items. A few lateralized changes in neuronal activity have been identified, including a predominance of inhibition in dominant hemisphere with naming, and polymodal memory responses in dominant hemisphere, unimodal in nondominant. Specific neuronal populations have been identified that are related to different aspects of memory, that differentiate correct from incorrect identification or memory performance and differentiate learned from unlearned associations, with some evidence of differences in neuronal activity related to subjects' ability.
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Affiliation(s)
- George A Ojemann
- Department of Neurological Surgery, University of Washington, P.O. Box 356470, Seattle, WA 98195, USA.
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12
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Ojemann JG, Ojemann GA, Lettich E. Cortical stimulation mapping of language cortex by using a verb generation task: effects of learning and comparison to mapping based on object naming. J Neurosurg 2002; 97:33-8. [PMID: 12134930 DOI: 10.3171/jns.2002.97.1.0033] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Cortical stimulation mapping has traditionally relied on disruption of object naming to define essential language areas. In this study, the authors reviewed the use of a different language task, verb generation, in mapping language. This task has greater use in brain imaging studies and may be used to test aspects of language different from those of object naming. METHODS In 14 patients, cortical stimulation mapping performed using a verb generation task provided a map of language areas in the frontal and temporoparietal cortices. These verb generation maps often overlapped object naming ones and, in many patients, different areas of cortex were found to be involved in the two functions. In three patients, stimulation mapping was performed during the initial performance of the verb generation task and also during learned performance of the task. Parallel to findings of published neuroimaging studies, a larger area of stimulated cortex led to disruption of verb generation in response to stimulation during novel task performance than during learned performance. CONCLUSIONS Results of cortical stimulation mapping closely resemble those of functional neuroimaging when both implement the verb generation task. The precise map of the temporoparietal language cortex depends on the task used for mapping.
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Ojemann GA, Schoenfield-McNeill J, Corina DP. Anatomic subdivisions in human temporal cortical neuronal activity related to recent verbal memory. Nat Neurosci 2002; 5:64-71. [PMID: 11753418 DOI: 10.1038/nn785] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We identified functional anatomical subdivisions of human lateral and basal temporal cortex related to recent verbal memory for object names, text and auditory words. Extracellular neuronal activity was recorded during memory encoding compared to identification, during encoding, storage or recall retrieval stages of the memory task, during recognition memory, and during implicit memory as measured by repetition priming. Changes in frequency of activity during encoding were recorded from most neurons. In lateral temporal cortex, these encoding changes in the dominant hemisphere were more likely to be polymodal, whereas those in nondominant hemisphere were unimodal. There was substantial separation of neurons with changes in other aspects of memory, defining additional subdivisions. Inferior lateral and basal cortex were related to memory stages, and superior-posterior lateral cortex was related to implicit and recognition memory.
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Affiliation(s)
- G A Ojemann
- Department of Neurological Surgery, Box 356470, University of Washington, Seattle, Washington 98195, USA.
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Bechtereva NP, Abdullaev YG. Depth electrodes in clinical neurophysiology: neuronal activity and human cognitive function. Int J Psychophysiol 2000; 37:11-29. [PMID: 10828372 DOI: 10.1016/s0167-8760(00)00092-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Depth intracranial electrodes are used in medicine for the diagnosis and treatment of certain medically intractable disorders including epilepsy and parkinsonism. Electrophysiological studies including the recording of neuronal activity via depth electrodes during cognitive tasks allow the mapping of the functional significance of various brain regions for certain cognitive functions. Knowledge accumulated throughout the last several decades allows us to draw some theoretical inferences about neuronal mechanisms of human cognition. The present paper provides a selective review of studies of neuronal activity of the human brain in relation to language, verbal memory and error detection.
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Affiliation(s)
- N P Bechtereva
- Brain Center and Institute for Human Brain, Acad. Pavlov Street 9, 197376, St. Petersburg, Russia.
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Lepage M, Habib R, Cormier H, Houle S, McIntosh AR. Neural correlates of semantic associative encoding in episodic memory. BRAIN RESEARCH. COGNITIVE BRAIN RESEARCH 2000; 9:271-80. [PMID: 10808138 DOI: 10.1016/s0926-6410(00)00005-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Associations between individual items are the basic building blocks of learning and memory. Functional neuroimaging has now made it possible to study neural correlates of such associations. The present PET study examined three associative encoding conditions differing in the number of words (0, 1, or 2) semantically related to a third word representing the name of a semantic category. A recall task consisting in the presentation of the category names as cues for retrieving the other two members of the triads followed each encoding condition. As expected, retrieval performance increased as the number of semantic exemplars at encoding increased (10%, 43%, 70% items recalled, respectively). A first analysis (partial least squares, PLS) of the PET data identified task-related patterns of activity for associative encoding and cued-recall tasks. A second analysis identified brain regions whose activity was modulated by the number of semantic exemplars at encoding. Some of the task-related brain regions also showed modulated activity by semantic relatedness and consisted in the left inferior prefrontal cortex, right medial temporal lobe, fusiform gyrus and inferior temporal gyrus bilaterally. Some of these regions showed greater activity when words in a triad were unrelated, whereas others did so when the three words were semantically related. These regions have been consistently reported in previous functional neuroimaging studies of associative encoding and may constitute key structures in association formation.
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Affiliation(s)
- M Lepage
- Rotman Research Institute of Baycrest Centre for Geriatric Care, 3560 Bathurst Street, University of Toronto, Toronto, ON, Canada.
