Express saccades elicited during visual scan in the monkey

Sommer, Marc A.

doi:10.1016/0042-6989(94)90030-2

Cited by 63 publications

(61 citation statements)

References 38 publications

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“…Latency distributions had means of approximately 200 ms or higher and there was no evidence of the bimodality indicative of express saccade generation (e.g., Sommer 1994). Hence, we were unable to determine whether inactivating the FEF affects express saccades.…”

Section: Results Using Random Target Durationsmentioning

confidence: 92%

Reversible inactivation of macaque frontal eye field

1997

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The macaque frontal eye field (FEF) is involved in the generation of saccadic eye movements and fixations. To better understand the role of the FEF, we reversibly inactivated a portion of it while a monkey made saccades and fixations in response to visual stimuli. Lidocaine was infused into a FEF and neural inactivation was monitored with a nearby microelectrode. We used two saccadic tasks. In the delay task, a target was presented and then extinguished, but the monkey was not allowed to make a saccade to its location until a cue to move was given. In the step task, the monkey was allowed to look at a target as soon as it appeared. During FEF inactivation, monkeys were severely impaired at making saccades to locations of extinguished contralateral targets in the delay task. They were similarly impaired at making saccades to locations of contralateral targets in the step task if the target was flashed for ≤100 ms, such that it was gone before the saccade was initiated. Deficits included increases in saccadic latency, increases in saccadic error, and increases in the frequency of trials in which a saccade was not made. We varied the initial fixation location and found that the impairment specifically affected contraversive saccades rather than affecting all saccades made into head-centered contralateral space. Monkeys were impaired only slightly at making saccades to contralateral targets in the step task if the target duration was 1000 ms, such that the target was present during the saccade: latency increased, but increases in saccadic error were mild and increases in the frequency of trials in which a saccade was not made were insignificant. During FEF inactivation there usually was a direct correlation between the latency and the error of saccades made in response to contralateral targets. In the delay task, FEF inactivation increased the frequency of making premature saccades to ipsilateral targets. FEF inactivation had inconsistent and mild effects on saccadic peak velocity. FEF inactivation caused impairments in the ability to fixate lights steadily in contralateral space. FEF inactivation always caused an ipsiversive deviation of the eyes in darkness. In summary, our results suggest that the FEF plays major roles in (1) generating contraversive saccades to locations of extinguished or flashed targets, (2) maintaining contralateral fixations, and (3) suppressing inappropriate ipsiversive saccades.

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Section: Results Using Random Target Durationsmentioning

confidence: 92%

Reversible inactivation of macaque frontal eye field

1997

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“…1), a task that frequently elicits express saccades. Removing the fixation cross at a fixed time before target presentation both frees fixation-related inhibition and creates a temporal cue, which allows visual stimulation to drive quick behavioral responses, including express saccades (32,(35)(36)(37). Three different saccade targets were used: a luminance target, a high-contrast S-cone target, and a low-contrast S-cone target.…”

Section: Resultsmentioning

confidence: 99%

Express saccades and superior colliculus responses are sensitive to short-wavelength cone contrast

