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OBJECTIVE To define the spatial, temporal, and functional characteristics of induced gamma (>30 Hz) activity during functional activation of the left superior temporal gyrus. METHODS Electrocorticographic (ECoG) recordings were made in 4 clinical subjects during auditory tone and phoneme discrimination tasks, and event-related changes in the ECoG band(More)
It has been shown in animals that neuronal activity in the 'gamma band' (>30 Hz) is associated with cortical activation and may play a role in multi-regional and multi-modal integration of cortical processing. Studies of gamma activity in human scalp EEG have typically focused on event-related synchronization (ERS) in the 40 Hz band. To assess further the(More)
Human scalp EEG studies have shown that event-related desynchronization (ERD) in the alpha (8-13 Hz) and beta (15-25 Hz) bands may be used to detect functional activation of sensorimotor cortex. However, in most previous studies somatotopy has not been examined in detail and brief, self-paced movements, focusing on the planning of motor output, have been(More)
OBJECTIVE To investigate the functional-neuroanatomic substrates of word production using signed versus spoken language. METHODS The authors studied single-word processing with varying input and output modalities in a 38-year-old woman with normal hearing and speech who had become proficient in sign language 8 years before developing intractable epilepsy.(More)
Recent studies using electrocorticographic (ECoG) recordings in humans have shown that functional activation of cortex is associated with an increase in power in the high-gamma frequency range ( approximately 60-200 Hz). Here we investigate the neural correlates of this high-gamma activity in local field potential (LFP). Single units and LFP were recorded(More)
Human intracranial EEG (iEEG) recordings are primarily performed in epileptic patients for presurgical mapping. When patients perform cognitive tasks, iEEG signals reveal high-frequency neural activities (HFAs, between around 40 Hz and 150 Hz) with exquisite anatomical, functional and temporal specificity. Such HFAs were originally interpreted in the(More)
Subdural electrocorticographic (ECoG) recordings in patients undergoing epilepsy surgery have shown that functional activation is associated with event-related broadband gamma activity in a higher frequency range (>70 Hz) than previously studied in human scalp EEG. To investigate the utility of this high gamma activity (HGA) for mapping language cortex, we(More)
The phase of ongoing theta (4-8 Hz) and alpha (8-12 Hz) electrophysiological oscillations is coupled to high gamma (80-150 Hz) amplitude, which suggests that low-frequency oscillations modulate local cortical activity. While this phase-amplitude coupling (PAC) has been demonstrated in a variety of tasks and cortical regions, it has not been shown whether(More)
Neuronal oscillations in the gamma frequency range have been reported in many cortical areas, but the role they play in cortical processing remains unclear. We tested a recently proposed hypothesis that the intensity of sensory input is coded in the timing of action potentials relative to the phase of gamma oscillations, thus converting amplitude(More)
Negative and positive laser evoked potential (LEP) peaks (N2*, P2**) were simultaneously recorded from the primary somatosensory (SI), parasylvian, and medial frontal (MF: anterior cingulate and supplementary motor area) cortical surfaces through subdural electrodes implanted for the surgical treatment of intractable epilepsy. Distribution of the LEP N2*(More)