Background-The cause of dementia in subcortical ischemic vascular disease (SIVD) is controversial.

Previous animal and human studies showed that photic stimulation (PS) increased cerebral blood flow and glucose uptake much more than oxygen consumption, suggesting selective activation of anaerobic glycolysis. In the present studies, image-guided 1H and 31P magnetic resonance spectroscopy (MRS) was used to monitor the changes in lactate and high-energy phosphate concentrations produced by PS of visual cortex in six normal volunteers. PS initially produced a significant rise (to 250% of control, p less than 0.01) in visual cortex lactate during the first 6.4 min of PS, followed by a significant decline (p = 0.01) as PS continued. The PCr/Pi ratios decreased significantly from control values during the first 12.8 min of PS (p less than 0.05), and the pH was slightly increased. The positive P100 deflection of the visual evoked potential recorded between 100 and 172 ms after the strobe was significantly decreased from control at 12.8 min of PS (p less than 0.05). The finding that PS caused decreased PCr/Pi is consistent with the view that increased brain activity stimulated ATPase, causing a rise in ADP that shifted the creatine kinase reaction in the direction of ATP synthesis. The rise in lactate together with an increase in pH suggest that intracellular alkalosis, caused by the shift of creatine kinase, selectively stimulated glycolysis.

Our data showed that elderly alcoholics that drank late into life, but with at least 6 months abstinence can exhibit normal cognitive functioning. Selective survivorship and selection bias probably play a part in these findings. Cognitively healthier alcoholics, with more brain reserve capacity, may be more likely to live into their 60s, 70s, or 80s of age with relatively intact cognition, and to volunteer for studies such as this. Our results do not imply that all elderly alcoholics with long-term abstinence will attain normal cognition.

Background-Most studies of the impact of alcohol dependence on the brain have examined individuals in treatment. Such samples represent a small proportion of alcoholics in the general population. Such samples may embody a bias ('Berkson's fallacy') if the association between variables (for example, alcoholism and cortical gray matter loss) differs between the population of alcoholics in treatment and alcoholics in the general population. Our objective was to determine if treatment-naive alcoholics show structural brain changes versus controls, and to compare our findings with reports evaluating alcoholic samples drawn from treatment populations.

No abstract

Hippocampal atrophy detected by MRI is a prominent feature of early Alzheimer's disease (AD), but it is likely that MRI underestimates the degree of hippocampal neuron loss, because reactive gliosis attenuates atrophy. We tested the hypothesis that hippocampal N-acetyl aspartate (NAA: a neuronal marker) and volume used together provide greater discrimination between AD and normal elderly than does either measure alone. We used proton MR spectroscopic imaging (1H MRSI) and tissue segmented and volumetric MR images to measure atrophy-corrected hippocampal NAA and volumes in 12 AD patients (mild to moderate severity) and 17 control subjects of comparable age. In AD, atrophy-corrected NAA from the hippocampal region was reduced by 15.5% on the right and 16.2% on the left (both p < 0.003), and hippocampal volumes were smaller by 20.1% (p < 0.003) on the right and 21.8% (p < 0.001) on the left when compared with control subjects. The NAA reductions and volume losses made independent contributions to the discrimination of AD patients from control subjects. When used separately, neither hippocampal NAA nor volume achieved to classify correctly AD patients better than 80%. When used together, however, the two measures correctly classified 90% of AD patients and 94% of control subjects. In conclusion, hippocampal NAA measured by 1H MRSI combined with quantitative measurements of hippocampal atrophy by MRI may improve diagnosis of AD.

This study tested the hypotheses that older adults make less advantageous decisions than younger adults on the Iowa gambling task (IGT). Less advantageous decisions, as measured by the IGT, are characterized by choices that favor larger versus smaller immediate rewards, even though such choices may result in long-term negative consequences. The IGT, and measures of neuropsychological function, personality, and psychopathology were administered to 164 healthy adults 18-85 years of age. Older adults performed less advantageously on the IGT compared with younger adults. Additionally, a greater number of older adult's IGT performances were classified as 'impaired' when compared to younger adults. Less advantageous decisions were associated with obsessive symptoms in older adults and with antisocial symptoms in younger adults. Performance on the IGT was positively associated with auditory working memory and psychomotor function in young adults, and in immediate memory in older adults.

BACKGROUND-Alcoholism is characterized by impaired decision-making (i.e., choosing intoxication in the face of mounting negative consequences). This impairment may involve a reduced brain response to the negative consequences of behavior, which supports an inclination to engage in risky behaviors. The feedback error-related negativity (F-ERN) is hypothesized to reflect the valence attached to the negative consequences of behavior. Performance on the Balloon Analogue Risk Task (BART) measures risk-taking propensity. We recorded F-ERNs during the BART and during a BART simulation, where individuals observed the rewards and consequences of (someone else's) BART performance.METHODS-EEGs were recorded on 22 actively drinking, treatment-naïve alcoholics during the BART and BART simulation. F-ERNs were measured and their association with psychological and alcohol use measures was examined. RESULTS-F-ERNsover fronto-central electrode sites were observed to balloon pops in the BART and BART simulation. F-ERNs during the BART were more than twice the amplitude of F-ERNs during the BART simulation. Smaller F-ERN amplitudes from the BART (but not the BART simulation) were associated with a greater family history density of alcohol problems. CONCLUSION-The results suggest a possible link between the genetic vulnerability toward developing alcoholism and the brain's response to the negative consequences of behavior.