TABLE 1.
Summary of main concepts, neural evidence, and future challenges about the theories explaining language semantic processing and evolution.
| Semantic processing | ||
| Embodied theory | Amodal/Symbolic theory | |
| Main concepts | Conceptual knowledge is grounded in body experience and in the sensorimotor systems | Semantic concepts are stored and processed as formal symbols |
| Neural systems | Primary motor and sensory systems, Fronto-Parietal Mirror Circuit | Temporal cortex (Anterior Temporal Lobe, Middle Temporal Gyrus) |
| Main references | Gallese and Lakoff, 2005; Barsalou, 2008; Casile, 2012; Kiefer and Pulvermüller, 2012 | Fodor, 1998; Patterson et al., 2007; Mahon and Caramazza, 2009; Visser et al., 2010 |
| Challenges | No shared model about the dynamic and interplay between sensorimotor and temporal brain areas at different stages of semantic comprehension Necessity to further support the essential contribute of sensorimotor system in abstract language processing | |
| Language evolution | ||
| Gestural origin of Language | Independent evolution of gestures and language | |
| Main concepts | Speech evolved from arm postures that were progressively integrated with mouth gestures and vocalization by mean of a double hand–mouth command system. Gesture and speech necessarily interact during their processing and production | Gestures and speech evolved independently. They are functionally dissociated and processed separately, or eventually integrated as amodal concepts). Communication with gestures is described as an auxiliary system |
| Neural systems | Inferior Frontal Gyrus | Sensorimotor systems for gestures, temporal cortex for language |
| Main references | McNeill, 1992; Rizzolatti and Arbib, 1998; Gentilucci and Corballis, 2006; Gentilucci et al., 2006 | Krauss and Hadar, 1999; Barrett et al., 2005 |
| Challenges | Overlapping activation of areas belonging to mirror circuit (IFG) and linguistic areas (MTG) during gesture and speech processing Limited evidence about neural dynamic of gesture and speech interplay Potential fields of research (i.e., FOXP2 genes variations and communication behavior) | |