Pupillary Dilatation Induced by Stimulation of Amygdaloid Nuclei

Koigegami, H; Yoshida, Koh

doi:10.1111/j.1440-1819.1953.tb00600.x

Cited by 32 publications

(31 citation statements)

References 14 publications

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“…Thus the hypothalamus receives an afferent input from the central nucleus of amygdala (LeDoux et al, 1988) and there is a well-documented inhibitory projection from the posterior hypothalamus to the Edinger-Westphal nucleus (Loewenfeld, 1958;Koss, 1986). Indeed, electrical stimulation of the amygdala evokes a mydriatic response (Koikegami and Yoshida, 1953;Fernandez de Molina and Hunsberger, 1962).…”

Section: Discussionmentioning

confidence: 95%

The inhibition of the pupillary light reflex by the threat of an electric shock: a potential laboratory model of human anxiety

1996

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It has been shown that the eye-blink response evoked by an abrupt loud white noise ('acoustic startle') is potentiated when the subjects anticipate an aversive stimulus, e.g. an electric shock ('fear-potentiated startle'). It has been proposed that this paradigm may be a useful laboratory model of human anxiety. We examined whether the threat of an electric shock, as used in the fear-potentiated startle paradigm, would affect the pupillary light reflex, in 12 healthy volunteers. Light stimuli (0.32 mW/cm(2), 200 msec) were generated by a light-emitting diode, and pupil diameter was monitored by computerized binocular infrared television pupillometry in the dark. The light reflex was recorded during either the anticipation of a shock ('threat' blocks) or periods in which no shocks were anticipated ('safe' blocks). The shock consisted of a single square wave current pulse (1.5 mA, 50 msec) applied to the median nerve. At the end of each 'threat' or 'safe' block, subjects rated their anxiety using visual analogue scales. Two-factor analysis of variance (condition x block) showed that in the 'threat' condition there was a consistent increase in initial pupil diameter, a decrease in light reflex amplitude and an increase in alertness and anxiety ratings. These effects were observable before the subjects received any shock (a single stimulation of the median nerve). These results show that the anticipation of an electric shock can modify not only the startle reflex response but also the pupillary light reflex, suggesting that the inhibition of the light reflex by threat may be another suitable laboratory model of human anxiety.

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Section: Discussionmentioning

confidence: 95%

The inhibition of the pupillary light reflex by the threat of an electric shock: a potential laboratory model of human anxiety

1996

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“…There is also evidence that stimulation of the amygdala causes pupillary dilatation in the cat (Koikegami and Yoshida 1953;de Molina and Hunsberger 1962), probably via well known excitatory amygdalo-hypothalamic connections (Le Doux 1988;Davis 1992). It is thus possible that stimulation of the amygdala by conditioned aversive stimuli enhances the inhibitory inßuence of the hypothalamus on the Edinger-Westphal nucleus, resulting in enhancement of the inhibition of the pupillary light reßex.…”

Section: Discussionmentioning

confidence: 97%

Sensitivity of the fear-inhibited light reflex to diazepam

1998

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We have shown previously that pupil diameter increases and the amplitude of the pupillary light reflex is reduced when subjects are under threat of an aversive event (electric shock), and that light reflex amplitude correlates negatively with subjective anxiety. We have suggested that the "fear-inhibited light reflex" paradigm could be used as a laboratory model of human anxiety. In the present study, we examined whether two doses (5 mg and 10 mg) of the anxiolytic drug diazepam would antagonize the effects of threat on the pupillary light reflex. Twelve healthy male volunteers participated in three weekly sessions, each associated with one of three treatments (diazepam 5 mg or 10 mg or placebo) in a double-blind, balanced, cross-over design. The light reflex was recorded during either the anticipation of a shock ("threat" blocks) or periods in which no shocks were anticipated ("safe" blocks). At the end of each "threat" or "safe" block, subjects rated their anxiety using visual analogue scales. Two-factor ANOVA (treatment x condition) showed that diazepam treatment antagonized the effect of threat on light reflex amplitude in a dose-dependent manner but it did not affect the threat-induced increase in pupil diameter. Diazepam had no effect on the pupillary light reflex in the "safe" condition. Diazepam also reduced subjective anxiety and alertness in the threat condition. These results show the sensitivity of the threat-induced reduction of light reflex amplitude to anxiolytic drugs, and provide further evidence for the utility of the fear-inhibited light reflex paradigm as a laboratory model of human anxiety.

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“…Thus, the effect we observed may be due to a task-related expectancy of seeing threatening faces. Stimulation of the amygdala results in pupil dilation (49), possibly through interconnections with the locus coeruleus; therefore, this effect could be the result of activity in the subcortical pathway.…”

Section: Discussionmentioning

confidence: 99%

Effect of distracting faces on visual selective attention in the monkey

Landman

Sharma

Sur

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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In primates, visual stimuli with social and emotional content tend to attract attention. Attention might be captured through rapid, automatic, subcortical processing or guided by slower, more voluntary cortical processing. Here we examined whether irrelevant faces with varied emotional expressions interfere with a covert attention task in macaque monkeys. In the task, the monkeys monitored a target grating in the periphery for a subtle color change while ignoring distracters that included faces appearing elsewhere on the screen. The onset time of distracter faces before the target change, as well as their spatial proximity to the target, was varied from trial to trial. The presence of faces, especially faces with emotional expressions interfered with the task, indicating a competition for attentional resources between the task and the face stimuli. However, this interference was significant only when faces were presented for greater than 200 ms. Emotional faces also affected saccade velocity and reduced pupillary reflex. Our results indicate that the attraction of attention by emotional faces in the monkey takes a considerable amount of processing time, possibly involving cortical-subcortical interactions. Intranasal application of the hormone oxytocin ameliorated the interfering effects of faces. Together these results provide evidence for slow modulation of attention by emotional distracters, which likely involves oxytocinergic brain circuits.attention | faces | oxytocin | social | vision

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Pupillary Dilatation Induced by Stimulation of Amygdaloid Nuclei

Cited by 32 publications

References 14 publications

The inhibition of the pupillary light reflex by the threat of an electric shock: a potential laboratory model of human anxiety

The inhibition of the pupillary light reflex by the threat of an electric shock: a potential laboratory model of human anxiety

Sensitivity of the fear-inhibited light reflex to diazepam

Effect of distracting faces on visual selective attention in the monkey

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