Rhythmic neural activity indicates the contribution of attention and memory to the processing of occluded movements in 10-month-old infants

Peak alpha frequency is linked to visual temporal attention in 6-month-olds

The temporal resolution of adults' visual attention has been linked to the frequency of alpha-band oscillations in electroencephalogram (EEG) signal, with higher Peak Alpha Frequency (PAF) being associated with better visual temporal processing skills. However, relatively less is known about neural mechanisms underlying individual differences in the temporal resolution of visual attention in infancy. This study investigated the role of PAF in visual temporal processing in early infancy. In a sample of 6-month-old infants (n = 62) we examined the relationship between PAF extracted from resting-state EEG, and saccadic latencies in a predictive cueing task where the appearance of a reward was predicted by higher or lower frequency of two flickering objects. Results showed that higher PAF was associated with shorter saccadic latencies in a condition with higher differences between the two flickering frequencies, speaking for the involvement of PAF in visual temporal attention in early development. Additionally, we found that infants were generally faster to orient to the reward in trials where both peripheral stimuli were flickering at relatively lower frequencies, roughly corresponding to the theta frequency band. Our findings support theoretical accounts highlighting the role of PAF in visual attention processing and extend this framework to early infancy.

Speaker Competence Affects Prefrontal Theta and Occipital Alpha Power during Selective Word Learning in Preschoolers

In the present study, we investigated the cognitive processes underlying selective word learning in preschoolers. We measured rhythmic neural activity in the theta (4-8 Hz) and alpha frequency range (7-12 Hz) in 67 four-year-olds. EEG was recorded during anticipation and encoding of novel labeling events performed by a speaker who had previously shown either competence (correct) or incompetence (incorrect) in labeling familiar objects. In both groups, children selected the target object equally often upon recall. However, children observing the incompetent speaker revealed weaker representations of novel words indicated by an increased likelihood for selecting familiar but incorrect items upon recall. Modulations in theta and alpha power suggest differential processing of novel label-object pairs depending on the speakers' competence. In the incompetent, but not the competent, speaker condition, increases in prefrontal theta power during anticipation and encoding were related to increased recall success. Findings suggest that theta power in the present study reflects cognitive control. In both conditions, occipital alpha power-indicating attentional processes-reflected familiarity with novel items, but in opposite directions. In familiar item trials, alpha power was increased observing the incompetent and decreased observing the competent speaker. Thus, both cognitive control and attention processes during word learning are differentially affected by speaker characteristics.

Effects of active and observational experience on EEG activity during early childhood

While it is accepted that action experience facilitates action understanding, it is debated whether first-hand motor and visual experience differentially influence this ability. Action understanding relies on relatively broad cortical activity, including that of the neural mirroring and visual attention systems. Infant and adult research has demonstrated that prior motor and visual experience have distinct effects on cortical activity during action perception, though this has yet to be investigated in young children. We used a within-subject design and an at-home training paradigm to manipulate 3- to 6-year-olds' experience with two relatively novel actions. On Days 1-4, children received brief active training with one tool (i.e., motor experience) and observational training with the other tool (i.e., visual experience: video of a demonstrator modeling the action). On Day 5, we measured children's EEG mu/alpha (8-10 Hz) and beta rhythm (16-20 Hz) activity during observation and execution of these actions in the laboratory. Although central-parietal mu and beta rhythm activity did not differ as a function of training condition, desynchronization of the occipital alpha rhythm was greater during perception of the active training task than of the observational training task. Our findings suggest that, during early childhood, action experience may modulate visual attention during subsequent action perception. Further, children exhibited neural mirroring-central-parietal desynchronization during both tool-use action observation and execution-within the mu rhythm, but not the beta rhythm. These findings have significant implications for our understanding of the broad cortical activity that supports action perception during this period.

10-Month-Old Infants Are Sensitive to the Time Course of Perceived Actions: Eye-Tracking and EEG Evidence

Research has shown that infants are able to track a moving target efficiently - even if it is transiently occluded from sight. This basic ability allows prediction of when and where events happen in everyday life. Yet, it is unclear whether, and how, infants internally represent the time course of ongoing movements to derive predictions. In this study, 10-month-old crawlers observed the video of a same-aged crawling baby that was transiently occluded and reappeared in either a temporally continuous or non-continuous manner (i.e., delayed by 500 ms vs. forwarded by 500 ms relative to the real-time movement). Eye movement and rhythmic neural brain activity (EEG) were measured simultaneously. Eye movement analyses showed that infants were sensitive to slight temporal shifts in movement continuation after occlusion. Furthermore, brain activity associated with sensorimotor processing differed between observation of continuous and non-continuous movements. Early sensitivity to an action's timing may hence be explained within the internal real-time simulation account of action observation. Overall, the results support the hypothesis that 10-month-old infants are well prepared for internal representation of the time course of observed movements that are within the infants' current motor repertoire.