Distinct neural systems subserve person and object knowledge

Abstract

Studies using functional neuroimaging and patient populations have demonstrated that distinct brain regions subserve semantic knowledge for different classes of inanimate objects (e.g., tools, musical instruments, and houses). What this work has yet to consider, however, is how conceptual knowledge about people may be organized in the brain. In particular, is there a distinct functional neuroanatomy associated with person knowledge? By using event-related functional magnetic resonance imaging (fMRI), we measured neural activity while participants made semantic judgments about people or objects. A unique pattern of brain activity was associated with person judgments and included brain regions previously implicated in other aspects of social-cognitive functioning: medial prefrontal cortex, superior temporal cortex, intraparietal sulcus, and fusiform gyrus. These regions were generally marked by relatively little change from baseline brain activity for person judgments along with significant deactivations for object judgments. Together, these findings support the notion that person knowledge may be functionally dissociable from other classes of semantic knowledge within the brain.

Brain activation when hearing one's own and others' names

“…These regions are similar to the activation at the temporo-parietal junction reported in an fMRI study when subjects perform a 'theory of mind' task (Gallagher et al, 2000), and activation in superior temporal cortex when making judgments about others (Mitchell et al, 2002). In addition, we found activation in left cuneus and fusiform gyrus (largely BA 18) similar to the activation of posterior cingulate when making judgments about others (Macrae et al, 2004) and to the activation of left fusiform gyrus in a recognition task of one's own face (Kircher et al, 2000).…”

“…For example, a network of brain regions involved in the ability to attribute mental states to self and others, known as "mentalizing", include the medial prefrontal cortex and the temporal-parietal junction near the anterior portions of the superior temporal gyrus (Frith, 2001). In addition, the left superior temporal gyrus and the left medial frontal gyrus are activated when subjects engage in a theory-of-mind task relative to reading sentences (Fletcher et al, 1995;Gallagher et al, 2000;Mitchell et al, 2002), and activation occurs in left superior temporal cortex (Brodmann area 22) and left inferior parietal cortex when subjects judge whether adjectives are relevant to themselves (Fossati et al, 2003;Macrae et al, 2004). Using fMRI, the medial surface of the superior frontal gyrus is activated when calling a subject's own name relative to calling the names of others (Kampe et al, 2003), and the right frontal cortex, including superior, middle, and inferior regions, is activated when subjects identified the faces of self and famous others (Platek et al, 2004).…”

Is Self Special? A Critical Review of Evidence From Experimental Psychology and Cognitive Neuroscience.

“…Self task activity was significantly higher in medial PFC and posterior cingulate. These results are difficult to interpret owing to the nature of the control conditions; the control condition used by Johnson and colleagues differed in its social content, and the areas activated are associated with social-emotional cognition in tasks lacking self-related processing (Adolphs, 2001;Adolphs, Tranel, & Damasio, 2003), with the medial PFC in particular associated with knowledge about people (J. P. Mitchell, Heatherton, & Macrae, 2002). In order to conclude that self-reflection per se is responsible for the activation, it must be contrasted with a condition involving a specific other person.…”

School-aged children exhibit domain-specific responses to biological motion

“…(4) The temporo-parietal junction (TPJ), which is a functionally defined region localized to an area of cortex medial and superior to the posterior STS region and that is involved in the attribution and analysis of other people's mental states (e.g., Saxe & Kanwisher, 2003). (5) The medial prefrontal cortex (mPFC), which is involved in evaluating the mental states of others (see Gallagher & Frith, 2003, for a review) and in representing semantic knowledge about the psychological aspects of other people (e.g., Mitchell, Banaji, & Macrae, 2005;Mitchell, Heatherton, & Macrae, 2002). (6) Portions of the parietal cortex, including the inferior and superior parietal lobules, and the anterior intraparietal sulcus (aIPS), and (7) frontal cortical regions, including the inferior frontal gyrus (IFG) that have been dubbed parts of the "mirror system" in humans because they activate equally to the execution of a motor action and the observation of a motor action by another person (e.g., Buccino et al, 2001;Decety & Chaminade, 2003;Iacoboni, Woods, Brass, Bekkering, Mazziotta, & Rizzolatti, 1999;Iacoboni et al, 2001;Pelphrey, Morris, & McCarthy, 2004;Rizzolatti, Fadiga, Gallese, & Fogassi, 1996;see Iacoboni, 2005, for a recent review).…”