Physiological responses of 5-month-old infants to smiling and blank faces

Abstract

Physiological responses (i.e., EEG, heart period, respiratory sinus arrhythmia (RSA)) were monitored in 5-month-old infants during the replacement of an adult's smiling (SF) with a blank face (BF) in a face-to-face setting. Affect, while the infant looked at and away from the adult's face during both conditions, was analyzed. Infants displayed neutral and some positive affect while looking at both SF and BF. RSA was quantified continuously during both conditions. RSA increased during BF relative to SF. EEG was quantified only while the infants were looking at the adult's face during both conditions. An increase in theta over multiple scalp areas (AF3,4; F7,8; FC3; T6) was observed during BF relative to SF. The data suggest that infant attention to BF and SF reflect different psychophysiological processes that can be indexed by RSA and scalp-recorded theta.

Theta- and alpha-band EEG activity in response to eye gaze cues in early infancy

“…Theta synchronization is suggested to reflect the involvement of an executive attention network and internal attentional processes (Bazhenova et al, 2007;Orekhova et al, 1999). We expected theta activity to alter with the development of this network.…”

“…So far, studies that have related theta synchronization to attentional processes have all investigated slightly older infants (Bazhenova et al, 2007;Orekhova et al, 1999;Orekhova et al, 2006;Stroganova et al, 1998). Theta synchronization has nonetheless been discussed to be related to the involvement of an attention network that is responsible for an executive control of attention that emerges between 4 and 6 months of age (Bazhenova et al, 2007;Mundy & Newell, 2007;Orekhova et al, 1999). As attention is thought to be guided automatically by social cues at four months, it is possible that this attention network is not yet involved in processing social cues in our sample.…”

“…Theta in infants, that we refer to in the current study, is primarily defined between 3 and 6 Hz and the frequency range does not seem to change between 4 and 12 months (Saby & Marshall, 2012;Stroganova & Orekhova, 2007). Theta synchronization may imply activity of the frontal cortex including an attention network involved in executive and voluntary control of attention as it has been proposed by Posner and Petersen (Bazhenova, Stroganova, Doussard-Roosevelt, Posikera, & Porges, 2007;Petersen & Posner, 2012;Posner & Petersen, 1990). It has been suggested that this attention system emerges at around 4-6 months and allows infants to monitor the relation between their own and others' gaze direction and goaldirected behavior (Mundy & Newell, 2007).…”

Mother-Infant Face-to-Face Interaction: The Communicative Value of Infant-Directed Talking and Singing

“…Previous studies concerning low frequency at the theta range in infants have reported increases in a range from 3 to 6 Hz over frontal electrodes before the first year of age related to emotion processing of faces [43] and negative mood [44,17]. Theta has also been reported for tasks involving effortful control, since theta (∼6 Hz) increases in 5-month-old infants have been reported when infants try to reengage in social contact [45]. Since in our study emotional face and voice were similar in ID talking and ID singing, we may propose that the sustained increase in 2-5 Hz during ID talking was associated with an increase in effortful control and looking for reengagement with the mother.…”

Consciousness

“…Bursts of theta can be detected not when the face is first seen nor when it reappears, but when the baby is anticipating the return of the face (Stroganova, Orekhova, & Posikera, 1998). It also is seen after repeated trials of still face presentations, when the child stops ignoring the face but smiles at it, presumably with the hope of reciprocity (Bahzenova, Stroganova, Doussard-Roosevelt, Posikera, & Porges, 2007). Theta activity therefore seems to correspond to the remembering of the hidden face or smiling face.…”