Good day everyone. My name is Leon Kaczmarek,
and as will be evident from this slide,
I'm going to be talking about the regulation of
neuronal accuracy by the modulation of potassium channels.
One of the key problems in neuroscience is to understand
how neurons are able to produce changes in the behavior of an animal.
This of course occurs during learning and memory
and in many other types of changes of behavior.
One of the things that's emerging about this is that there are
changes in the intrinsic excitability of
neurons that accompany many of these changes in behavior.
If one records the electrical activity of a neuron in the brain,
one can see that it is very variable.
Some neurons have short, narrow action potentials,
other neurons have wider action potentials that can be very different in amplitude.
Some neurons, when isolated from any other inputs,
have no spontaneous activity,
whereas others can fire repetitively by themselves,
still other neurons can generate repetitive bursts of action potentials,
and these are particularly favored in circuits that underlie
rhythmic activities, such as locomotion, breathing, etc.
Neurons also vary a lot in the way they respond to and maintain synaptic input.
Some neurons can be stimulated for a very brief period of time
and they will continue to fire once that input has stopped.
Still other neurons will fire continually as they're being stimulated,
whereas yet other neurons will adapt very
rapidly or sometimes not so rapidly to a maintained stimulus.
Now one of the interesting things about
these intrinsic properties of the neurons is that they're not fixed for all time,
but that changes in the environment or changes in synaptic inputs,
changes in hormone levels, etc,
can alter the behavior of these neurons so that
you can change the shape of, and the height of an action potential,
and when this happens at
a synaptic terminal this can change the strength of neurotransmitter release.
Neurons that are silent could be induced to fire
repetitively or go into bursts, and moreover,
neurons that respond to a particular way to maintain synaptic input can,
in response to changes in environment or synaptic or hormonal stimulation,
alter the way that they respond.
The main reason for these many different types of