Directional selectivity in hamster superior colliculus is modified by strobe-rearing but not by dark-rearing

Science ◽  
1978 ◽  
Vol 199 (4332) ◽  
pp. 998-1001 ◽  
Author(s):  
L. Chalupa ◽  
R. Rhoades
Keyword(s):  
Superior Colliculus ◽  
Directional Selectivity ◽  
Dark Rearing

Activity of Rostral Superior Colliculus Neurons During Passive and Active Viewing of Motion

2004 ◽  
Vol 92 (2) ◽  
pp. 949-958 ◽  
Author(s):  
Richard J. Krauzlis
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Visual Motion ◽  
Directional Selectivity ◽  
Pursuit Eye Movements ◽  
Passive Viewing ◽  
Superior Colliculus Neurons ◽  
Response Field

The superior colliculus (SC) has long been known to be important for the control of saccades, and recent findings indicate that the rostral SC (rSC) plays some role in pursuit as well. The recent finding that the prelude activity of some SC neurons exhibits directional selectivity suggests that the rSC might process visual motion signals relevant for the control of pursuit. We have now tested the activity of buildup neurons in the rSC during the passive viewing of motion stimuli placed within their response field and also during the previewing of visual motion stimuli that were subsequently tracked with pursuit eye movements. We found that rSC buildup neurons typically responded well to motion stimuli, but that they exhibited essentially no selectivity for the direction or speed of visual motion, and that they also responded well to stationary flickering dots. However, during the previewing of visual motion prior to the onset of pursuit, many neurons did exhibit a buildup of activity similar to that exhibited before saccades. These results are inconsistent with the notion that the rSC mediates visual motion signals used to drive pursuit, but instead support the idea that visual motion signals can be used by rSC neurons as part of a mechanism for selecting targets for pursuit and saccades.

Visual Experience Is Necessary for Maintenance But Not Development of Receptive Fields in Superior Colliculus

2005 ◽  
Vol 94 (3) ◽  
pp. 1962-1970 ◽  
Author(s):  
M. M. Carrasco ◽  
K. A. Razak ◽  
S. L. Pallas
Keyword(s):  
Superior Colliculus ◽  
Critical Period ◽  
Visual Experience ◽  
Sensory Deprivation ◽  
Receptive Fields ◽  
Visual Deprivation ◽  
Visual Development ◽  
Retinotopic Maps ◽  
Nmda Receptor Blockade ◽  
Dark Rearing

Sensory deprivation is thought to have an adverse effect on visual development and to prolong the critical period for plasticity. Once the animal reaches adulthood, however, synaptic connectivity is understood to be largely stable. We reported previously that N-methyl-d-aspartate (NMDA) receptor blockade in the superior colliculus of the Syrian hamster prevents refinement of receptive fields (RFs) in normal or compressed retinotopic projections, resulting in target neurons with enlarged RFs but normal stimulus tuning. Here we asked whether visually driven activity is necessary for refinement or maintenance of retinotopic maps or if spontaneous activity is sufficient. Animals were deprived of light either in adulthood only or from birth until the time of recording. We found that dark rearing from birth to 2 mo of age had no effect on the timing and extent of RF refinement as assessed with single unit extracellular recordings. Visual deprivation in adulthood also had no effect. Continuous dark rearing from birth into adulthood, however, resulted in a progressive loss of refinement, resulting in enlarged, asymmetric receptive fields and altered surround suppression in adulthood. Thus unlike in visual cortex, early visually driven activity is not necessary for refinement of receptive fields during development, but is required to maintain refined visual projections in adulthood. Because the map can refine normally in the dark, these results argue against a deprivation-induced delay in critical period closure, and suggest instead that early visual deprivation leaves target neurons more vulnerable to deprivation that continues after refinement.

