1. Biological Psychology and Neurotransmission

2. phrenology
Back in ye olden days, we believed many very stupid and silly things about humans and our minds (cough…hindsight bias..)
One of those things was phrenology- the believed that studying bumps on the skull could reveal your mental abilities and skills.

3. Biological psychologists
Today, we now rely on biological psychologists (people who study the links between biological [genetic, neural, hormonal] and psychological processes)

4. Neurons

5. Look a funny cat video!

6. Neurons are super cool
Individual nerve cells that receive, integrate, and transmit information
The basic elements of communication in the nervous system, but only the majority communicate with other neurons.
However, there are some exceptions
Approx. 100 billion neurons make up the brain
Millions of neurons are involved in producing a single thought

7. A “typical” Neuron*

8. Now let’s

9. Soma
Cell body that contains the nucleus and much of the machinery common to most cells (the rest of it deals with handling information)

10. dendrite
Parts of the neurons that are specialized to receive information
Look like tree branches

11. Axon
Long fiber that transmits signals away from the soma to other neurons or to muscles or glands
Quite long (sometimes several feet)
Branch off to communicate with many different cells

12. Myelin sheath
White, fatty substance insulating material that encases some axons
Speeds up the transmission of signals that move along axons
*signals may not be transmitted efficiently if the sheath has been deteriorated (multiple sclerosis- loss of muscle control)

13. Terminal buttons
Small knobs that secrete chemicals called neurotransmitters
Messengers that may activate neighboring neurons
The point at which neurons connect are called synapses

14. synapse
Synapses are junctions where information is transmitted from one neuron to another

15. Glia
Cells found throughout the nervous system that provide various types of support for neurons
Outnumber neurons 10-1, 50% of the brains volume
Nourish neurons
Remove waste products
Insulation
The heroes of the nervous system

16. The neural impulse-what happens when a neuron gets stimulated

17. Neuron at rest
Inside and outside the neuron are fluids containing electrically charged atoms and molecules called “ions”
Positively charged potassium and sodium and negatively charged chloride ions flow back and forth across the cell membrane, but do NOT cross at the same rate
HIGHER CONCENTRATION of negatively charged ions inside the cell------ resulting voltage/potential energy
RESTING POTENTIAL- stable, negative charge when the cell is inactive (-70 million volts)

18. Action potential
The neuron is relatively chill and doesn’t do anything while the charge is constant
However, if the neuron gets stimulated, channels in the cell membrane will open allowing positively charged sodium ions to rush in
At that moment, the charge becomes less negative/even positive, creating an action potential
ACTION POTENTIAL- a very brief shift in a neuron’s electrical charge that travels along an axon
Voltage change will race down the axon (like a spark in a line of gunpowder)

19. Refractory Periods
After all this excitement, the channels in the cell membranes will close up again (and this may take some time)
ABSOLUTE REFRACTORY PERIOD- minimal length of time after an action potential during which another action potential cannot begin
RELATIVE REFRACTORY PERIOD- the neuron can fire, but its threshold for firing is elevated, so more intense stimulation is required to initiate an action potential
Imagine running a sprint. After you finish running, you will need a period of time (ARP) to calm down before you will run again.
After you completely recover, you can run again, but you will need some more intense motivation (RRP), because you don’t really feel like sprinting again.

20. All-or-none law
The neural impulse is like a gun, either it fires or it doesn’t fire
Action potentials are all the same size as well
Neurons convey information about the strength of a stimulus by varying the rate at which they fire action potentials
Stronger stimulus- more rapid volley of neural impulses than a weaker stimulus

21. Synaptic cleft & Neurotransmitters
Neurons don’t actually touch
Synaptic Cleft-microscopic gap between the terminal button of one neuron and the cell membrane of another neuron
This gap must be jumped in order for neurons to communicate
Presynaptic neuron- sends signal
Postsynaptic neuron- receives signal
How does this happen?
The arrival of an action potential at an axon’s terminal triggers the release of NEUROTRANSMITTERS- chemicals that transmit information from one neuron to another
Collected together in little sacks called SYNAPTIC VESICLES
Vesicles fuse together with the membrane and spill contents into the synaptic gap
They may bind to certain areas at various receptor sites

22. Postsynaptic potentials
Postsynaptic potential- voltage change at a receptor site on a postsynaptic cell membrane (caused by a neurotransmitter and receptor molecule combining)
DO NOT FOLLOW THE ALL-OR-NONE LAW
Vary in size and increase or decrease the probability of a neural impulse in the receiving cell

24. Excitatory and inhibitory PSP
Excitatory (+)- increases the likelihood that the postsynaptic neuron will fire
Inhibitory(-)- decreases the likelihood that the postsynaptic neuron will fire
This stage lasts a short period of time, and neurotransmitters drift away from the receptor sites or are converted into inactive forms

25. Reuptake
Reuptake- the process through which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane.
Neurons receive thousands of signals, so it must integrate the signals as they arrive to decide whether or not it will fire
Firing is impacted heavily by IPSP and EPSP

26. The cat is back
Watch the cat again, however this time, watch it and imagine that the toilet flushing is like a neuron firing

27. Flushing Neuron-Cat
Write these out on a separate sheet of paper (label and EXPLAIN)
All-or-Nothing Principle
Refractory Period
Resting Potential
Action Potential
Dendrites
Axon
Myelin Sheath
Terminal Buttons
Soma

28. neurotransmitters
There are lots of neurotransmitters and they do very important things…
Ex. Ach (role in memory, learning, and is also the messenger at every junction between motor neurons (which carry info from the brain and spinal cord to the body’s tissues) and skeletal muscles
If ACh transmission is blocked then your muscles cannot contract---leading to paralysis

29. Drugs can impact neurotransmitters
Agonists- a molecule that, by binding to a receptor site, stimulates a response
Opiate drugs can produce a temporary “high”
Antagonists- a molecule, that by binding to a receptor site, inhibits or blocks a response
Botulin (poison found in improperly canned food causes paralysis by blocking ACh release
We call it Botox and inject it into our faces to paralyze underlying facial muscles 