Unit 3 Biological Bases of Behavior Neuroscience We

Unit 3 – Biological Bases of Behavior (Neuroscience) • We can’t have the mind without the body! • Without your genes, your brain, your appearance - you would be nobody. • Our understanding of how the brain gives birth to the mind has come a long way. – Ancient Greek philosophers Enlightenment/Scientific Revolution – Phrenology

Just as I Thought, low self esteem Why can’t my skull bumps be prettier? Phrenology Franz Gall-(1758 -1828) Why so popular? • Individual ability to change and develop Pseudoscience-based on false assumptions. • Improved treatment of the insane (organic) • Encouraged people to think scientifically

Modern Science We are a collection of systems: Ø Cells form organs Ø Organs form body systems (digestion, circulation, etc. ) Ø Body systems make up the individual Ø Individuals are parts of families, cultures and communities Ø We are biopsychosocial systems!

We are going to start small and go big

Module 9: Neural and Hormonal Systems Neurons: The Building Blocks of the Nervous System

Nervous System • The electrochemical communication system of the body • Sends messages from the brain to the body for movement • Brings information to the brain from the senses

What are the primary parts of a typical neuron? • • Nervous system • Axon • Terminal branches Neurons of Axon Dendrites • Myelin Sheath Soma

Neuron • The basic building block of the nervous system -- a nerve cell • Neurons perform three basic tasks – Receive information – Carry the information – Pass the information on to the next neuron

Neurons • Neurons “fire” -- send an impulse down their length -- or they don’t “fire” • Neurons come in a variety of shapes, sizes, etc.

Parts of the Neuron

Parts of the Neuron - Dendrites

Parts of the Neuron - Soma

Parts of the Neuron - Axon

Parts of the Neuron – Myelin Sheath

Parts of the Neuron - Terminals

Neuron

Candy Neuron Activity • Sign up for what to bring

Neural Communication: The Neural Impulse

Action Potential • A brief electrical charge that travels down the axon of the neuron. • A neural impulse • Considered an “on” condition of the neuron

$Refractory Period • The “recharging phase” when a neuron, after firing, cannot generate another$

Refractory Period • The “recharging phase” when a neuron, after firing, cannot generate another action potential • Once the refractory period is complete the neuron can fire again

Resting Potential • The state of a neuron when it is at rest and capable of generating an action potential • The neuron is set and ready to fire

Steps of Action Potential • Dendrites receive neurotransmitter from another neuron across the synapse. • Reached its threshold- then fires based on the all -or-none response. • Opens up a portal in axon, and lets in positive ions (Sodium) which mix with negative ions (Potassium) that is already inside the axon (thus Neurons at rest have a slightly negative charge). • The mixing of + and – ions causes an electrical charge that opens up the next portal (letting in more K) while closing the original portal. • Process continues down axon to the axon terminal. • Terminal buttons turns electrical charge into chemical (neurotransmitter) and shoots message to next neuron across the synapse.

Neuron firing like a Toilet 1. Like a Neuron, a toilet has an action potential. When you flush, an “impulse” is sent down the sewer pipe

$Neuron firing like a Toilet 2. Like a neuron, a toilet has a refractory$

Neuron firing like a Toilet 2. Like a neuron, a toilet has a refractory period. There is a short delay after flushing when the toilet cannot be flushed again because the tank is being refilled

Neuron firing like a Toilet 3. Like a Neuron, a toilet has a resting potential. The toilet is “charged” when there is water in the tank and it is capable of being flushed again 4. Like a Neuron, a toilet operates on the all-or-none principle – it always flushes with the same intensity, no matter how much force you apply to the handle

All-or-None Principle • The principle that if a neuron fires it will always fire at the same intensity • All action potentials are of the same strength. • A neuron does NOT fire at 30%, 45% or 90% but at 100% each time it fires.

Module 9: Neural and Hormonal Systems Communication Between Neurons

Synapse • The tiny, fluid filled gap between the axon terminal of one neuron and the dendrite of another neuron • The action potential cannot jump the gap

Neurotransmitters • A chemical messenger that travels across the synapse from one neuron to the next • Can influence whether the second neuron will generate an action potential or not

Neurotransmitters

Common Neurotransmitters & Functions Neurotransmitter Function Examples of Malfunctions Acetylcholine (ACh) Muscle action, learning, memory Deterioration assoc with Alzheimer’s disease Dopamine Movement, learning, emotion, attention Excess receptors assoc with Schizophrenia; Lack produces Pakinson’s disease Serotonin Mood, hunger, sleep, arousal Undersupply linked to depression; Prozac used to raise levels Norepinephrine Controls alertness & arousal Undersupply can depress mood GABA (gamma aminobutyric acid) Major inhibitory NT Undersupply linked to seizures, tremors, insomnia Glutamate Major excitatory NT Oversupply produces migraines/seizures.

Excitatory Effect • A neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential (impulse) • The second neuron is more likely to fire.

Inhibitory Effect • A neurotransmitter effect that makes it less likely that the receiving neuron will generate an action potential (impulse) • The second neuron is less likely to fire.

Threshold • The level of stimulation required to trigger a neural impulse.

How drugs alter neurotransmitters • Affected at the synapses by either blocking or amplifying NT activity. • AGONIST- amplify normal sensations of arousal or pleasure • ANTAGONIST- block NT functioning; can cause paralysis

How Neuron’s work video https: //www. youtube. com/watch? v=FR 4 S 1 B qd. FG 4&feature=related

Neuron Dance! https: //www. youtube. com/watch? v=mc. Q 1 H 4 K 64 k. A

Module 9: Neural and Hormonal Systems Neural Communication: The Neural Chain

Receptor Cells • Specialized cells in the sensory systems of the body that can turn other kinds of energy into action potentials that the nervous system can process • Receptor cells in the eye turn light into a neural impulse the brain understands.

Sensory Nerves (aka AFFERANT) • Nerves that carry information to the central nervous system • Connect the sense organs to the brain and spinal cord

Interneurons • Nerve cells in the brain and spinal cord responsible for processing information related to sensory input and motor output

Motor Nerves (aka EFFERANT) • Nerves that carry information from the central nervous system • Carries messages from the brain and spinal cord to other parts of your body

A Neural Chain

Module 10: Neural and Hormonal Systems The Structure of the Nervous System

The Nervous System

Central Nervous System (CNS) • The brain and spinal cord • The brain is the location of most information processing. • The spinal cord is the main pathway to and from the brain.