Ipsilateral fMRI Response in Primary Somatosensory Cortex (Area 3b) of Awake Marmosets

Junjie V. Liu¹, Matthew Huberty¹, Afonso C. Silva¹

We conducted systematic measurements of BOLD fMRI responses to unilateral electrical stimulation, in both the contralateral and the ipsilateral primary somatosensory cortex (SI) of awake non-human primates (marmosets). Taking advantage of T1 mapping co-registered with fMRI, we found many interesting differences between the responses in low-T1 and high-T1 regions within area 3b of SI, specifically regarding to their relationships with stimulus frequency, duration and intensity. Because T1 is correlated with density of thalamic inputs, with our results the ipsilateral SI responses driven mainly by corticocortical neural inputs can be distinguished from the contralateral SI responses driven mainly by thalamic inputs.