Mirror neurons (MNs) and embodied simulation (ES)
Intersubjectivity can be profitably understood if framedwithin a phylogenetic perspective. The discovery of MNs enabled establishing a relation between human intersubjectivity, the inter-individual relations of other animal species and their underpinning neural mechanisms.
MNs are motor neurons first discovered in macaques’ premotor area F5 and, later on, also in a sector of the posteriorparietal cortex reciprocally connected with area F5 (see Gallese, Gernsbacher, Heyes, Hickock, & Iacoboni,2011), in the primary motor cortex (see Vigneswaran, Philipp, Lemon, & Kraskov, 2013) and in the anterior cingulate cortex (see deAraujo et al., 2012). MNs have been interpreted as the expression of direct form of action understanding, hence their potential relevance for social cognition (Rizzolatti, Fogassi, &Gallese, 2001).
The existence of a mirror mechanism (MM) is now firmly established also in the human brain (see Kilner, Neal, Weiskopf, Friston, & Frith, 2009; Mukamel, Ekstrom, Kaplan, Iacoboni, & Fried, 2010). Motor goal detection, action anticipation and the hierarchical representation of action can be viewed as the direct consequence of the functional architecture of the motor system, organized in terms of goal-directed motor acts. Such perspective was qualified as “motor cognition” (Gallese, Rochat, Cossu, & Sinigaglia, 2009).
The motor system, together with its connections to viscero-motor and somatosensory cortical areas, structures action execution and action perception, action imitation and imagination. When the action is executed or imitated, the cortico-spinal pathway is activated, leading to movement. When the action is observed or imagined, its actual execution is inhibited. The cortical motor network is activated, however, not in all of its components and not with the same intensity: action is not produced, it is only simulated.
ES aims at providing a unitary account of basic aspects of intersubjectivity showing that people reuse their own mental states or processes represented in bodily format to functionally attribute them to others (Gallese, 2003; Gallese &Sinigaglia, 2011). Mental states or processes are embodied primarily because of their bodily format. ES theory neither provides a general Theory of Mind (ToM) reading, nor of mental simulation covering all types of simulation-based mindreading. ES aims at explaining the MM and related phenomena. For sake of concision, I will not deal here with emotions and sensations.
It was proposed that MM-driven ES plays a constitutive role in forms of mindreading, not requiring propositional attitudes, mapped onto mental representations with a bodily format (Gallese, 2007; Gallese & Sinigaglia, 2011). I am not implying that we experience the specific contents of others’ experiences, but only that we experience others as having experiences similar to ours.
ES posits that the capacity to understand others’ intentional behavior also relies on a more basic functional mechanism, which exploits the intrinsic organization of the motor system of primates. More simply put, there are several ways of understanding others: ES is one of them.
