Separate, Causal Roles of the Caudate in Saccadic Choice and Execution in a Perceptual Decision Task
ABSTRACT In contrast to the well-established roles of the striatum in movement generation and value-based decisions, its contributions to perceptual decisions lack direct experimental support. Here, we show that electrical microstimulation in the monkey caudate nucleus influences both choice and saccade response time on a visual motion discrimination task. Within a drift-diffusion framework, these effects consist of two components. The perceptual component biases choices toward ipsilateral targets, away from the neurons' predominantly contralateral response fields. The choice bias is consistent with a nonzero starting value of the diffusion process, which increases and decreases decision times for contralateral and ipsilateral choices, respectively. The nonperceptual component decreases and increases nondecision times toward contralateral and ipsilateral targets, respectively, consistent with the caudate's role in saccade generation. The results imply a causal role for the caudate in perceptual decisions used to select saccades that may be distinct from its role in executing those saccades. VIDEO ABSTRACT:
- Journal of Cognitive Neuroscience · 4.69 Impact Factor
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ABSTRACT: Our visual system has limited resources, which need to be allocated in priority to the most relevant elements of the environment. The brain centers of this allocation mechanism, called visual attention, have been studied primarily in cortex. In this review, we describe the role of the superior colliculus, a structure of the brainstem, in attention control. This nucleus exerts its influence on visual selection independently of cortical attentional mechanisms. The exact nature of the subcortical circuits involved remains unknown but it can be hypothesized that the loop connecting the superior colliculus to the basal ganglia are a central actor of this subcortical selection process.
Article: Decision makingCurrent opinion in neurobiology 11/2012; 22(6). DOI:10.1016/j.conb.2012.10.003 · 6.77 Impact Factor