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Abstract
Extracellular recordings of human temporal cortical neuronal activity during identification and memory for object names or words were obtained from 31 neurons at 18 sites in 12 left language dominant patients undergoing left (10) or right (2) awake craniotomy for epilepsy under local anesthesia. Frequency of activity during identification was compared with perceptual controls, that during the encoding phase of recent memory to identification of the same material. Statistically significant changes in one or more temporal epoch (p < 0.005) of one or more comparisons were present for 27 of the 31 neurons in either hemisphere. Few neurons changed activity in the same direction for both words and names. The instruction to retain an item in recent memory changed activity in most neurons from that during identification of the same material, although the items presented were identical and overtly identified in each task. Any individual neuron usually changed activity in one direction for only one task. There are separate, widely distributed neural networks for identification or recent memory for each type of material. The majority of nearby neurons recorded through the same extracellular microelectrode were related to the networks for different tasks. The temporal characteristics of these changes were also investigated; 31% of the changes were "phasic": temporally related to presentation or response to the item. Most of the remaining neuron changes were sustained throughout a task, often for several minutes. These task-specific sustained changes may reflect effects of thalamo-cortical attentional systems. Individual neurons had both sustained and phasic changes to different tasks.
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Ojemann GA, Schoenfield-McNeill J. Neurons in human temporal cortex active with verbal associative learning. BRAIN AND LANGUAGE 1998; 64:317-327. [PMID: 9743545 DOI: 10.1006/brln.1998.1982] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In neuronal activity recorded from human middle temporal gyrus during learning of associations between word pairs, a population was identified that had greater activity for associations that were learned rapidly during initial encoding compared to those learned slowly or not at all by an individual subject. This population can be separated from other neurons by the combination of inhibition during word reading when no learning is required and excitation during recent memory for words. These neurons are present in both hemispheres, predominately in deeper layers of cortex. During initial encoding, the increased activity appears at presentation of all word pairs but persists for several seconds only for the rapidly learned pairs, likely reflecting rehersal of items being learned. Human associative learning is related to activity of this specific population of "association" neurons, identified here for the first time.
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Affiliation(s)
- G A Ojemann
- Department of Neurological Surgery, University of Washington
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Ojemann GA, Ojemann SG, Fried I. Lessons from the Human Brain: Neuronal Activity Related to Cognition. Neuroscientist 1998. [DOI: 10.1177/107385849800400417] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Several special clinical settings provide opportunities for extracellular recording of neuronal activity in the human brain during measures of cognition. The limited experience with recordings obtained from human temporal and frontal cortex, medial temporal lobe, and subcortical structures in association with language, visuospatial processes, memory, learning, and music is reviewed here. The frequency of activity in a high proportion of neurons changes with a specific behavior. These neurons are widely distributed in both hemispheres. Relative inhibition of activity is prominent in cortical recordings made during language measures, particularly in the dominant hemisphere. Widespread excitation is prominent in recordings made during measures of recent explicit memory and learning. However, any individual neuron often has a narrow behavioral repertory, with activation to only one specific behavior in a range of behaviors. Some of the behaviors associated with consistent changes are not intuitively obvious. Nearby neurons often have different behavioral repertories. A few patterns of activity that may represent specific coding for a behavior, in some cases even sparse coding, have been identified. Neuronal recording in humans during cognitive measures provides an additional perspective on the neurobiological substrate of cognition that complements findings from other techniques.
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Affiliation(s)
- George A. Ojemann
- Department of Neurological Surgery (GAO) University of Washington Seattle, Washington Department of Neurological Surgery (SGO) University of California San Francisco, California Division of Neurosurgery (IF) University of California Los Angeles, California
| | - Steven G. Ojemann
- Department of Neurological Surgery (GAO) University of Washington Seattle, Washington Department of Neurological Surgery (SGO) University of California San Francisco, California Division of Neurosurgery (IF) University of California Los Angeles, California
| | - Itzhak Fried
- Department of Neurological Surgery (GAO) University of Washington Seattle, Washington Department of Neurological Surgery (SGO) University of California San Francisco, California Division of Neurosurgery (IF) University of California Los Angeles, California
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Zhuang P, Toro C, Grafman J, Manganotti P, Leocani L, Hallett M. Event-related desynchronization (ERD) in the alpha frequency during development of implicit and explicit learning. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1997; 102:374-81. [PMID: 9146500 DOI: 10.1016/s0013-4694(96)96030-7] [Citation(s) in RCA: 78] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
To understand the role of the motor cortex in implicit and explicit learning, we studied alpha event-related desynchronization (ERD) while 13 right-handed individuals performed a variation of the serial reaction time task (SRTT). EEG signals were recorded simultaneously from 29 scalp locations and the ERD was computed. During data collection, all subjects developed implicit knowledge, demonstrated by shortening of the response time, and explicit knowledge of the test sequence. The average ERD maps of all 13 subjects demonstrated that during the initial learning, there was a decline in alpha band power that was maximal over the contralateral central region. The ERD reached a transient peak amplitude at a point when the subjects attained full explicit knowledge, and diminished subsequently. The transient peak in ERD was highly significant at C3. These electrophysiologic findings support previous studies which have demonstrated that motor activity changes as behavior changes over the course of learning.
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Affiliation(s)
- P Zhuang
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1428, USA
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