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Biomedical subjects

Donald M Dougherty

Publications and source records attributed to Donald M Dougherty.

24 records · Page 2Linked to original sources
PubMed2002

Serotonin 2a receptor T102C polymorphism and impaired impulse control.

Patients homozygous for the C allele of the T102C serotonin (5-HT) 2a receptor polymorphism have shown increased suicidal ideation or behavior in some reports, but not in others. We conducted a pilot investigation to determine whether this polymorphism might relate more specifically to a dimension of impaired impulse control, which may underlie only a portion of suicides. Rates of commission (impulsive) errors in a variant of the Continuous Performance Test (CPT) were compared across the genotypes of the T102C polymorphism in adults recruited from the community. The 102C/102C genotype was jointly associated with a greater incidence of past mood disorder or substance-use disorder, as well as significantly more commission errors compared to the 102T/102C and 102C/102C genotypes. These preliminary data suggest that the T102C 5-HT2a receptor polymorphism may be a marker for impaired behavior control-perhaps in the context of psychiatric disorder history.

Adult↗
PubMed2002

Laboratory-measured aggressive behavior of women: acute tryptophan depletion and augmentation.

Plasma L-tryptophan (Trp) reductions have been related to aggression increases in men. Impairment of serotonin synthesis and neurotransmission is one explanation. Using repeated-measures, this Trp manipulation study measured laboratory-induced aggression in 12 women after Trp augmentation (T+), depletion (T-), and food-restricted (fasting control) conditions. Participants were provoked with periodic subtraction of money from their task earnings by a (fictitious) partner. Aggression was defined as the number of point subtractions participants made from their fictitious partner. Participants completed five testing sessions under each condition. T+ decreased aggressive responses and T- increased aggressive responses. Post-hoc analyses showed changes in aggressive behavior were specific to women with higher fasting control plasma Trp, which is consistent with research demonstrating that men with higher levels of baseline Trp are more aggressive. These findings indicate that both T+ and T- can influence aggressive behavior and that certain subgroups of women may be more susceptible to serotonin manipulation.

Adolescent↗
PubMed2002

Possible amotivational effects following marijuana smoking under laboratory conditions.

Human participants earned money by responding on a progressive-ratio (PR) schedule (initial value $50) or received money without responding on a fixed-time (FT) schedule. During the session, participants could terminate the PR schedule and initiate an FT 200-s schedule. In Experiment 1, increases in monetary value produced increased number of responses, time spent, and money earned in the PR component. In Experiment 2, marijuana smoking produced potency-related reductions in the number of responses, time spent, and money earned in the PR component, effects that can be interpreted as amotivational. Increasing the monetary value of the reinforcer diminished the acute marijuana effects on PR responding, suggesting that marijuana exerted an effect primarily on reinforcers of a smaller magnitude.

Adolescent↗
PubMed2002

Reliability estimates for the immediate and delayed memory tasks.

The Immediate and Delayed Memory Tasks are variations of the Continuous Performance Test. While previous research with the tasks has focused on group performance across multiple blocks and sessions, reliability estimates have not been established. We estimated reliability (1) between blocks of a single testing session (N=106), (2) across four sessions within a single testing day (N=20), and (3) across sessions on four consecutive testing days (N=20). Analyses indicated that the primary variable of interest, i.e., commission of errors, showed acceptable reliability within and across testing periods.

Adult↗
PubMed2002

Immediate and delayed memory tasks: a computerized behavioral measure of memory, attention, and impulsivity.

The Immediate and Delayed Memory Task (IMT/DMT), a variant of the Continuous Performance Test (CPT), is a new software package designed to be a flexible research tool for the study of attention, memory, and impulsivity. This package allows researchers to determine the design to be used during a testing session and to manipulate many of the parameters. It features two components: the IMT and the DMT, both of which present sequential 2- to 7-digit stimuli with variable presentation rates and intertrial intervals. Subjects respond to identically matched stimuli presented consecutively, spanning a brief period of time (IMT), or to stimuli spanning a greater period of time (during which intervening stimuli to be ignored appear; DMT). Task complexity can be adjusted to suit applications for both children and adults. Preliminary studies have demonstrated that these laboratory tasks are sensitive to group differences, produce stable baselines of performance, and are sensitive to drug-induced performance decrements.

Attention↗