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In neuroanatomy, the optic chiasm, or optic chiasma ( / ɒptɪk kaɪæzəm /; from Greek χίασμα 'crossing', from Ancient Greek χιάζω 'to mark with an X '), is the part of the brain where the optic nerves cross. It is located at the bottom of the brain immediately inferior to the hypothalamus. [1] The optic chiasm is found in all ...
Sphenoid bone. The sphenoid bone[note 1] is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the orbit. Its shape somewhat resembles that of a butterfly or bat with its wings ...
The dorsal column nuclei are a pair of nuclei in the dorsal columns of the dorsal column–medial lemniscus pathway (DCML) in the brainstem. [1] The name refers collectively to the cuneate nucleus and gracile nucleus, which are situated at the lower end of the medulla oblongata. Both nuclei contain second-order neurons of the DCML, which convey ...
The two-streams hypothesis is a model of the neural processing of vision as well as hearing. [ 1 ] The hypothesis, given its initial characterisation in a paper by David Milner and Melvyn A. Goodale in 1992, argues that humans possess two distinct visual systems. [ 2 ] Recently there seems to be evidence of two distinct auditory systems as well.
The dorsal column–medial lemniscus pathway (DCML) (also known as the posterior column-medial lemniscus pathway (PCML) is the major sensory pathway of the central nervous system that conveys sensations of fine touch, vibration, two-point discrimination, and proprioception (body position) from the skin and joints.
Lens (vertebrate anatomy) Lens of eye changing shape to focus near and far. Schematic diagram of the human eye. The lens, or crystalline lens, is a transparent biconvex structure in most land vertebrate eyes. Relatively long, thin fiber cells make up the majority of the lens. These cells vary in architecture and are arranged in concentric ...
Pineal gland. The pineal gland (also known as the pineal body[1] or epiphysis cerebri) is a small endocrine gland in the brain of most vertebrates. It produces melatonin, a serotonin -derived hormone, which modulates sleep patterns following the diurnal cycles. [2] The shape of the gland resembles a pine cone, which gives it its name. [3]
Commissural fiber. The commissural fibers or transverse fibers are axons that connect the two hemispheres of the brain. Huge numbers of commissural fibers make up the commissural tracts in the brain, the largest of which is the corpus callosum. In contrast to commissural fibers, association fibers form association tracts that connect regions ...