Start of Part 3 Eric W. Harris, PhD.

Basic Functional Subdivision of Neurons But, of course, there are exceptions – e.g., action potentials can originate from axon terminals and “back propagate”

“Integration” of excitatory inputs

Basic Functional Subdivision of Neurons But, of course, there are exceptions – e.g., action potentials can originate from axon terminals and “back propagate”

How neurons send a signal – Pt. 1 The “Action Potential” 

Basic Functional Subdivision of Neurons But, of course, there are exceptions – e.g., action potentials can originate from axon terminals and “back propagate”

How neurons send a signal – Part 2: Synaptic Transmission

Analogies of how neurons work

Neurotransmitters  Glutamate, Aspartate - major excitatory neurotransmitters in the brain  GABA - major inhibitory neurotransmitter in the brain  Acetylcholine - many different actions in the brain; neuromuscular junction transmitter  Serotonin – many different actions; associated with mood, sleep, perception (LSD)  Dopamine – many different effects; associated with reward, attention, movement (PD)  Opioid peptides (endorphins) – modulate pain signals  Substance P – pain signaling  Many others…

Summary of basic information processing in the brain Action Potential Synapse…

But it’s not so simple - Excitation and Inhibition

Physiological plasticity  Synapses are not static:  With repeated use can show “habituation”  With intense use can become stronger (“long-term potentiation”)  Simultaneous strong inputs can potentiate each other (“fire together, wire together”) Harris & Cotman, 1986

Electroencephalography (EEG) Synaptic currents create a small electrical field along a neuron If neurons are lined up, the electric fields add together. x Using electrodes placed on the scalp and sensitive amplifiers… …one can record “brain waves”!

Quantitative EEG (QEEG) EEG is the sum of many brain waves, like this: EEG can be “de-convoluted” to find and measure the underlying components, e.g.: Frequency (Hz) 0 scidavis.sourceforge.net/manual/c4166.html newsoffice.mit.edu/2012/faster- fourier-transforms-0118 QEEG data can be looked at many ways, For example:

And then there are glial cells… Astrocyte – various supportive functions Oligodendrocyte - makes myelin

The building blocks – Neurons and Glial Cells Ramon y Cajal, 1899 Miriam Ascagni, DIBIT San Raffaele Scientific Institute, Italy, 2010 Del Rio-Hortega,

Good sources of info about the brain,  The Society for Neuroscience ( – in particular, “Brain Briefings”  “The Brain Science Podcast” – not for total beginners  The Dana Foundation  (“Neuroscience for Kids”)  There is LOTS of new information every day…

Thank you for your attention Questions? Comments?