Eszter Somogyi

Gene × Environment Interactions in Autism Spectrum Disorders: Role of Epigenetic Mechanisms

Several studies support currently the hypothesis that autism etiology is based on a polygenic and epistatic model. However, despite advances in epidemiological, molecular and clinical genetics, the genetic risk factors remain difficult to identify, with the exception of a few chromosomal disorders and several single gene disorders associated with an increased risk for autism. Furthermore, several studies suggest a role of environmental factors in autism spectrum disorders (ASD). First, arguments for a genetic contribution to autism, based on updated family and twin studies, are examined. Second, a review of possible prenatal, perinatal, and postnatal environmental risk factors for ASD are presented. Then, the hypotheses are discussed concerning the underlying mechanisms related to a role of environmental factors in the development of ASD in association with genetic factors. In particular, epigenetics as a candidate biological mechanism for gene × environment interactions is considered and the possible role of epigenetic mechanisms reported in genetic disorders associated with ASD is discussed. Furthermore, the example of in utero exposure to valproate provides a good illustration of epigenetic mechanisms involved in ASD and innovative therapeutic strategies. Epigenetic remodeling by environmental factors opens new perspectives for a better understanding, prevention, and early therapeutic intervention of ASD.

Differences in Response Bias Among Younger and Older Preschoolers Investigating Japanese and Hungarian Preschoolers

Groups of children in Japan and Hungary aged 2 to 5 years were asked yes-no questions pertaining to familiar and unfamiliar objects by either strange adults or mothers. In Experiment 1, 3- to 5-year-old Japanese and Hungarian children were interviewed by strange adults, and 3-year-olds in both countries exhibited a yes bias for familiar objects. Japanese 3-year-olds exhibited a yes bias for unfamiliar objects as well. Japanese 4- and 5-year-olds exhibited a yes bias for familiar objects, whereas Hungarian 4- and 5-year-olds exhibited a nay-saying bias for unfamiliar objects. In Experiment 2, Hungarian 2-year-olds exhibited a yes bias for both familiar and unfamiliar objects when asked by strange adults. In Experiment 3, Japanese 3-year-olds exhibited a yes bias for both familiar and unfamiliar objects, whereas 4-year-olds did not exhibit it for familiar objects and exhibited a nay-saying bias for unfamiliar objects when they were asked by mothers. The results suggest that young preschoolers have a common mechanism for exhibiting a yes bias, but older preschoolers may have other reasons to exhibit response biases.

Humour production may enhance observational learning of a new tool-use action in 18-month-old infants

Many studies have shown that making children laugh enhances certain cognitive capacities such as attention, motivation, perception and/or memory, which in turn enhance learning. However, no study thus far has investigated whether laughing has an effect on learning earlier in infancy. The goal of this study was to see whether using humour with young infants in a demonstration of a complex tool-use task can enhance their learning. Fifty-three 18-month-old infants participated in this study and were included either in a humorous or a control demonstration group. In both groups infants observed an adult using a tool to retrieve an out-of-reach toy. What differed between groups was that in the humorous demonstration group, instead of playing with the toy, the adult threw it on the floor immediately after retrieval. The results show that infants who laughed at the demonstration in the humorous demonstration group reproduced significantly more frequent target actions than infants who did not laugh and those in the control group. This effect is discussed with regard to individual differences in terms of temperament and social capacities as well as positive emotion and dopamine release.

Which limb is it? Responses to vibrotactile stimulation in early infancy

This study focuses on how the body schema develops during the first months of life, by investigating infants’ motor responses to localized vibrotactile stimulation on their limbs. Vibrotactile stimulation was provided by small buzzers that were attached to the infants’ four limbs one at a time. Four age groups were compared cross‐sectionally (3‐, 4‐, 5‐, and 6‐month‐olds). We show that before they actually reach for the buzzer, which, according to previous studies, occurs around 7–8 months of age, infants demonstrate emerging knowledge about their bodys configuration by producing specific movement patterns associated with the stimulated body area. At 3 months, infants responded with an increase in general activity when the buzzer was placed on the body, independently of the vibrators location. Differentiated topographical awareness of the body seemed to appear around 5 months, with specific responses resulting from stimulation of the hands emerging first, followed by the differentiation of movement patterns associated with the stimulation of the feet. Qualitative analyses revealed specific movement types reliably associated with each stimulated location by 6 months of age, possibly preparing infants’ ability to actually reach for the vibrating target. We discuss this result in relation to newborns’ ability to learn specific movement patterns through intersensory contingency. Statement of contribution what is already known on infants’ sensorimotor knowledge about their own bodies 3‐month‐olds readily learn to produce specific limb movements to obtain a desired effect (movement of a mobile). infants detect temporal and spatial correspondences between events involving their own body and visual events. what the present study adds until 4–5 months of age, infants mostly produce general motor responses to localized touch. this is because in the present study, infants could not rely on immediate contingent feedback. we propose a cephalocaudal developmental trend of topographic differentiation of body areas.

Mimicry Enhances Observational Learning in 16-Month-Old Infants

We examined the effect of mimicry on how 16-month-old infants learn by observation a novel tool use action, which consisted of using a rake to retrieve a toy. Across four conditions, we manipulated whether during an initial play phase, an adult mimicked the infants play or not (testing the effect of mimicry), the infant played with the adult or played alone (controlling the effect of interacting with a contingent partner) and whether the infant saw a demonstration of the tools use or not (evaluating baseline performance). We found that infants who had been mimicked learned best from a demonstration of the rakes use and performed better than infants who only played with the experimenter without mimicry or played by themselves before the demonstration. As expected, infants did not learn from a demonstration of the rakes use when they played by themselves and thus had no previous interaction with an experimenter. The mechanisms driving this powerful learning effect of mimicry are discussed.

