Carlson (ARC Future Fellow, Department of Cognitive ScienceMacquarie University)
WHEN: Thursday 10th October 12-1pm
WHERE: AVLG17, Aviation Building, Callaghan Campus
Also videoconferenced to Ourimbah E1.32.
TITLE: Object representations in the human brain: How they
emerge, and their connection to semantic knowledge and
perceptual decision-making
ABSTRACT: Our capacity to recognize visual objects is mediated
by multiple visual areas, in particular inferior temporal cortex
(ITC). Recent technological and methodological advancements have
afforded researchers the capacity to measure the complex
geometrical structure of brain representations. In this talk, I
will describe several studies that examine how the structure of
object representations emerges in the brain, and how this
structure relates to behavior. I will first describe experiments
that use brain decoding methods and magnetoencephalography (MEG)
to study the emergence of object category structure. Our findings
suggest that hierarchical category structure (e.g. human face is
a member of the superordinate category human) is a process of
accumulating evidence in which categories solidified at early
stages of processing inform more abstract category representations
that emerge later. I will then describe two studies that examine correspondences between the structure of object representations in
human ITC and human word usage patterns and decision-making
behavior. These studies show that the structure of object
representations in ITC correlate with human word usage patterns in
language; and ITC’s representational structure predicts reaction
times for object categorization. These studies collectively provide
an important link between the geometry of brain representations and
functional behavior.
