Lecture 4: Brain and Behaviors
The Physiology and the Chemistry of the Brain
•Information comes from the dendrite spines. There are exceptions to that rule. Then
there is an action potential is created. When the dendrite spines are come in contact
with excitory stimulus it causes ion channels to open in the membrane so that
sodium can come pouring in into the inside of the neuron. Sodium has a positive
charge on it, so it causes the inside of the neuron, normally the dendrite spine to be
positive. When an area becomes positive it reaches a certain threshold, so it has a
certain amount of positive ions inside of it. It causes the ion channels to open up in
the area. When this threshold happens, the neuron has fired or an action potential.
•An action potential is a very high positive charge across a membrane. When action
potiental has occurred, the information zips out into the axon and into the nerve
•Synapses: know basic info about the synapses. The space inbetween is called the
synaptic cleft. When action potiential comes along they will merge with the terminal
and release transmitter substances. Transmitters interact with receptors on the
•Parkinson disease: don’t have enough dopamine. In his brain, we are trying to
increase in dopamine. Eskitsofrinic: overactive of dopamine. Excess in dopamine.
•Lifecycle of neurotransmitter:
oIt has to be made. Usually involved with basic stuff.
oWhen transmitters are made, you have to store them. If the package
transmitters are floating around there are things in the environment that
would eat it all up.
oThe packaged transmitters move towards the presynaptic area.
oThen it is released, usually upon an action potential.
oHave to interact with post synaptic receptors.
oInactivation : There are two methods of doing that.
Reuptake: the presynaptic terminal takes the transmitters back up.
Degradation/Breakdown: it is broken down and degraded.
Mimicker: Chemicals that can mimick the activity of a
neurotransmitters. They look very much like the transmitters itself, it
is not exactly it. They will go in and activate the receptors.
Blocker: deactivate the receptors. But look like the neurotransmitters
so it will lock in with the receptors.
•How to alter the system
oYou can increase its rate of activity or you can decrease. So you can decrease
or increase the functional activity of a system.