Biomedical subjects

J A Brian

Publications and source records attributed to J A Brian.

4 recordsLinked to original sources

PubMed2003

Inhibitory mechanisms in autism spectrum disorders: typical selective inhibition of location versus facilitated perceptual processing.

BACKGROUND: This study examined the inhibitory control mechanisms of selective attention in autism spectrum disorders. Two issues were engaged: First, we extend previous findings of normal inhibition of distractor identity in autism by examining whether inhibition of spatial location is also spared. The second issue concerns the selectivity of inhibition. In non-clinical participants inhibition is selectively directed to the properties of the distractor that compete for the control of action; we examined whether individuals with autism also show normal selectivity of inhibition. METHOD: A negative priming task was used to examine selective spatial inhibition in participants with autism relative to matched non-clinical controls. RESULTS: We discovered that inhibition of distractor spatial location is within normal limits in autism, as is the ability to selectively direct inhibition to task-relevant stimulus features. In addition, we unexpectedly found that the irrelevant perceptual feature of colour produced a facilitation effect in autism, which has not been observed previously in typical controls. CONCLUSIONS: Evidence of colour facilitation implicates more fluent, but presumably less adaptive, perceptual processes in autism.

Adolescent↗

PubMed1996

Disembedding performance and recognition memory in autism/PDD.

This study explored the claim that superior disembedding performance in autism reflects "less capture by meaning" and/or reduced "central coherence" [Shah & Frith, Journal of Child Psychology & Psychiatry, 24, 613-620 (1983); Shah & Frith, Journal of Child Psychology & Psychiatry, 34, 1351-1364 (1993)]. Meaningless as well as meaningful disembedding contexts were used, and memory for contextual information was examined. Neither qualitative (search strategy) nor quantitative (RT or accuracy) data indicated that high-functioning individuals with autism/PDD were superior to younger, developmentally matched controls. For both groups, disembedding was slowest from meaningful contexts, which generally were remembered best. No evidence was provided for "less capture by meaning" or reduced "central coherence" in autism/PDD, raising the possibility that earlier findings reflect a developmental, rather than a stable autism-specific, phenomenon.

Adolescent↗

PubMed1994

Effects of intra-oral sucrose on crying, mouthing and hand-mouth contact in newborn and six-week-old infants.

To determine whether a single intra-oral administration of sucrose would calm infants and elicit mouthing and hand-mouth contact, crying newborn and six-week-old infants were given sucrose solution before one feed and sterile water before another in a cross-over trial. Six-week-old infants were also given sucrose and water after feeding. For the newborn infants, the calming effect was rapid, substantial and lasted for at least four minutes. Mouthing and hand-mouth contact increased, but for shorter durations. For the six-week-old infants, sucrose calmed for one minute only before feeding, but had no effects on mouthing or hand-mouth contact. The results imply that intra-oral sucrose has acute age-related effects on crying and suckling-feeding behaviour mediated by a pre-absorptive mechanism. Sucrose may tap a functional system for reducing distress related to feeding and/or regulation of infant state.

Administration, Oral↗

PubMed1992

Short-term effects of feed composition on sleeping and crying in newborns.

To determine whether the composition of feedings would affect newborn behavior independently of the act of feeding itself, 53 two- to three-day-old normal newborns were randomly assigned to receive an extra feeding of water, carbohydrate (lactose), or balanced formula 3 hours after their usual early morning feeding. Previous studies in adult humans and animals, and a single study in human newborns, have indicated that more sleep might be expected following the carbohydrate feed compared with the water and balanced-formula feeds because of recruitment of centrally mediated serotonergic systems. Behavioral effects were assessed for 40 minutes postfeeding by direct observation of the newborn's states (quiet, active, and indeterminate sleep; drowsiness; non-cry wakefulness; and fret/cry). Feed composition did affect behavior, and the effects were fairly specific to particular newborn states. Non-cry wakefulness and drowsiness were unrelated to the presence or type of nutrients, but they tended to occur soon after the meal in all groups. Crying was increased in water-fed newborns relative to both carbohydrate- and formula-fed newborns. Sleeping showed specific patterns of change in all three groups. Sleep duration was increased in the balanced-formula group compared with the water group throughout the observation period. Contrary to the prediction, sleeping duration in carbohydrate-fed newborns never exceeded that of formula-fed newborns; rather, it resembled that of water-fed newborns early in the postprandial period, but formula-fed newborns later. These effects could not easily be explained by potential confounding factors such as handling, volume ingested, caloric intake, or plasma glucose concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Crying↗