Location specificity in response selection processes for visual stimuli

An fMRI study of human visual cortex in response to spatiotemporal properties of visual stimuli

  ABSTRACT  Background: The brain response to temporal frequencies (TF) has been already reported, but with no study reported for different TF with respect to various spatial frequencies (SF).  Materials and Methods: fMRI was performed by 1.5T GE-system in 14 volunteers during checkerboard, with TFs of 4, 6, 8 and 10Hz in low and high SFs of 0.5 and 8cpd.  Results: Average percentage BOLD signa...

an fmri study of human visual cortex in response to spatiotemporal properties of visual stimuli

abstract  background: the brain response to temporal frequencies (tf) has been already reported, but with no study reported for different tf with respect to various spatial frequencies (sf).  materials and methods: fmri was performed by 1.5t ge-system in 14 volunteers during checkerboard, with tfs of 4, 6, 8 and 10hz in low and high sfs of 0.5 and 8cpd.  results: average percentage bold signal ...

Overt Selection and Processing of Visual Stimuli

To see is to act. Most obviously, we are continuously scanning different regions of the world with the movement of our eyes, head, and body. These overt movements are intrinsically linked to two other, more subtle, actions: (1) the prior process of deciding where to look; and (2) the prediction of the sensory consequences of overt movements. In this thesis I describe a series of experiments tha...

Visual Cortex and Control Processes Stimuli in Opposite Visual Fields: Effects on Human On-Line Attentional Selection From Competing

On-line attentional selection from competing stimuli in opposite visual fields: effects on human visual cortex and control processes.

We used fMRI to investigate competition and on-line attentional selection between targets and distractors in opposite visual hemifields. Displays comprised a high-contrast square-wave grating, defined as target by its orientation, presented alone (unilateral) or with a similar distractor of orthogonal orientation in the opposite hemifield (bilateral displays). The target appeared unpredictably ...