The role of a shape-centred representations in the perception of complex shapes

Abstract

I further develop the Vannuscorps et al. [(2021). Shape-centered representations of bounded regions of space mediate the perception of objects. Cognitive neuropsychology, 1-50.] interpretation of Davida's deficit, as based on a failure of mapping information carried by the parvocellular pathway onto non-retinotopic coordinates. I assumed that magno-parvo cooperation is required to bind local features into 2-D shapes with sharp edges, although the relative role of either subsystem may depend on the task. My suggestion is that perception is un impaired when the imbalance is in favour of the magno system; that is, with images blurred or made up of either disconnected elements or isolated line segments not requiring binding. Conversely, misperception occurs when the task involves an imbalance in favour of parvo analysis; i.e., when orientation judgment is based mainly on the highest levels of parvo analysis devoted to binding in the ventral stream. In these last conditions, Davida's misperception of orientation of these 2-D shapes may result from a switch of magno-parvo cooperation to conflict.

Keywords: Shape representation; magno-parvo cooperation; magnocellular system; spatial frequency.