Longitudinal development of attention and inhibitory control during the first year of life. Developmental Science. 2018:e12690. Abstract
Longitudinal development of attention and inhibitory control during the first year of life
Executive functions (EFs) are key abilities that allow us to control our thoughts and actions. Research suggests that two EFs, inhibitory control (IC) and working memory (WM), emerge around 9 months. Little is known about IC earlier in infancy and whether basic attentional processes form the “building blocks” of emerging IC. These questions were investigated longitudinally in 104 infants tested behaviorally on two screen-based attention tasks at 4 months, and on IC tasks at 6 and 9 months. Results provided no evidence that basic attention formed precursors for IC. However, there was full support for coherence in IC at 9 months and partial support for stability in IC from 6 months. This suggests that IC emerges earlier than previously assumed.
Polymorphisms in dopamine system genes are associated with individual differences in attention in infancy. Developmental Psychology. 2010;46(2):404-16. Abstract
Polymorphisms in dopamine system genes are associated with individual differences in attention in infancy
Knowledge about the functional status of the frontal cortex in infancy is limited. This study investigated the effects of polymorphisms in four dopamine system genes on performance in a task developed to assess such functioning, the Freeze-Frame task, at 9 months of age. Polymorphisms in the catechol-Omethyltransferase (COMT) and the dopamine D4 receptor (DRD4) genes are likely to impact directly on the functioning of the frontal cortex, whereas polymorphisms in the dopamine D2 receptor (DRD2) and dopamine transporter (DAT1) genes might influence frontal cortex functioning indirectly via strong frontostriatal connections. A significant effect of the COMT valine158methionine (Val158Met) polymorphism was found. Infants with the Met/Met genotype were significantly less distractible than infants with the Val/Val genotype in Freeze-Frame trials presenting an engaging central stimulus. In addition, there was an interaction with the DAT1 3 variable number of tandem repeats polymorphism; the COMT effect was present only in infants who did not have two copies of the DAT1 10-repeat allele. These findings indicate that dopaminergic polymorphisms affect selective aspects of attention as early as infancy and further validate the Freeze-Frame task as a frontal cortex task.
Neural correlates of eye gaze processing in the infant broader autism phenotype. Biological Psychiatry. 2009;65(1):31-8. Abstract
Neural correlates of eye gaze processing in the infant broader autism phenotype
Background: Studies of infant siblings of children diagnosed with autism have allowed for a prospective approach to study the emergence of autism in infancy and revealed early behavioral characteristics of the broader autism phenotype. In view of previous findings of atypical eye gaze processing in children and adults with autism, the aim of this study was to examine the early autism phenotype in infant siblings of children diagnosed with autism spectrum disorder (sib-ASD), focusing on the neural correlates of direct compared with averted gaze. Methods: A group of 19 sib-ASD was compared with 17 control infants with no family history of ASD (mean age = 10 months) on their response to direct versus averted gaze in static stimuli. Results: Relative to the control group, the sib-ASD group showed prolonged latency of the occipital P400 event-related potentials component in response to direct gaze, but they did not differ in earlier components. Similarly, time-frequency analysis of high-frequency oscillatory activity in the gamma band showed group differences in response to direct gaze, where induced gamma activity was late and less persistent over the right temporal region in the sib-ASD group. Conclusion: This study suggests that a broader autism phenotype, which includes an atypical response to direct gaze, is manifest early in infancy.
Visual orienting in the early broader autism phenotype: disengagement and facilitation. Journal of Child Psychology and Psychiatry. 2009;50(5):637-42. Abstract
Visual orienting in the early broader autism phenotype: disengagement and facilitation
Recent studies of infant siblings of children diagnosed with autism have allowed for a prospective approach to examine the emergence of symptoms and revealed behavioral differences in the broader autism phenotype within the early years. In the current study we focused on a set of functions associated with visual attention, previously reported to be atypical in autism. We compared performance of a group of 9-10-month-old infant siblings of children with autism to a control group with no family history of autism on the 'gap-overlap task', which measures the cost of disengaging from a central stimulus in order to fixate a peripheral one. Two measures were derived on the basis of infants' saccadic reaction times. The first is the Disengagement effect, which measures the efficiency of disengaging from a central stimulus to orient to a peripheral one. The second was a Facilitation effect, which arises when the infant is cued by a temporal gap preceding the onset of the peripheral stimulus, and would orient faster after its onset. Infant siblings of children with autism showed longer Disengagement latencies as well as less Facilitation relative to the control group. The findings are discussed in relation to how differences in visual attention may relate to characteristics observed in autism and the broader phenotype.
Freeze-Frame: A new infant inhibition task and its relation to frontal cortex tasks during infancy and early childhood. Journal of Experimental Child Psychology. 2008;100(2):89-114. Abstract
Freeze-Frame: A new infant inhibition task and its relation to frontal cortex tasks during infancy and early childhood
The current study investigated a new, easily administered, visual inhibition task for infants termed the Freeze-Frame task. In the new task, 9-month-olds were encouraged to inhibit looks to peripheral distractors. This was done by briefly freezing a central animated stimulus when infants looked to the distractors. Half of the trials presented an engaging central stimulus, and the other half presented a repetitive central stimulus. Three measures of inhibitory function were derived from the task and compared with performance on a set of frontal cortex tasks administered at 9 and 24 months of age. As expected, infants' ability to learn to selectively inhibit looks to the distractors at 9 months predicted performance at 24 months. However, performance differences in the two Freeze-Frame trial types early in the experiment also turned out to be an important predictor. The results are discussed in terms of the validity of the Freeze-Frame task as an early measure of different components of inhibitory function. (C) 2007 Elsevier Inc. All rights reserved.