A new view of dorsal visual cortex in macaques revealed by submillimeter fMRI

Zhu, Qi; Vanduffel, Wim

doi:10.1101/283051

Cited by 2 publications

(4 citation statements)

References 73 publications

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“…However, we also found that this representation merged directly into a representation of the upper quadrant near the midline, thereby forming a single representation of the peripheral visual field. Complementing the results of a recent study of the lateral part of the third tier complex (Zhu and Vanduffel, 2018), these findings point to a reinterpretation of the areas rostral to dorsal V2 in the macaque.…”

Section: Introductionsupporting

confidence: 78%

“…4A, B, D). However, our recording grid did not include more lateral regions where a more extensive representation of the upper quadrant is reported to exist adjacent to V2 (Zhu and Vanduffel, 2018). Receptive field 5 in Figure 5A exemplifies the upper quadrant invasion in this region.…”

Section: Resultsmentioning

confidence: 99%

“…Because the grid of electrode penetrations did not extend far into the banks of the lunate sulcus, our data do not establish the full lateral extent of the redefined macaque V6. Whereas the traditional model proposes that its lateral part (V3d) extends adjacent to V2 all the way to the lateral end of the lunate sulcus (Gattass et al 1988), more recent studies have questioned this, proposing instead that part of the cortex rostral to V2 in this sulcus represents the central upper quadrant (Zhu and Vanduffel, 2018; meta-analysis by Angelucci and Rosa, 2015). Although we did observe a few receptive fields centered in the upper quadrant in the expected location, the sample was insufficient to ascertain the extent of this representation.…”

Section: Discussionmentioning

confidence: 99%

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Topographic organization of the “third tier” dorsomedial visual cortex in the macaque

Hadjidimitrakis

Bakola

Chaplin

et al. 2019

Preprint

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22The boundaries of the visual areas located anterior to V2 in the dorsomedial region of the 23 macaque cortex remain contentious. This region is usually conceptualized as including two 24 functional subdivisions: the dorsal component of area V3 (V3d), laterally, and another area, 25 named the parietooccipital area (PO) or V6, medially. However, the nature of the putative 26 border between V3d and PO/V6 has remained undefined. We recorded the receptive fields of 27 multiunit clusters in adult male macaques, and reconstructed the locations of recording sites 28 using histological sections and "unfolded" cortical maps. Immediately adjacent to 29 dorsomedial V2 we observed a representation of the lower contralateral quadrant, which 30 represented the vertical meridian at its rostral border. This region, corresponding to V3d of 31 previous studies, formed a simple eccentricity gradient, from approximately <5˚ in the 32 annectant gyrus, to >60° in the parietooccipital sulcus. However, there was no topographic 33 reversal where one would expect to find the border between V3d and PO/V6. Rather, near the 34 midline, this lower quadrant map continued directly into a representation of the peripheral 35 upper visual field, without an intervening lower quadrant representation that could be 36 unambiguously assigned to PO/V6. Thus, V3d and PO/V6 form a continuous topographic 37 map, which includes parts of both quadrants. Together with previous observations that V3d 38 and PO/V6 are both densely myelinated relative to adjacent cortex, and share similar input 39 from V1, these results suggest that they are parts of a single area, which is distinct from the 40 one forming the ventral component of the third tier complex. 41 42 Significance statement: The primate visual cortex has a large number of areas. Knowing the 43 extent of each visual area, and how they can be distinguished from each other, are essential 44 for the interpretation of experiments aimed at understanding visual processing. Currently, 45 there are conflicting models of the organization of the dorsomedial visual cortex rostral to 46 area V2 (one of the earliest stages of cortical processing of vision). By conducting large-scale 47 electrophysiological recordings, we found that what were originally thought to be distinct 48 areas in this region (dorsal V3, and the parietooccipital area [PO/V6]), together form a single 49 map the visual field. These results will help guide future functional studies, and the 50 interpretation of the outcomes of lesions involving the dorsal visual cortex. 51 Visual maps in macaque dorsomedial cortex 3 Introduction 52 53Despite four decades of research, there is still controversy regarding the boundaries of visual 54 areas in the "third tier" cortex, i.e., the areas located rostral to the second visual area (V2, 55 (Allman and Kaas, 1975). Here we focus on the parts of this complex located in the 56 dorsomedial region of the macaque brain, including the medial part of the lunate sulcus, 57 annectant gyrus, parietooccipital s...

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Section: Introductionsupporting

confidence: 78%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Topographic organization of the “third tier” dorsomedial visual cortex in the macaque

Hadjidimitrakis

Bakola

Chaplin

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…For the macaque, it is currently debated whether V2 is adjoined by a single area V3 or multiple third-tier areas (Angelucci et al, 2015; Zhu and Vanduffel, 2018). A recent high-resolution fMRI retinotopy study (Zhu and Vanduffel, 2018) provides strong evidence for at least three (and possibly four or five) third-tier areas in a pattern similar but not identical to New World monkeys in the six hemispheres (3 monkeys) that were studied. In contrast, many fMRI studies in humans point to a simpler arrangement in which a single V3 adjoins most of V2 and lacks a comparable degree of dorso-ventral asymmetry (see SI section 4.1.3).…”

Section: Introductionmentioning

confidence: 99%

Parcellating Cerebral Cortex: How Invasive Animal Studies Inform Noninvasive Mapmaking in Humans

Essen

Glasser

2018

Neuron

123

102

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The cerebral cortex in mammals contains a mosaic of cortical areas that differ in function, architecture, connectivity, and/or topographic organization. A combination of local connectivity (within-area microcircuitry) and long-distance (between-area) connectivity enables each area to perform a unique set of computations. Some areas also have characteristic within-area mesoscale organization, reflecting specialized representations of distinct types of information. Cortical areas interact with one another to form functional networks that mediate behavior, and each area may be a part of multiple, partially overlapping networks. Given their importance to the understanding of brain organization, mapping cortical areas across species is a major objective of systems neuroscience and has been a century-long challenge. Here, we review recent progress in multi-modal mapping of mouse and nonhuman primate cortex, mainly using invasive experimental methods. These studies also provide a neuroanatomical foundation for mapping human cerebral cortex using noninvasive neuroimaging, including a new map of human cortical areas that we generated using a semiautomated analysis of high-quality, multimodal neuroimaging data. We contrast our semiautomated approach to human multimodal cortical mapping with various extant fully automated human brain parcellations that are based on only a single imaging modality and offer suggestions on how to best advance the noninvasive brain parcellation field. We discuss the limitations as well as the strengths of current noninvasive methods of mapping brain function, architecture, connectivity, and topography and of current approaches to mapping the brain's functional networks.

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A new view of dorsal visual cortex in macaques revealed by submillimeter fMRI

Cited by 2 publications

References 73 publications

Topographic organization of the “third tier” dorsomedial visual cortex in the macaque

Topographic organization of the “third tier” dorsomedial visual cortex in the macaque

Parcellating Cerebral Cortex: How Invasive Animal Studies Inform Noninvasive Mapmaking in Humans

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