He was a physician to the gladiators. He made associations based off of injuries and identified the cerebellum as the main center for sensations and motor functions. He played with monkey and sheep brains.

His views lasted about 1500 years.

He wrote de humani corporis fabrica.

He was the first to disagree with Galen and was attaced by Sylvius.

Fluid-Mechanical Theory: the brain controlled blood flow by squeezing.

• ND: believed the CNS was compsed of separate neurons. Santiago Ramon y Cajal.
• FT: people who believed the CNS was one continuous organ/system. Camillo Golgi.

1. Molecular: looks at receptors and ion channels
2. Cellular: looks at behavior of individual cells
3. Systems: examines one system (e.g., auditory)
4. Behavioral: studies behavior
5. Cognitive: studies cognition

What are the six ways to study electrical signals?

No definitions

1. From the surface of the skull
2. From a nerve bundle
3. A wire hook on one axon
4. Extracellular recording
5. Intracellular recording
6. Patch-Clamping

Taking a glass pipette with a polished blunt tip and putting it against the membrane of a cell. Then apply suction and pull it away. It takes a patch of membrane with it.

You can measure the cell inside out, outside out, cell attached, and whole cell measurement this way.

1. All organisms are made up of one or more cells.
2. The cell is the reason there is life.
3. Every cell comes from a previous cell.

1. Axo-Dendritic
2. Axo-Somatic (cell body)
3. Axo-Axonal
4. Dendro-Dendritic (very rare)

• Retro: moving NTs from the axons to the cell body
• Antero: moving NTs from the cell body to the aon terminals

1. Unipolar
2. Bipolar
3. Multipolar
4. Anaxonal (none)

1. Mictrobulues: make of tubulin, they are hollow and rigid (scaffolding).
2. Neurofilaments: thy are not stiff by have good tension and flexibility
3. Microfilaments: made of actin, they are used for changing neuron shape

1. Golgi Type I: projection neurons
2. Golgi Type II: local curcuit neurons

• CNS: oligodendrocytes
• PNS: schwann cells

• Resistance (r): factor that determines relation between voltage and resistance; measured in ohms
• Conductance (g): the ease at which a current flows in a circuit; 1/r
• Capacitance (C): a circuits ability to store charge; q/v

I = V/R

I is current. You can rearrange this to get two more equations, one for voltage, one for resistance

The sodium-potassium ion pumps.

For every 3 Na ions that are pumped out, 2 K ions are pumped in.

• K: 20 times more inside than out
• Na: 10 times more outside than in
• Ca: 10,000 times more outside than in (but very very small amount in general)
• Cl: 11.5 times more outside than in

It flows out through leak channels with it's concentration gradient, but also in for it's electrical gradient, creating an equilibrium.

The Na-K pump is what keeps it from reaching equilibrium and keeps the outside positive and the inside negative.

It represents how large of a potential is necessary to balance the concentration difference across the membrane at equilibrium.

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• R is the thermodynamic gas constant
• T is the absolute temperature
• Z is the valence of the ion
• F is the Faraday (number of coulombs in one mole of the ion)

• Room Temperature: 58 mv
• Body Temperature: 61.54 mv

• K = 1
• Na = 0.025
• Cl = 0.45

It calculates the membrane potential.

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Use the conventional permeabilities for P.

Use the give values for RT and BT at the beginning.

Remember that Cl is switched.

It is the time constant. It is calculated by mulitplying resistance*capacitance.

It is the amount of time the neuron/membrane takes to reach 63% of its max voltage.

A long/large time constant is usually found in temporal summation because you need many triggers in a sequence to get the charge high enough.

A small/short time constant is usually found in spatial summation because you do not need much continous triggering to get the cell to fire. 

They are electrical potentials of varying intensity and are not all the same. They cannot spread very far but can still cause small amounts of de/hyperpolarization.

If enough graded potentials occur and move down a membrane, they may depolarize it enough to hit threshold, causing an AP.

• IPSP: the post cell will hyperpolarize, inhibiting it from any function
• EPSP: the post cell with depolarize, causing a response

• TTX (Tetrodotoxin): It blocks VG Na channels, but not leak channels. Pufferfish.
• TEA (Tetraethylammonium): blocks VG K channels, but not leak channels.

1. Type A: the fastest, they are motor neurons and proprioceptive neurons
2. Type B: most sensory neurons, including pain
3. Type C: the slowest, most ANS neurons and some sensory neurons (spiciness).