Search results for "Periaqueductal Gray"
showing 6 items of 6 documents
Central functional response to the novel peptide cannabinoid, hemopressin.
2013
Hemopressin is the first peptide ligand to be described for the CB₁ cannabinoid receptor. Hemopressin acts as an inverse agonist in vivo and can cross the blood-brain barrier to both inhibit appetite and induce antinociception. Despite being highly effective, synthetic CB₁ inverse agonists are limited therapeutically due to unwanted, over dampening of central reward pathways. However, hemopressin appears to have its effect on appetite by affecting satiety rather than reward, suggesting an alternative mode of action which might avoid adverse side effects. Here, to resolve the neuronal circuitry mediating hemopressin's actions, we have combined blood-oxygen-level-dependent, pharmacological-ch…
Transient and sustained BOLD signal time courses affect the detection of emotion-related brain activation in fMRI.
2014
A tremendous amount of effort has been dedicated to unravel the functional neuroanatomy of the processing and regulation of emotion, resulting in a well-described picture of limbic, para-limbic and prefrontal regions involved. Studies applying functional magnetic resonance imaging (fMRI) often use the block-wise presentation of stimuli with affective content, and conventionally model brain activation as a function of stimulus or task duration. However, there is increasing evidence that regional brain responses may not always translate to task duration and rather show stimulus onset-related transient time courses. We assume that brain regions showing transient responses cannot be detected in…
Beyond the amygdala: Linguistic threat modulates peri-sylvian semantic access cortices
2015
In this study, healthy volunteers were scanned using functional magnetic resonance imaging (fMRI) to investigate the neural systems involved in processing the threatening content conveyed via visually presented “threat words.” The neural responses elicited by these words were compared to those elicited by matched neutral control words. The results demonstrate that linguistic threat, when presented in written form, can selectively engage areas of lateral temporal and inferior frontal cortex, distinct from the core language areas implicated in aphasia. Additionally, linguistic threat modulates neural activity in visceral/emotional systems (amygdala, parahippocampal gyrus and periaqueductal gr…
Elevated [18F]FDOPA utilization in the periaqueductal gray and medial nucleus accumbens of patients with early Parkinson's disease
2010
Udgivelsesdato: 2010-Feb-15 PET studies with the DOPA decarboxylase substrate 6-[(18)F]fluoro-l-DOPA (FDOPA) reveal the storage of [(18)F]-fluorodopamine within synaptic vesicles, mainly of dopamine fibres. As such, FDOPA PET is a sensitive indicator of the integrity of the nigrostriatal dopamine innervation. Nonetheless, there have been several reports of focal elevations of FDOPA utilization in brain of patients with Parkinson's disease (PD), all based on reference tissue methods. To investigate this phenomenon further, we used voxel-wise steady-state kinetic analysis to search for regions of elevated FDOPA utilization (K; ml g(-1) min(-1)) and steady-state trapping (V(d); ml g(-1)) in a …
Distribution of basal-expressed c-fos-like immunoreactive cells of the periaqueductal grey matter of the rat.
1996
The distribution of c-fos proto-oncogene expression has been studied in the periaqueductal grey matter (PAG) of non-intentional-stimulated rats by immunohistochemistry. A mean number of 53 +/- 9 Fos-like immunoreactive cells per hemiPAG, distributed into three groups, dorsolateral, lateral and ventrolateral, was found. The dorsolateral and the lateral groups appeared along the entire rostrocaudal PAG, whereas the ventrolateral group appeared only in the caudal half. These results reveal new data on the number and extent of the longitudinal columns within the hypothetical organization of the PAG. They also indicate a continuous activation of a significant population of neurones in the PAG, i…
Nucleus incertus—An emerging modulatory role in arousal, stress and memory
2011
A major challenge in systems neuroscience is to determine the underlying neural circuitry and associated neurotransmitters and receptors involved in psychiatric disorders, such as anxiety and depression. A focus of many of these studies has been specific brainstem nuclei that modulate levels of arousal via their ascending monoaminergic projections (e.g. the serotonergic dorsal raphe, noradrenergic locus ceruleus and cholinergic laterodorsal tegmental nucleus). After years of relative neglect, the subject of recent studies in this context has been the GABAergic nucleus incertus,1 which is located in the midline periventricular central gray in the ‘prepontine’ hindbrain, with broad projection…