Hemispheric Activation of Anterior and Inferior Prefrontal Cortex during Verbal Encoding and Recognition: A PET Study of Healthy Volunteers |
| |
Authors: | J. Daniel Ragland Ruben C. Gur Mark G. Lazarev Robin J. Smith Lee Schroeder Jonathan Raz Bruce I. Turetsky Abass Alavi Raquel E. Gur |
| |
Affiliation: | a Department of Psychiatry, University of Pennsylvania Health Systems, Philadelphia, Pennsylvania, 19104;b Department of Radiology, University of Pennsylvania Health Systems, Philadelphia, Pennsylvania, 19104;c Department of Biostatistics, University of Pennsylvania Health Systems, Philadelphia, Pennsylvania, 19104 |
| |
Abstract: | Evidence of bilateral prefrontal activation during memory encoding and retrieval has increased attention given to anatomical subdivisions within the prefrontal cortex. The current study examined anterior and inferior aspects of the prefrontal cortex to determine their degree of functional and hemispheric overlap during encoding and recognition. Cerebral blood flow of 25 healthy volunteers was measured using PET 15O-water methods during four conditions: resting baseline, sequential finger movement, word encoding, and word recognition. Resting and motor images were averaged to provide a single reference that was subtracted from encoding and recognition using statistical parametric mapping (SPM96). Memory conditions were also subtracted from each other to identify differences in regional activity. Subjects performed well (86% correct) and had a slightly conservative response bias. Baseline subtraction from encoding revealed focal activation of left inferior prefrontal cortex (area 45) without significant contralateral activation. Recognition minus baseline subtraction produced a focal right anterior prefrontal activation (areas 9 and 10) that was not present in the left hemisphere. Bilateral effects were seen in area 45 during recognition. Subtraction of memory tasks from each other did not reveal any areas of greater activity during encoding. However, the recognition task produced greater activation in right area 9 extending into the anterior cingulate. Greater activity during recognition was also observed in left insula and bilateral visual integration areas. These results are discussed in relation to the prevailing model of prefrontal hemispheric asymmetry during episodic memory. |
| |
Keywords: | episodic memory positron emission tomography memory encoding memory retrieval prefrontal cortex |
本文献已被 ScienceDirect 等数据库收录! |
|