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

A moving frame can dramatically displace the perceived location of stimuli flashed before and after the motion. Here, we use a moving frame to rearrange flashed elements into the form of classic illusions. Without the moving frame, the initial arrangement of the flashed elements has no illusory effect. The question is whether the frame-induced displacement of position precedes or follows the processes underlying the illusions. This illusory offset of flashed chevrons does generate a Muller-Lyer illusion and the illusory offset of two line segments does create a Poggendorff illusion. We conclude that the site where the frame-induced position shift emerges must precede the site at which the Muller-Lyer and Poggendorf illusions arise.

https://journals.sagepub.com/doi/pdf/10.1177/20416695211015699

Flashed Müller-Lyer and Poggendorff Virtual Illusions:

Interlacing one’s fingers can cause misperception of finger positions. Observer’s (O’s) fingers were interlaced in six different ways and experimenter (E) tapped two adjacent fingers in quick succe...

Misperceived Positions of Interlaced Fingers.

OPINION article Front. Psychol., 07 February 2022Sec. Perception Science Volume 12 - 2021 | https://doi.org/10.3389/fpsyg.2021.817745 

/pdf/size-vs-stereo-in-illusory-depth-inversion-1nenta1q.pdf

Size vs. Stereo in Illusory Depth Inversion

We present a novel ‘dazzle’ illusion, in which a black/white negative bar embedded in a grating and viewed in near peripheral vision can look doubled, as if there were two bars lying side by side touching each other.

/pdf/a-line-doubling-illusion-2muuwbq797.pdf

A line-doubling illusion

In simultaneous contrast of spatial frequency (SF), a test grating surrounded by a coarser inducing grating looks apparently finer. We combined this effect with another visual illusion; the fact that flickering the inducing grating raises its apparent SF. We found that the inducer's apparent, not physical spatial frequency, drove the simultaneous contrast that it induced into a test grating. Thus, when the inducer was made to flicker, its SF appeared to be higher and consequently, the test's SF appeared lower than before. This suggests that simultaneous contrast of spatial frequency exists further downstream than the flicker-induced increase in perceived SF.

https://journals.sagepub.com/doi/pdf/10.1177/2041669517707766

Stuart Anstis

Papers

Flashed Müller-Lyer and Poggendorff Virtual Illusions:

Misperceived Positions of Interlaced Fingers.

Size vs. Stereo in Illusory Depth Inversion

A line-doubling illusion

Spatial Frequency Shifts From Counterphase Flicker and From Simultaneous Contrast.