PHRENOLOGY -Invented by Franz Gall in the early 1800?s -A theory that claimed that bumps on the skull could reveal our mental abilities and character traits The Nervous System It starts with an individual nerve cell called a NEURON Neuroanatomy Synapse Synapse How does a Neuron fire? Resting Potential: slightly negative charge Reach the threshold when enough neurotransmitters reach dendrites Go into Action Potential All-or-none response Transfer of ions across axon?s membrane causes electrical charge Neural Communication Types of Neurotransmitters Serotonin Involved in mood, sleep and wakefulness, eating, & aggressive behaviors Lack of serotonin has been linked to depression, anxiety, insomnia, OCD Norepinephrine