Abstract #2341

Decreased Cerebral Blood Volume and Flow in Areas with Negative BOLD Indicates the Mechanism for Negative BOLD May Be Stimulus- And Area-Specific

Jozien Goense¹, Yvette Bohraus¹, Nikos K. Logothetis¹,²

¹Dept. Physiology of Cognitive Processes, Max-Planck Institute for Biological Cybernetics, Tuebingen, Germany; ²Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, United Kingdom

In earlier work, we showed increased CBV in regions with negative BOLD responses. This seems to disagree with work in cats where CBV was decreased in areas with negative BOLD. Here, we used a full-field checkerboard stimulus and show decreased CBV and CBF in areas that show negative BOLD responses. However, this type of negative BOLD signals occurred in peripheral V1 and extrastriate visual cortex. Our results suggest that different mechanisms for negative BOLD exist and that these may be area-dependent.