Attenuated Neural Processing of Risk in Young Adults at Risk for Stimulant Dependence.

Objective: Approximately 10% of young adults report non-medical use of stimulants (cocaine, amphetamine, methylphenidate), which puts them at risk for the development of dependence. This fMRI study investigates whether subjects at early stages of stimulant use show altered decision making processing.

Methods: 158 occasional stimulants users (OSU) and 50 comparison subjects (CS) performed a "risky gains" decision making task during which they could select safe options (cash in 20 cents) or gamble them for double or nothing in two consecutive gambles (win or lose 40 or 80 cents, "risky decisions").

Preliminary evidence for reduced posterror reaction time slowing in hyperactive/inattentive preschool children.

Background: Attention deficit/hyperactivity disorder (ADHD) has been associated with deficits in self-regulatory cognitive processes, some of which are thought to lie at the heart of the disorder. Slowing of reaction times (RTs) for correct responses following errors made during decision tasks has been interpreted as an indication of intact self-regulatory functioning and has been shown to be attenuated in school-aged children with ADHD. This study attempted to examine whether ADHD symptoms are associated with an early-emerging deficit in posterror slowing.

Sociality in the spectral tarsier, Tarsius spectrum.

Recent studies indicate that many of the nocturnal prosimian primates are gregarious rather than solitary. This paper shows that the spectral tarsier is gregarious during its nightly activity period as well as in its sleeping tree. Using mist nets and radiotelemetry, focal follows were conducted on six groups at Tangkoko Nature Reserve in Sulawesi, Indonesia.

Effects of radio transmitter weight on a small nocturnal primate.

An increasing number of primatologists have begun using radio telemetry to study the behavioral ecology of nocturnal prosimian primates. Radio telemetry has enabled the collection of data on these nocturnal and cryptic prosimians that was previously difficult or impossible to otherwise obtain. A critical assumption of studies employing radio telemetry is that the radio transmitters have no appreciable negative effects on the study animals and the data being collected are not being biased by the presence of radio transmitters.