Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

A motion sequence may be represented as a single pattern in x–y–t space; a velocity of motion corresponds to a three-dimensional orientation in this space. Motion sinformation can be extracted by a system that responds to the oriented spatiotemporal energy. We discuss a class of models for human motion mechanisms in which the first stage consists of linear filters that are oriented in space-time and tuned in spatial frequency. The outputs of quadrature pairs of such filters are squared and summed to give a measure of motion energy. These responses are then fed into an opponent stage. Energy models can be built from elements that are consistent with known physiology and psychophysics, and they permit a qualitative understanding of a variety of motion phenomena.

/pdf/spatiotemporal-energy-models-for-the-perception-of-motion-43mzze32mc.pdf

Spatiotemporal energy models for the perception of motion

Anatomical and physiological observations in monkeys indicate that the primate visual system consists of several separate and independent subdivisions that analyze different aspects of the same retinal image: cells in cortical visual areas 1 and 2 and higher visual areas are segregated into three interdigitating subdivisions that differ in their selectivity for color, stereopsis, movement, and orientation. The pathways selective for form and color seem to be derived mainly from the parvocellular geniculate subdivisions, the depth- and movement-selective components from the magnocellular. At lower levels, in the retina and in the geniculate, cells in these two subdivisions differ in their color selectivity, contrast sensitivity, temporal properties, and spatial resolution. These major differences in the properties of cells at lower levels in each of the subdivisions led to the prediction that different visual functions, such as color, depth, movement, and form perception, should exhibit corresponding differences. Human perceptual experiments are remarkably consistent with these predictions. Moreover, perceptual experiments can be designed to ask which subdivisions of the system are responsible for particular visual abilities, such as figure/ground discrimination or perception of depth from perspective or relative movement--functions that might be difficult to deduce from single-cell response properties.

https://science.sciencemag.org/content/sci/240/4853/740.full.pdf

Segregation of form, color, movement, and depth: anatomy, physiology, and perception

https://science.sciencemag.org/content/sci/5/110/206.full.pdf

The american psychological association.

Functional magnetic resonance imaging (fMRI) is currently the mainstay of neuroimaging in cognitive neuroscience. Advances in scanner technology, image acquisition protocols, experimental design, and analysis methods promise to push forward fMRI from mere cartography to the true study of brain organization. However, fundamental questions concerning the interpretation of fMRI data abound, as the conclusions drawn often ignore the actual limitations of the methodology. Here I give an overview of the current state of fMRI, and draw on neuroimaging and physiological data to present the current understanding of the haemodynamic signals and the constraints they impose on neuroimaging data interpretation.

What we can do and what we cannot do with fMRI

Contrast adaptation is specific to precisely localised edges, so that adapting to a flickering photograph makes one less sensitive to that same photograph, but not to similar photographs. When two low-contrast photos, A and B, are transparently superimposed, then adapting to a flickering high-contrast B leaves no net afterimage, but it makes B disappear from the A+B picture, which now simply looks like A.

/pdf/pattern-specificity-of-contrast-adaptation-3c2o0dxvw3.pdf

Pattern specificity of contrast adaptation

falls off progressively with eccentricity,or distance from the fovea centralis. On the skinof the arm, the fingertips play a role analogous tothe fovea. Their high acuity can enable a personto discriminate two tactile points that are separatedby only 2 mm. Two-point localization thresholdsrise progressively along the arm, from 7 mm on thepalm to 10 mm at the shoulder, like a cutaneousretina (Weinstein, 1968). On the facial skin the two­point threshold is only 2 mm on the

Notes and Comment Pouting and smUlng distort tbe tactile perception of facial stimuli

Galileo found that fine lines on a balance scale dazzled his eyes and were unreadable. So he used a grid of fine wires instead and ran his dagger across it, counting the number of auditory clicks. This is the first known experiment on sensory substitution.

Galileo's Dagger.

A test cross that flickers between light yellow and dark blue at 5 to 8Hz looks apparently yellow on a dark gray surround and apparently blue on a light gray surround (flicker augmented contrast). ...

https://journals.sagepub.com/doi/pdf/10.1177/2041669520929047

Salience-Based Edge Selection in Flicker and Binocular Color Vision.

When two adjacent surfaces move in step, this can generate a sensation of transparency, even in the absence of intersections. Stopping the motion of one surface makes it look suddenly opaque.

/pdf/motion-driven-transparency-and-opacity-2ddfqusni2.pdf

Stuart Anstis

Papers

Pattern specificity of contrast adaptation

Notes and Comment Pouting and smUlng distort tbe tactile perception of facial stimuli

Galileo's Dagger.

Salience-Based Edge Selection in Flicker and Binocular Color Vision.

Motion-Driven Transparency and Opacity.