Reciprocal modulation of eye‐blink and pinna‐flexion components of startle during reward anticipation

Abstract

Because expectancies play a central role in current theories of dopaminergic neuron function, it is important to develop measures of reward anticipation processes. In the present study, reflexogenic bursts of white noise were presented to 39 healthy young adults as they awaited rewards and punishments in a gambling-like task. The rewards were small pieces of chocolate; the punishments, segments of bitter-tasting banana peel. Consistent with prior research on affective valence, postauricular reflexes were larger prior to rewards than punishments, whereas the reverse was true for acoustic blink reflexes. We theorized that potentiation of the postauricular reflex prior to consuming appetizing food is related to the priming of ear-retraction musculature during nursing in our remote ancestors.

The impact of early neglect on defensive and appetitive physiology during the pubertal transition: A study of startle and postauricular reflexes

“…The actual neural circuit of the PAR is unknown, but it is likely similar to the auditory eye blink reflex circuit in afferent input (the cochlear nucleus) and efferent output (the facial‐motor nucleus). However, the PAR is heightened to anticipation of eating appetizing food (Hackley, Munoz, Hebert, Valle‐Inclan, & Vila, ); and reward anticipation has been consistently linked to the activity of the basal ganglia (Ernst et al, ), particularly the ventral striatum, which supports processing of food and sex's visual cues, that reliably elicit the PAR in adults (Sandt et al, ). Startle and PAR are uncorrelated here and in the available literature; suggesting that these are, to some extent, independent reflexes.…”

The nursing hypothesis: An evolutionary account of emotional modulation of the postauricular reflex

“…By contrast, the human postauricular reflex is potentiated during positive and inhibited during negative emotions, as induced by viewing evocative photographs (Benning, Patrick, & Lang, ; Gable & Harmon‐Jones, ; Hess, Sabourin, & Kleck, ; Sandt, Sloan, & Johnson, ). Similarly, the PAR is enhanced prior to response‐contingent rewards as compared to punishments, whereas acoustic blink is larger prior to punishments than rewards (Hackley, Muñoz, Hebert, Valle‐Inclan, & Vila, ; Muñoz, Hackley, Valle‐Inclán, Ramirez, & Vila, submitted). If affective modulation reflects concordance between the valence of the reflex and the prevailing motivational state (Lang, Bradley, & Cuthbert, ), it is difficult to understand how two components of the same reflex could be modulated in opposite directions.…”

“…As an alternative, the grimace hypothesis postulates that the PAR is not associated with appetitive motivation as has been assumed (e.g., Benning et al., ; Hackley et al., ). Instead, ear retraction became linked in our simian ancestors to teeth‐baring expressions.…”

Postauricular and superior auricular reflex modulation during emotional pictures and sounds

“…They have also been extended in a study demonstrating that only happy facial expressions posed by women significantly potentiated postauricular reflex magnitudes, congruent with a functional equivalence hypothesis of facial expressivity (Hess, Sabourin, & Kleck, 2007). Additionally, postauricular reflexes are greater during anticipation of gustatory reward than punishment (Hackley, Muñoz, Hebert, Valle‐Inclán, & Vila, 2009), indicating that postauricular reflexes may be measures of appetitive processing in the absence of a foreground emotional stimulus. Nevertheless, the validity of the postauricular reflex as a measure of appetitive processing during emotional sounds has yet to be studied.…”