A..  Action Morphology
	I.  Elementary Units
		a. Reflex
		b. Oscillator
		c. Servomechanism
	II. Within-Category Combinations: 
		a)  Reflex chains
		b)  Fixed Action Patterns (FAPs)
		c)  Goals
	III. Across-Category Combinations
		a) Real actions
		b). Hierarchical Organization
				
B.  Brain Systems of Action
	I.  Pyramidal Motor System:
		a) Motor cortex and corticospinal tract
		b) Fine finger movements
		c)  Coordination by sensory feedback
		d)  Interaction with other cortical areas
			1.  Somatosensory cortex
			2.  Frontal cortex: action timing
			3.  Posterior Parietal cortex:  spatial representation
	
II.  Extrapyramidal Motor Systems
		a)  Red nucleus
			1.  Auxillary control of voluntary hand movement
		b)  Reticular Formation
			1.  Pattern generator
			2.  Postural servomechanism
			3.  Hierarchic intermediary for voluntary gesture

		c)  Striatum  & Substantia Nigra  (Nigrostriatal system)
			1.  Movement starting-and-stopping
			2.  Sensory, emotional, and cognitive interaction

		d)  Cerebellum
			1.  Proprioceptive sevomechanism
			2.  Programmed movement and habits

Normal Action is amorphous and complex; we can't see the parts.  
In order to action relate to brain function, we need to analyze action in terms of the main 'action components' the brain uses to create normal behavior.

There are 3 basic kinds of parts.
1. Reflex
	- Ex: Knee jerk reflex to tendon stretch 
	- Ex: gag to back of throat
These are crude & obvious, but thousands of others are "buried"
-Benefit of reflexes: 		Allows fast response to environment change
				Simple to program: each element can lead to next
-Costs of reflexive control:	Stimulus control is rigid and doesn't allow variation
				Even reflexes are too slow for some tasks

2.  Internal Program Generator  (via neural oscillators)
-Complex patterns of movement can be endogenously generated by superimposing simple "waves" of movement 
- Brain can generate simple waves using 
	a. Oscillator neurons 
	b. Oscillator groups

3.  Servomechanism (feedback mechanism).  
Uses:	1. Sensory input (sensory like reflex)
	2. Goal value (internally programmed like oscillator)
	3. Correction of output (act only when discrepancy)
-Allows controlled movement force (picking up an egg without breaking it) 
- Allows goal direction (ex: a moth homing in on a light source)

Simple components almost never occur alone.  Instead they are combined together, within categories and between categories, into groups.

A.Within-category combinations:
1.  Reflexes:  Reflex chains  
2.  Oscillators: Fixed Action Patterns (FAPS)
3.  Servomechanisms: Goals that have multiple features.

Cross-category combinations:
Real actions almost always involve combinations from all three categories (even FAPS as  .Dawkins points out)
Ex: Human reaching and catching ball
	-elements of central program (reach if deafferented)
	- guided to target by servomechanisms (visual, proprioceptive)
	- reflex (grasping on contact)

Chief Principle of combination: Hierarchical Organization
	Semi-autonomous units subject to potentiation & inhibition

1.  SEMI-AUTONOMOUS units -  do their own thing competently
2. Hierarchical potentiation & Inhibition:  tell when to do their thing
	Examples: normal walking, mantis copulation (male), mammalian sexual lordosis (female)

PART B.  BRAIN CONTROLS OF ACTION

Two Chief Systems : Pyramidal & Extrapyramidal
I.  PYRAMIDAL:  Direct cortical system:  Motor cortex, internal capsule, pyramids, spinal motoneurons
	Fine-tunes action
		- modulates spinal action as servomechanism
		-hierarchical  control of spinal reflexes & servomechanisms

Cortical INPUTS to M1  -  
A. Supplementary motor cortex
	Movement timing
B.  Posterior parietal cortex:  
	Spatial orientation & representation

II. EXTRAPYRAMIDAL SYSTEM
1. Red Nucleus
	Supplement to pyramidal system for voluntary movement: synergy 

2.  Reticular Formation
	1.  Pattern generation of 'instinctive' actions)
	2. Postural control via vestibulomotor loop (servomechanism)
	3. Hierarchical intermediary for voluntary action initiated by forebrain

3.  Striatum  and Substantia Nigra
	-Parkinson's disease: kill substantia nigra path
	-Huntington's Disease: Striatal degeneration
	Thus from disease:   Turns on and off movements
But there are subtle aspects of function:
	a.  Deficits depend on Emotional State 
	B. Deficits show SENSORY-motor features
	C. Deficits of  sequential patterning as well as movement:
	
4. Cerebellum  
	1. Simple servomechanism for proprioceptive control of movement (smoothing)
	2. Programs FAST pre-patterned actions
	3.  Motor learning
		"