Date on Master's Thesis/Doctoral Dissertation

8-2015

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Psychological and Brain Sciences

Degree Program

Experimental Psychology, PhD

Committee Chair

Petry, Heywood

Committee Co-Chair (if applicable)

Stilp, Chrisitan

Committee Member

Stilp, Chrisitan

Committee Member

Bickford, Martha

Committee Member

DeMarco, Paul

Committee Member

Zahorik, Pavel

Subject

Tupaiidae; Visual perception

Abstract

Visual neuroscience research has benefitted from decades of efforts of comparative studies of different species, since exploring and understanding the diversity of functional properties of visual system in different species has helped us identify both general organization rules and unique traits of certain species. In this study, spatio-temporal receptive fields (STRFs), together with some other functional properties (etc. stimulus preference to different visual stimuli, orientation tuning, temporal frequency tuning and the F1/F0 ratio of responses to sine-wave grating stimuli), of primary visual cortex (V1) cells were measured in normally reared and red-light reared tree shrews (Tupaia), a species considered the closest non-primate relative to human being. All data were sampled in anesthetized animals using extracellular recording techniques. In the current study, a diversity of STRFs structures were found in tree shrew V1, and the STRFs found were classified into two categories, Type I receptive fields (RFs) that had spatially discontinuous on- and off-regions, or had spatio-temporal inseparable RFs, and Type II RFs that had spatially overlapped circular or elliptical on- and off- regions, and spatio-temporal separable RFs. Spatial and temporal profile analysis indicated this Type I and Type II classification did not correspond to simple and complex RF types previously described in primates and carnivores. It was also found in the current study that the linear prediction based on STRFs did not predict temporal frequency tuning, orientation tuning or the F1/F0 ratio very well in tree shrew V1. In tree shrew V1, both low-pass and band-pass cells for temporal frequency were found, and the proportion of cells with different types of tuning curves also differed across layers, resulting in a low-pass filter between layer II/II and layer IV. Last but not least, it was found in this study that red light rearing after birth changes the population stimulus preference in layer IV in tree shrew V1.

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