How rats process natural scenes containing moving objects: Behavioral categorization and neural recordings

Summary

Date: 
November 20, 2014 - 10:30am
Location: 
NW 243
About the Speaker
Name: 
Hans Op de Beeck (University of Leuven)

Very little is known about how rodents process complex visual stimuli such as natural movies at the behavioral and neural level. At the behavioral level, we trained rats in a two-alternative forced choice procedure to categorize natural movies containing a rat versus movies containing another object and scrambled movies. With substantial training the animals were able to learn the category rule and pick the target rat movies, most easily when the distractors were scrambled movies but eventually also against natural non-rat movies. The rats generalized to new, untrained movies. At the neural level, we registered the single-neuron responses to these movies in three cortical areas in naïve rats: primary visual area V1, latero-intermediate area LI, and temporo-occipital area TO. Along this series of areas, the neural population showed an increasing clustering of natural movies versus scrambled movies, but not of rat movies versus nonrat movies. The degree to which neural responses could be predicted by a spatiotemporal motion energy model decreased from V1 to TO. Together, the results suggest that the rats can use relatively complex features at the behavioral level and that such features are encoded in extrastriate areas.