scholarly journals An Intracranial EEG Study of Visual Language Encoding: The Contribution of the Precentral Gyrus to Silent Reading

2021 ◽  
pp. 1-18
Author(s):  
Erik Kaestner ◽  
Thomas Thesen ◽  
Orrin Devinsky ◽  
Werner Doyle ◽  
Chad Carlson ◽  
...  
Keyword(s):  
Semantic Processing ◽  
Phase Locking ◽  
Silent Reading ◽  
Decision Task ◽  
Precentral Gyrus ◽  
Large Patient ◽  
High Gamma ◽  
Gamma Power ◽  
Spatio Temporal ◽  
Models Of Reading

Abstract Models of reading emphasize that visual (orthographic) processing provides input to phonological as well as lexical–semantic processing. Neurobiological models of reading have mapped these processes to distributed regions across occipital–temporal, temporal–parietal, and frontal cortices. However, the role of the precentral gyrus in these models is ambiguous. Articulatory phonemic representations in the precentral gyrus are obviously involved in reading aloud, but it is unclear if the precentral gyrus is recruited during reading silently in a time window consistent with participation in phonological processing contributions. Here, we recorded intracranial electrophysiology during a speeded semantic decision task from 24 patients to map the spatio-temporal flow of information across the cortex during silent reading. Patients selected animate nouns from a stream of nonanimate words, letter strings, and false-font stimuli. We characterized the distribution and timing of evoked high-gamma power (70–170 Hz) as well as phase-locking between electrodes. The precentral gyrus showed a proportion of electrodes responsive to linguistic stimuli (27%) that was at least as high as those of surrounding peri-sylvian regions. These precentral gyrus electrodes had significantly greater high-gamma power for words compared to both false-font and letter-string stimuli. In a patient with word-selective effects in the fusiform, superior temporal, and precentral gyri, there was significant phase-locking between the fusiform and precentral gyri starting at ∼180 msec and between the precentral and superior temporal gyri starting at ∼220 msec. Finally, our large patient cohort allowed exploratory analyses of the spatio-temporal reading network underlying silent reading. The distribution, timing, and connectivity results place the precentral gyrus as an important hub in the silent reading network.

scholarly journals The Precentral Gyrus Contributions to the Early Time-Course of Grapheme-to-Phoneme Conversion

2021 ◽  
pp. 1-61
Author(s):  
Erik Kaestner ◽  
Xiaojing Wu ◽  
Daniel Friedman ◽  
Patricia Dugan ◽  
Orrin Devinsky ◽  
...  
Keyword(s):  
Letter String ◽  
Time Course ◽  
Phase Locking ◽  
Silent Reading ◽  
Early Time ◽  
Superior Temporal Gyrus ◽  
Precentral Gyrus ◽  
High Concentration ◽  
High Gamma ◽  
Pars Opercularis

Abstract As part of silent reading models, visual orthographic information is transduced into an auditory phonological code in a process of grapheme-to-phoneme conversion (GPC). This process is often identified with lateral temporal-parietal regions associated with auditory phoneme encoding. However, the role of articulatory phonemic representations and the precentral gyrus in GPC is ambiguous. Though the precentral gyrus is implicated in many functional MRI studies of reading, it is not clear if the time course of activity in this region is consistent with the precentral gyrus being involved in GPC. We recorded cortical electrophysiology during a bimodal match/mismatch task from eight patients with perisylvian subdural electrodes to examine the time course of neural activity during a task which necessitated GPC. Patients made a match/mismatch decision between a three-letter string and the following auditory bi-phoneme. We characterized the distribution and timing of evoked broadband high gamma (BHG; 70–170 Hz) as well as phase-locking between electrodes. The precentral gyrus emerged with a high concentration of broadband high gamma responses to visual and auditory language as well as mismatch effects. The pars opercularis, supramarginal gyrus, and superior temporal gyrus were also involved. The precentral gyrus showed strong phase-locking with the caudal fusiform gyrus during letter-string presentation and with surrounding perisylvian cortex during the bimodal visual-auditory comparison period. These findings hint at a role for precentral cortex in transducing visual into auditory codes during silent reading.

