Dark adaptation is a gradual process that, especially for rods, takes tens of minutes. DOI: https://doi.org/10.1167/16.12.936, Wong, K. Y. a) The pupil constriction pathway. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Historically, the PLR was considered a purely reflexive response to the amount of light that falls on the retina. But even when participants are focused on detecting the AX sequence—and are therefore engaged in exploitation at this level of description—they still need to occasionally switch from the micro-task of not pressing a key to the micro-task of pressing a key; in other words, detecting the AX sequence and pressing a key is a form of brief (micro-)exploration, accompanied by a brief (phasic) pupil dilation. Learn a new word every day. (That is, we are not consciously aware of the effect that light has on synchronizing our circadian rhythm.) Journal of Cognition. Journal of Neurophysiology, 112(12), 3046–3052. Figure 7 shows a typical PPR during a working-memory task (cf. Enright (1987) asked participants to look at two-dimensional drawings of three-dimensional boxes (i.e. Vision Research, 36(12), 1827–1837. Vision Research, 15(6), 645–648. Simply put: because of rods and cones, the pupil rapidly constricts in response to sudden light increases; but because of ipRGCs, the pupil stays constricted throughout the day (Gooley et al., 2012; Wong, 2012). Task-evoked pupillary responses, processing load, and the structure of processing resources. The pupil light response is a constriction of the pupil in response to increased brightness. More recently, we showed that spontaneous pupil-size fluctuations correlate with changes in eye-movement behavior (Mathôt et al., 2015a; see also Marzouki, Dusaucy, Chanceaux, & Mathôt, 2017). Let’s trace the task hierarchy of my current situation, from simple to complex: I’m sitting behind my computer, writing this paragraph. New light on the mind’s eye: The pupillary light response as active vision. Crucially, they found that images that contained a sun triggered stronger pupil constriction than images that did not contain a sun, even when eye position and objective luminance were controlled for. the location in the visual field to which these neurons respond); next, they flashed a stimulus either within, or outside of, the stimulated RF. Journal of Neuroscience, 2433–16. The same response is sometimes also referred to as reflex dilation, arousal-related dilation, or effort-related dilation. Bombeke, K. (2017). Given that it takes at least 200 ms for the pupil to respond to light (Ellis, 1981), this would mean that by the time that the pupil start to respond to the brightness of a newly fixated object, gaze has already shifted elsewhere; or at least that’s what would happen in the absence of any preparation. Figure 4 shows a typical PLR, elicited by 10 s of blue or red light presented on … They directly measured brain activity, using a variety of techniques, as well as pupil size in awake, non-moving mice. Woodhouse, 1975), the pupil can be dilated with eye drops, or pupil size can be manipulated by changing ambient brightness or color (using the fact that red light leads to a more dilated pupil than blue light, cf. In contrast, if you are aroused and on the look-out for danger and opportunity (exploration, in the terminology of Aston-Jones & Cohen, 2005), visual sensitivity may be especially important; for example, a subtle movement somewhere may indicate danger, and it needs to be detected as quickly as possible.