Brain representation of habituation to repeated complex visual stimulationstudied with PET

To investigate CNS habituation (i.e. response decrement due to stimulus rep etition) the present study used positron emission tomography (PET) to measu re regional cerebral blood flow (rCBF) in eight healthy women during two re petitions of complex visual stimuli. Repeated visual stimulation resulted i n neural habituation bilaterally in the secondary visual cortex and in the right medial temporal cortex including the amygdala and the hippocampus. Re gional CBF in the left thalamus was elevated as a function of repeated stim uli presentations. Thus, repeated presentation of complex visual stimuli re sult in rCBF habituation in later stages of the visual processing chain. Th e elevated neural activity in the thalamus might be associated with interru ption of further neural transmission related to suppression of non-meaningf ul behavior. NeuroReport 11:123-126 (C) 2000 Lippincott Williams & Wilkins.