Positron emission tomography imaging of amphetamine‐induced dopamine release in the human cortex: A comparative evaluation of the high affinity dopamine D2/3 radiotracers [11C]FLB 457 and [11C]fallypride

The use of PET and SPECT endogenous competition binding techniques has contributed to the understanding of the role of dopamine in several neuropsychiatric disorders. An important limitation of these imaging studies is the fact that measurements of acute changes in synaptic dopamine have been restricted to the striatum. The ligands previously used, such as [¹¹C]raclopride and [¹²³I]IBZM, do not provide sufficient signal to noise ratio to quantify D₂ receptors in extrastriatal areas, such as cortex, where the concentration of D₂ receptors is much lower than in the striatum. Given the importance of cortical DA function in cognition, a method to measure cortical dopamine function in humans would be highly desirable. The goal of this study was to compare the ability of two high affinity DA D₂ radioligands [¹¹C]FLB 457 and [¹¹C]fallypride to measure amphetamine‐induced changes in DA transmission in the human cortex. D₂ receptor availability was measured in the cortical regions of interest with PET in 12 healthy volunteers under control and postamphetamine conditions (0.5 mg kg^?1, oral), using both [¹¹C]FLB 457 and [¹¹C]fallypride (four scans per subjects). Kinetic modeling with an arterial input function was used to derive the binding potential (BP_ND) in eight cortical regions. Under controlled conditions, [¹¹C]FLB 457 BP_ND was 30–70% higher compared with [¹¹C]fallypride BP_ND in cortical regions. Amphetamine induced DA release led to a significant decrease in [¹¹C]FLB 457 BP_ND in five out the eight cortical regions evaluated. In contrast, no significant decrease in [¹¹C]fallypride BP_ND was detected in cortex following amphetamine. The difference between [¹¹C]FLB 457 and [¹¹C]fallypride ability to detect changes in the cortical D₂ receptor availability following amphetamine is related to the higher signal to noise ratio provided by [¹¹C]FLB 457. These findings suggest that [¹¹C]FLB 457 is superior to [¹¹C]fallypride for measurement of changes in cortical synaptic dopamine. Synapse 63:447–461, 2009. © 2009 Wiley‐Liss, Inc.     

Attitudes of Major Employers Toward the Employment of People with Epilepsy: A 30-Year Study

Beginning in 1956, major San Francisco Bay area employers were sampled at 10-year intervals for a 30-year period to assess attitudes toward the employment of epileptic workers. In this time, we documented a trend of sustained positive change that appears to validate the efforts of organizations that have focused on raising public awareness of this disorder.     

False rape allegations

With the cooperation of the police agency of a small metropolitan community, 45 consecutive, disposed, false rape allegations covering a 9 year period were studied. These false rape allegations constitute 41% the total forcible rape cases (n =109) reported during this period. These false allegations appear to serve three major functions for the complainants: providing an alibi, seeking revenge, and obtaining sympathy and attention. False rape allegations are not the consequence of a gender-linked aberration, as frequently claimed, but reflect impulsive and desperate efforts to cope with personal and social stress situations.     

Date rapists: Differential sexual socialization and relative deprivation

Deviant sexual behavior has often been portrayed as the consequence of the frustration of legitimate sexual outlets. This study of date rapists reveals that these men, as a result of a hypersexual socialization process, are sexually very active, successful, and aspiring. These exaggerated aspiration levels are seen as responsible for instituting a high degree of sexual frustration. This acute relative deprivation, it is hypothesized, is a significant process responsible for precipitating these rape episodes.