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At least 1,153 records · Page 64Linked to original sources
PubMed2000

A preliminary functional brain study on amputees.

The purpose of this study was to verify whether brain activation could be used to modulate the movements of an artificial limb. This approach was begun 20 years ago with the fitting of prostheses immediately following lower-limb amputations. We studied 9 unilateral amputees and 9 control participants using functional MRI, electroneuromyography, gait laboratory, and neuropsychological assessments. The results demonstrated that brain activation is analogous when participants in the control group are asked to mentally move a foot, compared with amputees who are asked to move a nonexistent foot. The brain has not been damaged and maintains its areas of command. This can be applied in rehabilitation.

Adolescent↗
PubMed2004

Functional brain asymmetries during visuomotor tracking.

This study examined brain asymmetries elicited during visuomotor tracking. Thirty-two healthy participants performed a fixed gaze, dynamic, pinch force, visuomotor tracking task during a functional magnetic resonance imaging study. The dynamic task required the subject to press a rubber bulb with the thumb to trace a cosine square wave varying in force amplitude from 0-500 cN and having a frequency of 1.5 Hz. Response hand order and direction of the stimulus presentation (right-to-left or left-to-right) were permuted across participants. Two forms of functional cerebral asymmetry were observed, hemispheric specialization and homologous lateralized response. The superior portion of the right middle frontal gyrus and the left supplementary motor area appeared specialized for VM tracking regardless of response hand used or stimulus movement direction. Lateralized effects appeared in the primary sensorimotor hand area, putamen, parietal operculum/posterior insula, dentate nucleus of the cerebellum, precuneus, and middle occipital gyrus. These lateralized areas of activation surfaced when either response hand or direction of stimulus movement was manipulated. The VM task used in this study activated asymmetrical neural activity in the vertically organized skelotomotor system and in sensory systems involving visual attention or proprioception.

Adult↗
PubMed1999

Present and future capabilities of molecular imaging techniques to understand brain function.

This article focuses on the use of positron emitting tracers and positron emission tomography (PET) as the most specific and sensitive means for imaging molecular interactions and pathways within the human brain. The concept of the imaging science of PET is developed whereby the key components that contribute to the overall accuracy of the image of molecular activity need to be separately optimized. These include radiolabelling of tracer molecules and ligands with radioisotopes of short radioactive half-life, the search for specific radioligands and tracers, and hence the need to mine molecular databases for molecules suitable for in-vivo imaging. The sensitivity and accuracy of PET scanners need to be advanced along with improvements in the signal-to-noise ratio of the tomographic reconstruction algorithms. Finally, the models used for the analysis of serial time frames of kinetic data need to be developed, the operation of which have to be effected with the minimum of noise propagation. The future use of PET for drug discovery and development is discussed whereby it offers proof principle for assays of in-vivo expression of therapeutic molecular targets as accessed from the blood stream; tissue pharmacokinetics of novel compounds; degree of occupancy of molecular targets; and pharmacodynamic measures of drug action. The future application of PET rests heavily on drug discoverers contributing to discovering specific PET radioligands and tracers in order to provide these assays through in-vivo molecular imaging.

Algorithms↗
PubMed2005

Developmental changes in the functional brain responses of adolescents to images of high and low-calorie foods.

We examined cerebral responses to visually presented food images in children and adolescents. Eight healthy normal-weight females (ages 9-15) underwent functional magnetic resonance imaging (fMRI) while viewing photographs of high- and low-calorie foods and dining utensils. In general, food images yielded significant activation within the inferior orbitofrontal cortex, hippocampus, and fusiform gyri. High calorie food images activated the left hippocampus and subgenual cingulate, and age correlated positively with activity within the orbitofrontal cortex but negatively with activity within the anterior cingulate gyrus. Low-calorie foods activated the fusiform gyrus and demonstrated age-related increases in the left superior temporal gyrus and anterior cingulate. Utensils activated the fusiform gyrus and showed age-related increases in the prefrontal cortex. Data were also compared statistically to a sample of adults exposed to the same stimulus conditions. Findings support a developmental model of adolescent maturation whereby age-related changes in cerebral functioning develop from lower-order sensory processing toward higher-order processing of stimuli via prefrontal cortical systems involved in reward anticipation, self-monitoring, and behavioral inhibition.

