Behavioral Neuroscience Summers

Sexual Behavior Reflexes Sensory Reception - Tactile Receptors Spinal Synapses Afferent Spinal Pathways

Hypothalamic Gating Efferent Motor Cascade Neuromuscular Production of Lordosis Integrated Story of Lordosis VIP Substance P Estrogens

5-HT GnRH ACh Lordosis figures   Sensory Receptors Spinal Cord   Lordosis Circuitry end     Acronyms/Abbreviations

LORDOSIS
III. Sensory Reception - Afferent Circuitry 			
!First Neural Circuit for a Mammalian Behaivor!

	A. Tactile Receptors
	
		1. male's body against female's rump region
		
			a. or sensory inspection
		
		2. Ruffini endings
		
			a. slowly adapting: to a barrage of impulses
			
			
				i. sub-cutaneous mechanoreceptive units with soma in
				   dorsal root ganglia
			
			b. respond to sustained pressure stimulation
			
			
				i. most primary sensory neurons respond
				
				
				ii. only pressure units and type I (hair + pressure) units
				    have sustained responses to lordosis-triggering
					pressure
					
					(1) specialized sensory response
					
						(a) Ruffini end organs
						
							(i) run parallel to skin
                            
                            (ii) also found in finger tips
                            
                            (iii) respond to slippage, chage of angle, thermoreception
										
					(2) spatial summation across pressure units
						facilitates reflex				
		

			c. E2 stimulates increased Ruffini receptors

				i. expanded receptive field of pudendal nerve

					(1) broader 
					
					
			d. mating/repeated mating can increase receptivity
			
				i. increased LQ
				
				ii. requires intromission - vaginal, cervical stimulation
				
			
		3. Sensory fibers to spinal cord
		
			a. from skin of rump, tail base and perineum
			
				i. via the dorsal roots at L5, L6 and S1
				
				ii. pudendal nerve
			
			b. from flanks
			
				i. via L1 and L2
			
			c. cell bodies in dorsal root ganglia

			d. the terminals are deep in the dorsal horn
			   of the spinal cord

				i. units responding only to pressure
				   found primarily in the intermediate gray

				ii. Units responding to movement of hair located
				    more dorsally in the dorsal horn

				iii. Units responding to subdermal stimulation
				     usually found at greater depths


			e. transmitters of these neurons are colocalized peptides 
			
			
				i. inhibited by another peptide