Behavioral Neuroscience, lecture on Lateral Giant Neuron control of Crayfish Escape
USD Department of Biology
Behavioral Neuroscience
Summers
Rusty Crayfish Crayfish Escape Behavior
Crayfish Neuroanatomy
Fundamentals of Neurocircuitry
Sensory Afferent input for Tail Flip
Gating the Full Flip
Gating the Tail Flip for Upward Thrust
Parallel Gating of Crayfish Escape
Motor Neuron output for Crayfish Escape
Integration: Crayfish Escape
Acetylcholine ACh
GABA
5-HT
Crayfish figures
Crayfish Escape Neurocircuitry
end     Acronyms/Abbreviations
Escape - Crayfish
X. Parallel Circuits and Non-Giant Neurons 	

	A. Threats that develop gradually

		1. do NOT involve MG or LG neurons

		2. non-Giant (NG) responses

			a. result in adjustable tail flips

				i. not stereotypical

			b. not single flexions
                
	B. Sensory Interneurons (SI) also have electrical synapses with NG neurons
    
		1. broad range of sensory inputs
        
		2. many SI paths
        
	C. MG/LG - NG circuitry asymmetrical
        
		1. NGs do not innervate MG or LG circuitry        
        
		2. MG/LG recruit elements of the NG circuitry
        
			a. via  a single pair of SG  neurons      

	D. NG parallel distributed processing network

		1. produce very flexible behavior

			a. similar to the Mauthner vs M-homolog networks
            
				i. for C-start and escape behavior in fish
                
		2. NG neurons activate a suite of pre-motor interneurons

			a. each premotor interneuron has distinct output connections

		3. NG-activated Premotor interneurons innnervate FF motor neurons

			a. NG  PmI  FF  all abdominal segement muscles
        
		4. NG responses require more time

			a. MG/LG < 10 ms >> NG

			b. & depends on repetitive firing of premotor interneurons
            
	E. NG circuitry supports a wide range of response patterns

		1. exact parameters of response vary

			a. as a function of sensory stimulation

XI. Motor Neuron Output