Behavioral Neuroscience Summers

C-Start Behavior Fundamentals of Neurocircuitry Senstory Stimulus for Startle Mauthner Cells - Response Gating Mauthner Efferent output Neuromuscular Function Integration of C-Start Circuitry and Behavior

text:Kandel pages 180 Glu DA ACh Transmitter Figures Figures of C-Start Behavior C-Start Circuitry end   Acronyms/Abbreviations

Escape Behavior
I. Startle Responses in Fish  		

	A. Escape responses
	
		1. must be simple in quick
		
			a. slow and complicated = lunch (someone else's)
	
		
	B. C-Start startle response
	
	
		1. Unilateral bending of the body into a C-like shape
		
			a. Immediate response to stimulus
			
				i. Stage 1: 15-40 msec
	
			
		2. Counter-turn
			
			a. Away from stimulus appropriately
			
				i. Displacement of the head and tail to one side
			
			b. Vast range of angles
			
				i. rotates body 30-100 degrees about center of mass
			
			c. Grades into stage 2

			
		3. Stage 2
			
			a. Axial acceleration moves center of mass 2-6 cm
			
			b. Non-stereotyped flip of the tail to the opposite side
			
			c. Terminated usually after 2 tail flips
			
			d. No fixed movement pattern
				
				i. Trajectory change from 15-135 degrees
		
		4. Cold temperature affects reaction
			
			a. Increases probability of triggering the escape response 
			
			b. Increases likelihood of inappropriate direction
			
			c. Decreases peak velocity & acceleration

	
	C. C start drive: Two primary groups of reticulospinal neurons
		
		1. Full propulsive force and turning flexibility
		
			a. Mauthner Neurons
			
		2. Not all fish require Mauthner cells for reaction
			
			i. Lumpfish do C-start without Mauthner cell

	
	D. C-start Differs from S-start
		
		1. S-start has simultaneous anterior and posterior movement 
		
			a. but in Opposite directions
			
				i. produces S shape
		
		2. Used for both feeding and escape
		
		3. Simultaneous caudal muscle and rostral muscle activity
		
		4. Descending reticulospinal input to spinal neurons
		
		5. Slower acceleration and decreased velocity
		
		6. Less efficient initial tail flips
		
			a. More efficient with each additional tail flip
			
II. Animal Models for Escape Behavior

	A. Fish - C start
	
		1. Goldfish Carassius auratus
		
			a. Carp family - from east Asia
				
				i. earliest domesticated fish 
				
			b. maxima: length 0.6 m (23 inches), weight 4.5 Kg (9.9 lbs)
			
			c. life span 20 years (optimal conditions)
			
				i. usually 6-8 years
					
			d. C. auratus varieties: black moor, bubble eye,
			     butterfly tail, calico, celestial eye, comet, 
			     common, fantail, lionhead, shubunkin

				i. Pigments: black, red, yellow
				
					(1) in chromatophore cells
					
					(2) contain guanine crystals for reflectivity
				
				ii. Environmental factors

					(1) color intensity varies 
					    positively with light intensity 
					
						(a) bright light bright colors
					
					(2) Diet
					
				iii. Fins: single, double, fancy

					(1) single swim faster
	
			e. learning in goldfish
			
				i. swim through mazes 
				   push balls through hoops 
				   swim in synchronized patterns
			
				ii. associative learning
				
					(1) associate humans with food
					
				iii. social learning
				
					(1) distinguish between people
					
					(2) recognize vocal vibrations
				
				iv. c-start when golf ball dropped into water