Brain representation of habituation to repeated complex visual stimulation studied with PET

Abstract

To investigate CNS habituation (i.e. response decrement due to stimulus repetition) the present study used positron emission tomography (PET) to measure regional cerebral blood flow (rCBF) in eight healthy women during two repetitions of complex visual stimuli. Repeated visual stimulation resulted in neural habituation bilaterally in the secondary visual cortex and in the right medial temporal cortex including the amygdala and the hippocampus. Regional CBF in the left thalamus was elevated as a function of repeated stimuli presentations. Thus, repeated presentation of complex visual stimuli result in rCBF habituation in later stages of the visual processing chain. The elevated neural activity in the thalamus might be associated with interruption of further neural transmission related to suppression of non-meaningful behavior.

Habituation of Rostral Anterior Cingulate Cortex to Repeated Emotionally Salient Pictures

“…This is consistent with earlier work demonstrating that the prefrontal cortex, amygdala, and hippocampus habituate as the salience of the stimuli decreases with repetition (Breiter et al, 1996;Feinstein et al, 2002;Fischer et al, 2000;Whalen et al, 1998b;Wright et al, 2001). In addition to these regions, our findings suggest that the rACC also exhibits phasic temporal modulation of its activity by prior exposure, and that multiple interconnected brain regions (rACC, amygdala, hippocampus) undergo habituation during emotional processing.…”

“…These findings extend earlier evidence of habituation of limbic subcortical (eg amygdala, hippocampus) and cortical (DLFPC, precentral gyrus) regions because of successive viewing of emotional faces and other salient visual stimuli (Breiter et al, 1996;Feinstein et al, 2002;Fischer et al, 2000;Irwin et al, 1996;Whalen et al, 1998b;Wright et al, 2001). Interestingly, although the decrement in response (from T1 to T2) did not exceed our predetermined statistical threshold, we did find significant activations in hippocampus, extended amygdala, and amygdala during the first, but not second, presentation of aversive pictures suggesting that some habituation also occur in these regions as expected.…”

“…To minimize false positive activations, we only accepted activations with a spatial extent exceeding five contiguous voxels, based on our smoothing kernel of 8 mm FWHM. In order to determine the regional specificity of habituation, we also examined brain areas (sensory-motor cortex) that we would not expect to habituate (Feinstein et al, 2002;Fischer et al, 2000;Wright et al, 2001) such as the premotor/motor cortex, occipital cortex, and cerebellum serving as 'control regions' at the same threshold. For nonpredicted regions, we report activation foci exceeding a threshold of Z45.30 (po0.05, corrected).…”

“…Specifically, several groups have demonstrated that the amygdala rapidly habituates to repeated presentations of emotional faces (Breiter et al, 1996;Whalen et al, 1998b;Wright et al, 2001) and pictures (Fischer et al, 2000;Irwin et al, 1996). These studies suggest that activity in subcortical limbic regions (eg amygdala, hippocampus) may be modulated by repeated exposure.…”

Always on guard: emotion regulation in women with

“…3). Additional timing analysis, taking the fast habituation of amygdala responses into account, 34,35 could not explain this null finding. The right amygdala showed a significant stimulus × group interaction during the first run; however, the simple effect revealed no group differences, but rather increased activity during negative versus neutral stimuli in both groups.…”