State-Dependent TMS Reveals a Hierarchical Representation of Observed Acts in the Temporal, Parietal, and Premotor Cortices

Abstract

A transcranial magnetic stimulation (TMS) adaptation paradigm was used to investigate the neural representation of observed motor behavior in the inferior parietal lobule (IPL), ventral premotor cortex (PMv), and in the cortex around the superior temporal sulcus (STS). Participants were shown adapting movies of a hand or a foot acting on different objects and were asked to compare to the movie, a motor act shown in test pictures. The invariant features between adapting and test stimuli fitted a 2 3 2 design: same or different action made by the same or different effector. Neuronavigated TMS pulses were delivered at the onset of each test picture. TMS over the left and right PMv and over the left IPL induced a selective shortening of reaction times (RTs) to stimuli showing a repeated (adapted) action, regardless of the effector performing it. In a second experiment, TMS applied over the left STS induced shortening of RTs for adapted actions but only if also the effector was repeated. The results indicate that observed motor behavior is encoded with the body part that performs it in the temporal lobe. A hierarchically higher level of representation is carried by neural populations in the parietofrontal regions, where acts are encoded in an abstract way.

Event-Related Repetitive Transcranial Magnetic Stimulation of Posterior Superior Temporal Sulcus Improves the Detection of Threatening Postural Changes in Human Bodies

“…The present study shows that vPM cortex is not involved in the visual discrimination between two consecutive body postures, possibly because perception of subtle postural changes depends on higher-order visual areas (Taylor et al, 2007;Bracci et al, 2010;Cattaneo et al, 2010) rather than the sensorimotor system (Urgesi et al, 2007b). A recent TMS study provided compelling functional evidence that, while the activity of STS is involved in the visual description of observed actions (i.e., an action is linked to the body part that performs it), the activity of the left frontal gyrus is related to the representation of actions' meaning and not to the specific body part used to perform them , supporting the notion that higher-order action-related representation are supported by premotor regions (Rizzolatti and Craighero, 2004).…”

Knowing beans: human mirror mechanisms revealed through motor adaptation

“…However, the effect of direction of movement was completely eliminated when the pulse was directed at premotor cortex. Given that TMS is particularly effective on adapted systems (Cattaneo et al, 2010), this result indicates that the motor adaptation was primarily a premotor phenomenon. This finding helps to secure the claim that the adaptation paradigm is affecting a MM.…”

Top-down social modulation of interpersonal observation–execution

“…The neural substrate underpinning this coupling is suggested (Cattaneo, Sandrini, & Schwarzbach, 2010;Kilner, Neal, Weiskopf, Friston, & Frith, 2009) to be the human mirror system (inferior frontal gyrus, premotor cortex, inferior parietal lobule), which supports the imitation of actions (Iacoboni et al, 1999) and the acquisition of motor skills via observation (Cross, Kraemer, Hamilton, Kelley, & Grafton, 2009). In addition to representing motor actions, imitation is a very important mechanism for developing of social rapport (Chartrand & Bargh, 1999) and feelings of affiliation (Lakin & Chartrand, 2003;van Baaren, Janssen, Chartrand, & Dijksterhuis, 2009).…”