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Shorter latencies for motion trajectories than for flashes in population responses of cat primary visual cortex
Author(s) -
Jancke Dirk,
Erlhagen Wolfram,
Schöner Gregor,
Dinse Hubert R.
Publication year - 2004
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2003.058941
Subject(s) - receptive field , stimulus (psychology) , population , visual cortex , motion perception , visual field , neuroscience , computer vision , physics , artificial intelligence , communication , psychology , computer science , motion (physics) , cognitive psychology , medicine , environmental health
Psychophysical evidence in humans indicates that localization is different for stationary flashed and coherently moving objects. To address how the primary visual cortex represents object position we used a population approach that pools spiking activity of many neurones in cat area 17. In response to flashed stationary squares (0.4 deg) we obtained localized activity distributions in visual field coordinates, which we referred to as profiles across a ‘population receptive field’ (PRF). We here show how motion trajectories can be derived from activity across the PRF and how the representation of moving and flashed stimuli differs in position. We found that motion was represented by peaks of population activity that followed the stimulus with a speed‐dependent lag. However, time‐to‐peak latencies were shorter by ∼16 ms compared to the population responses to stationary flashes. In addition, motion representation showed a directional bias, as latencies were more reduced for peripheral‐to‐central motion compared to the opposite direction. We suggest that a moving stimulus provides ‘preactivation’ that allows more rapid processing than for a single flash event.