Understanding goals and intentions in low-functioning autism

We investigated ability to understand goals and attribute intentions in the context of two imitation studies in low-functioning, nonverbal children with autism (L-F CWA), a population that is rarely targeted by research in the domain. Down syndrome children (DSC) and typically developing children (TDC) were recruited to form matched comparison groups. In the two sets of simple action demonstrations only contextual indicators of the models intentions were manipulated. In the Head touch experiment the model activated a button on a toy by pushing it with the forehead, whereas in the Hidden box experiment the model used a ball with a magnet to lift a box out of its container. Both actions were unusual and non-affordant with regards to the objects involved, none of the children in the baseline condition produced them. L-F CWA imitated the experimenter exactly, regardless of the models intention. TDC showed appreciation of the models intention by imitating her actions selectively. DSC reproduced only the intentional action as often as they imitated the experimenter exactly. It is concluded that L-F CWA attributed goals to the observed model, but did not show an appreciation of the models intentions even in these simplified, nonverbal contexts.

The Relative Importance of Language in Guiding Social Preferences Through Development.

In this paper, we review evidence from infants, toddlers, and preschoolers to tackle the question of how individuals orient preferences and actions toward social partners and how these preferences change over development. We aim at emphasizing the importance of language in guiding categorization relatively to other cues such as age, race and gender. We discuss the importance of language as part of a communication system that orients infants and older children’s attention toward relevant information in their environment and toward affiliated social partners who are potential sources of knowledge. We argue that other cues (visually perceptible features) are less reliable in informing individuals whether others share a common knowledge and whether they can be source of information.

Working Memory Integration Processes in Benign Childhood Epilepsy with Centrotemporal Spikes.

Objective and Background:Benign epilepsy of childhood with centrotemporal spikes (BECTS) is the most frequent focal epilepsy in children; however, the pattern of affected memory processes remains controversial. Previous studies in BECTS imply deficits in complex working memory tasks, but not in simple modality-specific tasks. We studied working memory processes in children with BECTS by comparing performance in memory binding tasks of different complexities. Methods:We compared 17 children with BECTS (aged 6 to 13 years) to 17 healthy children matched for age, sex, and intelligence quotient. We measured spatial and verbal memory components separately and jointly on three single-binding tasks (binding of what and where; what and when; and where and when) and a combined-binding task (integration of what, where, and when). We also evaluated basic visuospatial memory functions with subtests of the Children’s Memory Scale, and intellectual abilities with verbal tasks of the Wechsler Intelligence Scale for Children®–Fourth Edition and the Raven Progressive Matrices. Results:We found no difference between the BECTS and control groups in single-binding tasks; however, the children with BECTS performed significantly worse on the combined task, which included integration of spatial, verbal, and temporal information. We found no deficits in their intellectual abilities or basic visuospatial memory functions. Conclusions:Children with BECTS may have intact simple maintenance processes of working memory, but difficulty with high-level functions requiring attentional and executive resources. Our findings imply no specific memory dysfunction in BECTS, but suggest difficulties in integrating information within working memory, and possible frontal lobe disturbances.

Know your body through intrinsic goals

The first “object” that newborn children play with is their own body. This activity allows them to autonomously form a sensorimotor map of their own body and a repertoire of actions supporting future cognitive and motor development. Here we propose the theoretical hypothesis, operationalized as a computational model, that this acquisition of body knowledge is not guided by random motor-babbling, but rather by autonomously generated goals formed on the basis of intrinsic motivations. Motor exploration leads the agent to discover and form representations of the possible sensory events it can cause with its own actions. When the agent realizes the possibility of improving the competence to re-activate those representations, it is intrinsically motivated to select and pursue them as goals. The model is based on four components: (1) a self-organizing neural network, modulated by competence-based intrinsic motivations, that acquires abstract representations of experienced sensory (touch) changes; (2) a selector that selects the goal to pursue, and the motor resources to train to pursue it, on the basis of competence improvement; (3) an echo-state neural network that controls and learns, through goal-accomplishment and competence, the agents motor skills; (4) a predictor of the accomplishment of the selected goals generating the competence-based intrinsic motivation signals. The model is tested as the controller of a simulated simple planar robot composed of a torso and two kinematic 3-DoF 2D arms. The robot explores its body covered by touch sensors by moving its arms. The results, which might be used to guide future empirical experiments, show how the system converges to goals and motor skills allowing it to touch the different parts of own body and how the morphology of the body affects the formed goals. The convergence is strongly dependent on competence-based intrinsic motivations affecting not only skill learning and the selection of formed goals, but also the formation of the goal representations themselves.

Fetal Origin of Sensorimotor Behavior

The aim of this article is to track the fetal origin of infants’ sensorimotor behavior. We consider development as the self-organizing emergence of complex forms from spontaneously generated activity, governed by the innate capacity to detect and memorize the consequences of spontaneous activity (contingencies), and constrained by the sensory and motor maturation of the body. In support of this view, we show how observations on fetuses and also several fetal experiments suggest that the fetus’s first motor activity allows it to feel the space around it and to feel its body and the consequences of its movements on its body. This primitive motor babbling gives way progressively to sensorimotor behavior which already possesses most of the characteristics of infants’ later behavior: repetition of actions leading to sensations, intentionality, some motor control and oriented reactions to sensory stimulation. In this way the fetus can start developing a body map and acquiring knowledge of its limited physical and social environment.