Separate, Causal Roles of the Caudate in Saccadic Choice and Execution in a Perceptual Decision Task

Department of Neuroscience, University of Pennsylvania, Philadelphia, PA 19104, USA.
Neuron (Impact Factor: 15.05). 09/2012; 75(5):865-74. DOI: 10.1016/j.neuron.2012.07.021
Source: PubMed


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:

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    • "fMRI studies also show that compared to non-food-related pictures, food-related pictures activate the striatum [92] in healthy individuals. Consistent with this finding, we observed right striatum activation when responses to high-calorie food pictures were compared to responses to low-calorie food pictures, although previous studies showed that the dorsal striatum is not strictly dedicated to habit behaviors, and that it can be involved in decision-making [28, 82, 93–95]. Animal studies also have shown that direct pharmacological activation of the striatum, amygdalo-hypothalamic circuit produced hyperphagia and increased preferentially the intake of foods high in fat and sugar, even in animals fed beyond apparent satiety [96]. "
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    • "The oculomotor loop caudate neurons in this region are sensitive to many of the same factors as LIP and FEF (Watanabe and Munoz, 2013). Ding and Gold (2010, 2012, 2013) found that multiple relevant variables for perceptual decision making were coded for in the body of the caudate, including cells sensitive to information accumulation, decision threshold, and bias before actual stimulus toward a left or right saccade. Harsay et al. (2011) have examined the system in humans, and found that functional connectivity between the cortical oculomotor regions and caudate predicts learning in a saccade task. "
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