This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Before the 1991 report of achiasma in dogs, [1] there was general acceptance that all vertebrates had decussation at the optic chiasm. [2] Exactly how, within the space of a few years, the achiasmatic condition came to be recognized in two mammalian species is an interesting confluence of interpersonal scientific communication and some serendipity. "Serendipity," a word coined by Walpole in a letter written in 1754, [3] based on a fairy tale he had written several years earlier, [4] has a long history in science. [5-9]
In 1991, Robert Williams, PhD (a Memphis neuroanatomist/biologist), who had been studying the anatomy of mutant Belgian sheepdogs that had no optic chiasm, sent me videos of their eye movements, asking if they were like human congenital nystagmus (CN). I replied that although they appeared to be similar, we would have to document the waveforms of the dominant horizontal oscillation. Also visible in the video were vertical components, which are less common in human CN, and what appeared to be transient see-saw nystagmus (SSN), a disconjugate vertical nystagmus with a conjugate torsional component such that each eye intorts as it goes upward and extorts as it goes downward. [10] SSN is not part of the human CN condition, and congenital SSN is extremely rare. [11-13]
I traveled to Memphis in 1992 and (with Williams) confirmed, by both direct observation and additional videos, the presence of SSN in one dog and vertical components of the nystagmus in the others. I discussed the canine condition with Josephine Shallo-Hoffmann, PhD (working in the vestibuloocular laboratory of Michael Gresty, PhD, in London) in 1991 …
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
Letters: Rapid online correspondence
REQUIREMENTS
You must ensure that your Disclosures have been updated within the previous six months. Please go to our Submission Site to add or update your Disclosure information.
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.
