The boundaries of the visual areas located anterior toV2in the dorsomedial region of the macaque cortex remain contentious. This region is usually conceptualized as including two functional subdivisions: the dorsal component of area V3 (V3d) laterally and another area named the parietooccipital area (PO) or V6 medially. However, the nature of the putative border between V3d and PO/V6 has remained undefined. We recorded the receptive fields of multiunit clusters in male macaques and reconstructed the locations of recording sites using histological sections and computer-generated maps. Immediately adjacent to dorsomedial V2, we observed a representation of the lower contralateral quadrant that represented the vertical meridian at its rostral border. This region formed a simple eccentricity gradient from ~<5° in the annectant gyrus to >60° in the parietooccipital medial sulcus. There was no topographic reversal where one would expect to find the border between V3d and PO/V6. Rather, near the midline, this lower quadrant map continued directly into a representation of the peripheral upper visual field without an intervening lower quadrant representation. Therefore, cortex previously assigned to the medial part of V3d and to PO/V6 forms a single map that includes parts of both quadrants. Together with previous observations that V3d and PO/V6 are densely myelinated relative to adjacent cortex and share similar input from V1, these results suggest that they are parts of a single area (for which we suggest the designation V6), which is distinct from the one forming the ventral component of the third-tier complex.

Topographic organization of the ‘third-tier’ dorsomedial visual cortex in the macaque / Hadjidimitrakis K.; Bakola S.; Chaplin T.A.; Yu H.-H.; Alanazi O.; Chan J.M.; Worthy K.H.; Rosa M.G.P.. - In: THE JOURNAL OF NEUROSCIENCE. - ISSN 0270-6474. - STAMPA. - 39:27(2019), pp. 5311-5325. [10.1523/JNEUROSCI.0085-19.2019]

Topographic organization of the ‘third-tier’ dorsomedial visual cortex in the macaque

Hadjidimitrakis K.;Bakola S.;
2019

Abstract

The boundaries of the visual areas located anterior toV2in the dorsomedial region of the macaque cortex remain contentious. This region is usually conceptualized as including two functional subdivisions: the dorsal component of area V3 (V3d) laterally and another area named the parietooccipital area (PO) or V6 medially. However, the nature of the putative border between V3d and PO/V6 has remained undefined. We recorded the receptive fields of multiunit clusters in male macaques and reconstructed the locations of recording sites using histological sections and computer-generated maps. Immediately adjacent to dorsomedial V2, we observed a representation of the lower contralateral quadrant that represented the vertical meridian at its rostral border. This region formed a simple eccentricity gradient from ~<5° in the annectant gyrus to >60° in the parietooccipital medial sulcus. There was no topographic reversal where one would expect to find the border between V3d and PO/V6. Rather, near the midline, this lower quadrant map continued directly into a representation of the peripheral upper visual field without an intervening lower quadrant representation. Therefore, cortex previously assigned to the medial part of V3d and to PO/V6 forms a single map that includes parts of both quadrants. Together with previous observations that V3d and PO/V6 are densely myelinated relative to adjacent cortex and share similar input from V1, these results suggest that they are parts of a single area (for which we suggest the designation V6), which is distinct from the one forming the ventral component of the third-tier complex.
2019
Topographic organization of the ‘third-tier’ dorsomedial visual cortex in the macaque / Hadjidimitrakis K.; Bakola S.; Chaplin T.A.; Yu H.-H.; Alanazi O.; Chan J.M.; Worthy K.H.; Rosa M.G.P.. - In: THE JOURNAL OF NEUROSCIENCE. - ISSN 0270-6474. - STAMPA. - 39:27(2019), pp. 5311-5325. [10.1523/JNEUROSCI.0085-19.2019]
Hadjidimitrakis K.; Bakola S.; Chaplin T.A.; Yu H.-H.; Alanazi O.; Chan J.M.; Worthy K.H.; Rosa M.G.P.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/698480
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