A prospective study of associations between early fearfulness and perceptual sensitivity and later restricted and repetitive behaviours in infants with typical and elevated likelihood of autism

Autism is diagnosed based on social and communication difficulties, restricted and repetitive behaviours and sensory anomalies. Existing evidence indicates that anxiety and atypical sensory features are associated with restricted and repetitive behaviours, but cannot clarify the order of emergence of these traits. This study uses data from a prospective longitudinal study of infants with and without a family history of autism ( N = 247; Elevated Likelihood N = 170 and Typical Likelihood N = 77). Longitudinal cross-lag models tested bidirectional pathways between parent-rated infant fear/shyness and perceptual sensitivity at 8, 14 and 24 months, and associations between these domains and parent-rated restricted and repetitive behaviours and social communication scores at 36 months. In addition to within-domain continuity, higher levels of fear/shyness at 14 months were associated with higher levels of perceptual sensitivity at 24 months. Higher levels of both fear/shyness and perceptual sensitivity at 24 months were associated with greater restricted and repetitive behaviours and social communication scores at 36 months. Results demonstrate the directionality of developmental pathways between fear/shyness and perceptual sensitivity in infancy and toddlerhood, but question theories that argue that these domains specifically underlie restricted and repetitive behaviours rather than autism. Identifying how early emerging anxiety and sensory behaviours relate to later autism is important for understanding pathways and developing targeted support for autistic children. Lay abstract Restricted interests and repetitive behaviours are central to the diagnosis of autism and can have profound effects on daily activities and quality of life. These challenges are also linked to other co-occurring conditions such as anxiety and sensory sensitivities. Here, we looked at whether early emerging signs of anxiety and sensory problems appear before symptoms of autism by studying infants with a family history of autism, as these infants are more likely to develop autism themselves. Studying infant siblings provides an opportunity for researchers to focus on early developmental markers of autism as these infants can be followed from birth. This study found that early infant signs of anxiety (e.g. fear/shyness) predicted later perceptual sensitivity, and those infants who scored higher on fear/shyness and sensitivity were more likely to experience more persistent repetitive behaviours, but also social and communication difficulties in toddlerhood. Early signs of anxiety and perceptual sensitivity may thus relate to both later social difficulties and repetitive behaviours. These findings support the importance of further research exploring the causal links between these domains in relation to autism, resulting in increased understanding of children who go onto develop autism in the future and guiding early interventions and supports.

TEMPERAMENTAL DIMENSIONS AMONG YOUNG STUTTERERS AND TYPICALLY DEVELOPING CHILDREN

Objective: To compare the temperamental characteristics of children who stutter with those who do not stutter. Study Design: Comparative cross-sectional study. Place and Duration of Study: Ayub Medical Complex, Abbottabad, from Jun to Nov 2018. Methodology: We recruited 120 children of both genders aged 3-8 years. Sample recruited included two groups including 60 children with stuttering (CWS) and 60 children with no stuttering (CWNS), using consecutive sampling. After taking consent, data was gathered using demographic sheet and Children Behavioral Questionnaire (CBQ) from the sample population. Statistical analysis was done using SPSS-21. Results: The sample included 82 (68.3% males and 38 (31.7%) female children. t-test results of children with stuttering and children with no stuttering showed statistically significant difference for effortful control (p<0.05) including dimension of inhibitory control, low intensity pleasure and perceptual sensitivity. However, the values for Surgency Extraversion and Negative affectivity were not statistically significant though results showed higher and lower mean scores respectively for stutterers compared to non-stutterers. However, the dimensions of anger, frustration, discomfort and falling reactivity showed statistically significant difference (p<0.05). Conclusion: Children with stuttering and children with no stuttering differ in their temperamental characteristics with statistically significant difference for effortful control with lower control in stutterers.

Respiration aligns perception with neural excitability

Recent studies from the field of interoception have highlighted the link between bodily and neural rhythms during action, perception, and cognition. The mechanisms underlying functional body-brain coupling, however, are poorly understood, as are the ways in which they modulate behaviour. We acquired respiration and human magnetoencephalography (MEG) data from a near-threshold spatial detection task to investigate the trivariate relationship between respiration, neural excitability, and performance. Respiration was found to significantly modulate perceptual sensitivity as well as posterior alpha power (8 - 13 Hz), a well-established proxy of cortical excitability. In turn, alpha suppression prior to detected vs undetected targets underscored the behavioural benefits of heightened excitability. Notably, respiration-locked excitability changes were maximised at a respiration phase lag of around -30° and thus temporally preceded performance changes. In line with interoceptive inference accounts, these results suggest that respiration actively aligns sampling of sensory information with transient cycles of heightened excitability to facilitate performance.

Spontaneous traveling waves naturally emerge from horizontal fiber time delays and travel through locally asynchronous-irregular states

Studies of sensory-evoked neuronal responses often focus on mean spike rates, with fluctuations treated as internally-generated noise. However, fluctuations of spontaneous activity, often organized as traveling waves, shape stimulus-evoked responses and perceptual sensitivity. The mechanisms underlying these waves are unknown. Further, it is unclear whether waves are consistent with the low rate and weakly correlated “asynchronous-irregular” dynamics observed in cortical recordings. Here, we describe a large-scale computational model with topographically-organized connectivity and conduction delays relevant to biological scales. We find that spontaneous traveling waves are a general property of these networks. The traveling waves that occur in the model are sparse, with only a small fraction of neurons participating in any individual wave. Consequently, they do not induce measurable spike correlations and remain consistent with locally asynchronous irregular states. Further, by modulating local network state, they can shape responses to incoming inputs as observed in vivo.

Minimal required exposures reveal the primacy of awareness in human face perception

The human visual system is capable of detecting extremely small light signals, as little as one single photon. But what is the visual system's minimal exposure threshold to detect meaningful stimuli? Due to hardware limitations, studies examining fast visual processing typically present stimuli for suprathreshold durations and disrupt processing with a mask. Here, we employed a newly developed tachistoscope that enables sub-millisecond presentations. Combining measures of perceptual sensitivity and recordings of neural activity, we find that both the holistic configuration and the emotional expression of a human face have the same minimal required exposure as the minimal required exposure for faces to reach awareness. These findings indicate that conscious awareness is required for processing meaningful visual information.

Signatures of vibration frequency tuning in human neocortex

Humans can perceive and discriminate vibration frequency, yet the central representation of this fundamental feature is unknown. Using fMRI, we discovered that cortical responses are tuned for vibration frequency. Voxel tuning was biased in a manner that reflects perceptual sensitivity and the response profile of the Pacinian afferent system. These results imply the existence of tuned populations that may encode naturalistic vibrations according to their constituent spectra.