Schlund, M. W. & Cataldo, M. F. (2005).
Integrating functional neuroimaging and human operant research: Brain activation
correlated with presentation of discriminative stimuli.
Journal of the Experimental Analysis of Behavior, 84, 505-
519.
Results of numerous human imaging studies and nonhuman neurophysiological
studies on “reward” highlight a role for frontal, striatal, and thalamic regions
in operant learning. By integrating operant and functional neuroimaging
methodologies, the present investigation examined brain activation to two types
of discriminative stimuli correlated with different contingencies. Prior to
neuroimaging, 10 adult human subjects completed operant discrimination training
in which money was delivered following button pressing (press-money contingency)
in the presence of one set of discriminative stimuli, and termination of trials
followed not responding (no response-next trial contingency) in the presence of
a second set of discriminative stimuli. After operant training, subjects were
instructed to memorize a third set of control stimuli unassociated with
contingencies. Several hours after training, functional magnetic resonance
imaging was performed while subjects viewed discriminative and control stimuli
that were presented individually for 1,500 ms per trial, with stimulus
presentations occurring, on average, every 6 s. Activation was found in frontal
and striatal brain regions to both sets of discriminative stimuli relative to
control stimuli. In addition, exploratory analyses highlighted activation
differences between discriminative stimuli. The results demonstrate the utility
of coupling operant and imaging technologies for investigating the neural
substrates of operant learning in humans.
Key words: neuroimaging, discriminative stimulus, striatum, caudate, observing,
human