On thursday the 20th of April, Barbara Nordhjem will give a talk on changes in V1 response maps following object recognition.
Bio
Barbara Nordhjem (Denmark, 1983) is a researcher specializing in visual perception and neuroscience. She studied Psychology at Aalborg University (DK) and graduated with a master degree in Cognitive Neuroscience from the University of Leiden (NL). Her journey into vision science started during a research project at the Laboratory of Neurobiology at University College London. Afterwards, Barbara did her PhD in the Visual Neuroscience group of the Laboratory of Experimental Ophthalmology at the University Medical Centre in Groningen (NL). Her scientific research focuses on visual recognition and uses behavioral, eye tracking and neuroimaging techniques. She is interested in vision as an interpretive process and often uses stimuli that take time to recognize or that can be experienced in different ways.
Abstract
Changes in V1 response maps following object recognition
Comprehending the world necessitates the reliable and efficient segmenting of complex visual scenes into coherent objects that can be acted upon. This requires the integration of sensory data and information on behavioral relevance. In the present fMRI study, we test the hypothesis that V1 represents priority by evaluating its response during an object recognition task. Participants viewed emerging images – similar to the famous Gestalt image of a Dalmatian – for which the recognition process is extended. For such stimuli, the percept changes dramatically within a trial, even though the physical stimulus remains the same. Therefore, our paradigm provides insight into the neuronal responses associated with recognition. For the analysis, we developed a methodological approach combining population receptive field (pRF) mapping with BOLD responses to chart spatially detailed maps of cortical activity. For many active pRFs, the responses were modulated following recognition, despite the physical stimulus remaining the same. A possible explanation for such changes is that V1 activity represents priority rather than just the visual input.