Evidence suggesting common mechanisms underlie contralateral and ipsilateral negative BOLD responses in the human visual cortex.

ABSTRACT: The task-evoked positive BOLD response (PBR) to a unilateral visual hemi-field stimulation is often accompanied by robust and sustained contralateral as well as ipsilateral negative BOLD responses (NBRs) in the visual cortex. The signal characteristics and the neural and/or vascular mechanisms that underlie these two types of NBRs are not completely understood. In this paper, we investigated the properties of these two types of NBRs. We first demonstrated the linearity of both NBRs with respect to stimulus duration. Next, we showed that the hemodynamic response functions (HRFs) of the two NBRs were similar to each other, but significantly different from that of the PBR. Moreover, the subject-wise expressions of the two NBRs were tightly coupled to the degree that the correlation between th

SUBMITTER: He H 

PROVIDER: S-EPMC9523581 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature