西本　伸志（脳神経工学講座　視覚神経科学研究室　D3)
派遣期間：平成16年10月22日-10月29日（8日間）
派遣目的：Neuroscience 2004 34th Annual Meeting（San Diego, U.S.A.)に参加し、研究成果発表を行う

Meeting attendance report: Society for Neuroscience 34th annual meeting

Destination:
San Diego Convention Center, California, USA

Purpose:
The purposes are to:
1) Deliver an oral presentation on our recent findings at the 34th annual meeting of Society for Neuroscience (SfN)
2) Obtain up-to-date information on neuroscience

Meeting report:
　The SfN meeting is the world’s largest annual conference for researchers working on neuroscience. This year, the meeting was held in San Diego, a port town on the west coast of USA. More than 31,000 people had attended the meeting during the five-day session from Oct. 23 to the 27. I delivered my oral presentation at a session specialized for motion and depth signal processing in the visual cortex, concerning linear and nonlinear temporal interactions of spatial frequency tunings in the early visual cortex and its implication for extracting motion-in-depth information. We had a fruitful discussion after the session.
　At sessions about shape representations in the higher visual area, plenty of groups presented their new approaches to studying how visual objects are coded in the cortex, especially in areas V4 and inferior temporal cortex. One of such studies was by the group of Dr. M. S. Livingstone (Harvard University). They reported their new approach to map nonlinear receptive field profiles for cells in area V4, together with the fine consistency with response profiles obtained from the non-Cartesian grating stimuli. Another such study was reported by Dr. B. Jagadeesh (University of Washington). She reported a new, highly computer-intensive way to extract critical features for cells in inferior temporal cortex by examining visual features shared by stimuli that elicit spikes. The group of Dr. J. L. Gallant (University of California, Berkeley) examined several nonlinear operations to explain nonlinear response profiles observed for cells in areas V1 and V4. These theoretical and highly computer-aided approaches seem to reduce difficulties in addressing high dimensionality inherited in input/output relationship for cells in the higher cortical areas.
　Among many attractive studies throughout the meeting, the most exciting presentation for me and surely for many other researchers in the same area was about a realization of in vivo two-photon calcium imaging of the visual cortex. Dr. Kenichi Ohki (Japanese post-doc!) in Dr. R. Clay Reid’s laboratory (Harvard University) presented their new technique to visualize neural responses of visual cortex with single-cell resolution. Thanks to this technique, one can obtain simultaneously hundreds of single-cell activities, with a 3-D structure in the cortex in vivo. This might be a new standard technique in neurophysiology for the coming decade. What was impressive to me was that every time researcher came to talk to Dr. Reid and suggested new protocols using this new technique, he replied, with confidence, “Next, next, next.” Certainly, there are many things we can do next, and studies with the technique would yield a breakthrough for understanding functions in the cortex.

Benefits from the trip:
　 Through the meeting, we had many productive discussions concerning our current studies. Several reports about shape representations in the visual cortex had close relation to our current experiments. Discussions with these authors were good opportunities for considering our future studies. This conference also gave me nice occasions to talk with post-docs working in the USA, about how they can manage to live as foreign researchers.

Perspective and future plans:
　Several theoretical studies that were presented in the meeting could potentially be background to support our experimental study. I will further analyze our data with their findings as references. The in vivo two-photon imaging technique is promising, so I will think of the application.