Behavioral Neuroscience Summers

Syllabus Yawning Behavior Evolution of Yawning Sensory Afferents to Yawn Gating the Yawn

Regulating Yawn Gating Efferent Yawn Output Neuromuscular Production of Yawns Integration of Yawn Circuitry and Behavior

norepinephrine (NE) Oxytocin (OT) ACTH & aMSH Yawning figures Yawn Circuitry end     Acronyms/Abbreviations

YAWNING

XII. Integration of Yawn Circuitry and Behavior 

	A. Basic Linear Circit: Input  Þ Output
    
		1. Sensory Inputs

			a. Eyes-RGCs-Glu  Þ RHT  Þ SCN core

			b. SCN core ó SCN shell

			c. SCN shell  Þ AVP Þñ V1A PVN

		2. Modulation / Gating Nuclei

			a. AVP Þñ V1A PVN Þñ OT

			b. PVN Þñ OT Þñ OT-R NST

		3. Efferent Outputs

			a. NST Þñ Glu Þñ AMPA/NMDA CCC8-T2

				i. CCC8-T2 =  Ciliospinal Center in C8-T2 spinal cord

				ii. CCC8-T2 = sympathetic NS preganlionic cell bodies

			b. CCC8-T2 Þñ ACh Þñ Nicotinic-R SCGÞ hypoglossal nerve

				i. SCG = Superior Cervical Ganglion 

				ii. SCG = sympathetic NS postganlionic cell bodies

				iii. hypoglossal nerve contains some postganlionic axons

			c. SCG Þñ NE Þñ a1-Gp/Ca++ & b2-Gs/cAMP Þñ ACh release
 
				i. ACh released from geniohyoid motor neuron

					1) presynaptic sympathetic stimulation

				ii. also housed in C8-T2 spinal cord

				iii. delivered in parallel via the hypoglossal nerve

			d. ñ ACh Þñ Nicotinic-R Þñ geniohyoid contraction

				i. also genioglossus and sterothyroid contraction
                
				ii. pharynx expansion Þñ 1st stage of initial yawn phase

	B. Enhancing Modulation at Gating Nuclei

		1. Self-reinforcing OT potentiation

			a. PVN OT secreted Þ    
 
				i. OT-Rs in brainstem

					1) NST (output)

					2) VTA (DA)

					3) LC (NE)

				ii. OT-Rs in limbic system

					1) vSubiculum

					2) pMeA

			b. Þñ OT-R vSubiculum Þñ Glu release

				i. Þñ OT-R pMeA Þñ Glu release

				ii. Þñ Glu Þñ AMPA/NMDA VTA

			c. Þñ OT-R VTA Þñ DA release

				i. Þñ AMPA/NMDA VTA Þñ DA release

				ii. Þñ DA Þñ D1 PVN

					1) Þñ D1 PVN Þñ OT

		2. enhanced ACTH & aMSH potentiation

			a. Þñ OT-R LC Þñ NE release

				i. Þñ NE Þñ a1-R ARC Þñ aMSH release

					1) aMSH Þñ MC4 PVN Þñ OT

			b. SCN Þñ AVP & VIP release

				i. AVP Þñ V1A ARC Þñ ACTH PVN

				ii. VIP Þñ VPAC1 ARC Þñ ACTH & aMSH PVN

					1) ACTH Þñ MC4 PVN Þñ OT 
   
	C. Alternative Motor outputs
    
		1.Þñ NE Þñ geniohyoid a1-R Þñ Gp/PLC/IP3/Ca++

		2. Ca++ Þ troponin Þñ myosin binds actin Þñ geniohyoid contraction
                

	D. Inspiration follows Pharyngeal Dilation

		1. sensory feedback

			a. pharyngeal stretch Þñ NST

		2. NST GluÞñ AMPA/NMDAC3-5 spinal cord motor neurons Þ phrenic nerve

			a.  motor neurons Þ phrenic nerve Þ end plate terminal ACh  Þ 

			b. ACh Þñ Nicotinic-R diaphragm contraction

				i. downward movement

		3. NST GluÞñ AMPA/NMDAT2-7 spinal cord motor neurons

			a. Þ intercostal nerves  Þ end plate terminal ACh  Þ

			b. ACh Þñ Nicotinic-R intercostal muscles contraction

				i. intercostal contraction Þñ rib cage expansion
 

	E. Acme phase also includes   

		1. thorax reaches maximum capacity

			a. followed by a brief interruption of inspiration

		2. eyes close

		3. limb stretching

			a. yawning + stretching = Pandiculation

			b. generalized stretching of respiratory tract muscles

				i. diaphragm, intercostals, face and neck

	F. Conclusion phase: short expiration and relaxation

---

Syllabus

---

Neuroscience Group at USD                     Biology Department                     Summers' Biology Webpage                     Summers' Course Offerings                     Contact Us

---