Neural Circuits Underlying Imitation Learning of Hand Actions

Abstract

The neural bases of imitation learning are virtually unknown. In the present study, we addressed this issue using an event-related fMRI paradigm. Musically naive participants were scanned during four events: (1) observation of guitar chords played by a guitarist, (2) a pause following model observation, (3) execution of the observed chords, and (4) rest. The results showed that the basic circuit underlying imitation learning consists of the inferior parietal lobule and the posterior part of the inferior frontal gyrus plus the adjacent premotor cortex (mirror neuron circuit). This circuit, known to be involved in action understanding, starts to be active during the observation of the guitar chords. During pause, the middle frontal gyrus (area 46) plus structures involved in motor preparation (dorsal premotor cortex, superior parietal lobule, rostral mesial areas) also become active. Given the functional properties of area 46, a model of imitation learning is proposed based on interactions between this area and the mirror neuron system.

The functional role of the parieto-frontal mirror circuit: interpretations and misinterpretations

“…Additional cortical areas (such as the dorsal premotor cortex and the superior parietal lobule) have also been occasionally found to be active during action observation and execution [19][20][21] . Although it is possible that their activation is due to a mirror mechanism, it is equally possible that it reflects motor preparation.…”

Experience-based priming of body parts: A study of action imitation

“…Furthermore, the hypothesis that imitation is mediated by the mirror neuron system is supported by evidence that the mirror neuron system, and particularly the inferior frontal gyrus, is more active during imitation than during either observation or execution of actions (e.g. Aziz-Zadeh et al, 2006;Iacoboni et al, 1999;Koski et al, 2003;Nishitani and Hari, 2000;Williams et al, 2006), and is involved in imitation learning (Buccino et al, 2004;Vogt et al, 2007).…”

“…Järveläinen et al (2004) found that the degree of primary motor cortex activation when observing actions involving chopsticks correlated with the amount of recent experience with using chopsticks. Furthermore, highly familiar actions activate human premotor cortex more than non-familiar actions (Grezes et al, 1998), and in musically naïve observers activation in mirror areas is elicited by the observation of guitar playing which they are required to imitate (Buccino et al, 2004;Vogt et al, 2007), and by hearing sequences of tones which they had learned to play on the piano (Lahav et al, 2007).…”

Being an agent or an observer: Different spectral dynamics revealed by MEG

“…This putative mirror--like activity in humans was found in the 39 precentral gyrus (vPM), the inferior frontal gyrus (IFG), the inferior parietal lobule (IPL), and 40 regions within the intraparietal sulcus (for a review see Rizzolatti and Sinigaglia, 2010). In addition 41 to this limited number of regions, neuroimaging studies observed a broader action observation 42 network (AON) which seems to be involved during action observation (OBS) and execution (EXE) 43 (Avenanti et al, 2012;Buccino et al, 2004;Gazzola and Keysers, 2009). A proposed theoretical 44 framework postulates that such AON implements forward and inverse internal models (Wolpert 45 and Ghahramani, 2000), which should be engaged during EXE and OBS.…”