Table 2.

Cortical Regions Showing Positive or Negative Correlations between rCBF Response and Task Difficulty before and during Physostigmine Infusion

			Placeboa				Physostigmine				Task × Drug Interaction
Brain Areas	BA	Hem	Z Score	x	y	zb	Z Score	x	y	z	Z Score	x	y	z
Positive Correlation
Anterior middle frontal	9/46	R	2.97	26	45	13					3.45	26	45	13
Inferior frontal	45	R	2.89	33	28	5
Cingulate	32	R	2.83	19	37	2					2.17	20	32	−2
	34	R									2.1	19	4	−11
Basal ganglia		R	2.59	8	1	3					2.9	13	−3	3
		R	2.13	6	10	4					1.91	17	4	−4
		R	2.05	8	16	−3
Negative Correlation
Occipital	18	R	4.65	31	−79	−11	4.59	31	−69	−21
		R	4.01	41	−63	−18	3.77	31	−83	−15
		R	2.93	13	−87	−22	3.74	26	−85	−22
	18	L	2.87	−34	−85	−19	2.93	−27	−71	−18
	18	L	2.58	−25	−67	−14	2.8	−40	−71	−18
	19	L	2.18	−29	−91	−16	2.63	−25	−85	2

^aSearch volumes for correlation analyses were restricted by the masks that identified brain regions responding to task during placebo and during drug. Statistical significance was assumed at an individual voxel level of p < .005 and required 50 contiguous significant voxels.

^bTalairach and Tournoux (1988) brain atlas coordinates: x = distance in millimeters to the right (+) or to the left (−) of the midline; y = distance anterior (+) or posterior (−) to the anterior commissure; z = distance superior (+) or inferior (−) to a horizontal plane through the anterior and posterior commissures.