Table 1.

Recognition performance for pictures and wordsleft most image in each row relative to the AC-PC line. The right side of the image represents the right side of the brain. (A) Brain areas with increased rCBF during encoding of pictures are shown in yellow and red, and areas with increased activity during encoding of words are shown in blue (LV1). (B) Brain areas with increased rCBF during semantic encoding, compared with the other two conditions (LV2), are shown in red. (C) Brain areas with increased rCBF during intentional learning, compared with the other two conditions (LV3), are shown in red. Selected maxima from these regions are shown in Table 2.

Encoding condition	Pictures	Words
Incidental nonsemantic	64.8 ± 3.5	46.1 ± 4.9
Incidental semantic	73.0 ± 3.4	73.5 ± 4.6
Intentional learning	83.9 ± 2.6	76.9 ± 4.6

Values are percent of “old” items correctly identified (i.e., proportion of hits) expressed as mean ± SE. N = 23 [12 subjects from pilot study and 11 from positron emission tomography study (one positron emission tomography subject had missing data)]. There was a significant main effect of stimulus type (F = 10.1, P < 0.004), a significant main effect of encoding condition (F = 39.4, P < 0.0001), and a significant interaction of stimulus type and encoding (F = 4.2, P < 0.025).