Striatal involvement in visual encoding

A capacity limited system, such as the human brain, needs effective strategies to deal with large amounts of incoming information. The theory of visual attention (TVA) allows for formal quantification of specific processes related to selection and recognition of visual information. In the present model-based fMRI study, parameters derived from the TVA-framework were used to determine trial-by-trial changes in the distribution of attention and to relate these to specific cortical attentional networks. Trial-by-trial changes in the single trial likelihood (STL), an inferred variable representing an element's probability of being encoded into the visual short term memory (VSTM) and thus consciously perceived, were accompanied by changes in activity in the bilateral putamen and a right-lateralized network involving the inferior parietal lobule. Moreover, attentional networks were activated by additional display elements: With higher competition between relevant display elements (i.e., when two targets rather than one target and a distractor were presented), a bilateral dorsal network comprising the frontal eye fields and superior parietal regions was more active. Bilateral temporo-parietal junction and superior frontal regions showed higher activity in the reversed contrast, reflecting distractor-related filtering processes.

We demonstrate that basal ganglia, i.e., the bilateral striatum, are critically involved in the encoding of visual information into the VSTM to a perceptual level of processing. Moreover, we specify the function of the dorsal attention network in resolving competition between equally important display elements, whereas a bilateral ventral network processes imbalances in the distribution of attentional resources.