42nd CiNet Monthly Seminar: Yumiko Yoshimura “Involvement of V1 neurons preferring low-contrast stimuli in orientation discrimination”

CiNet Monthly Seminar

February 21, 2020
CiNet 1F Conference Room

“Involvement of V1 neurons preferring low-contrast stimuli in orientation discrimination”

Yumiko Yoshimura
Division of Visual Information Processing, National Institute for Physiological Sciences

Host : Hiroshi Tamura (Fujita G)

Animals can easily discriminate the visual object repeatedly experienced, even if the contrast of the object becomes vague. We explored the neural mechanism for the improvement of visual discrimination after training. To this end, we conducted multiple single-unit recordings from deep layers in rat primary visual cortex (V1). The head-fixed rats were trained to push or pull a lever depending on stimulus orientations (vertical or horizontal) presented at high contrast. After enough training, we decreased the stimulus contrast to make visual iscrimination more difficult. We found that a part of neurons showed low-contrast preference during task performance, that is, the firing rates increased with a reduction of the stimulus contrast. Interestingly, these low-contrast preferring neurons fired more frequently in correct-choice trials than in error trials. In addition, the low-contrast preference was rarely observed in awake rats before training or in anesthetized rats after training. Thus, the low-contrast preferring neurons that appeared after iterative training may be one of the neural mechanisms for the perception of familiar but vague visual stimulation. In this seminar, I will introduce our unpublished data on low-contrast preference in rat V1. I would like to discuss how low-contrast preferring neurons in V1 are involved in information coding and the accuracy of sensory discrimination.