A distributed model of the saccadic system: The effects of internal noise

Das, Sanjoy; Keller, Edward L.; Arai, Kuniharu

doi:10.1016/0925-2312(95)00068-2

Cited by 17 publications

(14 citation statements)

References 28 publications

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“…SGI has been proposed as a site for this competition, because it spatially encodes the loci of these multiple objects (Basso and Wurtz, 1998) and generates a spatially encoded output that commands a gaze shift toward the selected target (Sparks, 1978;Anderson et al, 1998). Some models propose that inputs to SGI encoding stimulus location combine with local recurrent excitation to increase local activity to a threshold for a command, whereas widespread inhibition originating at this locus attenuates the activity of distant cells that otherwise might command undesired movements (Van Opstal and Van Gisbergen, 1989;Arai et al, 1994;Das et al, 1996). Our objective was to test this model.…”

Section: Discussionmentioning

confidence: 99%

“…(Chevalier et al, 1981;Hikosaka and Wurtz, 1983;May and Hall, 1984;Karabelas and Moschovakis, 1985;Harting et al, 1988;Bickford and Hall, 1992;Basso and Wurtz, 2002). A winner-take-all mechanism could be mediated by local disinhibition of the premotor cells produced by a spatially selective decrease in nigral cell activity, in combination with a build up in the activity of the premotor cells by afferent pathways and recurrent excitation (Das et al, 1996).…”

Section: Evidence For Widespread Inhibition and Excitation Within Sgimentioning

confidence: 99%

“…Some models (Van Opstal and Van Gisbergen, 1989;Arai et al, 1994;Das et al, 1996) propose that the competition is mediated by short-range excitatory connections that build up the activity of neurons in one region to the command threshold required for an orienting movement and by wide-ranging inhibitory projections that attenuate activity in other regions that might otherwise command undesired movements.…”

Section: Introductionmentioning

confidence: 99%

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AnIn VitroStudy of Horizontal Connections in the Intermediate Layer of the Superior Colliculus

Lee

Hall²

2006

J. Neurosci.

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Some models propose that the spatial and temporal distributions of premotor activity in the intermediate layer of the superior colliculus are shaped by neuronal ensembles that give rise to local excitatory and distant inhibitory connections. One function proposed for these connections is to mediate a "winner-take-all" network; the short-range excitatory connections build up the activity of neighboring cells that command orienting movements in one direction, whereas the wide-ranging inhibitory projections attenuate the activity of remote cells that command incompatible movements. We used in vitro photostimulation and whole-cell patch-clamp recording to test these models by measuring the spatial extent of synaptic interactions within the rat intermediate layer.

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Section: Discussionmentioning

confidence: 99%

Section: Evidence For Widespread Inhibition and Excitation Within Sgimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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AnIn VitroStudy of Horizontal Connections in the Intermediate Layer of the Superior Colliculus

Lee

Hall²

2006

J. Neurosci.

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“…Models of the SC in saccade generation have been developed primarily using single-point visual stimulation (Lee et al, 1988;Van Opstal and Van Gisbergen, 1989;McIlwain, 1991;Arai et al, 1993aArai et al, ,b, 1994Van Opstal and Kappen, 1993;Das et al, 1996;Bozis and Moschovakis, 1998;Quaia et al, 1998Quaia et al, , 1999. Based on the well known fact that individual saccades are associated with a large population of active SC neurons (Schiller and Koerner, 1971;Wurtz and Goldberg, 1972;Sparks et al, 1976;Sparks and Mays, 1980;Munoz and Wurtz, 1995) and that there are excitatory connections linking large regions of the SC (McIlwain, 1982), the models fall into the general class of distributed coding models (Lee et al, 1988;McIlwain, 1991;Quaia et al, 1998Quaia et al, , 1999.…”

Section: Implications For Population Coding In Scmentioning

confidence: 99%

Competitive Stimulus Interactions within Single Response Fields of Superior Colliculus Neurons

Li¹,

Basso²

2005

J. Neurosci.

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In addition to its role in saccade generation, the superior colliculus (SC) is involved in target selection, saccade selection, and shifting the focus of spatial attention. Here, we investigated the influence of saccade selection on sensory interactions within single response fields (RFs) of SC neurons. One or two differently shaped stimuli were presented within single RFs of SC neurons, and the shape of a centrally located cue indicated whether and where to make a saccade (Go-Go) or whether to make or withhold a saccade (Go/No-Go). We found that, when two stimuli appeared at different locations within a single RF, SC neuronal activity was reduced compared with when a single stimulus appeared in isolation within the center of the RF in both the Go-Go and Go/No-Go tasks. In both tasks, a subsequent cue indicating one stimulus as a saccade target reduced the influence of the second stimulus located within the RF. We found that the time course of the suppression resulting from the two stimuli was ϳ130 ms, a time close to that seen in cortex. Finally, we found that the influence of two stimuli within single RFs of SC neurons changed over time in both the Go-Go and the Go/No-Go tasks. Initially, the neurons averaged the influence of two stimuli. As the trial progressed, the SC neurons signaled only the saccade vector that was produced. We conclude that cues to shift gaze, like attention, modulate the influence of sensory interactions, providing additional support for the linkage between attention and saccade selection.

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“…However, the lateral (inhibitory) interactions within the SC motor map (Meredith & Ramoa, 1998) are not taken into account in the latter model, and without such an interaction, saccades to one out of multiple competing targets are hard to predict. Other models have been proposed that do take these lateral interactions into account, and can hence simulate behavior in multiple target configurations (Das, Keller, & Arai, 1996;Massone, 1994a,b).…”

Section: A Possible Coupling Mechanismmentioning

confidence: 99%