[Date updated!!] Dr Terufumi Fujiwara: Multimodal, multi-timescale signals in the visual system orchestrate robust, rapid, and flexible walking control
We are excited to have an online seminar by Dr. Terufumi Fujiwara from Champalimaud Foundation, Portugal. He has investigated the neural bases of motor control using fruit flies. He will also start his lab in Nov. 2022 at Riken. Everyone is welcome to join the seminar!
Multimodal, multi-timescale signals in the visual system orchestrate robust, rapid, and flexible walking control
Dr. Terufumi Fujiwara
Champalimaud Foundation, Portugal
During navigation, we must utilize multimodal self-motion cues to faithfully estimate the ongoing body state for coordinating subsequent movement. Moreover, we must rapidly monitor and adjust our body movements, which also must be flexible depending on behavioral goals. I leverage a compact walking course control circuit in the Drosophila visual system to investigate how the brain combines multimodal self-motion signals during locomotion, how sub-second neural activity dynamics reciprocally interact with fine leg movement parameters, and how behavioral contexts modulate neural processing. I performed a whole-cell patch-clamp recording from a class of optic-flow sensitive cells, HS cells, informing of self-motion visually while a fly walked spontaneously on a spherical treadmill ball. I found that HS cells combine extraretinal walking-related and visual signals to faithfully encode walking course drift, which is used to promote corrective steering. Furthermore, HS cells receive periodic modulations coupled to leg stride cycles. The stride modulation contributed to walking course control on multi-timescales: On a stride timescale, the periodic modulation sets a time window within which HS-cell activity is tuned contingent on a course drift for a rapid course correction. On a longer timescale, the signal is gradually integrated over several strides to represent a steady forward speed. This speed context representation recruits the circuit for course control as needed. Therefore, the multi-type walking-related signals tune the activity of visual neurons for robust, rapid, and flexible course control. The discovery of rich walking movement representations in the fly visual system opens up the opportunity to use this powerful genetic model for understanding single cell-level and single stride-level computational mechanisms of navigation and motor control.
You can join the seminar via ZOOM (meeting ID: 782 721 4941, Password: 436475).