Colliculoreticular Organization in the Oculomotor System

El, Keller

doi:10.1016/s0079-6123(08)60869-9

Cited by 164 publications

(13 citation statements)

References 18 publications

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“…Relative to cells in the upper intermediate gray layer, they may be more strongly influenced by input from sources that terminate preferentially in the lower part of the intermediate gray layer, such as the frontal eye fields, substantia nigra pars reticulata and cerebellum (May & Hall, 1984;May et al, 1993;Lee & Hall, 1995). In a variety of species, they apparently make a substantial contribution to the predorsal bundle (Keller, 1979;Moschovakis & Karabelas, 1985;May & Hall, 1984;Moschovakis et al, 1988a;May & Porter, 1992;Lee & Hall, 1995). Physiologically, they may correspond to the buildup neurons, which in the primate may be preferentially located in the lower intermediate gray layer (Keller & Edelman, 1994;Munoz & Wurtz, 1995).…”

Section: The Intermediate Gray Layermentioning

confidence: 99%

Interlaminar connections of the superior colliculus in the tree shrew. III: The optic layer

Hall

Lee

1997

Vis Neurosci

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These experiments were designed to test the idea that the optic layer in the tree shrew, Tupaia belonged is functionally distinct and provides a link between the visuosensory superficial and the premotor intermediate layers of the superior colliculus. First, cells in the optic layer were intracellularly labeled with biocytin in living brain slices. Compared to cells in the adjacent lower part of the superficial gray layer, which have apical dendntes that ascend toward the tectal surface, optic layer cells have dendritic fields that are restricted for the most part to the optic layer itself The differences in dendritic-field location imply that superficial gray and optic layer cells have different patterns of input The axons of optic layer cells terminate densely within the optic layer and, in addition, project in a horizontally restricted fashion to the overlying superficial gray and subjacent intermediate gray layers. This pattern also is different from the predominantly descending interlaminar projections of lower superficial gray layer cells Next cells in the intermediate gray layer were labeled in order to examine the relationships between optic layer cells and these subjacent neurons that project from the superior colliculus to oculomotor centers of the brain stem Neurons in the upper part of the intermediate gray layer send apical dendrites into the optic layer and therefore can receive signals from the superficial gray layer either directly, from descending axons of lower superficial gray layer cells, or indirectly, through intervening optic layer cells. In contrast, lower intermediate gray layer cells have more radiate dendritic fields that are restricted to the intermediate gray layer. Thus, these lower cells must depend on descending projections from optic or upper intermediate gray layer cells for signals from the superficial gray layer Together, these results support the idea that the optic layer is a distinct lamina that provides ; link between the superficial and intermediate gray layers. They also are consistent with the traditional view that descending intracollicular projections play a role in the selection of visual targets for saccades.

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Section: The Intermediate Gray Layermentioning

confidence: 99%

Interlaminar connections of the superior colliculus in the tree shrew. III: The optic layer

Hall

Lee

1997

Vis Neurosci

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“…The spatially organized distribution of these saccade‐related neurons forms a topographic map of saccade vectors, which can also be revealed by delivering short trains of low‐current electrical pulses (Robinson, 1972). Many of these saccade‐related neurons also send axons to the premotor saccade‐generating circuit (Keller, 1979; Gandhi & Keller, 1997; Rodgers et al. , 2006; see also Moschovakis et al.…”

Section: Introductionmentioning

confidence: 99%

Investigating the role of the superior colliculus in active vision with the visual search paradigm

Shen

Valero

Day

et al. 2011

Eur J of Neuroscience

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We review here both the evidence that the functional visuomotor organization of the optic tectum is conserved in the primate superior colliculus (SC) and the evidence for the linking proposition that SC discriminating activity instantiates saccade target selection. We also present new data in response to questions that arose from recent SC visual search studies. First, we observed that SC discriminating activity predicts saccade initiation when monkeys perform an unconstrained search for a target defined by either a single visual feature or a conjunction of two features. Quantitative differences between the results in these two search tasks suggest, however, that SC discriminating activity does not only reflect saccade programming. This finding concurs with visual search studies conducted in posterior parietal cortex and the idea that, during natural active vision, visual attention is shifted concomitantly with saccade programming. Second, the analysis of a large neuronal sample recorded during feature search revealed that visual neurons in the superficial layers do possess discriminating activity. In addition, the hypotheses that there are distinct types of SC neurons in the deeper layers and that they are differently involved in saccade target selection were not substantiated. Third, we found that the discriminating quality of single-neuron activity substantially surpasses the ability of the monkeys to discriminate the target from distracters, raising the possibility that saccade target selection is a noisy process. We discuss these new findings in light of the visual search literature and the view that the SC is a visual salience map for orienting eye movements.

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“…Of the different types of burst cells in the intermediate layers of the monkey SC, detailed reports on the dynamic behavior of only the SRBNs are available (Waitzman et al 1991;Keller and Edelman 1994). Because they are known to project to the region of the burst generator (Keller 1979;Moschovakis et al 1988;Scudder et al 1989;Istvan et al 1994;Keller and Edelman 1993), we based our study on the SRBNs as the source of both inputs to the model. We picked purely horizontal saccades for analysis so that the centers of the active regions on the SC lay near the representation of the horizontal meridian on the SC motor map as shown schematically in Fig.…”

Section: Preparation Of the Physiological Signals For Use As Model Inmentioning

confidence: 99%

Open-loop simulations of the primate saccadic system using burst cell discharge from the superior colliculus

1995

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Saccade-related burst neurons (SRBNs) in the monkey superior colliculus (SC) have been hypothesized to provide the brainstem saccadic burst generator with the dynamic error signal and the movement initiating trigger signal. To test this claim, we performed two sets of open-loop simulations on a burst generator model with the local feedback disconnected using experimentally obtained SRBN activity as both the driving and trigger signal inputs to the model. First, using neural data obtained from cells located near the middle of the rostral to caudal extent of the SC, the internal parameters of the model were optimized by means of a stochastic hill-climbing algorithm to produce an intermediate-sized saccade. The parameter values obtained from the optimization were then fixed and additional simulations were done using the experimental data from rostral collicular neurons (small saccades) and from more caudal neurons (large saccades); the model generated realistic saccades, matching both position and velocity profiles of real saccades to the centers of the movement fields of all these cells. Second, the model was driven by SRBN activity affiliated with interrupted saccades, the resumed eye movements observed following electrical stimulation of the omnipause region. Once again, the model produced eye movements that closely resembled the interrupted saccades produced by such simulations, but minor readjustment of parameters reflecting the weight of the projection of the trigger signal was required. Our study demonstrates that a model of the burst generator produces reasonably realistic saccades when driven with actual samples of SRBN discharges.

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Colliculoreticular Organization in the Oculomotor System

Cited by 164 publications

References 18 publications

Interlaminar connections of the superior colliculus in the tree shrew. III: The optic layer

Interlaminar connections of the superior colliculus in the tree shrew. III: The optic layer

Investigating the role of the superior colliculus in active vision with the visual search paradigm

Open-loop simulations of the primate saccadic system using burst cell discharge from the superior colliculus

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