Anticipatory adjustments to being picked up in infancy

Anticipation of the actions of others is often used as a measure of action understanding in infancy. In contrast to studies of action understanding which set infants up as observers of actions directed elsewhere, in the present study we explored anticipatory postural adjustments made by infants to one of the most common adult actions directed to them - picking them up. We observed infant behavioural changes and recorded their postural shifts on a pressure mat in three phases: (i) a prior Chat phase, (ii) from the onset of Approach of the mother's arms, and (iii) from the onset of Contact. In Study 1, eighteen 3-month-old infants showed systematic global postural changes during Approach and Contact, but not during Chat. There was an increase in specific adjustments of the arms (widening or raising) and legs (stiffening and extending or tucking up) during Approach and a decrease in thrashing/general movements during Contact. Shifts in postural stability were evident immediately after onset of Approach and more slowly after Contact, with no regular shifts during Chat. In Study 2 we followed ten infants at 2, 3 and 4 months of age. Anticipatory behavioural adjustments during Approach were present at all ages, but with greater differentiation from a prior Chat phase only at 3 and 4 months. Global postural shifts were also more phase differentiated in older infants. Moreover, there was significantly greater gaze to the mother's hands during Approach at 4 months. Early anticipatory adjustments to being picked up suggest that infants' awareness of actions directed to the self may occur earlier than of those directed elsewhere, and thus enable infants' active participation in joint actions from early in life

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Table_1_The Games Infants Play: Social Games During Early Mother–Infant Interactions and Their Relationship With Oxytocin.PDF

<p>The present study examined early social game routines during natural face-to-face mother–infant interactions and their relationship with oxytocin. Forty-three mother–infant dyads were observed, when infants were 4 months old, during a procedure involving a baseline and a natural interaction, where mothers were instructed to interact with their infants as they would at home. During this procedure four saliva samples from mothers and infants were collected to determine levels of oxytocin at different time points. Social game routines and infant social engagement (gaze, positive, and negative affect) were coded during the natural interaction. Social games were observed in 76.7% of the mother–infant dyads, and 46 different types of games were identified. Mothers initiated games to re-engage infants significantly more often than when infants were already engaged with them. During the games, infants showed more positive affect and less negative affect in comparison to the rest of the interaction. Finally, maternal increase in oxytocin from before to after the natural interaction was positively correlated with game rate and time spent in games, while infant increase in oxytocin from before to after the natural interaction was inversely related to game rate. These results indicate that social games are an inherent part of early mother–infant interactions, and their occurrence is associated with oxytocin of both infants and mothers.</p

Moving developmental social neuroscience toward a second-person approach.

Infants' cognitive development and learning rely profoundly on their interactions with other people. In the first year, infants become increasingly sensitive to others' gaze and use it to focus their own attention on relevant visual input. However, infants are not passive observers in early social interactions, and these exchanges are characterized by high levels of contingency and reciprocity. Wass and colleagues offer first insights into the neurobehavioral dynamics of caregiver-infant interactions, demonstrating that caregivers' scalp-recorded theta band activity responds to their infant's changes in attention, and parental brain activation is associated with infants' sustenance of attention. This research opens up entirely new ways of exploring caregiver-infant interactions and to understand early social attention as a reciprocal and dynamic process

Illustrations of Common Arm and Leg Adjustments During Approach at 3 Months.

<p>Note: (a) Infant LU: Mother’s Arms approach above the infant’s chest. Infant Arms still and up and back; Chin raised (back arched); Legs still. (b) Infant VI: Mother’s Arms approach above the infant’s chest. Infant Legs still, extended and slightly raised; Arms widened outwards. (c) Infant TO: Mother’s Arms approach above the infat’s chest. Infant Arms still and up and back; Legs extended and slightly raised. Participants have given written informed consent, as outlined in the PLOS consent form, to publication of their photographs.</p

Illustrative Example of Recurrence Force Profiles for (a) Chat, (b) Approach and (c) Contact Phases.

<p>Note: The Recurrence Force Profiles show the sum of individual recurrence points (using the measure of %RECurrence). The more saturated parts of the plots show a higher density of recurrence points (i.e., the small black dots). Areas of higher density indicate greater sameness of posture (which could either be continuing stillness or continuing small scale movements). Areas of low saturation show little recurrence and could either indicate irregular movements or large scale movements. In Figures (b) and (c), 0.0 on the axes marks the approximate point of Onset of Approach or Onset of Contact (because each dot in the plot consists of several data points in the time series, the absolute point of Onset cannot be precisely located). The three red squares in each figure highlight the three 1 second time segments of analysis in each plot.</p