Measurement And Stimulation Of The Nervous System
Measurement And Stimulation Of The Nervous System BME 52800
Popular in Course
Popular in Biomedical Engineering
This 11 page Class Notes was uploaded by Brisa Lehner on Saturday September 19, 2015. The Class Notes belongs to BME 52800 at Purdue University taught by Thomas Talavage in Fall. Since its upload, it has received 88 views. For similar materials see /class/207879/bme-52800-purdue-university in Biomedical Engineering at Purdue University.
Reviews for Measurement And Stimulation Of The Nervous System
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/19/15
BME 528 ECE 528 Measurement and Stimulation of the Nervous System Neurophysiology ll Membrane Models and Action Potentials Neurophysiology lll Membrane Models Action Potentials BM EECE 528 Cell Types Small Cells Exhibit equipotentials throughout the cell such that Vm is independent of position Large Cells m varies as a function of position typically physically larger cells BMEECE 528 Small Cell Membrane Model DCac Model Small signal model lJma limm C m FCCmuffs letl Cm 0 vmlt quot111 gm vmlt iquotf Areax cm dvgtm ngmt BMEECE 528 Small Cell Small Signal Analysis Consider a step function mm Cum and solve for vquott39 4 e era Mt vm o vm0 vm e 0 12 m Aleaxcm cm 7 1 Areaxgm 39 gm a lam117 Note Time constant is property of membrane not size Gm amazes sza Large Cell Model DCac model Small signal model 8vquotzt m a gmvmltugt kquotzt c amazes sza Large Cell Small Signal Analysis From the core conductor model 2 W ri roKmZ39troKez39t Z The total acDC quantities may be expanded Vmzt Vm0 vmzt Kmzt K3 kmzt Kez t K kez t BM EECE 528 Large Cell Small Signal Analysis But at equilibrium 2 0 38 V r ram 4ng 0 z So we are left with our ac terms 2 aVam Zzyt rokmz39trokez39t Z the core conductor model still holds Now we plug in the excitation current from before kmltz gtcmana ftgmvmltztgt BM EECE 528 Large Cell Small Signal Analysis Substitution yields 62 t r rogmvmzt r mom a t Vquot rokezt This resembles a classic cable equation 62v 2 t 6v 2 t 2m v ztr m 2rk zt c 622 m M c n e with time constant and space constant T 04 2nacm amp in M gm 2mgquot Gm C Kro BM EECE 528 Neurophysiology lll Membrane Models Action Potentials BM EECE 528 The Action Potential 3 Inc g Lx u BM EECE 528 Unmyelinated Axon BMEECE 528 12 Ion Channel Behavior Na 60 r w n I u a 392 g Q 0 84 U 3 quotR l g R sungquot Copyright 2002 by Mosby Inc BMEECE 528 13 Ion Channel Behavior in AP BMEECE 528 14 Snapshot of AP BMEECE 528 Spatial Propagation of AP LL JL t Copyrighl 2002 by Mosby Inc BMEECE 528 Spread of Excitation RC model BMEECE 528 Effect of Myelin on AP Saltatory Conduction AP quotjumpsquot Nodes of Ranvier BMEECE 528 Ion Channel Distribution Concentrated at Nodes of Ranvier BMEECE 528 Saltatory Conduction Consider two axons r1dlush Axonl I v J I radius2h Axonzl W W W I ll J L J k J L J ex Area Recall Cm T Myelln Thickness T Capacrrancel BMEECE 528 Saltatory Conduction 80 more myelin yields lower capacitance Consider behavior of C Continuity equation q 2 CV V21 C Lower C gt less q required to achieve same V BMEECE 528 21 Saltatory Conduction Fewer ions q required to produce an AP Greater spatial constant 1 Fewer channels under myelin is W Lower gm gt Higher we Depolarization propagates more quickly Faster conduction BM EECE 528 22
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'