Previous human brain imaging studies have revealed multiple cortical and subcortical areas that are activated when decision uncertainty is linked to outcome probability. However, the neural mechanisms of uncertainty modulation in different perceptual decision tasks have not been systematically investigated. Uncertainty of perceptual decision can

originate either from highly ABT-263 manufacturer similar object categories (e.g. tasks based on criterion comparison) or from noise being added to visual stimuli (e.g. tasks based on signal detection). In this study, we used functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms of task-dependent modulation of uncertainty in the human brain during perceptual judgements.

We observed correlations between uncertainty levels and fMRI activity in a network of areas responsible for performance monitoring and sensory evidence comparison in both tasks. These areas are associated with late stages of perceptual decision, and include the posterior medial frontal cortex, dorsal lateral prefrontal cortex, and intraparietal sulcus. When the modulation of uncertainty on the two tasks was compared, dissociable cortical networks were identified. Uncertainty in the criterion comparison task modulated activity in the left lateral prefrontal cortex Protein kinase N1 related to rule retrieval.

In the signal detection task, uncertainty modulated activity in higher see more visual processing areas thought to be sensory information ‘accumulators’ that are active during early stages of perceptual decision. These findings offer insights into the mechanism of information processing during perceptual decision-making. “
“Specific motor symptoms of Parkinson’s disease (PD) can be treated effectively with direct electrical stimulation of deep nuclei in the brain. However, this is an invasive procedure, and the fraction of eligible patients is rather low according to currently used criteria. Spinal cord stimulation (SCS), a minimally invasive method, has more recently been proposed as a therapeutic approach to alleviate PD akinesia, in light of its proven ability to rescue locomotion in rodent models of PD. The mechanisms accounting for this effect are unknown but, from accumulated experience with the use of SCS in the management of chronic pain, it is known that the pathways most probably activated by SCS are the superficial fibers of the dorsal columns. We suggest that the prokinetic effect of SCS results from direct activation of ascending pathways reaching thalamic nuclei and the cerebral cortex. The afferent stimulation may, in addition, activate brainstem nuclei, contributing to the initiation of locomotion.