Information processing in the cerebral cortex involves interactions among distributed areas. Anatomical connectivity suggests that certain areas form local hierarchical relations such as within the visual system. Other connectivity patterns, particularly among association areas, suggest the presence of large-scale circuits without clear hierarchical relations. In this study the organization of networks in the human cerebrum was explored using resting-state functional connectivity MRI. Data from 1,000 subjects were registered using surface-based alignment. A clustering approach was employed to identify and replicate networks of functionally coupled regions across the cerebral cortex. The results revealed local networks confined to sensory and motor cortices as well as distributed networks of association regions. Within the sensory and motor cortices, functional connectivity followed topographic representations across adjacent areas. In association cortex, the connectivity patterns often showed abrupt transitions between network boundaries. Focused analyses were performed to better understand properties of network connectivity. A canonical sensory-motor pathway involving primary visual area, putative middle temporal area complex (MT+), lateral intraparietal area, and frontal eye field was analyzed to explore how interactions might arise within and between networks. Results showed that adjacent regions of the MT+ complex demonstrate differential connectivity consistent with a hierarchical pathway that spans networks. The functional connectivity of parietal and prefrontal association cortices was next explored. Distinct connectivity profiles of neighboring regions suggest they participate in distributed networks that, while showing evidence for interactions, are embedded within largely parallel, interdigitated circuits. We conclude by discussing the organization of these large-scale cerebral networks in relation to monkey anatomy and their potential evolutionary expansion in humans to support cognition.

The organization of the human cerebral cortex estimated by intrinsic functional connectivity

https://www.allpsych.uni-giessen.de/rauisch06/readings/Bullier.BrainResRev.2001.pdf

Integrated model of visual processing

http://brain-mind.med.uoc.gr/sites/default/files/VanEssenStriateAnisotropies1984_1.pdf

The visual field representation in striate cortex of the macaque monkey: Asymmetries, anisotropies, and individual variability

https://www.cns.nyu.edu/~tony/vns/readings/kapadia-ito-gilbert-westheimer-1995.pdf

Improvement in Visual Sensitivity by Changes in Local Context: Parallel Studies in Human Observers and in V1 of Alert Monkeys

The visual recognition of complex movements and actions is crucial for the survival of many species. It is important not only for communication and recognition at a distance, but also for the learning of complex motor actions by imitation. Movement recognition has been studied in psychophysical, neurophysiological and imaging experiments, and several cortical areas involved in it have been identified. We use a neurophysiologically plausible and quantitative model as a tool for organizing and making sense of the experimental data, despite their growing size and complexity. We review the main experimental findings and discuss possible neural mechanisms, and show that a learning-based, feedforward model provides a neurophysiologically plausible and consistent summary of many key experimental results.

Neural mechanisms for the recognition of biological movements.

Receptive field size and magnification have been studied in striate cortex of awake, behaving rhesus monkeys at visual eccentricities in the range of 5–160 min. The major findings that emerge are (1) magnification in the foveola achieves values in the range of 30 mm/deg, (2) mean field size is not proportional to inverse magnification in contrast with previous reports, and (3) the product, magnification X aggregate field size, is greater in central vision than in peripheral vision. Thus, a point of light projected onto foveal retina is “seen” by larger numbers of striate cortical cells than a point of light projected onto peripheral retina. Implications of these findings for visual localization and two-point discrimination are discussed.

Magnification factor and receptive field size in foveal striate cortex of the monkey.

Visuotopic maps of foveal striate cortex have been obtained by means of single cell recordings from four hemispheres in two awake, behaving macaque monkeys. The numbers of successful separate striate penetration sites in the four hemispheres were 42, 58, 81, and 61, for a total of 242. The resolution of the maps is 10 min of visual angle, nearly an order of magnitude finer than previous maps. No striate receptive field center was found more than 5 min into the ipsilateral visual field. The four maps were sufficiently compatible with one another that they could be combined into one. There are only minor magnification differences between the right and left hemispheres and between the upper and lower quadrants. There is a vertical/horizontal magnification anisotropy of about 1.5:1 in central foveal cortex (0 to 20 min). The composite map can be approximated by the complex logarithmic equation, w = 7.7 * ln (x + iy + 0.33), where w is expressed in millimeters and x and y are expressed in degrees.

https://www.jneurosci.org/content/jneuro/5/4/890.full.pdf

The mapping of visual space onto foveal striate cortex in the macaque monkey

Microelectrode penetrations normal to the layers of foveal striate cortex in awake, behaving monkeys have revealed two new facts about the distribution of orientation preferences in this tissue: (1) In the top layers there is a predominance of vertical orientation preferences at eccentricities of less than 30 min, and a predominance of oblique orientation preferences at eccentricities of 30 min to 2 deg. (2) At all eccentricities between 0 and 2 deg there is a striking difference in orientation preference between upper layer (supragranular) and lower layer (infragranular) cells.

Laminar distribution of preferred orientations in foveal striate cortex of the monkey.

Microelectrode penetrations nearly normal to the layers of foveal striate cortex in awake, behaving monkeys reveal a shift in orientation preference between cells in the upper and lower layers. Mean shift size for 57 penetrations is 54.8 degrees, with 70% of the penetrations showing shifts of 45-90 degrees. Marking lesions localize the shift to the border between layers 4C and 5. The data are suggestive of inhibition between the upper and lower layers within an "orientation column".

R. G. Vautin

Papers

Magnification factor and receptive field size in foveal striate cortex of the monkey.

The mapping of visual space onto foveal striate cortex in the macaque monkey

Laminar distribution of preferred orientations in foveal striate cortex of the monkey.

Orientation shift between upper and lower layers in monkey visual cortex.