There has been a controversy on the neural basis of processing animacy. Proponents of the majority view argue that regions in the social network of the brain mediate social processing. These regions include medial prefrontal cortex (MPC), cingulate cortex (CC), amygdala, and superior temporal sulcus (STS). The supporters of the minority view have suggested that “social processing is mediated by regions of the mirror network that includes the inferior frontal gyrus, just anterior to and including the ventral premotor cortex, and the anterior inferior parietal lobule” (Slotnick). In class, we’ve discussed four studies about this controversy that had mixed views.
For example, Wheatley et al. (2007) and Heberlein and Adophs (2004) are proponents of the majority view. Wheatley et al. (2007) investigated the areas of the brain that were activated when people interpreted and imagined moving shapes as animate or inanimate. Figure 3B shows the average hemodynamic responses as a function of animacy, and the results demonstrated that when the moving shapes were imagined as animate beings rather than inanimate objects, the activity across the entire social network increased. Also, the study argued that “even at a greatly reduced threshold, mirror-system activation was not modulated by the interpretation of animacy during either motion observation or imagery” (p. 473). Wheatley et al. (2007) concluded that only activation of the social network was modulated by animacy. Heberlein and Adophs (2004) argued that Subject SM, who had bilateral damage to the amygdala due to Urback-Wiethe disease, used fewer emotional and social words to describe the movie but used more movement words as compared to control participants (Figure 3). The control group used consistently more Affect and Social words, but fewer Movement words. The results of the study are consistent with “other findings regarding the amygdala’s role in processing social information, including functional imaging studies showing amygdala activity in response to similar animated videos in normal subjects” (p. 7490).
Iacoboni et al. (2005) and Fabbri-Destro and Rizzolatti (2008) are proponents of the minority view. Iacoboni et al. (2005) argued that premotor mirror neuron areas that were thought to be involved only in action recognition are also involved in understanding the intentions of others. The observation of Intention and of the Action clips led to a significant signal increase in the parieto-frontal cortical circuit for grasping. Furthermore, the Intention condition led to significant signal increase in visual areas and in the right inferior frontal cortex (Figure 3). The study claims that the increased “right inferior frontal activity is located in a frontal area known to have mirror neuron properties, thus suggesting that this cortical area…is critical for understanding the intentions behind others’ actions” (p. 2005). Fabbri-Destro and Rizzolatti (2008) investigated the mirror mechanism involved in action and intention understanding. Also, they reviewed the mirror system involved in coding non-object-directed movements and verbal material. This review article suggested that the mirror network can include the amygdala, the insula, and the anterior cingulate that processes emotion. Furthermore, this article argued that “activations in the anterior insula and in the anterior cingulate cortex were also obtained in studies in which emotional reactions to pain were investigated using an event-related fMRI paradigm (p. 177). Fabbri-Destro and Rizzolatti (2008) concluded that in both action and intention conditions, there is an activation of the mirror system.
Taking all these articles together, I cannot ignore the significant findings of the Iacoboni et al. (2005) and Fabbri-Destro and Rizzolatti (2008), and I am siding with the proponents of the minority view. I thought Singer et al. (2004) was an interesting study. I would propose a follow up study to learn about the neural basis of the mirror neurons. I would focus on how F5 mirror neurons respond to action observation in full vision and hidden conditions. I would create a video of a baby putting his hand in a fake fireplace. For animation, I would start from a fixed position, moving toward the fireplace, and crying from the burning sensation vs not crying. I would expect a significant activation in the amygdala. Then, I would use fMRI and a functional connectivity map to determine whether there is a link between the amygdala and RIFG. I would predict to observe significant activities in several regions, including regions of the mirror network.
Fabbri-Destro, M., & Rizzolatti, G. (2008). Mirror neurons and mirror systems in monkeys and humans. Physiology, 23: 171–179, 2008; doi:10.1152/physiol.00004.2008.
Heberlein, A. S., & Adolphs, R. (2004). Impaired spontaneous anthropomorphizing despite intact perception and social knowledge. Proceedings of the National Academy of Sciences, 101(19), 7487–7491. doi: 10.1073/pnas.0308220101
Iacoboni, M., Molnar-Szakacs, I., Gallese, V., Buccino, G., Mazziotta, J. C., & Rizzolatti, G. (2005). Grasping the Intentions of Others with Ones Own Mirror Neuron System. PLoS Biology, 3(3). doi: 10.1371/journal.pbio.0030079
Slotnick, S. (2013). Controversies in cognitive neuroscience. Basingstoke: Palgrave Macmillan.
Singer T, Seymour B, O’Doherty J, Kaube H, Dolan RJ, Frith CD. Empathy for pain involves the affective but not sensory components of pain. Science 303: 1157–1162, 2004.
Wheatley, T., Milleville, S. C., & Martin, A. (2007). Understanding Animate Agents Distinct Roles for the Social Network and Mirror System. Psychological Science.