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The understanding of individual differences in responses to disgusting stimuli is important to gain more insight into the development of certain psychiatric disorders. The aim of this study was to investigate conditioned disgust responses, its potential overlap with conditioned fear responses (CRs) and the influence of disgust sensitivity on blood oxygen level-dependent responses. Yet even though current studies report evidence that disgust sensitivity is a vulnerability factor, the knowledge about the underlying neural mechanisms remains very limited. Two groups were exposed either to a disgust- or a fear-conditioning paradigm. Using functional magnetic resonance imaging, we identified a conjoint activated network including the cingulate cortex, the nucleus accumbens, the orbitofrontal cortex, and the occipital cortex within the disgust- and the fear-conditioning group. Moreover, we report evidence of increased insula activation in the disgust-conditioning group. In addition, functional connectivity analysis revealed increased interconnections, most pronounced within the insula in the high disgust sensitivity group compared with the low disgust sensitivity group. The conjunction results suggest that the conditioned responses in disgust and fear conditioning recruit the same neural network, implicating that different conditioned responses of aversive learning depend on a common neural network. Increased insula activation within the disgust-conditioning group might be attributable to heightened interoceptive processes, which might be more pronounced in disgust. Finally, the findings regarding disgust sensitivity are discussed with respect to vulnerability factors for certain psychiatric disorders.
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BACKGROUND AND PURPOSE: In PD, tissue damage occurs in specific cortical and subcortical regions. Conventional MR images have only limited capacity to depict these structural changes. The purpose of the current study was to investigate whether voxel-based MT imaging could indicate structural abnormalities beyond atrophy measurable with T1-weighted MR imaging. MATERIALS AND METHODS: Thirty-six patients with PD without dementia (9 in H&Y stage 1, thirteen in H&Y 2, eleven in H&Y 3, three in H&Y 4) and 23 age-matched control subjects were studied with T1-weighted MR imaging and MT imaging. Voxel-based analyses of T1-weighted MR imaging was performed to investigate brain atrophy, while MT imaging was used to study abnormalities within existing tissue. Modulated GM and WM probability maps, sensitive to volume, and nonmodulated maps, indicative of tissue density, were obtained from T1-weighted MR imaging. Effects seen on MTR images, but absent on density maps, were attributed to damage of existing tissue. RESULTS: Contrary to T1-weighted MR imaging, MT imaging was sensitive to the progression of brain pathology of the neocortex and paraventricular WM. MTR images and T1-based volume images, but not density images, showed a progression of disease in the olfactory cortex, indicating the occurrence of atrophy as well as damage to existing tissue in this region. MTR images revealed bilateral damage to the SN, while T1-weighted MR imaging only showed left-sided abnormalities. CONCLUSIONS: The findings suggest that voxel-based MT imaging permits a whole-brain unbiased investigation of CNS structural integrity in PD and may be a valuable tool for identifying structural damage occurring without or before measurable atrophy.
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Executive working memory operations are related to prefrontal regions in the healthy brain. Moreover, neuroimaging data provide evidence for a functional dissociation of ventrolateral and dorsolateral prefrontal cortex. Most authors either suggest a modality-specific or a function-specific prefrontal cortex organization. In the present study we particularly aimed at the identification of different prefrontal cerebral areas that are involved in executive inhibitory processes during spatial working memory encoding. In an fMRI study (functional magnetic resonance imaging) we examined the neural correlates of spatial working memory processing by varying the amount of executive demands of the task. Twenty healthy volunteers performed the Corsi Block-Tapping test (CBT) during fMRI. The CBT requires the storage and reproduction of spatial target sequences. In a second condition, we presented an adapted version of the Block-Suppression-Test (BST). The BST is based on the original CBT but additionally requires the active suppression of visual distraction within the target sequences. In comparison to the CBT performance, particularly the left dorsolateral prefrontal cortex (BA 9) showed more activity during the BST condition. Our results show that the left dorsolateral prefrontal cortex plays a crucial role for executive controlled inhibition of spatial distraction. Furthermore, our findings are in line with the processing model of a functional dorsolateral-ventrolateral prefrontal cortex organization.
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Team
- Vaitl (3)
Eintragsart
Sprache
- Englisch (3)
Thema
- Male
- Adult (2)
- Algorithms (1)
- Attention (1)
- Brain (3)
- Brain Mapping (2)
- Conditioning, Psychological (1)
- Executive Function (1)
- Expressed Emotion (1)
- Fear (1)
- Female (3)
- Galvanic Skin Response (1)
- Humans (3)
- Image Enhancement (1)
- Image Interpretation, Computer-Assisted (1)
- Image Processing, Computer-Assisted (1)
- Imaging, Three-Dimensional (1)
- Magnetic Resonance Imaging (3)
- Memory, Short-Term (1)
- Middle Aged (1)
- Neuropsychological Tests (1)
- Oxygen (1)
- Parkinson Disease (1)
- Photic Stimulation (1)
- Prefrontal Cortex (1)
- Reaction Time (1)
- Reproducibility of Results (1)
- Sensitivity and Specificity (1)
- Space Perception (1)
- Young Adult (2)