Authors:

LAWSON, R. & CALDER, A.J.

Reference:

Year of publication:

2009

CBU number:

6957

Abstract:

Electrophysiological recording in the anterior superior temporal sulcus (aSTS) of macaques has demonstrated separate cell populations responsive to different gaze directions, head directions and body orientations (Perrett et al. 1992). A proportion of these cells responded to different cues (e.g. heads or bodies) oriented in the same direction (e.g. facing left). Recent psychophysical studies have found direction-specific aftereffects in humans following adaptation to a single gaze direction (Jenkins et al, 2006; Calder et al. 2008); similar effects have also been found for heads and bodies (Fang & He, 2007; Lawson et al, in press). However, it is unclear if these effects occur at the level of direction-selective cells tuned to specific classes of social cue (i.e., gaze, head, and body representations) or putative social attention cells tuned to the same direction irrespective of cue type. We address this by measuring participants’ discrimination of head direction following adaptation to 20° left and right oriented heads and bodies. A third “non-social” adaptor, directionally oriented chairs, was included to rule out the possibility that any aftereffects simply reflect recruitment of general 3D object representations. Aftereffects were found for the head adaptor condition only. These effects transferred across changes in the size and identity of the heads, indicating that these effects were not the result of adaptation to low-level properties. Our study provides the first evidence that direction-specific aftereffects in humans occur as a result of adapting direction-selective cells tuned to specific classes of social cue.