TY - JOUR

T1 - Saccade latency bias toward temporal hemifield: Evidence for role of retinotectal tract in mediating reflexive saccades

AU - Koller, Kristin

AU - Rafal, Robert D.

N1 - Neural Routes to Awareness in Vision, Emotion and Action: A tribute to Larry Weiskrantz

PY - 2019/5

Y1 - 2019/5

N2 - The superior colliculus (SC) plays a critical role in mediating reflexive eye movements. Under optimal conditions, for example including a temporal ‘gap’ of 200 ms after fixation offset and prior to target onset, it is possible to isolate a population of ‘express saccades' with very short latencies between 80 and 120 ms. Ablation of the SC abolishes express saccades in monkeys. However, it remains to be established whether express saccade generation is dependent upon visual afferents transmitting direct retinal projections to SC via the retinotectal tract (RTT). In nineteen healthy human participants, we used a gap paradigm to investigate whether express saccades demonstrate shorter latencies to targets in the temporal hemifield, a marker for RTT function. A population of predominantly reflexive saccades (with latencies between 70 and 150 ms) was isolated in which latencies toward temporal hemifield targets were shown to be shorter than toward nasal hemifield targets. The advantages for reflexive saccades toward temporal hemifield targets suggest that visual efferents from the retina to the superior colliculus contribute to generating reflexively triggered saccades.

AB - The superior colliculus (SC) plays a critical role in mediating reflexive eye movements. Under optimal conditions, for example including a temporal ‘gap’ of 200 ms after fixation offset and prior to target onset, it is possible to isolate a population of ‘express saccades' with very short latencies between 80 and 120 ms. Ablation of the SC abolishes express saccades in monkeys. However, it remains to be established whether express saccade generation is dependent upon visual afferents transmitting direct retinal projections to SC via the retinotectal tract (RTT). In nineteen healthy human participants, we used a gap paradigm to investigate whether express saccades demonstrate shorter latencies to targets in the temporal hemifield, a marker for RTT function. A population of predominantly reflexive saccades (with latencies between 70 and 150 ms) was isolated in which latencies toward temporal hemifield targets were shown to be shorter than toward nasal hemifield targets. The advantages for reflexive saccades toward temporal hemifield targets suggest that visual efferents from the retina to the superior colliculus contribute to generating reflexively triggered saccades.

KW - Superior colliculus

KW - Retinotectal tract

KW - Temporal hemifield

KW - Gap effect

U2 - 10.1016/j.neuropsychologia.2018.01.028

DO - 10.1016/j.neuropsychologia.2018.01.028

M3 - Article

VL - 128

SP - 276

EP - 281

JO - Neuropsychologia

JF - Neuropsychologia

SN - 0028-3932

ER -