In search of the self: A positron emission tomography study

Previous work using positron emission tomography (PET) has shown that memor y encoding processes are associated with preferential activation of left fr ontal regions of the brain, whereas retrieval processes are associated pred ominantly with right frontal activations. One possible reason for the asymm etry is that episodic retrieval necessarily involves reference to the self; and the self-concept may be represented (at least partially) In right fron tal regions. Accordingly, the present study investigated the possibility th at encoding of self-related material might also activate right frontal area s. Eight right-handed volunteers judged trait adjectives under four separat e PET scan conditions: (a) relevance to self (b) relevance to a well-known public figure, (c) social desirability, and (d) number of syllables. The re sults showed that self-related encoding yielded left frontal activations si milar to those associated with Other types of semantic encoding, but also s pecific activations in the right frontal lobe. It is concluded that the con cept of self involves both general schematic structures and further specifi c components involved in episodic memory retrieval.