Neural Science and Vision – Part 5


On this visual processing tour from Principles of Neural Science we’ve passed through low-level processing in the retina parsing patterns of light in part 3 to intermediate levels of processing so-called visual primitives in part 4, and now arrive at high-level visual processing which integrates information from a variety of sources as the final stage in the visual pathway leading to visual perception. In the authors’ words: “High-level visual processing is concerned with identifying behaviorally meaningful features of the environment and thus depends on descending signals that convey information from short-term working memory, long-term memory, and executive areas of cerebral cortex.” In figure 24-1 the authors use the properties of a horse to represent high-level visual processing. (Take note of emotional valence, a feature we previously blogged about regarding strabismus.)

The late, great Dr. Irwin Suchoff, in the early days of the Optometric Center of New York, would often speak about “the invariant” in this regard. Albright and Freiwald, co-authors of chapter 24, do a nice job of addressing the subject as follows:

“The ability to recognize objects as the same under different viewing conditions, despite the sometimes markedly different retinal images, is one of the most functionally important requirements of visual experience. The invariant attributes of an object – for example, spatial and chromatic relationships between image features or characteristic features such as the stripes of a zebra – are cues to the identity and meaning of objects. For object recognition to take place, these invariant attributes must be represented independently of other image properties. The visual system does this with proficiency, and its behavioral manifestation is termed perceptual constancy.”

If you haven’t read Dr. Suchoff’s monograph on visual-spatial development in the child before, it is now available through OEPF bundled together with Dr. Gerry Getman’s monograph on optometric care of children’s vision.

Neurologically, the center of object recognition has been localized to the inferior temporal cortex. Object recognition relies on past experience. Perceptual learning can improve the ability to discriminate between complex objects and refine neural selectivity in inferior temporal cortex. This and many other aspects of Chapter 24 are summarized at NeuPsyKey.com.

It is also worth pointing out that the parsing of visual information processing we have overviewed is consistent with the clinical model advanced by Dr. Lea Hyvärinen with regard to visual cognition, depicted here:

You may recall the name of Dr. Lea Hyvärinen from the Lea Symbols Test, or perhaps from a blog we did about the first edition of her book. You can now see how chapter 9 of that book (What and How Does This Child See: Assessment for Development and Learning) dovetails nicely with the material presented in Principles of Neural Science:

Chapter 9 – Processing of Visual Information
9.1 Brain structures involved in visual processing
9.2 Typical Behaviours
9.3 Assessment, general considerations
9.3.1 Functions to be tested
9.4 Early visual processing functions
9.4.1 Direction and length in the early processing of visual information
9.5 Ventral stream functions
9.5.1 Pictures as representations of objects and activities
9.5.2 Copying basic forms, texts, and pictures as visual tasks
9.5.3 Face blindness, prosopagnosia
9.5.4 Perception and recognition of facial expressions
9.5.5 Recognition of concrete objects and landmarks
9.6 Reading
9.7 Mathematical spatial, memory and recognition problems
9.8 Dorsal stream functions
9.8.1 Spatial awareness and orientation
9.9 Depth perception
9.10 Simultaneous perception, simultanagnosia
9.11 Eye-hand coordination
9.12 Integration of sensory and motor information
9.13 Mirror neuron system
9.14 Visual and auditory overload
9.15 Reporting on visual processing problems
9.15.1 Profile of visual functioning
9.15.2 Dual sensory processing losses

6 thoughts on “Neural Science and Vision – Part 5

  1. I have editions 1-3 on my shelf……amazed at the growth of our knowledge and understanding! So much still to learn and understand, always looking forward to more from you Len! Thanks for being you!

  2. I am thoroughly enjoying this blog series. Such great information. Thank you for taking the time to read and summarize these chapters for us. I enjoyed learning from you in the 90’s and still enjoy your insightful posts today. Manisha, SUNY class of ’96

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