Methamphetamine effects on cognitive processing during extended wakefulness

We examined the effects of both 5- and 10-mg/7O kg body weight of d-methamphetamine HCl on high event rate vigilance and tracking performance in a 13.5-hr sustained-performance session during one night of sleep loss. At 0116 hours participants were administered either a 5 mg/70 kg oral dose of d-methamphetamine (n=10), 10 mg/70 kg d-methamphetamine (n=10), or a placebo (n=10) using standard double-blind procedures. Performance on all measures degraded markedly during the night in the placebo group. Both the 5- and 10-mg methamphetamines treatment reversed an initial decline in d', and reversed increases in nonresponses (lapses) and tracking error within approximately 3 hr of administration. No evidence that amphetamine treatment increased impulsive responding (fast guesses) was observed. The magnitude of the performance effects of the methamphetamine treatments was similar at 3 hr postadministration. However, the effects of the 5-mg dose were shorter-lived, disappearing by the last testing session (6.5 hr postadministration), whereas effects of the 10-mg dose tended to remain throughout testing. Both amphetamine treatments decreased subjective sleepiness during the night and tended to increase subjective sleep latencies during a post-testing sleep period.     

Complex visual analysis of ecologically relevant signals in Siamese fighting fish

Animal Cognition - We currently have limited knowledge about complex visual representations in teleosts. For the specific case of Siamese fighting fish (Betta splendens), we do not know whether...     

Attachment Anxiety,Depressive Symptoms,and Adolescent Dating Violence Perpetration: A Longitudinal Mediation Analysis

Adolescent dating violence (ADV) is a prevalent public health issue that has been linked to many negative effects, including attachment anxiety and depressive symptoms. Previous literature suggests that the negative mental states characteristic of attachment anxiety could be associated with dating violence perpetration. Similarly, the negative mental states characteristic of depression have also been linked to perpetration, and might potentially increase an anxiously attached individual’s likelihood of engaging in dating violence perpetration. This study used a 10-month longitudinal design with a sample of 140 middle school and high school students from Southern California. Participants ranged in age from 13 to 18 years and were ethnically diverse. The study aimed at exploring depressive symptoms as a potential mediator for the relationship between attachment anxiety and ADV perpetration. Positive associations were found between attachment anxiety and perpetration (10 months after), attachment anxiety and depressive symptoms (10 months after), and between depressive symptoms and perpetration (both 10 months after). Furthermore, depressive symptoms partially mediated the relationship between attachment anxiety and ADV perpetration (10 months after). These findings have implications for the development of empirically driven school-based prevention and intervention programs.     

Validation of a solid-state anomaloscope used to assess red-green color vision defects

Solid-state anomaloscopes whose stimuli are derived from light-emitting diodes (LEDs) are simpler and less expensive than conventional anomaloscopes. We have assessed the test-retest reliability and the validity of one solid-state anomaloscope and have obtained normative data for it. Reliability and validity were assessed by classifying 36 color-defective observers into one of five categories defined by degree of defect. When all color defectives were considered, both the validity and reliability of the solid-state anomaloscope were found to be high. The primary stimuli of the solid-state anomaloscope are less well separated in chromaticity space than are those of conventional anomaloscopes, but there is no evidence that this results in the incorrect classification of anomalous trichromats as dichromats. The solid-state anomaloscope appears to be an acceptable alternative to standard anomaloscopes for both research and screening applications.     

Difference in sensorimotor adaptation to horizontal and vertical mirror distortions during ballistic arm movements

When learning a novel motor task, the sensorimotor system must develop new strategies to efficiently control the limb(s) involved, and this adaptation appears to be developed through the construction of a behavioral map known as an 'internal model'. A common method to uncover the mechanisms of adaptation and reorganization processes is to expose the system to new environmental conditions, typically by introducing visual or mechanical distortions. The present study investigated the adaptation mechanisms of the human sensorimotor system to horizontal and vertical mirror distortions (HMD and VMD) during the execution of fast goal-directed arm movements. Mirror distortions (MDs) were created by means of virtual visual feedback on a computer screen while the movement was executed on a graphics tablet. Twenty healthy adult participants were recruited and assigned to one of two groups of 10 people each. Tests were divided in two subsequent blocks of five trials. The first block consisted of trials with no mirror distortion (NMD), while the second block was recorded when exposing one group to HMD and the other to VMD. Both MDs resulted in kinematic changes: during the tests with the MDs the participants did not reach the performance level found at the NMD test. Motor performance during HMD appeared to be globally better than during VMD and the adaptation process to VMD appeared to be slower than to HMD, but data interpretation was hampered by large within-participant and between-participant variability. In-depth analyses of the data revealed that most of the motor performance information was contained in the direction of movement. The data supported the idea that the internal model for HMD was already partially built.     

Brain functional connectivity correlates of coping styles

Coping abilities represent the individual set of mental and behavioral strategies adopted when facing stress or traumatic experiences. Coping styles related to avoidance have been linked to a disposition to develop psychiatric disorders such as PTSD, anxiety, and major depression, whereas problem-oriented coping skills have been positively correlated with well-being and high quality of life. Even though coping styles constitute an important determinant of resilience and can impact many aspects of everyday living, no study has investigated their brain functional connectivity underpinnings in humans. Here we analyzed both psychometric scores of coping and resting-state fMRI data from 102 healthy adult participants. Controlling for personality and problem-solving abilities, we identified significant links between the propensity to adopt different coping styles and the functional connectivity profiles of regions belonging to the default mode (DMN) and anterior salience (AS) networks—namely, the anterior cingulate cortex, left frontopolar cortex, and left angular gyrus. Also, a reduced negative correlation between AS and DMN nodes explained variability in one specific coping style, related to avoiding problems while focusing on the emotional component of the stressor at hand, instead of relying on cognitive resources. These results might be integrated with current neurophysiological models of resilience and individual responses to stress, in order to understand the propensity to develop clinical conditions (e.g., PTSD) and predict the outcomes of psychotherapeutic interventions.