Differences in Neural Activation between Actual Tool Use and Pantomime: Evidence for Two Different Streams?

Using tools is an extraordinarily refined motor skill in humans (Vaesen, 2012). The neural correlates of tool use have been studied for a long time, initially with neuropsychological investigations (Liepmann, 1908) and more recently with neuroimaging techniques (Brandi et al., 2014; Thibault et al., 2021). These studies converge to show that using tools involves a left-lateralized network including the frontal, parietal, and occipitotemporal areas (Lewis, 2006). One way to assess tool-related actions and the associated neural correlates is to use a proxy action called pantomime, in which the use of tools is mimicked without the tool being held in hand. After left-hemisphere stroke, individuals can suffer of a specific impairment at correctly pantomiming tool use actions even with their nonparetic arm, a neurological condition called apraxia. Surprisingly, however, these same individuals' ability to use actual tools can remain relatively unimpaired (Hermsdörfer et al., 2012). This dissociation might reflect the fact that pantomime and actual tool use involve different cognitive processing that relies on partially distinct brain areas. Previous neuroimaging work corroborates this idea, showing distinct neural correlates for pantomime and actual tool use (Hermsdörfer et al., 2007; Lausberg et al., 2015). In a recently published paper, Chen et al. (2023) revisited the neural differences between actual tool use and pantomime using multivoxel pattern analyses (MVPA) in … Correspondence should be addressed to Simon Thibault at simon.thibault{at}jefferson.edu.