superior colliculus


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su·pe·ri·or col·lic·u·lus

[TA]
the paired, larger, rounded anterior eminence of the laminae of mesencephalic tectum; major afferent connections of the superficial layers are the retina and striate cortex; input to deep layers of the colliculus are polymodal. Its efferent connections are with the lower brainstem and spinal cord (tectobulbar tract and tectospinal tract) and with the pulvinar and other cell groups in the caudal part of the thalamus; it participates in the extrageniculate visual pathway. The layers of the superior colliculus from superficial to deep are: zonal layer (stratum zonale), superficial gray layer (stratum griseum superficial), optic layer (stratum opticum), intermediate gray layer (stratum griseum intermedium), intermediate white layer (stratum medullare intermedium), deep gray layer (stratum griseum profundum), and deep white layer (stratum medullare profundum).

quadrantanopia 

Visual field loss in a quarter of the visual field of the eye. The defect is usually bilateral, as it is caused by a lesion past the optic chiasma. It may be homonymous (binasal, bitemporal, upper or lower), crossed (one upper and the other lower), congruous (equal size of the defects), or incongruous (unequal size of the defects) (Fig. Q1). Syn. quadrantanopsia; quadrantic anopsia; quadrantic hemianopia. See hemianopia.
Fig. Q1 Complete, right, superior homonymous quadrantanopia due to a lesion of the optic radiations in the left temporal lobeenlarge picture
Fig. Q1 Complete, right, superior homonymous quadrantanopia due to a lesion of the optic radiations in the left temporal lobe
References in periodicals archive ?
It is probable that the adverse effects of efavirenz on dizziness and headache may be due to direct effect of efavirenz on the superior colliculus and lateral geniculate body.
Optic tectum: The more rostral part of the midbrain roof, called the superior colliculus in mammals.
Inhibitory effect of remote visual stimuli on the visual responses of the cat superior colliculus: spatial and temporal factors.
Selective retrograde labeling with D-[3H] aspartate in afferents to the mammalian superior colliculus. Journal of Comparative Neurology, 241, 34-49.
However, the VEPs did not improve in the visual cortex nor in the superior colliculus for the 4 weeks post-ONC in either group (DPZ or saline), suggesting that either VEPs or physiological activity in the remaining retina-visual cortex pathways is insensitive to the changes--although after ONC, the surviving ganglion cells adapt to the need of the visual functions and have a better activity [26, 59, 60].
The substantia nigra pars reticulata tonically inhibits the superior colliculus (SC) via GABA-ergic projections, whereas pausing the inhibitory SC input provides a prerequisite for saccadic release [48].
In their current study, the Salk researchers specifically asked whether the superior colliculus is necessary for covert attention.
Disorders of voluntary control of eye movementsThe cerebral cortex and superior colliculus exert voluntary control over eye movements.
Among them, the superior colliculus shows strong response to novel visual stimuli [100] as well as novel multisensory information [101].
We want to understand how these decisions are formed in the brain, and how information is processed along the hierarchy of visual areas and in superior colliculus (SC), a motor structure of the midbrain.
Attentional control could be exerted from a number of higher cortical centres to the fixation neurons in the superior colliculus (SC) that generate the saccade.
[Prn-p.sup.b] mice (VM) showed mild to moderate gray matter vacuolation of the medulla, superior colliculus, thalamus, and septum.

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