The Cognitive Neurosciences

When our practice recently underwent its first site accreditation visit from the ACOE, the reviewers noted that our Residency Program in Vision Therapy and Rehabilitationhas the following mission statement:

The resident will experience a unique opportunity to develop proficiency in pediatric optometry, developmental vision, binocular vision, and rehabilitative vision therapy. Merging principles in cognitive visual neuroscience with human factors in private practice, the post-graduate clinician will acquire the skills needed to excel in education, research, and patient care.

Very nice, the team, said, but what do you mean by cognitive visual neuroscience?  What I had in mind was the merge between the Visual Neurosciences and the Cognitive Neurosciences.  My bible for the Visual Neurosciences is an incredible two volume set edited by Leo Chalupa and John Werner.  My bible for the Cognitive Neurosciences is a book by the same name, edited by Michael Gazzaniga, which is now it is fourth edition.  The book is based on mega-meetings that are held every five years in Squaw Valley in Arizona, gathering the giants in the field.

The 4th and most recent edition of The Cognitive Neurosciences was published in 2009, but I had put giving it the immersive read it deserves on the back burner for a rainy day.  Well I got several of those days last weekend, and more than I bargained for, thanks to Hurricane Irene.  Once I picked up the massive 1294 page volume I found it too difficult to put down, and continued it right on into this weekend.  It’s not just that it weighs a ton, it’s the spellbinding read of each chapter, in the tradition of its predecessors, that makes this work difficult to merely browse.   There are many among the 89 chapters worthy of blog pieces, but I’m going to begin with Chapter 54 co-authored by Laurent Cohen and Stanislas Dehaene on the Ventral and Dorsal Contributions to Word Reading.

If the name Dehaene sounds familiar, it may be because we blogged about him in a Part 1 and Part 2 mini-series last year.  We have encouraged him to do a presentation at a COVD Annual Meeting because there is so much of his research that is relevant to vision and reading.  I love, absolutely love, love, love Cohen & Dehaene’s opening to their chapter which states:

The acquisition of reading by children rests on a delicate tuning of the visual system and of the verbal system, and on the elaboration of novel interactions between these two preexisting domains.

There’s a nice figure in this chapter which captures its essence:

See the OTS in the middle of everything?  That’s the occipitotemporal sulcus of the brain, home of the visual word-form area (VWFA) or system.  See the IPS?  That’s the intraparietal sulcus, home to visuo-spatial attention, which has a significant modulatory effect on low level visual processes that interact with sight word recognition and word identification.

I’m going to jump right to Cohen & Dehaene’s conclusion, becuase it’s so powerful:

The present review emphasizes that fluent reading results from an intimate collaboration of multiple areas forming a distributed network.  Although the VWFA clearly plays an essential role in expert reading, the recent literature has tended to forget that the dorsal spatial-attentional system also makes a major contribution through attention orienting, word selection, and within-word serial decoding …. Although phonological sources of developmental reading impairments have received vast attention, our analysis suggests that occipito-temporal impairments are also very likely to have an impact on developmental dyslexia, as indeed suggested by recent research. 

One of the research papers that Cohen and Dehaene cite in support of their conclusion is Developmental Dyslexia as a Visual Attention Span Disorder – Cognition – 07.  This paper supports a multfactorial view of dyslexia, indicating that in many cases developmental reading disorder do not seem to be due to phonological disorders.  This dovetails nicely with the results of another paper on Visual Deficits in Pre-Readers at Familial Risk for Dyslexia – Vision Research 08.  The conclusion of that paper complements Cohen & Dehaene’s message, indicating that an understanding of the visual mechanisms underlying reading is crucial to the development of effective remediation.

We’ve alluded to this in our blog here, and here, and here, and here.  Do you think this might be the year when all this becomes clear?  Turns out Dr. Seuss was only kidding when he wrote I Can Read With My Eyes Shut!

– Leonard J. Press, O.D, FCOVD, FAAO

2 thoughts on “The Cognitive Neurosciences

  1. Len,

    Thanks for powering through this literature. I think that Laurent Cohen and Stanislas Dehaenes’ work on the Ventral and Dorsal Contributions to Word Reading is probably overlooked by those who are enamored with the phonetic side of the system.

    Thanks again.


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