[Abstract Title]. - Society for Neuroscience

The new target appeared 10 cm left or right to, and 2 cm below the central target. TMS was
sometimes delivered over V1, 70 or 100 ms after disappearance of the center target. When the
new target appeared, subjects were instructed to reach it, and their arm positions were monitored
by Optotrak system (NDI). After each trial, subjects were required to report if they saw a new
target (1-4 scale) and where it was (forced choice between left and right). Brightness of the
background was adjusted, so that subjects could detect the new target in trials without TMS.
Subjects reached around the center of the monitor, when new target did not appear. In addition
without TMS, they could reach toward the new target, irrespective of the duration of its
appearance. When TMS was delivered, they sometimes missed detecting the new target.
Especially when using TMS with 100 ms delay, they occasionally made switching toward the
new target, even if they did not perceive it. However with TMS of 70 ms delay, the switching
movement was deteriorated in both frequency and amplitude. In trials without conscious
perception of the new target, subjects‟ judgments about the position of the new target were rather
accurate, and were above the chance level. We conclude that early switching movements could
be induced without conscious visual experiences, though V1 could partly be involved in the
movement..
Disclosures: Y. Ohki, None; S. Shibuya, None; H. Sekiguchi, None; H. Kadota, None; S.
Takeuchi, None; Y. Nakajima, None.
Poster
262. Visually-Guided Reaching II
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 262.17/CC31
Topic: D.05.d. Visually guided reaching
Support: CIHR Grant 74634
Title: Gaze-biased misreaching in optic ataxia does not generalize to other spatial planes
Authors: *J. A. GRANEK 1 , L. PISELLA 2 , A. BLANGERO 2 , Y. ROSSETTI 2 , L. E. SERGIO 1 ;
1 Kinesiol & Hlth. Sci., York Univ., Toronto, ON, Canada; 2 Inserm U864, Lyon, France
Abstract: In our everyday movements, we typically interact directly with the object that we are
viewing. Hence, the visual stimulus guiding the action is itself the target of the action. Such
behaviour can be considered “standard”, or “direct”. However, the evolution of the capacity for
tool-use in primates has resulted in situations where the correspondence between vision and
action is not direct. Rather, the mapping between stimulus and response must be learned and
calibrated. This situation has been referred to as “non-standard” sensorimotor mapping. In non-