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m →Primary visual cortex (V1): Tiny change to wording to clarify meaning. |
→Primary visual cortex (V1): Reconnecting a sentence which was first added on 2005-11-16. A couple of paragraphs were erroneously inserted in the middle of this sentence on 2024-01-26.. |
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{{Clarify|reason=unclear what "highly specialized" and "excellent" means in this sentence.|date=November 2016}}
The primary visual cortex, which is defined by its function or stage in the visual system, is approximately equivalent to the striate cortex, also known as Brodmann area 17, which is defined by its anatomical ___location. The name "striate cortex" is derived from the line of Gennari, a distinctive stripe visible to the naked eye that represents [[myelin]]ated [[axons]] from the [[lateral geniculate body]] terminating in layer 4 of the [[gray matter]].
Brodmann area 17 is just one subdivision of the broader Brodmann areas, which are regions of the cerebral cortex defined based on cytoarchitectural differences. In the case of the striate cortex, the line of Gennari corresponds to a band rich in myelinated nerve fibers, providing a clear marker for the primary visual processing region.{{cn|date=October 2024}}
Additionally, the functional significance of the striate cortex extends beyond its role as the primary visual cortex. It serves as a crucial hub for the initial processing of visual information, such as the analysis of basic features like orientation, spatial frequency, and color. The integration of these features in the striate cortex forms the foundation for more complex visual processing carried out in higher-order visual areas. Recent neuroimaging studies have contributed to a deeper understanding of the dynamic interactions within the striate cortex and its connections with other visual and non-visual brain regions, shedding light on the intricate neural circuits that underlie visual perception.<ref>{{cite journal |vauthors=Glickstein M, Rizzolatti G |title=Francesco Gennari and the structure of the cerebral cortex |journal=Trends in Neurosciences |volume=7 |issue=12 |pages=464–467 |date=1 December 1984|doi=10.1016/S0166-2236(84)80255-6 |s2cid=53168851 }}</ref>
The primary visual cortex is divided into six functionally distinct layers, labeled 1 to 6. Layer 4, which receives most visual input from the [[lateral geniculate nucleus]] (LGN), is further divided into 4 layers, labelled 4A, 4B, 4Cα, and 4Cβ. Sublamina 4Cα receives mostly [[Magnocellular cell|magnocellular]] input from the LGN, while layer 4Cβ receives input from [[Parvocellular cell|parvocellular]] pathways.<ref>{{cite journal | vauthors = Hubel DH, Wiesel TN | title = Laminar and columnar distribution of geniculo-cortical fibers in the macaque monkey | journal = The Journal of Comparative Neurology | volume = 146 | issue = 4 | pages = 421–450 | date = December 1972 | pmid = 4117368 | doi = 10.1002/cne.901460402 | s2cid = 6478458 }}</ref>
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