Thalamus là gì
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Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Neuroscience. 2nd edition. Sunderland (MA): Sinauer Associates; 2001.
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Although the primary subdivisions of the cerebral hemispheres can be appreciated froma lateral view, other key landmarks are better seen from the dorsal và ventralsurfaces. When viewed from the dorsal surface (Figure1.13A), the approximate bilateral symmetry of the cerebral hemisphere isapparent. Although there is some variation, major landmarks lượt thích the central sulciand parieto-occipital sulci are usually very similar in arrangement on the twosides. If the cortical hemispheres are spread slightly apart, another majorstructure, the corpus callosum, can be seen bridging the two hemispheres. This tractcontains axons that originate from neurons in both cerebral hemispheres that contacttarget nerve cells in the opposite hemisphere.
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Figure 1.13
Dorsal view (A) và ventral view (B) of the human brain, indicating someof the major features visible from these perspectives. (C) The cerebral cortex has been removed in this dorsal view to lớn reveal the underlyingcorpus callosum. (After Rohen et al., (more...)
The external features of the brain best seen on its ventral surface are shown inFigure 1.13B. Extending along the inferiorsurface of the frontal lobe near the midline are the olfactory tracts, which arisefrom enlargements at their anterior ends called the olfactory bulbs. The olfactorybulbs receive input from neurons in the epithelial lining of the nasal cavity whoseaxons make up the first cranial nerve (cranial nerve I is therefore called theolfactory nerve; see Table1.1). On the ventromedial surface of the temporal lobe, theparahippocampal gyrus conceals the hippocampus, a highly convolutedcortical structure that figures importantly in memory. Slightly more medial khổng lồ theparahippocampal gyrus is the uncus, a slightly conical protrusion thatincludes the pyriform cortex. The pyriform cortex is the target of the lateral olfactory tract and processes olfactory information. At the most central aspect ofthe ventral surface of the forebrain is the optic chiasm, and immediately posterior,the ventral surface of the hypothalamus, including the infundibularstalk (the base of pituitary gland) & the mammillary bodies. Posteriorto the hypothalamus are two large tracts, oriented roughly rostral/caudally, calledthe cerebral peduncles. These tracts contain axons from the cerebral hemispheresthat project khổng lồ the motor neurons in the brainstem and into the lateral & ventralcolumns of the spinal cord. Finally, the ventral surfaces of the pons, medulla, andcerebellar hemispheres can be seen on the ventral surface of the brain (see alsoBox A).
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