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Link to original content: https://pubmed.ncbi.nlm.nih.gov/15200711
Consistent chronostasis effects across saccade categories imply a subcortical efferent trigger - PubMed Skip to main page content
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Comparative Study
. 2004 Jun;16(5):839-47.
doi: 10.1162/089892904970780.

Consistent chronostasis effects across saccade categories imply a subcortical efferent trigger

Kielan Yarrow  1 , Helen Johnson, Patrick Haggard, John C Rothwell
Affiliations
Comparative Study

Consistent chronostasis effects across saccade categories imply a subcortical efferent trigger

Kielan Yarrow et al. J Cogn Neurosci. 2004 Jun.

Abstract

Saccadic chronostasis refers to the subjective temporal lengthening of the first visual stimulus perceived after an eye movement, and is most commonly experienced as the "stopped clock" illusion. Other temporal illusions arising in the context of movement (e.g., "intentional binding") appear to depend upon the volitional nature of the preceding motor act. Here we assess chronostasis across different saccade types, ranging from highly volitional (self-timed saccades, antisaccades) to highly reflexive (peripherally cued saccades, express saccades). Chronostasis was similar in magnitude across all these conditions, despite wide variations in their neural bases. The illusion must therefore be triggered by a "lowest common denominator" signal common to all the conditions tested and their respective neural circuits. Specifically, it is suggested that chronostasis is triggered by a low-level signal arising in response to efferent signals generated in the superior colliculus.

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Figures

Figure 1
Figure 1
Schematic of procedure for pro/anti-saccade experiment. (a) Sequence of visual stimuli. (b) Eye position. A trial from an anti-saccade block is shown (saccade made away from the box-shaped “go” cue). Eye movement triggered the appearance of a circle (frame 3) and subjects were required to compare its duration with that of a reference stimulus (frame 5). In pro-saccade trials, the circle replaced the cross within the box-shaped cue. Stimuli shown in grey were actually displayed in red.
Figure 2
Figure 2
Schematic of procedure for express saccade experiment. (a) Sequence of visual stimuli. (b) Eye position. A trial from a gap (express saccade) block is shown. Red stimuli are shown in grey, green stimuli in black. Eye movement towards the appearance of a peripheral red LED caused it to change colour to green. Subjects were required to compare the duration of this fixated green stimulus (frame 4) to that of a reference stimulus (frame 6). In cued saccade blocks, no gap was inserted between central fixation and peripheral onset (i.e. frame 1 lasted 500 ms and frame 2 was removed). In self-timed saccade blocks, both central and peripheral LEDs were initially displayed, and subjects made a saccade in their own time eliciting the sequence shown in frames 4 to 6.
Figure 3
Figure 3
Mean subjective duration estimates following different kinds of saccade for (a) pro/anti saccade and (b) express saccade experiments. The control conditions show values derived from constant fixation trials. Error bars show standard deviations.
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