neuroscience and behavior - s. buck home · parts of a neuron • dendrites - bushy fibers on the...

Neuroscience and Behavior T/F: We only use 10% of our brains: Lucy

It’s all about the body! crash course

Neural Communication

Neuron – a nerve cell; “building block” of the nervous system Icons of Science

Opening Activity

• Draw and label a Neuron

• Markers & colored pencils are in the back

Parts of a Neuron • Dendrites - bushy fibers on the neuron that

receive messages and conduct impulses

toward the cell body

• Cell Body - the nerve cell’s life-support

system (also known as the Soma)

• Axons - long fiber that passes messages to

other neurons or to muscles & glands

• Myelin Sheath - fatty tissue that encases the

axon to speed up transmission of messages

• degeneration of myelin sheath results in

loss of muscle control (Multiple Sclerosis)

Neuroanatomy (include glial cells)

Khan Academy, stop @ 3:30

Neuroanatomy

• Synapse – the junction (space) between the axon of one neuron and the dendrite of another

• Neurotransmitter – chemicals that carry messages across the synapse from one neuron to another

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How a Neuron Fires Khan: stop @ 4:45

• an electrochemical process – Electrical inside the neuron; chemical

outside the neuron (neurotransmitters).

• called an action potential • an “all or nothing” process

– like a gun

– greater intensity of stimulus does not equal faster/more intense firing; greater stimulus can mean more neurons firing or more frequent firing

Action Potential 1. Resting Potential - the neuron is ready to

fire 2. Reaches its threshold , then fires based on

the all-or-none response 3. Polarization Depolarization

a) opens up portals in axon letting in positive ions (Sodium) which mix with negative ions (Potassium) that are already inside the axon

b) process continues down axon to the axon terminal

4. Terminal buttons convert electrical charge into chemical response (neurotransmitter) and sends message to next neuron, across the synapse

Action Potential 1. Resting Potential - the neuron is ready to

fire 2. Reaches its threshold , then fires based on

the all-or-none response 3. Action Potential – Neuron fires, sends

electrical impulse down axon to next neuron, muscle, or gland

Action Potential

The Role of Neurotransmitters

•Excitatory - neurotransmitter effect that makes it more likely that the receiving neuron will generate an action potential or “fire”

•Inhibitory - neurotransmitter effect that makes it less likely that the receiving neuron will generate an action potential or “fire”

SPECIFIC NEUROTRANSMITTERS

Acetylcholine (ACh)

• vital role in movement and memory

• too much – muscle contractions, convulsions – some spider venoms cause

floods of ACh

• too little – immobility, extreme lethargy – Botulin causes paralysis by

blocking its release

• Undersupply of ACh has been linked to Alzheimer’s disease

PET Scan

Shows glucose levels in brain

Provided by UC Berkley

Department of Neuroscience

Dopamine

• deals with movement, learning, attention & emotion

• lack of dopamine has been linked to Parkinson’s Disease

• too much has been linked to Schizophrenia

Serotonin

• involved in mood control, hunger, sleep / arousal

• lack of serotonin has been linked to clinical depression (Prozac and other antidepressants raise serotonin levels)

Endorphins

• can produce feelings of euphoria

• involved in pain control

• Exercise can cause endorphin release “Runner’s High”

• most addictive drugs work with endorphins

Neurotransmission Drugs • Agonists - mimics / blocks reuptake / excites

• Antagonists - prevents release / blocks / inhibits

Types of Neurons Khan;start @ 4:50

• Efferent (Motor) Neurons – info to body parts for movement

• Interneurons – info within central nervous

system

• Afferent (Sensory) Neurons – info to CNS from body parts

• Remember… S.A.M.E.

