Neurophysiological studies in monkeys and neuroimaging studies in humans support a model of empathy according to which there exists a shared code between perception and production of emotion. The neural circuitry critical to this mechanism is composed of frontal and parietal areas matching the observation and execution of action, and interacting heavily with the superior temporal cortex. Further, this cortical system is linked to the limbic system by means of an anterior sector of the human insular lobe.

Depth electrode recordings in the human mesial frontal cortex have revealed individual neurons with mirror properties. A third of these cells have excitatory properties during action execution and inhibitory properties during action observation. These cells provide the neural mechanism that implements the functions of layers 3+4 of the shared circuits model (SCM).

The neural substrates of context effects in word perception are still largely unclear. Interhemispheric priming phenomena in word recognition, typically observed in normal subjects, are absent in commissurotomized patients. This suggests that callosal fibers may provide contextual integration. In addition, certain characteristics of human frontal cortical fields subserving sensorimotor learning, as investigated by positron emission tomography, provide evidence for contextual integration not confined to the visual system. This supports the notion of common aspects of cortical computations in different cerebral areas.

We believe that an account of the role of mirror neurons in language evolution should involve a greater emphasis on the auditory properties of these neurons. Mirror neurons in premotor cortex which respond to the visual and auditory consequences of actions allow for a modality-independent and agent-independent coding of actions, which may have been important for the emergence of language.

Although we fundamentally agree with Schilbach et al., we argue here that there is still some residual utility for non-interactive scenarios in social neuroscience. They may be useful to quantify individual differences in prosocial inclination that are not influenced by concerns about reputation or social pressure.