The postauricular reflex (PAR) is anomalous because it seems to be potentiated during positive emotions and inhibited during negative states, unlike eyeblink and other components of the startle reflex. Two evolutionary explanations based on simian facial emotion expressions were tested. Reflexes were elicited while 47 young adult volunteers made lip pursing or grimacing poses and viewed neutral, intimidating, or appetitive photos. The PAR was enhanced during appetitive slides, but only as subjects carried out the lip-pursing maneuver. These results support the nursing hypothesis, which assumes that infant mammals instinctively retract their pinnae while nursing in order to comfortably position the head. Appetitive emotions prime the ear-retraction musculature, even in higher primates whose postauricular muscles are vestigial.
This is a 25-year observational retrospective review of 372 consecutive participants with optic disc drusen or resolved papilloedema from idiopathic intracranial hypertension. The prevalence of optic disc drusen at 19% among eyes with resolved papilloedema was approximately 10 times higher and significantly increased (p < 0.001) as compared with the occurrence in the general population. Eyes with both resolved papilloedema and optic disc drusen had similar visual acuity and visual field outcome as compared with resolved papilloedema alone. Eyes with exposed drusen had significantly worse visual acuity and visual field outcome (p < 0.001) than buried drusen. The high prevalence of optic disc drusen after papilloedema has resolved suggests a non-coincidental relationship. Optic disc drusen formation can be a sequela of papilloedema.ARTICLE HISTORY
The onset of BEB and HFS was often preceded by a major lifetime stressor. The development of these conditions was significantly related to the number of stressful life events occurring within the preceding year rather than to the total number of stressful life events. Subjects who sustain closely spaced stressful life events may be at increased risk of developing BEB and HFS.
[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] The post-auricular reflex (PAR) is a vestigial microreflex which is thought to be a component of startle. However, unlike prototypical components of startle (e.g. acoustic blink reflex), the PAR is potentiated during appetitive motivational states and suppressed during defensive ones. An electromyographic (EMG) experiment with 37 men and 47 women tested if the Nursing Hypothesis could satisfactorily explain this anomalous PAR response. The Nursing Hypothesis proposes that infants of an ancestral mammalian species instinctively retracted their pinnae to signal their intention to nurse. Accordingly, appetitive emotions would still prime the ear-retraction musculature of adult humans, thereby causing facilitation of the PAR if a startling stimulus occurred. The present study failed to support the Nursing Hypothesis. Participants viewed one of 14 categories of slides while a series of startle probes was presented. Male participants showed the expected enhancement of PAR amplitude as nursing-related stimuli such as photographs of delicious food were viewed. Female participants by contrast had suppression of PAR amplitude when photographs of healthy breasts or of faces of beautiful women were viewed. Alternate hypotheses of PAR modulation are discussed.
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