Dopamine transporter imaging is a valuable tool to investigate the integrity of the dopaminergic neurons. To date, several reports have shown an age-associated decline in dopamine transporters in healthy volunteers. Although animal studies suggest an effect of gender on dopamine transporter density, this gender effect has not yet been confirmed in human studies. To study the influence of age and gender on dopamine transporter imaging in healthy volunteers, we performed single-photon emission tomography imaging with [123I]FP-CIT to quantify dopamine transporters. Forty-five healthy volunteers (23 males and 22 females) were included, ranging in age from 18 to 83 years. SPET imaging was performed 3 h after injection of +/-110 MBq [123I]FP-CIT. An operator-independent volume of interest analysis was used for quantification of [123I]FP-CIT binding in the striatum. The ratio of specific striatal to non-specific [123I]FP-CIT binding was found to decrease significantly with age. Moreover, we found a high variance in [123I]FP-CIT binding in young adults. Finally, females were found to have significantly higher [123I]FP-CIT binding ratios than males. This effect of gender on [123I]FP-CIT binding ratios was not related to age. The results of this study are consistent with findings from previous studies, which showed that dopamine transporter density declines with age. The intriguing finding of a higher dopamine transporter density in females than in males is in line with findings from animal studies.

BEP induced clinical recovery in PTSD patients, and appeared to modulate the functioning of specific PTSD-related sites in the prefrontal cortical regions.

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Disturbances in the serotonin (5-HT) system are associated with various neuropsychiatric disorders. The 5-HT system can be studied in vivo by measuring 5-HT transporter (SERT) densities using 123 iodine-labeled 2b-carbomethoxy-3b(4-iodophenyl)tropane ([ 123

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Background There is lack of validation and standardisation of acquisition parameters for myocardial 123

Ecstasy use is associated with tissue changes in the globus pallidus. These findings are in agreement with findings in case reports, suggesting that the globus pallidus is particularly sensitive to the effects of ecstasy.

In this study the dynamic properties of goldfish horizontal cell (HC) receptive fields were evaluated. The size of HC receptive fields increases up to about 60 msec after stimulus onset, and then reduces to a smaller end value. They can therefore not adequately be described by the cable equation. Estimates of the length constant of the HC network based on the sustained responses are about 43% smaller than those based on the initial part of the response. This difference can be accounted for by feedback connections from HCs to cones because negative feedback reduces the receptive field size. The implication is that HCs are strongly coupled when the retina is stimulated more or less homogeneously but that they partly uncouple from the rest of the HC network when they are stimulated differently than the rest of the retina. The HCs thus generate a feedback signal based on the "local" stimulus properties. The size of the HC receptive fields depends on the spatial detail of the stimulus.