Dissociable Somatotopic Representations of Chinese Action Verbs in the Motor and Premotor Cortex

Abstract

The embodied view of language processing holds that language comprehension involves the recruitment of sensorimotor information, as evidenced by the somatotopic representation of action verbs in the motor system. However, this review has not yet been examined in logographic scripts such as Chinese, in which action verbs can provide explicit linguistic cues to the effectors (arm, leg, mouth) that conduct the action (hit, jump, drink). We compared the somatotopic representation of Chinese verbs that contain such effector cues and those that do not. The results showed that uncued verbs elicited similar somatotopic representation in the motor and premotor cortex as found in alphabetic scripts. However, effector-cued verbs demonstrated an inverse somatotopic pattern by showing reduced activation in corresponding motor areas, despite that effector-cued verbs actually are rated higher in imageability than uncued verbs. Our results support the universality of somatotopic representation of action verbs in the motor system. E arly neuroimaging studies on human language production and comprehension focus primarily on the classical language network in the left inferior frontal and superior temporal cortex, such as Wernicke's and Broca's areas 1 . However, growing evidence from patient and neuroimaging studies have shown that language processing activates a much more complex and widely distributed network [2][3][4][5][6] . Increasingly research has reported a semantic category-specificity effect, such that specific semantic categories such as objects, relations, and actions might be represented in particular brain regions 3,7-11 . In particular, the processing of action verbs has been found to be associated with the frontal and motor cortex [12][13][14][15][16][17][18] .Studying how action verbs are represented in the brain is particularly interesting among various specific semantic categories, because it connects language processing to another debating theory in cognition, that is, embodied cognition 7,8 . The embodied view of language processing proposes that the internal representation of the action, which is related to the motor system, plays a key role in language comprehension 19 . In line with this proposal, a rich body of literature has linked the motor and language systems and shown that motor simulation is an automatic and necessary component of meaning representation 3,20 . A crucial case is the somatotopic representation of action verbs [21][22][23] . For example, Hauk and colleagues found that reading action verbs denoting leg, arm and face actions activated the corresponding motor and premotor cortex areas in a somatotopic pattern 21 . Similar somatotopic patterns were also found when participants listening to the action-related sentences 24 , reading idioms with action-related words 25 , reading literal or metaphoric action sentences 26 , and reading idioms [27][28][29][30][31] . In addition, imaging actions and listening action sounds demonstrated a body-part specific somatotopic representation 32,33 .Moreove...

Visual recognition of words learned with gestures induces motor resonance in the forearm muscles

“…Some authors have reported enhanced activity within the premotor cortex 71 , 72 , which could endow individuals with information needed to prepare upcoming actions. Other studies have identified more extensive activity involving also the primary motor cortex 61 , 65 , 66 , 68 , 73 , suggesting that MR can extend further towards the nervous system’s motor pathways and closer to the musculature responsible for movement execution.…”

“…However, MR is known to occur during the perception of action semantics in language. Brain imaging experiments have found increased activity in the motor regions elicited by words describing action execution 64 – 68 . This is to say that action-related semantics in language can induce a somatotopically fine-grained MR 69 , 70 .…”

Object words modulate the activity of the mirror neuron system during action imitation

“…Subject words and verbs showed stronger activation than control stimuli (checkerboard) in the word reading stage ( ps  < .05), and the control condition had less activation than the other three word conditions ( ps  < .05) in the imitation stage. The language enhancement effect on both the word reading and imitation stages in the left precentral gyrus may have been due to that the semantic processing of hand action‐related words automatically activates the hand action area (Hauk et al., 2004; Postle, McMahon, Ashton, Meredith, & de Zubicaray, 2008; Pulvermüller, 2005; Wu et al., 2013). …”

“…Subject words and verbs showed stronger activation than control stimuli (checkerboard) in the word reading stage (ps < .05), and the control condition had less activation than the other three word conditions (ps < .05) in the imitation stage. The language enhancement effect on both the word reading and imitation stages in the left precentral gyrus may have been due to that the semantic processing of hand action-related words automatically activates the hand action area(Hauk et al, 2004;Postle, McMahon, Ashton, Meredith, & de Zubicaray, 2008;Pulvermüller, 2005;Wu et al, 2013).In the left IPL (−50, −59, 43), right postcentral gyrus (PostG) (47, −22, 48) and right IFG (50, 16, 10), the significant main effect of word type in the imitation stage (IPL: F 3,54 = 6.133, p < .01; PostG: F 3,54 = 11.361, p < .01; IFG: F 3,54 = 6.278, p < .01) indicated that the object word condition (IPL: M = 0.08, SE = 0.22; PostG: M = 0.15, SE = 0.12; IFG: M = 0.39, SE = 0.16) had a stronger signal change than the subject word (IPL: M = −0.78, SE = 0.19; PostG: M = −0.33, SE = 0.12; IFG: M = 0.02, SE = 0.14) and control condition (IPL: M = −0.76, SE = 0.22, ps < .05; PostG: M = −0.34, SE = 0.14, ps < .001;…”

Solving the Interface Problem Without Translation: The Same Format Thesis

“…Furthermore, Wu et al . (), showed that this somatotopic organization of action concept representation concerns the common way agents use and understand action categories in different languages and cultures. In this experiment, processing Chinese action verbs elicited similar somatotopic representations in the motor and premotor cortex as already established for alphabetic scripts.…”