Psychology Lecture 6: Synaptic Communication
1. How do Neurons work?
2. Neural communication
3. The Synapse
4. How do neurons produce an electrical signal?
5. How does a neuron code intensity?
6. How does one neuron communicate with another?
Destroy myelin sheath, slower neural conduction
How Do Neurons Work?
2/3 of all neurons housed in cortex
Each neuron has a job, communicate with other neurons
Brain works by creating networks among nerve cells
Neurons use electric and chemical signals to communicate
One neuron releases chemicals over the synapse, and the gates of the other receive the sodium
and potassium ions to continue the action potential, through this creating a communication
between 2 neurons
How does a cell produce an electrical signal?
Extracellular fluid, has a semipermeable cell membrane
Contains Na, Cl, K, A(protein molecule) ions within the neuron
Na, K and Cl ions outside the cell as well
Way more Na outside the cell
Ionic charge on the cell membrane because of ion concentration, inside negative, outside
Action Potential – Takes 5-7 ms
o -70 mV, resting potential when nothing is happening
o Stimulated, incoming sensation, change in electrical potential, goes from -70 and goes
Depolarization, result of Na inflow, changing the ionic concentration inside the
cell with stimulation
Makes inside of cell more positive
o -55 mV is the threshold, all holes open and Na has a giant inflow into the cell
Rushes straight into the cell, goes all the way to +40 mV ionic charge
Only takes 2 ms to complete
o Repolarization, K outflow, bringing the neuron back to the resting potential
Goes further than resting potential, below -70
Eventually drifts back to resting potential and waiting for next action potential
When below -70, known as hyperpolarization Important Points
During repolarization, the steepest drop is known as the Absolute
o Nothing can change the neuron at this point, very quick, no
At end of repolarization, Relative Refractory Period
o Can be stimulated, but it takes a lot to do so
o Can be stimulated for it to return to resting potential quicker
than it normally would
Sodium coming in starts the action potential, then potassium is kicked out, then sodium comes
in and it keeps going down the axon making the action potential car