Main Lab Location：Osaka Univ. (Suita Campus)
Mailing Address：1-3 Yamadaoka, Suita City Osaka, 565-0871
Email：kitazawa at fbs.osaka-u.ac.jp
My research in CiNet focuses on neural basis for space and time perception.
Space and time that we perceive in our mind are, of course, based on the counterparts in the physical world, but it remains still unknown exactly how the mental space and mental time are constructed in our brain.
Take the mental space for example. We swing our eyes three times a second on average, with a peak angular velocity as fast as 100-500 degrees/s. But the world in our mind are so stable that we do not even notice our own eye movements. Why do blurred images on the retina not appear in our conscious mind? What are we looking at, while the blurred retinal images are blocked from our mind? How are two distinct retinal images, one before and the other after the rapid eye movement, mapped to the same part in the mental space? As for the mental time, it does not flow equably as hypothesized in physics. For example, subjective temporal order of successive stimuli are inverted just by crossing our arms, or just before the onset of each rapid eye movement. A key word for solving these problems is “postdiction”, a notion that the mental space and the mental time are constructed by our brain from sensory signals sampled over the past ~100 ms by combining information across multiple areas in the brain. We are searching for the neural basis of “postdiction” by applying techniques in psychophysics and neuroimaging to human participants, and neurophysiological techniques to monkeys.
Why the world remains stable while we move our eyes has been repeatedly questioned by great thinkers like Alhazen, Descartes, and Helmholtz, for more than 1000 years at least. We hope that our research would ultimately yield final answers to the long-lasting historical question, in addition to other important questions regarding the mental space, time, and their interactions.
Uchimura, M. & Kitazawa, S. Cancelling prism adaptation by a shift of background: a novel utility of allocentric coordinates for extracting motor errors. J Neurosci 33, 7595-602 (2013).
Takahashi, T., Kansaku, K., Wada, M., Shibuya, S. & Kitazawa, S. Neural correlates of tactile temporal-order judgment in humans: an fMRI study. Cereb Cortex 23, 1952-64 (2013).
Miyazaki, M., Yamamoto, S., Uchida, S. & Kitazawa, S. Bayesian calibration of simultaneity in tactile temporal order judgment. Nat Neurosci 9, 875-7 (2006).
Yamamoto, S. & Kitazawa, S. Reversal of subjective temporal order due to arm crossing. Nat Neurosci 4, 759-65 (2001).