Crossing of neuronal pathways: Is it a response to the occurrence of separated parts for the body (limbs, eyes, etc.) during evolution?

Banihani, Saleh M.

doi:10.1016/j.mehy.2009.10.037

Cited by 7 publications

(7 citation statements)

References 18 publications

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“…2 ) is curled, the eye may receive visual information about ipsilateral as well as contralateral body parts. Banihani [2010] proposed that locomotion and other body movements will inevitably involve both sides of the body in a limbless animal, i.e., motor commands to on one side of the body will also influence the contralateral body part. As a consequence, motor commands to either side must be coordinated with those of the contralateral body part.…”

Section: Fishes Reptiles and Amphibiansmentioning

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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Section: Fishes Reptiles and Amphibiansmentioning

confidence: 99%

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

Larsson

2011

Brain Behav Evol

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“…At the optic chiasm, approximately 50% of retinal ganglion cell and interconnecting optic nerve fibers cross the midline in humans whereas about 90% cross the midline in the rat ( 19 ). The position of the eyes on the head represents a trade-off between binocular vision and field of vision.…”

Section: Discussionmentioning

confidence: 99%

Effects of Primary Blast Overpressure on Retina and Optic Tract in Rats

DeMar

Sharrow²,

Hill

et al. 2016

Front. Neurol.

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Blast has been the leading cause of injury, particularly traumatic brain injury and visual system injury, in combat operations in Iraq and Afghanistan. We determined the effect of shock tube-generated primary blast on retinal electrophysiology and on retinal and brain optic tract histopathology in a rat model. The amplitude of a- and b-waves on the electroretinogram (ERG) for both right and left eyes were measured prior to a battlefield simulation Friedlander-type blast wave and on 1, 7, and 14 days thereafter. Histopathologic findings of the right and left retina and the right and left optic tracts (2.8 mm postoptic chiasm) were evaluated 14 days after the blast. For two experiments in which the right eye was oriented to the blast, the amplitude of ERG a- and b-waves at 7 days post blast on the right side but not on the left side was diminished compared to that of sham animals (P = 0.005–0.01) Histopathologic injury scores at 14 days post blast for the right retina but not the left retina were higher than for sham animals (P = 0.01), and histopathologic injury scores at 14 days for both optic tracts were markedly higher than for shams (P < 0.0001). Exposure of one eye to a blast wave, comparable to that causing human injury, produced injury to the retina as determined by ERG and histopathology, and to both postchiasmatic optic tracts as determined by histopathology. This model may be useful for analyzing the effect of therapeutic interventions on retinal damage due to primary blast waves.

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“…In contradiction to the crossing of all retinal fibers in the lateral-eye species, the retinal fibers of binocular vision in frontal-eye species run either ipsilaterally or cross the midline twice to terminate the ipsilateral cerebral hemisphere. 1 It is hypothesized that carrying separated information, such as vision in lateral eyes, seems to create the need for functional coordination between the 2 cerebral hemispheres. This coordination appears to be mediated by fiber crossing.…”

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confidence: 99%

“…In this situation, both cerebral hemispheres receive the same information; therefore, functional coordination between the 2 hemispheres via fiber crossing is mostly unnecessary. 1 In another view, 2 the eye-forelimb hypothesis suggests that the ipsilateral retinal fibers of binocular vision as the right fibers of the right retina carry binocular vision from the left hemifield of the right visual field and run ipsilaterally to reach the right cerebral hemisphere. The latter controls the left limbs; thus, enabling more target-oriented motor response to stimuli in the left hemispace including the left hemifield of the right visual field.…”

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confidence: 99%