Brain Signatures of Meaning Access in Action Word Recognition

Abstract

The brain basis of action words may be neuron ensembles binding language- and action-related information that are dispersed over both language- and action-related cortical areas. This predicts fast spreading of neuronal activity from language areas to specific sensorimotor areas when action words semantically related to different parts of the body are being perceived. To test this, fast neurophysiological imaging was applied to reveal spatiotemporal activity patterns elicited by words with different action-related meaning. Spoken words referring to actions involving the face or leg were presented while subjects engaged in a distraction task and their brain activity was recorded using high-density magnetoencephalography. Shortly after the words could be recognized as unique lexical items, objective source localization using minimum norm current estimates revealed activation in superior temporal (130 msec) and inferior frontocentral areas (142-146 msec). Face-word stimuli activated inferior frontocentral areas more strongly than leg words, whereas the reverse was found at superior central sites (170 msec), thus reflecting the cortical somatotopy of motor actions signified by the words. Significant correlations were found between local source strengths in the frontocentral cortex calculated for all participants and their semantic ratings of the stimulus words, thus further establishing a close relationship between word meaning access and neurophysiology. These results show that meaning access in action word recognition is an early automatic process ref lected by spatiotemporal signatures of word-evoked activity. Word-related distributed neuronal assemblies with specific cortical topographies can explain the observed spatiotemporal dynamics reflecting word meaning access.

Does comprehension of symbolic gestures and corresponding-in-meaning words make use of motor simulation?

“…However, the delay we used (150-200 ms) is in agreement with the beginning of motor area activation found by the magneto-encephalography study carried out by Pulvermüller et al [21] during which action verbs were presented. Nevertheless, future studies will test whether or not M1 is modulated by TMS applied at different delays after presentation of symbolic gestures and communicative words.…”

“…the hand waving beginning for gesture "ciao"), and 150 ms [21] after the isolation point (i.e. the point after which it was possible to discriminate if the string of letters, was meaningful or meaningless) for videos presenting spoken words and pseudo-words.…”

Brain dynamics in the comprehension of action-related language. A time-frequency analysis of mu rhythms

“…Neuroimaging studies have reported activations in the motor and premotor brain regions during the comprehension of action-related language. Some of these studies found motor activation when people process action verbs presented in isolation (Hauk and Pulvermüller, 2004;Pulvermüller, 1996;Pulvermüller et al, 2005;Rizzolatti and Luppino, 2001), and others have found similar motor activation when people process action-related sentences (Aziz-Zadeh et al, 2006;Moody and Gennari, 2010;Raposo et al, 2009;Tettamanti et al, 2005;Urrutia et al, 2012;De Vega et al, 2014).…”

“…One of these issues is the need to determine whether language-induced motor activations are exclusively lexical or are dependent to some extent on the semantic context. One possibility is that the activation of the motor cortex occurs automatically about 150-200 ms after the onset of action verbs, as part of their lexical processing (Pulvermüller et al, 2005;Boulenger et al, 2006;Buccino et al, 2001;Nazir et al, 2008;Sato et al, 2008). Another alternative is that the activation of the motor cortex associated with reading is a non-automatic, context-dependent process, involving lexical-semantic integration across the sentence.…”

Subliminal display of action words interferes with motor planning: A combined EEG and kinematic study

“…First attempts to identify the functional role of language-related activity in cortical motor regions have also been made by investigating the time course of this activity (Boulenger et al, 2006;Pulvermüller et al, 2005a). Using magnetoencephalography (MEG), Pulvermüller et al (2005a) revealed a short-lived somatotopic activity in motor cortex while participants were listening to face-and leg-related action words.…”