Class Notes (808,549)
Canada (493,288)
Psychology (2,017)
PSYC 304 (16)
Lecture 4

Lecture 4 Oct 3.doc

3 Pages
Unlock Document

University of British Columbia
PSYC 304
Steven Barnes

Oct. 03, 2013 PSYC304 *midterm will only include up to1 half of Chapter 5 from textbook Neural Conduction & Synaptic Transmission e.g. Parkinson's: set of behaviour symptoms as result of decrease in neurotransmitter (dopamine) how does 1 cell transmit electrochemical signal to other cells? − oversimplification of process − some neurons don't have axons communication within a single neuron: − use intracellular recording a.k.a. the 'sharps microelectrode' technique (stretch glass tube really sharp and thin undng pipette pullers, fill with conductive solution): penetrate cell with sharp electrode; use 2 electrode to record potential outside cell − neuron has resting membrane potential (constant charge across neuron) BUT not static state − healthy neurons have resting membrane potential of -60 to -80 mV (i.e. voltage inside neuron is -60 to -80 mV less than outside neuron) − when neuron fires -> voltage reversal to positive charge (polarization) why polarization at -70 mV? − due to unequal distribution of ions − proteins = negative charge − lower # of Cl- ions why unequal? 1) membrane has differential permeability (presence of ion channels/”pores”, function of proteins, of various species/specific to each ion); at resting potential some pores are open and some are closed; folding of protein changes with charge 2) ions move down concentration gradient (high concentration -> low concentration); Na+ tends to enter, K+ tends to exit 3) the negative internal charge creates pressure for both Na+ and K+ to enter (negative charge attracts positive charge = electrostatic force) 4) sodium-potassium pump transports 3 Na+ out for every 2 K+ it transports in (active transport); energy-consuming process (dephosphorylation) what affects resting membrane potential? (inputs from other cells) Generation and Conduction of Postsynaptic Potentials (PSPs) − when a neurotransmitter (NT) binds to a postsynaptic receptor, 1 of 2 effects: − 1) depolarize membrane (brings charge closer to 0): -70 to -67 mV − produces excitatory postsynaptic potential (EPSP) = increases likelihood of firing an action potential (AP) − 2) hyperpolarize membrane (charge further from 0): -70 to -72 mV − produces inhibitory postsynaptic potential (IPSP) = decreases likelihood of firing anAP − potential travels rapidly along cell, like electrical signal along wire = decremental (decreases in charge) − once membrane potential reaches certain threshold, anAP can be generated! − EPSPs + IPSPs summate -> reaches/exceeds level of threshold ->AP (massive momentary reversal to positive voltage then goes back down) EPSPs + IPSPs sum spatially (location-wise of cell) as well as temporally − PSPs are always overlapping and interacting − temporal summation: single input from 1 other neuron; not static entity; multiple PSPs in rapid succession to produce a larger sum of PSP AP generation − if the sum of the PSPs that reaches theAXON INITIAL SEGMENT (below axon hillock, may be mobile) is sufficient to depolarize the membrane above its threshold of excitation (e.g. -65 mV) ->AP to +55 mV − as function of certain species of ion channels − AP travels slower, relative to PSPs
More Less

Related notes for PSYC 304

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.