Behavioral Neuroscience, lecture on Honey Bee Proboscis Extension Motor output
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
XIV. A Bee's First Foraging Trip  
	    
	A.	Arrival at a Flower - Inspection
    
		1. Flower specific nectar oder (+ flower odor)    
    
			a. enter Antennae placode sensilla
            
				i. diffuse through sensillum lymph           

			b. Bind to odorant binding proteins (OBP)

				i. directed diffusion
                
			c. OBP + odorant move to ORNs    
    
			d. OBP + odorant bind to olfactory receptor proteins (OR) on ORNs    
    
		2. triggers Antennae ORNs action potential   
 
		3. ORN AP to antennal lobe glomeruli

			a. ORN ACh  nAChR on AL PN 

		4. AL PN  SEG proboscis-related motor neuron			
            
			a. AL ACh  nAChR on mandible abductor (M8) neuron            

				i. ORN  AL PN   SEB M8 neuron  M8 = reflexive motor pathway            

			b. M8 neuron ACh  nAChR on mandible abductor muscle  contracts              

				i. mandibles spread
                            
 		5. proboscis extend mechanically           
            
            
	B. Specific Nectar-Odor pairing            
            
		1. ORN  ACh nAChR AL PN  ACh nAChR MB KC

			a.  ORN  AL PN  LH

			b. via lAPT + mAPT

				i. lAPT: AL  LH  MB KC
                
				ii. mAPT: AL  MB KC  LH

			c. odor signal NOT sufficient to potentiate downstream effector neurons 

				i. not enough alone to trigger Pe-1
                
		2.	Extended proboscis/glossa (ORN/AL/M8 neuron) enters nectar

			a. Nectar sucrose activates chemoreceptors on GRN

			b. GRN action potential ACh  nAChR on VUMmx1
            
				i. GRN AP  ACh  nAChR AL PN ACh  

			c. AL PN ACh  nAChR on VUMmx1 

				i. VUMmx1  OA  AmOA1

		3. Binds to octopamine receptor AmOA1 in AL
        
        	a. OA  AmOA1 LH

			b. OA  AmOA1 MB KC
	
		4. Coincident ACh and OA signalling in MB KC
        
			a. also in AL and LH
                        
    C. Gating Coincidence output - CS + US pairing produces: 

		1. MB KC nAChR   Vm   VGCC   Ca++
        
		2. MB KC AmOA1  GPq11  IP3  Ca++

		3.  Ca++   rutAC

			a.  rutAC   cAMP   PKA   pAmCREB   CRE activation

				i.  CRE   ubiquitin hydrolase   PKA

					1)  PKA   pAmCREB   CRE
 
 		4.  CRE   C/EBP    EF1a 

			a.  formation of new synapses

			b. similar coincidence effects at LH

		5. New synapses potentiates Pe-1 signal output

			a. and LH signal output

		6. Pe-1 and LH projections converge on the SEG M8 motor neurons

			a. doubles the signal strength on M8 neurons 

				i. another kind of potentiation 
                
			b. AmOA1-facilitated PE-1 + LH potentiation adds to the strength of convergence  
                
				i.  M8 neuron potentiation
 
 			c. proboscis stays extended
                                                
 	D. Drinking  is enabled by continued proboscis/glossa extension    
        
      
	E. Coincidence + Aversion
    
		1. CS + US convergence: ORN  AL PN  LH + MB KC    
    
			a. GRN  SEG Maxillary ganglion VUMmx1 AL PN + LH + MB KC
			
 		2. Toxin: GRN "deterent"  AL DA PN  a lobe MB GABAergic neurons           
            
 			a. GRN "deterent"  AL DA  AmD2 aMB GABA GABAA   MB KC
            
			b. GRN "deterent"  AL inhibitory GABAergic local neurons (LN)           
            
				i. GRN "deterent"  AL LN   GABA  GABAA   AL PN				            
            
		3.  weak or blocked AL PN signal
        
		4.  weak or blocked MB KC signal

			a.  weak or blocked LH signal
        
		5. NO Pe-1 or LH potentiation
        
			a. no Pe-1 + LH potentiation of SEB M8 neuron        	    

				i. in Mandibular ganglion

		6. labium and glossa retractor muscles M17, M20

			a. can remove glossa/proboscis from toxic nectar

Syllabus