Lateral occipitotemporal cortex and action representation

Abstract

Representation of body and body movements is essential for identifying others intentions or actions or for learning from them. Over the last 10 years, a large collection of research has demonstrated that body representations are distributed across a widely distributed brain network. In this functional magnetic resonance imaging study, we focus on lateral occipitotemporal cortex (LOTC), a recently identified brain region that could represent the body in a multisensory and dynamic manner. We addressed the question of LOTC involvement in visual processing of others׳ actions through a factorial analysis that manipulated the meaning of an observed action, completed by a psychophysiological interaction analysis. The results show that only left LOTC was significantly activated in relation to others׳ actions meaning. In addition, only left LOTC was activated during both action observation and action production but it was more dorsal than the activation related to the meaning of observed actions. Furthermore, the psychophysiological interaction analysis showed that when watching meaningless actions, the more dorsal part of the LOTC (the area active during both action production and action observation) had higher functional connectivity with primary visual areas while the more ventral part (that responded to action meaning) had higher correlation with anterior cingulate and medioprefrontal cortices. Taken together these results plead in favour of a strong implication of left LOTC in action observation and understanding, with a possible functional specialisation between the more ventral and the more dorsal parts of LOTC.