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...and I'm not sure it's where Professor Grobstein intended to go, but when he began disucssion central pattern generators my mind went immediately to fixed action patterns. A fixed action pattern is an innate "pattern of action potentials across motor neurons" produced by an internal releasing mechanism upon seeing a key stimulus. Tinbergen showed such fixed behavior in male red bellied stickleback threat displays towards passing red trucks, and Lorenz showed it in egg rolling behavior in waterfowl after an experimenter had removed the egg. These behaviors were thought to be very unmodifiable; once triggered they had to be completed and they were insensitive to their consequences (another way of saying they are insensitive to the reafferent loop) (1). But they're not reflexes, like the patellar-stretch reflex discussed in class.

True these behaviors are readily discernable, but instead of being a single instance (like a kick) FAPs represent more of a "pattern" of behaviors (like grabbing a cup and bringing it to your mouth). The relationship between the illiciting stimulus and subsequent behavior isn't as tight as in a reflex loop: FAPs tend to be difficult to interrupt, but other FAPs can interrupt them. The key stimulus, or input, is very specific and often narrowed to a feature of the organism's environment - say the shape of a parent's head in seagulls. The last feature that distinguishes FAPs from a simple reflex is that they are modifiable by learning -- their form isn't as fixed as previously thought. (2)

Could FAPs, which may even exert their control over behavior genetically (3) and are commonly accepted to have at least neural substrates (4), be an example of Grobstein's "motor score"? Could investigating FAPs further illuminate any of the previous issues raised when considering the motor score? Are FAPs related in anyway to "muscle memory," a related concept brought up in class?

I would like to end with a caveat introduced in the "Kurze Mitteilung" portion of the Journal of Ornithology by authors Peter H. Klopfer and Norman Budnitz --

"Wir meinen, daß diese Formulierung eher einer modernen Form des Homunculus des 17. Jh. als einer echten Erklärung entspricht, weil sie nicht erklären kann, wie das exakt reproduzierbare Nervennetz entsteht. Außerdem ist bekannt, daß dasselbe Verhalten auch bei enormen Unterschieden in der Neuralanatomie auftreten kann; stereotype Bewegungen brauchen keine spezifischen Nervennetze."

"We believe that this interpretation is more a modern form of the 17th century homonculous than an actual explanation, because it cannot explain how the eact neural network is formed. Anyway, it is known that the same behaviors can be reached with extremely different neuroanatomy; stereotyped movements need no specific neural network." (My very poory translation)

Have we resurrected the homonculous? Does this reintroduce the mind-body dichotomy?

(1) http://www.cerebromente.org.br/n09/fastfacts/comportold_i.htm

(2)http://books.google.com/books?id=OeXfeyVTtJ8C&pg=PA473&lpg=PA473&dq=fixed+action+pattern&source=web&ots=FTsYime2IC&sig=a5n4EsdrhXBiMeh4jRwcQ8eUm2E&hl=en#PPA473,M1

(3)http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WSN-42T4FS9-4&_user=400777&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000018819&_version=1&_urlVersion=0&_userid=400777&md5=70ce50e673a039849d989daf7e611e93

(4)http://www.sciencemag.org/cgi/content/abstract/166/3912/1549

(5)http://www.springerlink.com/content/h624724t17161021/