**1.1 Social deficits**

There is lack of social attention and attention shifting in the autistic children in parallel with lack of development of joint attention skills [2]. The affected children display emotional reactions that do not associate with the surrounding events. They show negative emotions more frequently than positive emotions, without justifiable cause for inducing either response. Their play patterns are solitary, and they do not develop typical interactive social play with other children [3].

Abnormality in face perception is a core feature in autism. Face processing includes unchangeable facial features as those relating to gender and identity and changeable facial features such as emotional expression and gaze direction. Autistic children ignore looking at faces of others and are unable to understand facial expressions. Fixation time on the eye area of the face is reduced in ASD individuals. Opposite to what occurs in typically developing individuals, processing of gaze direction in autism experimentally produced more activation in fusiform gyrus for averted than for direct look. This was termed "covert attention," as autistic individuals are visually attentive and perceptive, but in an atypical manner.

During recognition of neutral faces, the autistic children exhibit a reduced activation of fusiform gyrus, superior temporal sulcus, amygdala, and occipital lobes, the primary areas for face recognition. In spite of this fact, autistic children showed typical activation when looking at familiar faces like that of a mother. Inferior temporal, middle, and inferior frontal gyri are also involved in face processing. It is important to note that reduced connectivity in brain networks between areas of face processing emerged as a holistic approach to explain the atypical face perception in autistic children [4].

The social processing involves social cognition and social motivation. Social cognition involves processes like attention, memory, and theory of mind, by which the person infers the internal state of others. Social motivation resembles directing attention to socially relevant stimuli and enjoying social activities. Both activities depend on the function of face processing. So it is related to the areas of face processing in addition to striatum (social interaction) and orbitofrontal cortex (social motivation) [5]. Impaired connectivity in social executive functions is present in ASD children [6].

## **1.2 Restricted repetitive behavior**

Autistic individuals resist change in their daily routine or the familiar surroundings. They do not explore while playing, and the toys are manipulated with little creativity or symbolic function. They are cognitively inflexible, as they may be preoccupied with parts of objects, or attached to unusual objects or movements, as watching the rotatory activity of fans. They could show stereotypic repetitive behavior that may be injurious to self or others. They tend to have a repetitive sensory motor behavior, insistence on sameness, and sometimes self-injurious acts [7].
