Using pupil dilation, eye-blink rate, and the value of mother to investigate reward learning mechanisms in infancy

Abstract

The brain is adapted to learn from interactions with the environment that predict or enable the procurement of rewards ( Schultz, 2010 ). For infants, the main caregiver (often the mother) is most associated with primary biological rewards such as food and warmth, as well as the most likely provider of emotional and social rewards such as comfort and responsiveness. In this study we capitalize on the reward value of mother to examine reward learning mechanisms in infancy using multiple eye-tracking measures. Converging lines of research have demonstrated links between reward-related striatal dopamine activity and measurable changes in spontaneous eye-blink rate (EBR) and pupil dilation (Eckstein et al., 2017). We presented 7-month-old infants with video stimuli that parametrically increased in social-emotional value (male stranger, female stranger, mother) or in visual attention value (static image, slowed silent cartoon, dynamic cartoon). After establishing infants’ baseline responses to these stimuli, we paired the videos with arbitrary shape cues in an associative learning task. Infants showed superior learning from their own mother’s video and a heightened anticipatory arousal response to the mother-associated cue following learning. Both learning measures were predicted by infants’ baseline EBR to their mother’s video, providing the first evidence of reward learning and transfer in human infants.

Prepronociceptin-Expressing Neurons in the Extended Amygdala Encode and Promote Rapid Arousal Responses to Motivationally Salient Stimuli

“…In humans, rapid (within seconds) increases in physiological arousal, as measured by pupil size changes, follow exposure to negatively salient stimuli, such as threat-inducing images (Cascardi et al, 2015;Price et al, 2013). The same is true when humans are presented with positively salient stimuli, such as rewarding images of money or videos of caregivers (Schneider et al, 2018;Tummeltshammer et al, 2019). Thus, in addition to long-term adaptations in arousal (e.g., sleep/wake states; de Lecea et al, 2012), an important component of motivation is the rapid changes in physiological arousal upon presentation of salient stimuli.…”

Prepronociceptin expressing neurons in the extended amygdala encode and promote rapid arousal responses to motivationally salient stimuli

“…In humans, rapid (within seconds) increases in physiological arousal, as measured by pupil size changes, follow exposure to negatively salient stimuli, such as threat-inducing images (Cascardi et al, 2015;Price et al, 2013). The same is true when humans are presented with positively salient stimuli, such as rewarding images of money or videos of caregivers (Schneider et al, 2018;Tummeltshammer et al, 2019). Thus, in addition to long-term adaptations in arousal (e.g.…”

Learning Process of Gaze Following: Computational Modeling Based on Reinforcement Learning

“…Infant studies have also shown results supporting the relation between physiological arousal and attentional state (Wass et al, 2016;de Barbaro et al, 2017). Also, empirical studies have shown that affective states and reward expectations can be reflected in physiological arousal (Critchley et al, 2005;Tummeltshammer et al, 2019). Because it is difficult to define which factors induce infant physiological arousal in gaze-following situations, here we use a broad concept of internal state, which could be measured by neurophysiological measurements.…”