4-3-14The brain- Behavioral neuroscienceo The study of the biological underpinnings of behavioro Examples Phineas Gage: personality - Railroad construction worker- Metal rod shot through his left eye and exited his left frontal lob- For the most part he was okay, but his personality changed from being well mannered to really profane and violent “Tan”: language- Lost the ability to pronounce words, only used the word tan- Frontal lobe was severely damaged Nick A.: memory- Air force technician- Fencing foil and was lodged up his nose and up into the middle of his brain- Had profound trouble with his memory, couldn’t make new memories- Severe damage to hippocampus Self-stimulating rats: pleasure- Septum was activated - Some rats ignored hunger for repeated rewardo Basic assumption ALL thought and behavior is a function of the nervous system (and, most fundamentally, the brain)Goal of nervous system- To collect, transform, and transmit informationo Enormous, complex system o Most complex we’ve ever known- Where does the information come from?o The external world, through your senseso The internal world, through your viscera o From other parts of the nervous system (e.g. your brain talks to itself – a lot!) More interactivity than interpreting information from the outside- Your brain is one big information processing system! (much like a computer is an information processing system)- A computer: simple, fast computation- Our brains: complex, simple computations (relative to a computer)Basic divisions of the nervous system- Nervous systemo Peripheral nervous system Somatic- Link to external worldo Voluntary muscleso Sensory systems Autonomic - Link to internal world (viscera)o Involuntary muscles Sympathetic (arousal)- Increase in blood pressure- Heart rate increase- Dilation of eyes- 4 f’s Parasympathetic (calming)- Reduced heart rate- Reduced blood pressure- Constriction of eyeso Central nervous system Brain  Spinal cordMicroscopic view of the brain- Structure and function of neuronso Neurons are the functionally important cells which make up the nervous system (including the brain)o What do neurons do? Collect, integrate, and transmit informationo How many do we have in our brains? About 100 billion (but you lose about 10,000 every day)o How many connections are between neurons? About 100 trillion connections between neurons (synapses)o Parts of a neuron Dendrites: receive input from other neurons and from muscles, organs, etc. Cell body: integrates information collected from other neurons, organs, etc. - Typically integrates thousands of dendritic inputs at any given momentin time- Based on the integrated input, cell body is constantly deciding whetheror not to send a signal to other neurons Axon: transmits signals to other neurons (or muscles, etc.)- Although the cell body is microscopic, axons can be up to 3 feet in length Axon terminal: location of a synapse, which is where neurons communicate  Myelin sheath: fatty cells wrapped around the axon; insulating the axon, making information transmission faster and more reliable - Not all axons are myelinated- For those that are, some are more myelinated than