Journal: The Journal of Neuroscience

Article Title: Large Visual Stimuli Induce Two Distinct Gamma Oscillations in Primate Visual Cortex

doi: 10.1523/JNEUROSCI.2270-17.2017

Figure Lengend Snippet: Slow and fast gamma oscillations in human EEG. A , Change in time–frequency power spectrum from baseline (−0.5–0 s) for an example subject (S1). Power is averaged across three bipolar pairs in the left occipital and parietal area, shown as black dots (encircled and pointed by an arrow) in B . B , Scalp maps for slow and fast gamma ranges for stimulus orientation of 45° (highlighted with a black box in A ). Similar time–frequency difference spectra and scalp maps for the rest of the subjects is shown in . C , Change in power from baseline for nine orientations for S1. D , E , Preferred orientations ( D ) and orientation selectivity ( E ) for slow and fast gamma rhythms for 12 human subjects, monkey EEG (2 sites per monkey) and monkey LFP (65 and 34 sites). Different symbols in D and E indicate statistical significance for orientation selectivity (calculated from original data) compared against randomly permuted data (see “Statistical analysis” section in Materials and Methods for details) for slow and fast gamma (as indicated above D ). Significance level (α) is Bonferroni corrected (from 0.05) for number of human subjects or electrodes (for monkeys). shows results for orientation tuning after data containing microsaccades are discarded from analysis.

Article Snippet: We recorded monkey LFP in area V1 using chronic arrays (96 microelectrodes, Utah array, Blackrock Microsystems) from two monkeys and human EEG (64 active electrodes, BrainAmp DC, Brain Products) from 15 healthy young adults while presenting full-screen sinusoidal grating stimuli.

Techniques:

Journal: The Journal of Neuroscience

Article Title: Large Visual Stimuli Induce Two Distinct Gamma Oscillations in Primate Visual Cortex

doi: 10.1523/JNEUROSCI.2270-17.2017

Figure Lengend Snippet: Tuning for contrast and spatial frequency. A , Mean change in power for two gamma bands as a function of stimulus contrast for 65 and 36 sites for the two monkeys (top row) calculated at stimulus orientations that induced largest power change in fast gamma (90° for both monkeys) and slow gamma (0° and 45°). B , Same as A but for two EEG electrodes for each of the two monkeys. C , Mean change in power for 12 human subjects computed for a stimulus orientation that induced robust gamma in both bands (shown in a thick black box in A and . D – F , Mean peak gamma frequency in slow and fast bands. Same format as in A – C . G – I , Spatial frequency tuning for 65 and 34 sites in the two monkeys ( G ), two EEG electrodes each for the two monkeys ( H ), and 12 human subjects ( I ). shows change in power spectra for contrast and spatial frequency tuning experiments.

Article Snippet: We recorded monkey LFP in area V1 using chronic arrays (96 microelectrodes, Utah array, Blackrock Microsystems) from two monkeys and human EEG (64 active electrodes, BrainAmp DC, Brain Products) from 15 healthy young adults while presenting full-screen sinusoidal grating stimuli.

Techniques:

Journal: The Journal of Neuroscience

Article Title: Large Visual Stimuli Induce Two Distinct Gamma Oscillations in Primate Visual Cortex

doi: 10.1523/JNEUROSCI.2270-17.2017

Figure Lengend Snippet: Field–field and spike–field coherence. A , LFP–LFP phase coherence spectra for different interelectrode distances for Monkeys 1 (top row) and 2 (bottom row). Interelectrode distance ranges (d, in μm) are shown in B . The number of pairs ( N ) for each group is indicated on the top right corner. LFP–LFP phase coherence when both are taken from the same electrode (i.e., interelectrode distance of zero) is trivially 1 at all frequencies and is therefore omitted. Mean LFP–EEG phase coherence is shown in black. B , Average LFP–LFP phase coherence at the peak slow (32 and 36 Hz for the two monkeys) and fast gamma bands (62 and 56 Hz) as a function of interelectrode distance. C , Mean spike–LFP coherence for spike–LFP pairs separated by different interelectrode distances. Mean spike-EEG coherence is shown in black.

Article Snippet: We recorded monkey LFP in area V1 using chronic arrays (96 microelectrodes, Utah array, Blackrock Microsystems) from two monkeys and human EEG (64 active electrodes, BrainAmp DC, Brain Products) from 15 healthy young adults while presenting full-screen sinusoidal grating stimuli.

Techniques: