Behavioral Neuroscience, lecture on Acetylcholine
USD Department of Biology
Behavioral Neuroscience
Summers
Honey Bee Ecology and Behavior
Honey Bee Neuroanatomy
Fundamentals of Neurocircuitry
Sensory Afferent input for Proboscis Extension
Apis mellifera Gating Proboscis Extension
Learning to Drink
Conditioned Proboscis Extenstion
Motor Neuron output for Proboscis Extension
Acetylcholine ACh
Octopamine OA
Integration: Honey Bee Conditioned Drinking
Honey Bee figures
Honey Bee Conditioned Drinking Neurocircuitry
end     Acronyms/Abbreviations
Honey Bee Conditioned Drinking
XII. Learning/Conditioning Mechanism 

	A.  Coincidence and Convergence
    
		1. ORN  AL PN  l-APT  LH    

			a. l-APT  MB KC

			b. smiliar via m-APT  LH or MB KC
            
			c. AL PN ACh  nAChR on MB KC

				i. nAChR also on LH neurons

		2. GRN  VUMmx1  MB KC

			a. GRN  VUMmx1  AL & LH 

			b. GRN ACH  nAChR on VUMmx1  AmOA1 on MB KC

				i. VUMmx1  AmOA1 on LH neurons

		3. Simultaneous nACHR and AmOA1 signals potentiate MB KC neurons

			a. greater signal, greater current
            
			b. greater current + 2nd messeger action   neural plasticity

			c. plasticity  learning

				i. ORN + GRN concurrence heightens KC signal  Pe-1

				ii. Pe-1 + LH concurrence potentiates signal  SEG motor

				iii. requires lack of aversive stimuli

					1) lack of GRN "deterent" signaling  AL
                    
					2) lack of AL DA signaling  AmD2 MB GABA interneurons
    
	B. Plastic changes Necessary for Learning
	    occur at the microglomeruli in the MB calyces

		1.  cAMP is important

			a.  Produced by rutabaga adenylyl cyclase (rut AC; AC)

				i.  responds differentially to calcium (Ca++) influx

					1) invoked by voltage-gated Ca++ channels (VGCC)

						a) opened during ACh-nAChR stimulation

							i) nAChR  Nai+  D Vm  VGCC

				ii.  and G-protein activation

					1)  OA  AmOA1  GPqll  PLC  PIP2  
					    IP3  Ca++ rutAC

					2) OA  OAR2B  Gs  AC  cAMP

		2.  acts as coincidence detector for reward

			a. OA release (US) paired with ACh release (CS) 
            
			b. coordianted activation of cAMP 

				i. other signals involved
                
			c. Stimulates Protein Kinase A (PKA) activity

				i. PKA  pAmCREB  CRE (on DNA)

				ii. CREB/CRE  transcription of ubiquitin hydrolase
                
					1) persistent PKA  long-term sensitization
                
				iii. CREB/CRE  transcription of C/EBP
                
					1) transcription of growth-related proteins
                    
						a) elongation factor 1a (EF1a)

							i) neurite outgrowth

			d. new synapses formed

				i. stronger KC signal  Pe-1
                
			e. pAmCREB stimulation of CRE promotes memory formation

				i. Flower smell + nectar taste = reliable food cue
                            
		3. coincidence detector during aversive stimulation 
       
			a. GRN "deterent"  AL DA release  

				i. toxin (quinine) or shock (different RN) (US) 
                        
			b. paired with AL ACh release  

				i. from olfactory stimulation (CS) 
                                
				ii. results in synergistic increases in cAMP

						b)  during appetitive stimulation (i.e. sugar)

				i.  DA  PKA activity in MB a-lobe GABA interneurons

					1) inhibits ACh-OA synergy at MB KC   
                    
					2) inhibits stronger positive Pe-1 signal

			c.  DA stimulation promotes aversive memory

				i. AL DA signals  MB KC
                
					1) pAmCREB/CRE promotes these memories
                    
				ii. learn to avoid the odor/nectar pair if toxin is present

XIII. Motor Neuron output for Proboscis Extension