scholarly journals Emotion-Involved Semantic Processing and L2 Vocabulary Memory: A Micro-Level Emotion Manifesto

2017 ◽  
Vol 6 (2) ◽  
pp. 23-30
Author(s):  
Yu Kanazawa ◽  
◽  
Keyword(s):  
Second Language Acquisition ◽  
Foreign Language ◽  
Lexical Decision ◽  
Semantic Processing ◽  
Memory Performance ◽  
Judgment Task ◽  
Foreign Language Anxiety ◽  
Decision Task ◽  
Micro Level ◽  
L2 Vocabulary

Emotion is a pervasive phenomenon whose pivotal impacts on cognition have been proposed and increasingly acknowledged (e.g., operator effect and “(de-)energizing” effect; cf. Ciompi & Panksepp, 2005; Damasio, 2003; LeDoux, 2012). In accordance with this, second language acquisition (SLA) studies have recently seen an “affective turn” (Pavlenko, 2013) and several theories have been proposed and studies conducted concerning the effect of affect in SLA from such perspectives as motivation (Dörnyei & Ushioda, 2011), foreign language anxiety/enjoyment (Dewaele & MacIntyre, 2016), Directed Motivational Currents (Dörnyei, Henry, & Muir, 2016), and emotional intelligence (Gregersen & MacIntyre, 2017; Kanazawa, 2016b). The purpose of the experiments was to examine whether emotion-involved semantic processing (EmInvSemProc) results in better incidental L2 memory performance compared to other types of semantic processing (viz., a lexical decision task [LDT] for Experiment A and an imageability judgment task [IJT] for Experiment B).

scholarly journals Including measures of high gamma power can improve the decoding of natural speech from EEG

2019 ◽  
Author(s):  
Shyanthony R. Synigal ◽  
Emily S. Teoh ◽  
Edmund C. Lalor
Keyword(s):  
Brain Imaging ◽  
Neural Activity ◽  
Speech Processing ◽  
Signal To Noise Ratio ◽  
Low Frequency ◽  
Natural Speech ◽  
Low Frequencies ◽  
High Gamma ◽  
Gamma Power ◽  
Speech Tracking

ABSTRACTThe human auditory system is adept at extracting information from speech in both single-speaker and multi-speaker situations. This involves neural processing at the rapid temporal scales seen in natural speech. Non-invasive brain imaging (electro-/magnetoencephalography [EEG/MEG]) signatures of such processing have shown that the phase of neural activity below 16 Hz tracks the dynamics of speech, whereas invasive brain imaging (electrocorticography [ECoG]) has shown that such rapid processing is even more strongly reflected in the power of neural activity at high frequencies (around 70-150 Hz; known as high gamma). The aim of this study was to determine if high gamma power in scalp recorded EEG carries useful stimulus-related information, despite its reputation for having a poor signal to noise ratio. Furthermore, we aimed to assess whether any such information might be complementary to that reflected in well-established low frequency EEG indices of speech processing. We used linear regression to investigate speech envelope and attention decoding in EEG at low frequencies, in high gamma power, and in both signals combined. While low frequency speech tracking was evident for almost all subjects as expected, high gamma power also showed robust speech tracking in a minority of subjects. This same pattern was true for attention decoding using a separate group of subjects who undertook a cocktail party attention experiment. For the subjects who showed speech tracking in high gamma power, the spatiotemporal characteristics of that high gamma tracking differed from that of low-frequency EEG. Furthermore, combining the two neural measures led to improved measures of speech tracking for several subjects. Overall, this indicates that high gamma power EEG can carry useful information regarding speech processing and attentional selection in some subjects and combining it with low frequency EEG can improve the mapping between natural speech and the resulting neural responses.