Hall

Colby

2016

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

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A key structure for directing saccadic eye movements is the superior colliculus (SC). The visual pathways that project to the SC have been reported to carry only luminance information and not color information. Short-wavelength-sensitive cones (S-cones) in the retina make little or no contribution to luminance signals, leading to the conclusion that S-cone stimuli should be invisible to SC neurons. The premise that S-cone stimuli are invisible to the SC has been used in numerous clinical and human psychophysical studies. The assumption that the SC cannot use S-cone stimuli to guide behavior has never been tested. We show here that express saccades, which depend on the SC, can be driven by S-cone input. Further, express saccade reaction times and changes in SC activity depend on the amount of S-cone contrast. These results demonstrate that the SC can use S-cone stimuli to guide behavior. We conclude that the use of S-cone stimuli is insufficient to isolate SC function in psychophysical and clinical studies of human subjects.S-cone | SC | macaque D ecades of oculomotor research have led to an incongruous conclusion: The oculomotor system does not use color information to guide the eyes (1, 2). However, it is natural to direct one's gaze to objects defined by color. Color vision in primates evolved because of the tremendous benefit of being able to discriminate colors and direct our actions accordingly (3, 4). The superior colliculus (SC) is a brainstem structure with a central role in the transformation of visual sensory signals into saccadic eye movements (2). Visual projections to the SC lack color opponent responses and appear to be dominated by luminance information (5-9). Luminance signals arise almost exclusively from long-and medium-wavelength-sensitive cones (L-and M-cones) in the retina, but not short-wavelength-sensitive cones (S-cones) (10). Instead, S-cones evolved to contribute to color vision (11). The takeaway is that the SC does not use color or S-cone input to guide saccades. This conclusion is surprising because both the SC and S-cones are evolutionarily ancient, and the SC has a central role in visually guided orienting behavior (2, 11).The proposition that the SC cannot detect S-cone stimuli has been leveraged to test SC function in diverse clinical and human psychophysical studies (12, 13). The scope of these investigations has ranged from mechanisms of blindsight (14-16), interhemispheric transfer in patients without a corpus callosum (17), face processing (18), and visual development (19) to inhibition of return (20), nasotemporal asymmetry (21), and the gap effect (22). The rationale for these experiments comes from an influential study by Sumner et al. (23), who noted that previous physiological and anatomical experiments had failed to find S-cone input to the SC. The idea is to present subjects with either a luminance or S-cone stimulus on separate trials of a visual or oculomotor task. If behavior [usually saccadic reaction time (RT)] is different in response to the S-cone stimulus, the ...

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“…Even then, small biases can be observed in perceptual and motor processes, as evidenced by the effect that previous trials and experimental sessions have on subsequent neuronal activity and behaviors (Bichot and Schall, 1999;Dorris et al, 2000;Fecteau et al, 2004;Fecteau and Munoz, 2003). Instead of minimizing these biasing effects, the current experimental task maximizes them by making the timing and location of the upcoming target fully predictable (Dorris and Munoz, 1998;Sommer, 1994;van Zoest et al, 2004). Unlike competition between visual signals, which influence parameters related to ongoing saccades, preparatory signals influence the preexisting baseline activity to affect whether a visual stimulus will trigger a saccade in the first place (Dorris et al, 1997).…”

Section: Saccade Preparation Biases Saccade Target Selectionmentioning

confidence: 99%

“…During each experimental session, a certain proportion of saccades were "captured" by the presentation of the visual distractors (i.e., error saccades) (Sommer, 1994;Theeuwes et al, 1998) rather than being directed toward the prespecified saccadic goal (i.e., correct saccades). The distribution of error saccades as a function of the location of distractors in the visual field (black circles) is shown for a typical experimental session in Figure 2 A.…”

Section: Combining Visual and Preparatory Processes To Influence Saccmentioning

confidence: 99%

Competitive Integration of Visual and Preparatory Signals in the Superior Colliculus during Saccadic Programming

Dorris

Olivier²,

Munoz³

2007

J. Neurosci.

144

128

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Efficient behavior requires that internally specified motor plans be integrated with incoming sensory information. Motor preparation and visual signals converge in the intermediate and deep layers of the superior colliculus (SC) to influence saccade planning and execution; however, the mechanism by which these sometimes conflicting signals are combined remains unclear. We studied this issue by presenting visual distractors as monkeys prepared saccades toward an upcoming target whose timing and location were fully predictable. Monkeys made more distractor-directed errors when the spatial location of visual distractors more closely coincided with the saccadic goal. Concomitant pretarget activity of SC visuomotor neurons, whose response fields were centered on the saccadic goal, was similarly increased by the presentation of nearby distractors and inhibited by the presentation of distant distractors. Finally, subthreshold microstimulation of the SC shifted the pattern of distractor-directed errors away from the saccadic goal toward that specified by the site of stimulation. Together, our results suggest that the likelihood of saccade generation is influenced by the spatial register of internal motor preparation signals and external sensory signals across the topographically organized SC map.

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Express saccades elicited during visual scan in the monkey

Cited by 63 publications

References 38 publications

Reversible inactivation of macaque frontal eye field

Reversible inactivation of macaque frontal eye field

Express saccades and superior colliculus responses are sensitive to short-wavelength cone contrast

Competitive Integration of Visual and Preparatory Signals in the Superior Colliculus during Saccadic Programming

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