Event-related functional MRI of cortical activity evoked by microsaccades, small visually-guided saccades, and eyeblinks in human visual cortex.

ABSTRACT: We used event-related functional magnetic resonance imaging (fMRI) to determine blood oxygen-level-dependent (BOLD) signal changes following microsaccades, visually-guided saccades, and eyeblinks in retinotopically mapped visual cortical areas V1-V3 and hMT+. A deconvolution analysis revealed a similar pattern of BOLD activation following a microsaccade, 0.16 degrees voluntary saccade, and 0.16 degrees displacement of the image under conditions of fixation. In all areas, an initial increase in BOLD signal peaking at approximately 4.5 s after the event was followed by a decline and decrease below baseline. This modulation appears most pronounced for microsaccades and small voluntary saccades in V1, diminishing in strength from V1 to V3. In contrast, 0.16 degrees real motion under conditions

SUBMITTER: Tse PU 

PROVIDER: S-EPMC2764842 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature