Brain development in autism: early overgrowth followed by premature arrest of growth

Due to the relatively late age of clinical diagnosis of autism, the early brain pathology of children with autism has remained largely unstudied. The increased use of retrospective measures such as head circumference, along with a surge of MRI studies of toddlers with autism, have opened a whole new area of research and discovery. Recent studies have now shown that abnormal brain overgrowth occurs during the first 2 years of life in children with autism. By 2-4 years of age, the most deviant overgrowth is in cerebral, cerebellar, and limbic structures that underlie higher-order cognitive, social, emotional, and language functions. Excessive growth is followed by abnormally slow or arrested growth. Deviant brain growth in autism occurs at the very time when the formation of cerebral circuitry is at its most exuberant and vulnerable stage, and it may signal disruption of this process of circuit formation. The resulting aberrant connectivity and dysfunction may lead to the development of autistic behaviors. To discover the causes, neural substrates, early-warning signs and effective treatments of autism, future research should focus on elucidating the neurobiological defects that underlie brain growth abnormalities in autism that appear during these critical first years of life.     

Short and long-term motor skill learning in an accelerated rotarod training paradigm

Rodent models of motor skill learning include skilled forelimb reaching and acrobatic locomotor paradigms. This study characterizes motor skill learning in the accelerated rotarod task. Thirty Long-Evans rats (300-400 g) were trained on an accelerated rotarod (1cm/s(2)) over eight consecutive sessions (=days, 20 trials each). Improvement in rotarod velocities mastered before falling off the rod was observed within and between sessions (plateau after five sessions). Intrasession improvement was incompletely retained at the beginning of the next day's session. Over several training sessions, intrasession improvement diminished, suggesting a ceiling effect. After 1 week of pause, the rotarod skill was retained. Locomotor exercise in a running wheel for 30 min before the first rotarod session did not affect intrasession improvement. Running-wheel exposure for 6 days did not diminish the rate of rotarod skill learning (steepness of the learning curve) but improved overall performance (upward shift of curve). Video analysis of gait on the rotarod showed that rats developed a motor strategy by modifying their gait patterns during training. The data demonstrate that rotarod improvement is not the result of enhanced general locomotor ability or fitness, which are trained in the running wheel, but requires a change in the motor strategy to master the task. Accelerated rotarod training can be regarded a valid paradigm for motor skill learning over short (intrasession, minutes) and long time frames (intersession, days).     

Comorbidity in compulsive hoarding: a case report

A 56-year-old male presented with compulsive hoarding along with attention-deficit/hyperactivity disorder and schizotypal personality disorder. Hoarding has been described as difficult to treat both pharmacologically and behaviorally, and this patient's comorbid conditions also contributed to his overall impairment. The patient's treatment regimen of fluvoxamine, amphetamine salts, and risperidone, along with behavioral therapy, has helped with hoarding behaviors, motivation, procrastination, and increased socialization. Hoarding may be a unique subtype of obsessive-compulsive disorder with poorer prognosis and distinct neuroanatomic dysfunction. Augmentation with stimulants may provide benefits in aspects of hoarding such as procrastination, especially in patients with comorbid attention-deficit hyperactivity disorder.     

Impact of recent findings on study design of future autism clinical trials

There are specific challenges to studying the design of pharmacologic trials in child/adolescent and adult autism, such as subject stratification and parallel versus crossover designs. This article describes how optimal study design is influenced by subject selection and outcome measures chosen. Lessons learned in study design from the Research Units on Pediatric Psychopharmacology Autism Network trial with risperidone, Seaver Center trials with fluoxetine and valproate, Dartmouth trials with amantadine, and National Institutes of Health secretin trials are highlighted. The Internet System for Assessing Autistic Children system for managing multicenter clinical trials in autism and statistical issues in autism research are also described.     

Illusory conjunctions in the time domain and the resulting time-course of the attentional blink

Illusory conjunctions in the time domain are errors made in binding stimulus features presented In the same spatial position in Rapid Serial Visual Presentation (RSVP) conditions. Botella, Barriopedro, and Suero (2001) devised a model to explain how the distribution of responses originating from stimuli around the target in the series is generated. They proposed two routes consisting of two sequential attempts to make a response. The second attempt (sophisticated guessing) is only employed if the first one (focal attention) fails in producing an integrated perception. This general outline enables specific predictions to be made and tested related to the efficiency of focal attention in generating responses in the first attempt. Participants had to report the single letter in an RSVP stream of letters that was presented in a previously specified color (first target, T1) and then report whether an X (second target, T2) was or was not presented. Performance on T2 showed the typical U-shaped function across the T1-T2 lag that reflects the attentional blink phenomenon. However, as was predicted by Botella, Barriopedro, and Suero's model, the time-course of the interference was shorter for trials with a correct response to T1 than for trials with a T1 error. Furthermore, longer time-courses of interference associated with pre-target and post-target errors to the first target were indistinguishable.     

The use of a distractor-assigned response slows later responding in a location negative priming task

Responding to a target's location takes longer when that location has recently contained a distractor event (ignored-repetition [IR] trial) relative to when it has been unoccupied (control trial). This is known as the location negative priming (NP) effect. We aimed to determine whether the elevated reaction time observed for IR trials was due to the reuse of a distractor location (location locus) and/or to the need to execute a (just inhibited) distractor response (response locus). We isolated these loci latency effects by using many-to-one and one-to-many location-response assignments. Our results showed that reusing a distractor location hastened target processing at that position (facilitative location locus), whereas the production of a distractor response was associated with a time cost (interfering response locus). Accordingly, part of the latency elevation seen with IR trials results from the need on these occasions to execute ajust inhibited (distractor) response, and, hence, the location NP effect has a response locus.     

Competitive martial arts and aggressiveness: a 2-yr. longitudinal study among young boys

This study is a follow-up study of Reynes and Lorant's studies assessing the effect of one year of judo and karate training on aggressiveness scores among young boys. The data reported here were obtained after a second year of practice, 14 judoka, 9 karateka, and 20 control participants who filled out the Buss-Perry Aggression Questionnaire three times, 1 year apart. At the first assessment, all participants, born the same year, were 8 yr. old and at the third they were 10 yr. old. Analysis indicated that after two years of practice, karate training seemed to have neither positive nor negative effects on aggressiveness scores, while judo training seemed to have a negative effect on anger scores. However, the results suggested the importance of kata or meditation in training sessions on self-control acquisition for such young boys.     

Equivalents of Mingle and Positive Paradox

Relevant logic is a proper subset of classical logic. It does not include among its theorems any ofpositive paradox A (B A)mingle A (A A)linear order (A B) (B A)unrelated extremes (A ) (B B¯)This article shows that those four formulas have different effects when added to relevant logic, and then lists many formulas that have the same effect as positive paradox or mingle.     

Transition planning and recidivism among mentally ill juvenile offenders

OBJECTIVES: To determine the extent to which transition planning and community service would predict lower levels of recidivism among mentally ill juvenile offenders. DESIGN: Review of legal, medical and social service records including examination of 3-month period following community release. PARTICIPANTS: Juvenile offenders incarcerated for 6 months or more (N = 44) transitioning to community. MEASURES: Child and Adolescent Functional Assessment Scale (CAFAS), sum of different documented pre- and post-release discharge planning contacts, documented community service contacts. OUTCOMES: Re-offense during the first year post-release. RESULTS: Documented community service contacts in the 3 months following discharge were rare for mental health (20.5%), substance abuse (38.6%), financial assistance (29.5%), and school placement (34.1%). The average number of different pre-release and post-release discharge planning contacts was also low, M(SD)=1.86(1.68) and M(SD)= 2.34(1.71) respectively. Post-release discharge planning and the receipt of financial assistance and mental health services were all associated with lower levels of reoffending. CONCLUSIONS: Community transition planning, including the coordination and provision of community services, is an essential component of community reintegration for juvenile offenders and is associated with lower rates of recidivism during the first year post-discharge.