Biomedical subjects

Stuart Derbyshire

Publications and source records attributed to Stuart Derbyshire.

3 recordsLinked to original sources

PubMed2005

Education-associated cortical glucose metabolism during sustained attention.

Despite research suggesting that education may mitigate cognitive sequelae of neural injury, little is known about interactions between education and regional brain function. We examined whether educational experience is associated with relative glucose metabolism in brain regions that are important for sustained attention and learning. Fourteen healthy adults, with 12-18 years of schooling, underwent positron emission tomography scanning with 18F-fluorodeoxyglucose during an auditory continuous discrimination task. Years of education correlated positively with relative glucose metabolism in the lingual gyri (bilaterally), left posterior cingulate gyrus, and left precuneus. Previously, these structures have shown early impairment in dementia. Further investigation should explore whether metabolic changes in these regions contribute to the possible protective effect of education on cognition.

Adult↗

PubMed2005

Brain control of normal and overactive bladder.

PURPOSE: Bladder control problems are common but their cause is often unclear. Many investigators have sought causes in the lower urinary tract, but fewer in the supraspinal control system. We have used functional magnetic resonance imaging (fMRI) to determine brain responses to bladder filling in subjects with normal and with poor bladder control (detrusor overactivity). MATERIALS AND METHODS: Cerebral responses to bladder infusion were recorded in 1 male and 11 females without overt neurological abnormality, aged 26 to 83 years. Six had good bladder control and 6 had poor control on prior urodynamics. fMRI was performed while repeatedly infusing and withdrawing liquid into and out of the bladder, and monitoring intravesical pressure. Measurements were made at small and large bladder volumes. RESULTS: fMRI detected activation of many brain regions involved in bladder control, including periaqueductal gray, thalamus, insula, dorsal anterior cingulate, and ventromedial cerebellum. Orbitofrontal cortex, pontine micturition center and preoptic hypothalamus were visible in subgroup analyses. Activations outweighed deactivations and responses became stronger at large bladder volumes. Among subjects with good control, this strengthening of response was prominent in the orbitofrontal cortex. Among those with poor control cortical responses were exaggerated at larger bladder volumes, except in the orbitofrontal cortex, which remained weakly activated. This difference was not due to concurrent detrusor activity. CONCLUSIONS: Poor bladder control is specifically associated with inadequate activation of orbitofrontal cortex. Clinically, frontal cortical lesions cause bladder control problems. This study suggests a similar neurophysiological basis for poor bladder control in the absence of overt neurological lesion.

Adult↗

PubMed2003

Brain responses to visceral and somatic stimuli in patients with irritable bowel syndrome with and without fibromyalgia.

OBJECTIVE: Symptoms of irritable bowel syndrome (IBS) and fibromyalgia (FM) commonly coexist. We hypothesized that one of the mechanisms underlying this comorbidity is increased activation of brain regions concerned with the processing and modulation of visceral and somatic afferent information, in particular subregions of the anterior cingulate cortex (ACC). METHODS: Regional cerebral blood flow (rCBF) was assessed in age-matched female IBS (n = 10) and IBS + FM (n = 10) subjects using H(2)(15)O positron emission tomography during noxious visceral (rectal) and somatic pressure stimuli. RESULTS: GI symptom severity was significantly higher in the IBS patients compared with the IBS + FM patients (p < 0.05). In addition, IBS + FM patients rated somatic pain as more intense than their abdominal pain (p < 0.05). Whereas the somatic stimulus was less unpleasant than the visceral stimulus for IBS patients without FM, the somatic and visceral stimuli were equally unpleasant in the IBS + FM group. Group differences in regional brain activation were entirely within the middle subregion of the ACC. There was a greater rCBF increase in response to noxious visceral stimuli in IBS patients and to somatic stimuli in IBS + FM patients. CONCLUSION: Chronic stimulus-specific enhancement of ACC responses to sensory stimuli in both syndromes may be associated with cognitive enhancement of either visceral (IBS) or somatic (IBS + FM) sensory input and may play a key pathophysiologic role in these chronic pain syndromes.

Adult↗