Introduction to Neurobiology: Day 1

What is this class about? Start with quick review of syllabus: We are going to start with the most basic operating principles and build up an understanding of how nervous systems work. Spend 8 weeks on one cell. Another 3 weeks on how two cells communicate. Then use this knowledge to understand how things like this happen Optical illusion: https://www.youtube.com/watch?v=tVgOLWVYytM Clive wearing: http://bcove.me/0z4ryde3

Optical illusion: https://www.youtube.com/watch?v=tVgOLWVYytM Clive wearing: http://bcove.me/0z4ryde3 We are going to build up an understanding of how nervous systems work.

About this room.

What is my approach to teaching this class What is my approach to teaching this class? If you don’t believe me, then check out what last year’s students had to say.

Rules of the road Respect – both ways.

Learning resources The course website: www.BIOL3833.net Canvas Free online texts Free online software Your instructor! Your classmates and your team The internet

Learning activities Equizzes Quizzes Lectures In-class activities Group activities Homework Exams

Today’s activity (your first two STEP points) Personal information sheet Talent release form

Go forth and prosper: Install EOTN software (submit a screenshot of the program on your computer through Canvas for one STEP point) Equiz 1 available NOW – feel free to start using it!

Introduction to Neurobiology: Day 2

The SORTING HAT has spoken!

Agenda: 1. Get to know your teammates, exchange contact information (~10 min) 2. Team activities (~30 min). 3. Lecture – basics of electricity and Ohm’s Law (~35 min)

The spaghetti-marshmallow challenge!! 20 sticks of spaghetti Three feet of tape Three feet of string One marshmallow Build the tallest free-standing structure that supports one marshmallow on top. You have 18 minutes http://www.ted.com/talks/tom_wujec_build_a_tower?language=en

The Big Picture for the semester: Neurons, Neural circuits, and Behavior Neurons have intrinsic properties Passive properties Active properties Intrinsic plasticity – changes in these properties Neurons are organized into functional circuits defined by their network properties Topographical properties (the wiring) Synaptic properties (the strength of the connections) Synaptic plasticity – changes in these properties Neural networks produce behavior

Passive membrane properties

Start with passive properties of a spherical cell – the simplest case we have.

Passive Membrane properties Basics of electricity Ohms law Resistors, Capacitors, and RC circuits Biological membranes as RC circuits Why are we starting here? Because neural systems are bioelectric signaling systems. What defines neurons is their electrical activity, so we need to have a very clear understanding of the key laws that govern electricity

Basics of Electricity Voltage: The separation of charge Current: The movement of charge Resistance: opposition to the movement of charge Conductance: the opposite of resistance CHALK TALK: Intuitive explanation of voltage, current, and resistance.

CHALK TALK: Intuitive explanation of voltage, current, and resistance.

V = IR Ohms Law is Central Voltage = Current * Resistance CHALK TALK: The effects of changing voltage, resistance

Introduction to Neurobiology

Agenda: 1. Finish lecture on passive properties (~30 min) 2 Agenda: 1. Finish lecture on passive properties (~30 min) 2. Intro & Overview: Neural simulations (~15 min). 3. Begin first simulation assignment (~30 min) 4. Thursday: VERY brief lecture then complete simulations

Ohms Law is Central V = IR Voltage = Current x Resistance

Electrical Components Voltage source – fixed voltage, infinite current Current source – fixed current, infinite voltage Resistors – oppose the flow of current Capacitors – store & release charge

Thought experiment: What happens if we apply a steady current to a resistor and measure the voltage across the resistor?

Capacitors Capacitors are funny things Capacitors consist of two conductors separated by a very thin insulator. Capacitors store and release charge The capacitance is directly proportional to the surface area. Draw this out on this page!

Thought experiment: What happens if we apply a steady voltage to a capacitor and measure the voltage across the capacitor?

Another thought experiment: What happens if we add a resistor in parallel with the capacitor and apply a current to the RC circuit?

t = Time Constant The time required for an RC circuit to reach 63% of its final voltage (or decrease to 37% of its initial voltage) t = RC V(t) = V(0)e(-t/RC)

Why does this matter?

Because passive properties yield the most basic and the first line of information processing in the nervous system! There are disease states that arise from failures of these mechanisms. The functional specialization of many cell types starts with their passive properties.

The cell membrane as an RC circuit The membrane exhibits resistance and capacitance The primary passive properties of the cell Resistance determined by open ion channels Capacitance determined by cell size (surface area of membrane) Gives rise to the membrane time constant Resistance determines the magnitude of the membrane’s voltage response to an input current Membrane time constant (resistance x capacitance) determines the speed and duration of the membrane voltage response

Homework (STEP point #3). Create and sign a team contract Homework (STEP point #3) Create and sign a team contract Typed, and signed by all team members Upload your contract to Canvas