Reward-Associated Gamma Oscillations in Ventral Striatum Are Regionally Differentiated and Modulate Local Firing Activity

2010 ◽  
Vol 103 (3) ◽  
pp. 1658-1672 ◽  
Author(s):  
Tobias Kalenscher ◽  
Carien S. Lansink ◽  
Jan V. Lankelma ◽  
Cyriel M. A. Pennartz
Keyword(s):  
Ventral Striatum ◽  
Phase Locking ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Reward Processing ◽  
Temporal Organization ◽  
Gamma Activity ◽  
Neural Ensembles ◽  
Gamma Range ◽  
Gamma Power

Oscillations of local field potentials (LFPs) in the gamma range are found in many brain regions and are supposed to support the temporal organization of cognitive, perceptual, and motor functions. Even though gamma oscillations have also been observed in ventral striatum, one of the brain's most important structures for motivated behavior and reward processing, their specific function during ongoing behavior is unknown. Using a movable tetrode array, we recorded LFPs and activity of neural ensembles in the ventral striatum of rats performing a reward-collection task. Rats were running along a triangle track and in each round collected one of three different types of rewards. The gamma power of LFPs on subsets of tetrodes was modulated by reward-site visits, discriminated between reward types, between baitedness of reward locations and was different before versus after arrival at a reward site. Many single units in ventral striatum phase-locked their discharge pattern to the gamma oscillations of the LFPs. Phase-locking occurred more often in reward-related than in reward-unrelated neurons and LFPs. A substantial number of simultaneously recorded LFPs correlated poorly with each other in terms of gamma rhythmicity, indicating that the expression of gamma activity was heterogeneous and regionally differentiated. The orchestration of LFPs and single-unit activity by way of gamma rhythmicity sheds light on the functional architecture of the ventral striatum and the temporal coordination of ventral striatal activity for modulating downstream areas and regulating synaptic plasticity.

Semantic processing in the neglected visual field: Evidence from a lexical decision task

1993 ◽  
Vol 10 (1) ◽  
pp. 79-108 ◽  
Author(s):  
Regina McGlinchey-berroth ◽  
William P. Milberg ◽  
Mieke Verfaellie ◽  
Michael Alexander ◽  
Patrick T. Kilduff
Keyword(s):  
Visual Field ◽  
Lexical Decision ◽  
Lexical Decision Task ◽  
Semantic Processing ◽  
Decision Task ◽  
Field Evidence

Phasic basal ganglia activity associated with high-gamma oscillation during sleep in a songbird

2012 ◽  
Vol 107 (1) ◽  
pp. 424-432 ◽  
Author(s):  
Shin Yanagihara ◽  
Neal A. Hessler
Keyword(s):  
Basal Ganglia ◽  
Phase Locking ◽  
Critical Role ◽  
Field Potential ◽  
Vocal Plasticity ◽  
Song System ◽  
Gamma Frequency ◽  
High Gamma ◽  
Area X

The basal ganglia is thought to be critical for motor control and learning in mammals. In specific basal ganglia regions, gamma frequency oscillations occur during various behavioral states, including sleeping periods. Given the critical role of sleep in regulating vocal plasticity of songbirds, we examined the presence of such oscillations in the basal ganglia. In the song system nucleus Area X, epochs of high-gamma frequency (80–160 Hz) oscillation of local field potential during sleep were associated with phasic increases of neural activity. While birds were awake, activity of the same neurons increased specifically when birds were singing. Furthermore, during sleep there was a clear tendency for phase locking of spikes to these oscillations. Such patterned activity in the sleeping songbird basal ganglia could play a role in off-line processing of song system motor networks.

scholarly journals Oscillatory Correlates of Retrieval-induced Forgetting in Recognition Memory

2009 ◽  
Vol 21 (5) ◽  
pp. 976-990 ◽  
Author(s):  
Bernhard Spitzer ◽  
Simon Hanslmayr ◽  
Bertram Opitz ◽  
Axel Mecklinger ◽  
Karl-Heinz Bäuml
Keyword(s):  
Retrieval Practice ◽  
Time Window ◽  
Phase Locking ◽  
Memory Representation ◽  
Late Time ◽  
Alpha Power ◽  
Theta Power ◽  
Beneficial Effects ◽  
Gamma Power ◽  
Induced Forgetting

