Physiology and Behavior: Neurotransmission Using one or more examples, explain effects of neurotransmission on behavior

Neurons 100 billion in the brain alone Main Goal  Receive and send information How? Electrical impulse that “push” chemicals from one neuron to another Parts of the Neuron Dendrite Cell Body Axon Most important part  SYNAPSE

Neuron Communication Chemical Process BETWEEN neurons Chemicals  neurotransmitters Neuron may or may not send message Voluntary movement: release of neurotransmitters Sent to motor cortex Sent to appropriate muscles Three main parts of the transmission process

Step ONE Neurotransmissions are stored in the terminal button of the axon Step ONE

Step TWO Neurotransmitters can only fit into certain receptor sites (like a key) Neuron fires Right amount of neurons Right type of neurotransmitters Repeated over and over again Step TWO

Step THREE Extra neurotransmitters are absorbed back into the neuron they came from Reuptake Can be used again Step THREE

Reflex Faster neurotransmission that involves the spinal cord

Mirror Neurons Function: Empathize and learn from others the neuron fires when an animal/person PERFORMS an action or OBSERVES and action First discovered in monkeys

Iacobone, 2004 Method: Correlational using MRI Hypothesis: Humans have mirror neurons Procedure: Observe and then imitate facial expressions Results: Yes, there are motor neurons The same neurons fired when they did the action and when they viewed the action Limbic system also responds to viewing emotion in others Implications: empathy and learning in humans is based on mirror neurons

Drugs Alter Neurotransmission

Caffeine Impacts step TWO What happens when you feel sleepy? Adenosine is released Inhibit activity Prepare body for sleep What does caffeine do? Binds with receptor sites Prohibits adenosine from communicating PLUS…increases brain activity Movements and thoughts may become faster Adenosine Caffeine

What if you drink too much caffeine? Tolerance: Increase receptor sites that respond to adenosine Increase amount of adenosine

Dopamine How does it impact behavior? Voluntary Movement Goal-directed behavior (motivation) Reward system Pleasure seeking Addictive behavior Disorders/Disease Parkinson’s disease Schizophrenia

Parkinson’s & Schizophrenia What is Parkinson’s? Degenerative disease (tremors, difficulty in movement) Too little dopamine TX: L-dopa Increase dopamine (caused schizophrenia symptoms) What is Schizophrenia: Psychotic disorder that causes a break from reality (hallucinations, delusions) Too much dopamine OR too sensitive TX: Chlorpromazine Decrease dopamine Problem The brain adapts/tolerance Additional symptoms (Tardive dyskinesia)

Dopamine and Schizophrenia

Parkinson’s Disease

Connection with Addiction Addictive drugs increase dopamine in reward system of the brain View drug related items and dopamine is triggered Viewing cigarettes, food or gambling machine Nicotine is addictive drugs Causes dopamine to be released Drug Usage Dopamine

Berridge and Kringelback, 2009 Method: correlational using brain scans AIM: investigate the connection between pleasure, dopamine and specific brain locations. Results: frontal cortex Implications: Subjective experience of pleasure is linked to frontal cortex neurons (dopamine) that trigger endorphins

Love is like an ADDICTION High levels of dopamine Passion Low Levels of dopamine Rejection

Serotonin Purpose Prozac regulates mood Mood regulation Inhibit dreaming while we are not sleeping Blocks reuptake of serotonins Increasing mood regulating messages Prozac regulates mood LSD causes hallucinations (dreams while awake)

Bonson et al, 1996 Method: Survey Major limitations AIM: to see the impact on behavior when individual was on Prozac for depression and took LSD Results: Prozac decreased symptoms of depression BUT LSD never gave the same effect

Acetylcholine (ACh) Function Synaptic plasticity in hippocampus Learning and short term memory

Martinez and Kesner, 1991 Aim: investigate the role of ACh in memory formation Method: Experiment (rats) Procedure: Memory task (maze) Group 1: received injection to block ACh Group 2: received injection that cleans out the synapse allowing more ACh availability Group 3: Control Group Results: Group 1 had difficulty with maze Group 2 made few mistakes, quicker than control group Implications: ACh is important to the neurobiology of memory But it is very complex

SAQ Discussion Create an outline for Explain, using one or more examples, the effects of neurotransmission on human behavior