Positive and Negative Somatotopic BOLD Responses in Contralateral Versus Ipsilateral Penfield Homunculus.

ABSTRACT: One of the basic properties of sensory cortices is their topographical organization. Most imaging studies explored this organization using the positive blood oxygenation level-dependent (BOLD) signal. Here, we studied the topographical organization of both positive and negative BOLD in contralateral and ipsilateral primary somatosensory cortex (S1). Using phase-locking mapping methods, we verified the topographical organization of contralateral S1, and further showed that different body segments elicit pronounced negative BOLD responses in both hemispheres. In the contralateral hemisphere, we found a sharpening mechanism in which stimulation of a given body segment triggered a gradient of activation with a significant deactivation in more remote areas. In the ipsilateral cortex, deactivati

SUBMITTER: Tal Z 

PROVIDER: S-EPMC6093432 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature