Ta. Blaxton et al., FUNCTIONAL MAPPING OF HUMAN LEARNING - A POSITRON EMISSION TOMOGRAPHYACTIVATION STUDY OF EYEBLINK CONDITIONING, The Journal of neuroscience, 16(12), 1996, pp. 4032-4040
Regional cerebral blood flow (rCBF) was measured using positron emissi
on tomography during eyeblink conditioning in young adults. Subjects w
ere scanned in three experimental conditions: delay conditioning, in w
hich binaural tones preceded air puffs to the right eye by 400 msec; p
seudoconditioning, in which presentations of tone and air puff stimuli
were not correlated in time; and fixation rest, which served as a bas
eline control. Compared with fixation, pseudoconditioning produced rCB
F increases in frontal and temporal cortex, basal ganglia, left hippoc
ampal formation, and pens. Learning-specific activations were observed
in conditioning as compared with pseudoconditioning in bilateral fron
tal cortex, left thalamus, right medial hippocampal formation, left li
ngual gyrus, pens, and bilateral cerebellum; decreases in rCBF were ob
served for bilateral temporal cortex, and in the right hemisphere in p
utamen, cerebellum, and the lateral aspect of hippocampal formation. B
lood flow increased as the level of learning increased in the left hem
isphere in caudate, hippocampal formation, fusiform gyrus, and cerebel
lum, and in right temporal cortex and pens. In contrast, activation in
left frontal cortex decreased as learning increased. These functional
imaging results implicate many of the same structures identified by p
revious lesion and recording studies of eyeblink conditioning in anima
ls and humans and suggest that the same brain regions in animals and h
umans mediate multiple forms of associative learning that give meaning
to a previously neutral stimulus.