Structure–Function Relationships in the Superior Colliculus of Higher Mammals

Grantyn, A.; Moschovakis, Adonis

doi:10.1201/9780203501504.ch5

Cited by 8 publications

(14 citation statements)

References 118 publications

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“…This implied that the superior colliculus influenced the center of the air-righting reflex, but the action was not indispensable for activation of the reflex. The superior colliculus has been thought to be the center of orienting action, by which the animal moves the eyes, head, or body to face a novel object that is of interest [12,[14][15][16][17][18]. In rodents it is presumably involved in negatively orienting action, avoidance and defensive actions [19][20][21].…”

Section: Discussionmentioning

confidence: 99%

“…Neuronal substrates for the orienting behavior are largely thought to be crossed tectoreticular and tectospinal neurons, descending the predorsal bundle via the dorsal tegmental decussation [12,[14][15][16][17][18][19][20][21]. Considering that orienting movement was rather similar to the axial rotation of the airrighting reflex toward the same side, we supposed that the unilaterally affected abnormalities were related to the crossed descending neurons of the predorsal bundle, unilateral ablation of which presumably decreased facilitating effects on the air-righting center of the opposite side, resulting in motor deficiencies in the contraversive airrighting reflex.…”

Section: Discussionmentioning

confidence: 99%

“…Among descending targets of the basal ganglia [10][11][12][13], one of the candidates is the superior colliculus, which has been known to be a center of orientation [12,[14][15][16][17][18] and avoidance [19][20][21] movements. Orienting and avoidance movements in relation to a target usually induce a postural change, which might evoke postural reflexes, but if it is evoked, the intended action could be disturbed.…”

Section: Introductionmentioning

confidence: 99%

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Effects of superior colliculus ablation on the air-righting reflex in the rat

2010

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To examine how the superior colliculus, the motor center of orientation and avoidance, could interact with postural reflexes, we investigated effects of unilateral and bilateral ablations on air-righting reflex movements in otherwise intact rats. Superior colliculus ablations variously modified righting movements: After falling from the supine position, the rats sometimes showed dorsiflexion instead of normal ventriflexion; the motor sequence of rotation from the fore- to the hindquarter was often modified to simultaneous rotation; lateral turn from supine to prone position was occasionally insufficient; body direction that was normally kept constant during falling was often changed; final posture sometimes deviated from the horizontal position. The first three abnormalities occurred almost twice in frequency as lesions increased from unilateral to bilateral ablation, and in unilaterally ablated rats, did so in righting contraversive to the lesions. Multiple influences of tectoreticular input to the air-righting reflex center are discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of superior colliculus ablation on the air-righting reflex in the rat

2010

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“…We are not aware of similar results in cats that could shed a complementary light on our invariant integral hypothesis. Since the morphology and physiology of SC neurons is quite different in felines and primates (Grantyn and Moschovakis 2003), such studies are necessary to test the validity of the hypothesis in cats.…”

Section: The Six Basic Propertiesmentioning

confidence: 99%

Geometry of the superior colliculus mapping and efficient oculomotor computation

Tabareau¹,

Bennequin²,

Berthoz³

et al. 2007

Biol Cybern

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Numerous brain regions encode variables using spatial distribution of activity in neuronal maps. Their specific geometry is usually explained by sensory considerations only. We provide here, for the first time, a theory involving the motor function of the superior colliculus to explain the geometry of its maps. We use six hypotheses in accordance with neurobiology to show that linear and logarithmic mappings are the only ones compatible with the generation of saccadic motor command. This mathematical proof gives a global coherence to the neurobiological studies on which it is based. Moreover, a new solution to the problem of saccades involving both colliculi is proposed. Comparative simulations show that it is more precise than the classical one.

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“…The large overlap between the RVF and left visual field is a primate visual specialization [Cartmill, 1974]. A wide binocular field is related to high visual acuity, specialization of visual pathways in the brain, adaptations of the visuomotor system, and elaboration and differentiation of the visual cortex [Grantyn and Moschovakis, 2004;Heesy, 2009]. It also correlates with the degree to which the bony orbits face in the same direction [Heesy, 2009].…”

Section: Larssonmentioning

confidence: 99%

Binocular Vision and Ipsilateral Retinal Projections in Relation to Eye and Forelimb Coordination

Larsson

2011

Brain Behav Evol

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It is commonly proposed that the number of fibers that do not cross in the optic chiasm (OC) is proportional to the size of the binocular visual field, and that the major advantage of binocular vision is acute depth perception. I present an alternative, an ‘eye-forelimb’ (EF) hypothesis, suggesting that alterations in the OC influence the length of neural pathways that transmit visual information to motor nuclei and somatosensory areas involved in forelimb coordination. Evolutionary processes resulting in increased ipsilateral retinal projections (IRP) are of adaptive value in animals that regularly use the forelimbs in a frontal position, while evolutionary change towards reduced IRP is of value for animals that mainly use the forelimbs in lateral positions. Primates and cats, to a large extent, use visually guided forelimb maneuvers, and both groups have high proportions of IRP. The fact that vertebrates’ IRP arise exclusively from the temporal retina supports the hypothesis, since IRP from the nasal retina would increase the length of neural pathways involved in forelimb coordination. The EF hypothesis offers new perspectives on why a high proportion of IRP among early limbless vertebrates became reduced during the evolution of laterally situated limbs, and why reptiles that lost their limbs (snakes) evolved more IRP. Anatomical, neurophysiological, phylogenetic, ontogenetic and ecological data suggest that mutations changing the proportions of ipsilateral visual connections in the OC may have selective value for EF coordination.

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Structure–Function Relationships in the Superior Colliculus of Higher Mammals

Cited by 8 publications

References 118 publications

Effects of superior colliculus ablation on the air-righting reflex in the rat

Effects of superior colliculus ablation on the air-righting reflex in the rat

Geometry of the superior colliculus mapping and efficient oculomotor computation

Binocular Vision and Ipsilateral Retinal Projections in Relation to Eye and Forelimb Coordination

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