* Visual cortical gamma-band activity during free viewing of natural images.
- Gamma-band activity in visual cortex has been implicated in several cognitive operations, like perceptual grouping and attentional selection. So far, it has been studied primarily under well-controlled visual fixation conditions and using well-controlled stimuli, like isolated bars or patches of grating. If gamma-band activity is to subserve its purported functions outside of the laboratory, it should be present during natural viewing conditions. We recorded neuronal activity with a 252-channel electrocorticographic (ECoG) grid covering large parts of the left hemisphere of 2 macaque monkeys, while they freely viewed natural images. We found that natural viewing led to pronounced gamma-band activity in the visual cortex. In area V1, gamma-band activity during natural viewing showed a clear spectral peak indicative of oscillatory activity between 50 and 80 Hz and was highly significant for each of 65 natural images. Across the ECoG grid, gamma-band activity during natural viewing was present over most of the recorded visual cortex and absent over most remaining cortex. After saccades, the gamma peak frequency slid down to 30-40 Hz at around 80 ms postsaccade, after which the sustained 50- to 80-Hz gamma-band activity resumed. We propose that gamma-band activity plays an important role during natural viewing.
=>役目, 役割, 任務, 職務, 役
Overview of noun role
The noun role has 4 senses (first 4 from tagged texts)
1. (34) function, office, part, role -- (the actions and activities assigned to or required or
expected of a person or group; "the function of a teacher"; "the government must do its part"; "play
its role")
2. (10) character, role, theatrical role, part, persona -- (an actor's portrayal of someone in a
play; "she played the part of Desdemona")
3. (8) function, purpose, role, use -- (what something is used for; "the function of an auger is to
bore holes"; "ballet is beautiful but what use is it?")
4. (6) role -- (normal or customary activity of a person in a particular social setting; "what is
your role on the team?")
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