Subcortical afferent and efferent connections of the superior colliculus in the rat and comparisons between albino and pigmented strains

1986 ◽  
Vol 62 (1) ◽  
Author(s):  
A.M. Taylor ◽  
G. Jeffery ◽  
A.R. Lieberman
Keyword(s):  
Superior Colliculus ◽  
Efferent Connections

The superior colliculus of the ferret: Cortical afferents and efferent connections to dorsal thalamus

2010 ◽  
Vol 1353 ◽  
pp. 74-85 ◽  
Author(s):  
Paul R. Manger ◽  
C. Ernesto Restrepo ◽  
Giorgio M. Innocenti
Keyword(s):  
Superior Colliculus ◽  
Dorsal Thalamus ◽  
Efferent Connections ◽  
Cortical Afferents

scholarly journals Subcortical Projections of Area V2 in the Macaque

2014 ◽  
Vol 26 (6) ◽  
pp. 1220-1233 ◽  
Author(s):  
Leslie G. Ungerleider ◽  
Thelma W. Galkin ◽  
Robert Desimone ◽  
Ricardo Gattass
Keyword(s):  
Amino Acids ◽  
Visual Field ◽  
Superior Colliculus ◽  
Spatial Attention ◽  
Visual Fields ◽  
Central Visual Field ◽  
Efferent Connections ◽  
Intermediate Layers ◽  
Area V2 ◽  
Tritiated Amino Acids

To investigate the subcortical efferent connections of visual area V2, we injected tritiated amino acids under electrophysiological control into 15 V2 sites in 14 macaques. The injection sites included the fovea representation as well as representations ranging from central to far peripheral eccentricities in both the upper and lower visual fields. The results indicated that V2 projects topographically to different portions of the inferior and lateral pulvinar and to the superficial and intermediate layers of the superior colliculus. Within the pulvinar, the V2 projections terminated in fields P1, P2, and P4, with the strongest projection being in P2. Central visual field injections in V2 labeled projection zones in P1 and P2, whereas peripheral field injections labeled P1, P2, and P4. No projections were found in P3. Both central and peripheral field injections in V2 projected topographically to the superficial and intermediate layers of the superior colliculus. Projections from V2 to the pulvinar and the superior colliculus constituted cortical–subcortical loops through which circuits serving spatial attention are activated.

Intrinsic circuitry in the deep layers of the cat superior colliculus

1996 ◽  
Vol 13 (6) ◽  
pp. 1031-1042 ◽  
Author(s):  
M. Behan ◽  
N.M. Kime
Keyword(s):  
Superior Colliculus ◽  
Injection Site ◽  
Small Groups ◽  
Saccadic Eye Movements ◽  
Distributed Network ◽  
Mutual Inhibition ◽  
Efferent Connections ◽  
Deep Layers ◽  
Efferent Neurons ◽  
Cat Superior Colliculus

AbstractThe mammalian superior colliculus is involved in the transformation of sensory signals into orienting behaviors. Sensory and motor signals are integrated in the colliculus to produce movements of the eyes, head, and neck. While there is a considerable amount of information available on the afferent and efferent connections of the colliculus, almost nothing is known about its intrinsic circuitry, particularly that of its deepest layers. It is likely that intrinsic connections in these deeper layers of the colliculus participate in the sensory-motor transformations leading to orienting movements. In this study, we used the neuroanatomical tracer biocytin to label small groups of neurons in the deeper layers of the cat superior colliculus and examine the distribution of their axons and terminals. We found a broadly distributed network of intrinsic projections throughout the deep layers of the superior colliculus. While the majority of terminals were found in a 1–2 mm radius around the injection site, labeled terminals were found throughout the deep layers of the colliculus up to 5 mm from the injection site. In addition, these injections sometimes labeled terminals in the superficial tectum. Extensive projections were demonstrated by the more superficial injections, but few terminals were found when injections were confined to the deepest layers of the colliculus. There was no evidence of anisotropy in the distribution of terminals from injections made at different rostrocaudal or mediolateral locations; neurons located in any one region in the colliculus could potentially influence any other region. This network of intrinsic connections in the cat superior colliculus could provide a means for deeper-layer efferent neurons to associate, and to modulate or coordinate their output. Interneurons could also provide a substrate for mutual inhibition between neurons at the rostral pole of the colliculus that are active during fixation, and more caudally located neurons whose activity is associated with saccadic eye movements.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

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