Activation of medial prefrontal cortex during selective attention to subjective emotional responses

NeuroImage

11, Number

5, 2000, Part 2 of 2 Parts 1 QEal@

SENSORIMOTOR

Activation

of Medial Prefrontal Cortex During Selective Attention to Subjective Emotional Responses Richard D. Lane*‘, Clay L. Fort*, Lee Ryan+, Ted Trouard’

Cognition and Neuroimaging Laboratories and the Departments of Psychiatry*, Psychology’ and Radiology’, University of Arizona, Tucson, Arizona, USA Introduction In a previous PET study in healthy men we observed that medial subjective emotional responses to emotional pictures (1). In contrast, in matched pictures, activation of bilateral posterior pa&al and contained pleasant, unpleasant and neutral pictures. In this study envimmneat. We also sought to cornpam the relative influence of medial prefrontal cortex.

prefrontal cortex was activated as subjects attended to their during attention to the spatial location of the scenes depicted occipital areas was observed. All picture sets in that study we sought to replicate the previous results in the fMRI pleasant, unpleasant and neutral stimuli on the activation of

Metbods Subjects included four male and one female student ages 21-30. Subjects viewed pictures from the International Affective Picture System using a high-resolution video goggle projection system (Resonance Technologies, San Diego, CA) and attended either to their emotional responses (an intefnal focus of attention) or to the spatial location of the depicted scene (an external focus of attention). There were 4 internal attention conditions defined by picture type: 1) pleasant (P); 2) unpleasant (U); 3) neutral (N); and 4) mixed (P,U,N); and 1 external attention condition consisting of 5) mixed (P,U,N) pictures. During conditions l-4 subjects made a keypad rating of the feeling induced by the picture (P, U or N); during condition 5 they rated whether the scene depicted was indoors, outdoors or indeterminate. The 450 pictures (no repeats)‘were presented for 500 msec each with an interstimulus interval of 3.0 sec. Each condition, consisting of 6 pictures, was repeated 15 times (90 TRs each). The serial order of conditions was counterbalanced within and across subjects. Imaging was performed with a 1.5 T Signa echospeed scanner (General Electric, Milwaukee, WI) using a single-shot spiral acquisition sequence. Image processing and statistical analysis of 450 T2* fMRl volumes (TR 3.0 set, 64x64~23, 3.5x3.5x5) were performed with AFNI. Significant activation was defined as a minimum cluster size of 3 voxels (each p<.Ol) within a 4 mm radius. Results Reaction time was slightly greater for the external (x= 1324 msec) vs. internal (x= 1286 msec) attention conditions (t=3.0, pc.05). The accuracy of keypad responses (relative to normative values) during the internal (x=69% correct) and external (x=77% correct) attention conditions was comparable (t=2.0, NS). The accuracy rates for P (x=79%), U (x=80%) and N (x=55%) internal attention conditions were significantly different (F,,,=4.3, p<.O5). In 5 of 5 subjects medial prefrontal cortex (BA8, 9) was activated during the mixed internal relative to the mixed external attention conditions, replicating PET results (see figure of single subject; peak activity in medial prefrontal cortex: r = .39; p
by NIMH

MHO0972

to RDL

and the University

S926

of Arizona

Cognition

and Neuroimaging

Laboratories.