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It can affect one eye but usually affects both eyes. Homonymous hemianopsia (or homonymous hemianopia) is hemianopic visual field loss on the same side of both eyes. Homonymous hemianopsia occurs because the right half of the brain has visual pathways for the left hemifield of both eyes, and the left half of the brain has visual pathways for ...
An example of this is when a person steps on a nail: The leg that is stepping on the nail pulls away, while the other leg takes the weight of the whole body. [ 4 ] The crossed extensor reflex is contralateral, meaning the reflex occurs on the opposite side of the body from the stimulus.
The visual pathway consists of structures that carry visual information from the retina to the brain.Lesions in that pathway cause a variety of visual field defects. In the visual system of human eye, the visual information processed by retinal photoreceptor cells travel in the following way:
Horizontal gaze palsies can be caused by a lesion affecting any structure in these pathways. Lesions to abducens nucleus or PPRF typically create an ipsilateral gaze palsy, while lesions to MLF typically cause Internuclear ophthalmoplegia , a type of horizontal gaze palsy in which the affected eye cannot adduct in conjugation with the ...
One instance would be (as already stated) in some reflexes. Reflexes usually are mediated at the level of the spinal cord through reflex arcs . In humans, mono-, oligo-, and poly-synaptic reflex arcs, propriospinal interneuron systems, and internuncial gray matter neurons collectively participate continuously to produce spinal cord reflex that ...
The tract transmits slow nociceptive/pain information (but thermal, and crude touch information as well) from the spinal cord to reticular formation which in turn relays the information to the thalamus via reticulothalamic fibers as well as to other parts of the brain (as opposed to the spinothalamic tract - the direct pathway of the ...
Descartes' pain pathway: "Particles of heat" (A) activate a spot of skin (B) attached by a fine thread (cc) to a valve in the brain (de) where this activity opens the valve, allowing the animal spirits to flow from a cavity (F) into the muscles causing them to flinch from the stimulus, turn the head and eyes toward the affected body part, and ...
Noxious stimuli activate the endings of nociceptive C and A delta nerve fibers, which carry the signal to neurons in the dorsal horn of spinal cord.DNIC refers to the mechanism by which dorsal horn wide dynamic range neurons responsive to stimulation from one location of the body may be inhibited by noxious stimuli (such as heat, high pressure or electric stimulation) applied to another ...