Spin-L共催　生理学研究所 感覚認知情報研究部門 部門公開セミナー（第18回）を11月13日（木）に開催します。

今回のセミナーでは、MRIを用いてヒト脳における視知覚の神経基盤をクラウディングという現象を通じて明らかにした最新の成果について、マーストリヒト大学のJan W Kurzawski先生にご講演いただくことになりました。
本セミナーは、オンライン形式で開催いたします。
所外の方におかれましても、ご関心のある方は奮ってご参加ください。皆様のご参加をお待ちしております。

In this seminar, Dr. Jan W. Kurzawski from Maastricht University will present the latest findings on the neural basis of visual perception in the human brain, as revealed through the phenomenon of crowding using MRI. We encourage all interested individuals to attend.

Human V4 size predicts crowding distance

Jan W Kurzawski, Ph.D (Assistant Professor, Maastricht University, Netherlands)

Visual recognition is limited by both object size (acuity) and spacing. The spacing limit, called “crowding”, is the failure to recognize an object in the presence of other objects. Here, we take advantage of individual differences in crowding to investigate its biological basis. Crowding distance, the minimum object spacing needed for recognition, varies 2-fold among healthy adults. We test the conjecture that this variation in psychophysical crowding distance is due to variation in cortical map size. To test this, we make paired measurements of brain and behavior in 49 observers. We use psychophysics to measure crowding distance and calculate λ, the number of letters that fit into each observer’s visual field without crowding. In the same observers, we use functional magnetic resonance imaging (fMRI) to measure the surface area of retinotopic maps V1, V2, V3, and V4. Across observers, λ is proportional to the surface area of V4 but is uncorrelated with the surface area of V1 to V3. The proportional relationship of λ to area of V4 indicates conservation of cortical crowding distance across individuals: letters can be recognized if they are spaced by at least 1.4 mm on the V4 map, irrespective of map size and psychophysical crowding distance. We conclude that the size of V4 predicts the spacing limit of visual perception.