Time and decision making: differential contribution of the posterior insular cortex and the striatum during a delay discounting task

• Published in: Experimental brain research 2007-06, Vol.179 (4), p.643-653
• Main Authors: WITTMANN, Marc, LELAND, David S, PAULUS, Martin P
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Anatomical correlates of behavior; Behavioral psychophysiology; Biological and medical sciences; Brain Mapping; Caudate Nucleus - anatomy & histology; Caudate Nucleus - physiology; Cerebral Cortex - anatomy & histology; Cerebral Cortex - physiology; Corpus Striatum - anatomy & histology; Corpus Striatum - physiology; Decision making; Decision Making - physiology; Female; Functional Laterality - physiology; Fundamental and applied biological sciences. Psychology; Humans; Hyperactivity; Impulsivity; Judgment - physiology; Magnetic Resonance Imaging; Male; Monte Carlo Method; Motor control and motor pathways. Reflexes. Control centers of vegetative functions. Vestibular system and equilibration; Nerve Net - anatomy & histology; Nerve Net - physiology; Neuropsychological Tests; Neurosciences; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Putamen - anatomy & histology; Putamen - physiology; Reward; Time Factors; Time Perception - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0014-4819; 1432-1106
• DOI: 10.1007/s00221-006-0822-y

Delay discounting refers to the fact that an immediate reward is valued more than the same reward if it occurs some time in the future. To examine the neural substrates underlying this process, we studied 13 healthy volunteers who repeatedly had to decide between an immediate and parametrically varied delayed hypothetical reward using a delay discounting task during event-related functional magnetic resonance imaging. Subject's preference judgments resulted in different discounting slopes for shorter ( or =1 year) delays. Neural activation associated with the shorter delays relative to the longer delays was associated with increased activation in the head of the left caudate nucleus and putamen. When individuals selected the delayed relative to the immediate reward, a strong activation was found in bilateral posterior insular cortex. Several brain areas including the left caudate nucleus showed a correlation between the behaviorally determined discounting and brain activation for the contrast of intervals with delays or =1 year. These results suggest that (1) the posterior insula, which is a critical component of the decision-making neural network, is involved in delaying gratification and (2) the degree of neural activation in the striatum, which plays a fundamental role in reward prediction and in time estimation, may code for the time delay.