Retrieval practice on a subset of previously studied material enhances later memory for practiced material but can inhibit memory for related unpracticed material. The present study examines the effects of prior retrieval practice on evoked (ERPs) and induced (oscillatory power) measures of electrophysiological activity underlying recognition of practiced and unpracticed words. Compared to control material, recognition of unpracticed words was characterized by reduced amplitudes of the P2 ERP component and by reduced early (200–400 msec) oscillatory theta power. The reduction in P2 amplitude was associated with decreased evoked theta power but not with decreased theta phase locking (phase-locking index). Recognition of unpracticed material was further accompanied by a reduction in occipital gamma power (>250 msec). In contrast, the beneficial effects of retrieval practice on practiced words were reflected by larger parietal ERP positivity (>500 msec) and by a stronger decrease in oscillatory alpha power in a relatively late time window (>700 msec). The results suggest that the beneficial and detrimental effects of retrieval practice are mediated by different processes. In particular, they suggest that reduced theta (4–7 Hz) and gamma (60–90 Hz) power reflect the specific effects of inhibitory processes on the unpracticed material's memory representation.

scholarly journals Faulty Suppression of Irrelevant Material in Patients with Thought Disorder Linked to Attenuated Frontotemporal Activation

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
S. M. Arcuri ◽  
M. R. Broome ◽  
V. Giampietro ◽  
E. Amaro ◽  
T. T. J. Kircher ◽  
...  
Keyword(s):  
Language Processing ◽  
Semantic Processing ◽  
Event Related Potential ◽  
Thought Disorder ◽  
Decision Task ◽  
Formal Thought Disorder ◽  
Specific Effects ◽  
Semantic Decision ◽  
Semantic Decision Task ◽  
Schizophrenic Patients

Formal thought disorder is a feature schizophrenia that manifests as disorganized, incoherent speech, and is associated with a poor clinical outcome. The neurocognitive basis of this symptom is unclear but it is thought to involve an impairment in semantic processing classically described as a loosening of meaningful associations. Using a paradigm derived from the n400 event-related, potential, we examined the extent to which regional activation during semantic processing is altered in schizophrenic patients with formal thought disorder. Ten healthy control and 18 schizophrenic participants (9 with and 9 without formal thought disorder) performed a semantic decision sentence task during an event-related functional magnetic resonance imaging experiment. We employed analysis of variance to estimate the main effects of semantic congruency and groups on activation and specific effects of formal thought disorder were addressed using post-hoc comparisons. We found that the frontotemporal network, normally engaged by a semantic decision task, was underactivated in schizophrenia, particularly in patients with FTD. This network is implicated in the inhibition of automatically primed stimuli and impairment of its function interferes with language processing and contributes to the production of incoherent speech.

Semantic Processing of Foveally and Parafoveally Presented Words in a Lexical Decision Task

1992 ◽  
Vol 45 (2) ◽  
pp. 299-322 ◽  
Author(s):  
Luis J. Fuentes ◽  
Pío Tudela
Keyword(s):  
Visual Field ◽  
Lexical Decision ◽  
Lexical Decision Task ◽  
Semantic Processing ◽  
Stimulus Onset ◽  
Decision Task ◽  
Inhibitory Effects ◽  
Target Stimulus Onset Asynchrony ◽  
Onset Asynchrony ◽  
Prime Target

Using a lexical decision task in which two primes appeared simultaneously in the visual field for 150 msec followed by a target word, two experiments examined semantic priming from attended and unattended primes as a function of both the separation between the primes in the visual field and the prime-target stimulus-onset asynchrony (SOA). In the first experiment significant priming effects were found for both the attended and unattended prime words, though the effect was much greater for the attended words. In addition, and also for both attention conditions, priming showed a tendency to increase with increasing eccentricity (2.3°, 3.3°, and 4.3°) between the prime words in the visual field at the long (550 and 850 msec) but not at the short (250 msec) prime-target SOA. In the second experiment the prime stimuli were either two words (W-W) or one word and five Xs (W-X). We manipulated the degree of eccentricity (2° and 3.6°) between the prime stimuli and used a prime-target SOA of 850 msec. Again significant priming was found for both the attended and unattended words but only the W-W condition showed a decrement in priming as a function of the separation between the primes; this decrement came to produce negative priming for the unattended word at the narrow (2°) separation. These results are discussed in relation to the semantic processing of parafoveal words and the inhibitory effects of focused attention.

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