B5 - Linking attention and decision signals in the macaque mid-level visual cortex

We will investigate how signals in the mid-level visual cortex in both the ventral and dorsal stream of the visual processing hierarchy are used to support perceptual decisions in different behavioural contexts. Insights into perceptual decision-making and into the top-down attentional selection of visual signals have largely been gained via separate lines of research using different behavioural paradigms. While studies of perceptual decision-making have been dominated by variants of the classical two-alternative direction-discrimination task (Newsome et al. 1989), studies of selective visual attention have heavily relied on visual search (Bichot et al. 2005) or detection tasks e.g. (Treue & Maunsell 1996, Fries et al. 2001) that are well suited to isolate neuronal correlates of attentional selection. As a consequence, theoretical accounts of perceptual decision-making have long ignored the role played by top-down cognitive factors on sensory processing. To combine the detailed insights from studies of top-down visual attention with the formalisms and theoretical accounts of perceptual decision-making, we will combine a classical perceptual decision paradigm (a two-alternative discrimination task) with a classical spatial attention paradigm. This will allow us to test strong predictions derived directly from empirical findings of top-down feature selective attention (Aim 1), and to explore theoretical accounts of spatial attention in the context of classical perceptual decision making paradigms (Aim 2). Together, this project promises to elucidate general principles of how the brain encodes information in sensory population in different behavioural contexts and decodes it to guide behaviour.