Turning Touch into Perception

Abstract

Many brain areas modulate their activity during vibrotactile tasks. The activity from these areas may code the stimulus parameters, stimulus perception, or perceptual reports. Here, we discuss findings obtained in behaving monkeys aimed to understand these processes. In brief, neurons from the somatosensory thalamus and primary somatosensory cortex (S1) only code the stimulus parameters during the stimulation periods. In contrast, areas downstream of S1 code the stimulus parameters during not only the task components but also perception. Surprisingly, the midbrain dopamine system is an actor not considered before in perception. We discuss the evidence that it codes the subjective magnitude of a sensory percept. The findings reviewed here may help us to understand where and how sensation transforms into perception in the brain.

Keywords: behaving monkeys; bimodal sensory coding; conscious sensory experience; decision making; microstimulation; midbrain dopamine system; neural coding; perception; population coding; psychophysics; sensation; sensory and frontal cortices; somatosensory thalamus; working memory.