Adolescent↗
PubMed2006

Patterns of fMRI activity dissociate overlapping functional brain areas that respond to biological motion.

Accurate perception of the actions and intentions of other people is essential for successful interactions in a social environment. Several cortical areas that support this process respond selectively in fMRI to static and dynamic displays of human bodies and faces. Here we apply pattern-analysis techniques to arrive at a new understanding of the neural response to biological motion. Functionally defined body-, face-, and motion-selective visual areas all responded significantly to "point-light" human motion. Strikingly, however, only body selectivity was correlated, on a voxel-by-voxel basis, with biological motion selectivity. We conclude that (1) biological motion, through the process of structure-from-motion, engages areas involved in the analysis of the static human form; (2) body-selective regions in posterior fusiform gyrus and posterior inferior temporal sulcus overlap with, but are distinct from, face- and motion-selective regions; (3) the interpretation of region-of-interest findings may be substantially altered when multiple patterns of selectivity are considered.

Adult↗
PubMed2001

RNAi and brain function: was McConnell on the right track?

RNA interference (RNAi), one of the hottest topics of molecular biology research today, has unique features that are eerily reminiscent of the phenomenon of "RNA-mediated memory transfer," a controversial line of work that was investigated with great enthusiasm in the 1960s. If not a coincidence, then this suggests taking a new look at RNA-mediated modulation of neural function and raises the possibility that RNAi might be one of the physiologic mechanisms that regulate long-term gene expression in the brain.

Animals↗
PubMed2006

[Research on effect of acupuncture at Sanyinjiao on brain function by means of positron emission tomographic imaging].

OBJECTIVE: To explore the mechanism of puncturing at Sanyinjiao (SP6) on modulatory function of central nerve system. METHODS: Positron emission tomography (PET) was performed, using 18F-FDG as contrast medium, in six healthy female volunteers before and after puncturing right SP6 to detect the cerebral districts with changed glucose metabolism, using statistical parametric mapping (SPM) analysis. RESULTS: Glucose metabolism was increased in contralateral primary somatosensory cortex, primary somatic motor cortex, pre-supplementary motor cortex (BA8), and medial prefrontal cortex (BA10), bilateral supplementary motor cortex (BA6), anterior cingulate gyrus (BA24, BA32), and dorsolateral prefrontal cortex (BA9), while glucose metabolism was decreased in lingual gyrus (BA17,18), hippocampus and parahippocampal gyrus (BA28, BA35, BA30). CONCLUSION: Functions of cerebral districts with changed glucose metabolism after puncturing SP6 was well parallels to the clinical effect of puncturing SP6, illustrating the brain plays a great role in the body regulation of acupuncture at SP6, which possibly was the central foundation of acupuncture therapy.

Acupuncture↗
PubMed1996

Pharmacological effects of phosphatidylserine enzymatically synthesized from soybean lecithin on brain functions in rodents.

Soybean transphosphatidylated phosphatidylserine (SB-tPS) was prepared from soybean phosphatidylcholine by transphosphatidylation using phospholipase D, and the fatty acids composition and pharmacological properties were compared with those of bovine brain cortex-derived phosphatidylserine (BC-PS) which was reported to improve cognitive disorders of senile dementia patients by oral administration (300 mg/day). The molecular species of SB-tPS are rich in linoleic and palmitic acids whereas those of BC-PS are stearic and oleic acids. Despite the differences in fatty acid composition, SB-tPS displayed significant activities on the increase in brain glucose concentrations in mice (79 mg/kg, i.v.) and the restoration of scopolamine-induced amnesia in rats (60 mg/kg, i.p.) as did BC-PS. These results suggest the possibility that SB-tPS may prevent and/or improve senile dementia by oral administration.

Amnesia↗