Dark rearing reveals the mechanism underlying stimulus size tuning of superior colliculus neurons

2006 ◽  
Vol 23 (5) ◽  
pp. 741-748 ◽  
Author(s):  
KHALEEL A. RAZAK ◽  
SARAH L. PALLAS
Keyword(s):  
Superior Colliculus ◽  
Visual Stimuli ◽  
Stimulus Size ◽  
Size Selectivity ◽  
Small Stimulus ◽  
Inhibitory Circuitry ◽  
Classical Receptive Field ◽  
Superior Colliculus Neurons ◽  
Retinal Afferents ◽  
Dark Rearing

Neurons in the superficial layers of the midbrain superior colliculus (SC) exhibit distinct tuning properties for visual stimuli, but, unlike neurons in the geniculocortical visual pathway, most respond best to visual stimuli that are smaller than the classical receptive field (RF). The mechanism underlying this size selectivity may depend on the number and pattern of feedforward retinal inputs and/or the balance between inhibition and excitation within the RF. We have previously shown that chronic blockade of NMDA receptors (NMDA-R), which increases the convergence of retinal afferents onto SC neurons, does not alter size selectivity in the SC. This suggests that the number of retinal inputs does not determine size selectivity. Here we show, using single unit extracellular recordings from the SC of normal hamsters, that size selectivity in neurons selective for small stimulus size is correlated with the strength of inhibition within the RF. We also show that dark rearing causes concomitant reductions in both inhibition and size selectivity. In addition, dark rearing increases the percentage of neurons non-selective for stimulus size. Finally, we show that chronic blockade of NMDA-R, a procedure that does not alter size tuning, also does not change the strength of inhibition within the RF. Taken together, these results argue that inhibition within the RF underlies selectivity for small stimulus size and that inhibition must be intact for size tuning to be preserved after developmental manipulations of activity. In addition, these results suggest that regulation of the balance between excitation and inhibition within the RF does not require NMDA-R activity but does depend on visual experience. These results suggest that developmental experience influences neural response properties through an alteration of inhibitory circuitry.

scholarly journals Development of cortical influences on superior colliculus multisensory neurons: effects of dark-rearing

2013 ◽  
Vol 37 (10) ◽  
pp. 1594-1601 ◽  
Author(s):  
Liping Yu ◽  
Jinghong Xu ◽  
Benjamin A. Rowland ◽  
Barry E. Stein
Keyword(s):  
Superior Colliculus ◽  
Dark Rearing

Directional selectivity in the superior colliculus of the golden hamster

1976 ◽  
Vol 118 (2) ◽  
pp. 334-338 ◽  
Author(s):  
Robert W. Rhoades ◽  
Leo M. Chalupa
Keyword(s):  
Superior Colliculus ◽  
Golden Hamster ◽  
Directional Selectivity

Early visual experience prevents but cannot reverse deprivation-induced loss of refinement in adult superior colliculus

2006 ◽  
Vol 23 (6) ◽  
pp. 845-852 ◽  
Author(s):  
MARÍA MAGDALENA CARRASCO ◽  
SARAH L. PALLAS
Keyword(s):  
Visual System ◽  
Superior Colliculus ◽  
Visual Experience ◽  
Time Window ◽  
Brain Plasticity ◽  
Light Exposure ◽  
Receptive Fields ◽  
Adult Brain ◽  
Early Postnatal Development ◽  
Dark Rearing

The role of sensory experience in the development and plasticity of the visual system has been widely studied. It has generally been reported that once animals reach adulthood, experience-dependent visual plasticity is reduced. We have found that visual experience is not needed for the refinement of receptive fields (RFs) in the superior colliculus (SC) but instead is necessary to maintain them in adulthood (Carrasco et al., 2005). Without light exposure, RFs in SC of hamsters refine by postnatal day 60 as usual but then enlarge, presumably reducing visual acuity. In this study we examine whether a brief period of light exposure during early postnatal development would be sufficient to prevent RF enlargement in adulthood, and whether prolonged light exposure in adulthood could reverse the deprivation-induced increase in RF size. We found that an early postnatal period of at least 30 days of visual experience was sufficient to maintain refined RFs in the adult SC. Prolonged visual experience in adulthood could not reverse the RF enlargement resulting from long-term dark rearing, reflecting a loss of plasticity at this age. Our results suggest that, unlike in visual cortex, dark rearing does not indefinitely extend the critical period of plasticity in SC. Rather, there is a limited time window when early experience can protect RFs from the detrimental effects of visual deprivation in adulthood. These results contribute to understanding adult brain plasticity and argue for the importance of early visual experience in protecting the adult visual system.

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