# Camma and alpha coactivation

**URL:** http://discourse.iapct.org/t/camma-and-alpha-coactivation/2305
**Category:** CSG1992
**Created:** [December 13, 1992, 3:52pm UTC](http://discourse.iapct.org/t/camma-and-alpha-coactivation/2305 "1992-12-13T15:52:50Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![William\_T\_Powers2](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/w/c67d28/32.png) [@William\_T\_Powers2](http://discourse.iapct.org/u/William_T_Powers2)
#### Post date: [December 13, 1992, 3:52pm UTC](http://discourse.iapct.org/t/camma-and-alpha-coactivation/2305/1 "1992-12-13T15:52:50Z")

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[From Bill Powers (921213.0845)]

Avery Andrews (921213) --

Avery, you also asked for a source on the combining of gamma and  
alpha reference signals for the Little Man model.

A reference is McMahon, Thomas A.; \_Muscles, Reflexes, and  
Locomotion\_ (Princeton, NJ; Princeton University Press, 1984).  
See Chapter 6, Reflexes and Motor Control, subhead Coactivation  
of Alpha and Gamma Motor Neurons (p. 148). " ... so the  
experiments are in harmony with the idea that both alpha and  
gamma motor neurons are excited by higher motor centers at the  
same time."

I think that gamma outputs are also involved in autonomic  
reflexes, but don't want to get into that kind of detail.

> **···**
>
> -------------------------------------------------------------  
> Best,
> 
> Bill P.