Neural network involved in self-judgment in young and elderly adults

In agreement with the literature, we have recently observed that the ventro-medial prefrontal cortex (VMPFC) is activated both in young and elderly subjects during a adjective judgment task requiring judgment about self vs. other in the context of a first (1PP) or third (3PP) perspective-taking (Ruby et al., submitted). Here, we have performed functional connectivity analyses to determine the network of cerebral areas associated to the performance of young and elderly subjects.
<br />Results indicate that, in the 1PP condition, activity of the VMPFC is related to the inferior frontal gyrus, parahippocampal gyrus in elderly but to the occipital cortex only in young subjects. In the 3PP condition, functional connectivity exist between the VMPFC and medial frontal gyrus, inferior frontal gyrus and superior temporal areas in elderly, but with occipital and parietal areas only in young subjects.
<br />The cerebral areas associated to VMPFC activity in young subjects were previously described as involved both in autobiographical memory retrieval and mentalizing processes. With regard to elderly, the cerebral network evidenced is related to retrieval of semantic and episodic memories (parahippocampal and superior temporal) but also to the attribution of emotional valence to the adjectives (inferior frontal) and perspective taking (medial frontal gyrus).
<br />These results indicate (1) that the VMPFC is connected to a larger cerebral network in elderly than in young subjects during self judgements; (2) that young subjects perform the task on the basis of autobiographical information retrieval only, while elderly subjects use supplementary, more reflexive, cognitive processes.