Types of Neurons

A Neural Chain

A Neural Chain

A Neural Chain

A Neural Chain

The Nervous System crash course

Khan

Central Nervous System

• brain and spinal cord

• CNS

Peripheral Nervous System

• all nerves that are not encased in bone

• everything but the brain and spinal cord

• divided into two categories – somatic

– autonomic

Somatic Nervous System

• controls voluntary muscle movement

• uses motor (efferent) neurons

Autonomic Nervous System

• controls the automatic functions of the body

• divided into two categories – sympathetic

– parasympathetic

Sympathetic Nervous System

• “Fight or Flight” response

• automatically accelerates heart rate, breathing, dilates pupils, slows down digestion

Parasympathetic Nervous System

• automatically calms the body down after a stressful event

• heart rate and breathing slow down, pupils constrict, and digestion speeds up

• think, “parachute”

Reflexes

• normally, afferent neurons spine brain & brain sends orders for movement efferent neurons

• some reactions occur when sensory neurons reach just the spinal cord & spinal cord sends orders

brain rap

Neural Networks fact or fiction? crash course: brain

• interconnected neurons

• regular connections or routes of communication for different tasks, processes, etc.

• body/brain “learns” networks over time

• “muscle memory” in sports (“practice makes permanent”)

• answer

Ways to Study the Brain

• Case Studies / Clinical Observation – Accidents (i.e. –

Phinneas Gage)

– Diseases / Disorders

Invasive Exploration

• Lesion - a natural or man-made destruction of brain tissue

• Electrical Probing • Psychosurgery

Less Invasive Methods

• Electroencephalogram (EEG)

• Computerized Axial Tomography (CAT Scan / CT Scan)

• Magnetic Resonance Imaging (MRI)

• Positron Emission Tomography (PET)

• Functional MRI (fMRI)

The Brain Pinky & the Brain

• made up of… – neurons

– glial cells (or glia - support neural cells by insulating them, removing waste, etc.)

– connective tissues

– cerebrospinal fluid

• can be divided into three major sections: hindbrain, midbrain, forebrain

"Playdough" brain

Brain Structures brain mneumonics

• Be familiar with functions/roles.

• Location / ability to label might be helpful, but not required.

Brainstem • Pons - involved in sleep,

arousal, facial recognition

• Medulla Oblongata located just above the spinal

cord

involved in the control of heart rate, blood pressure, respiration.

• Reticular Formation - arousal and ability to focus attention

Cerebellum

• coordinates voluntary muscle movements

• balance/coordination

• injury = difficulty walking, keeping balance, shaking hands, etc.

Thalamus switchboard example

• Receives sensory information and sends them to appropriate areas of forebrain.

• Like a switchboard.

• Everything but smell.

Limbic System #24

• EMOTIONAL

CONTROL CENTER of the brain.

• Made up of Hypothalamus, Amygdala and Hippocampus.

Hypothalamus • Pea sized in brain,

but plays a not so pea sized role.

• Body temperature

• Hunger

• Thirst

• Sexual Arousal (libido)

• Endocrine System

Hippocampus and Amygdala

• Hippocampus is involved in forming new memories.

• Amygdala is vital for our basic emotions.

Cerebral Cortex

• Top layer of our brain.

• Contains wrinkles called fissures.

• The fissures increase surface area of our brain.

• Laid out it would be about the size of a large pizza.

Hemispheres

• Divided into a left and right hemisphere.

• Contralateral controlled- left controls right side of body and vice versa.

• Brain Lateralization.

Split-Brain Patients

• Corpus Collosum attaches the two hemispheres of cerebral cortex.

• right & left sides working together?

• When removed (usually b/c of severe seizures) you have a split-brain patient. #5

Areas of the Cerebral Cortex

• Divided into eight lobes, four in each hemisphere (frontal, parietal, occipital and temporal).

• Any area not dealing with our senses or muscle movements are called association areas.

Frontal Lobe

• Deals with planning, maintaining emotional control and abstract thought.

• Contains Broca’s Area.

• Broca’s Aphasia.

• Contains Motor Cortex.

Parietal Lobes

• Located at the top of our head.

• Contains the somato-sensory cortex.

• Rest are association areas (intelligence!).

Occipital Lobes

• In the back of our head.

• Handles visual input from eyes.

• Right half of each retina goes to left occipital lobe and vice versa.

Temporal Lobes

• Process sound sensed by ears.

• Not lateralized.

• Contains Wernicke’s area.

• Wernicke’s Aphasia.

Brain Plasticity # 7

• ability of our brains to form new connections (repair itself) after being damaged

• the younger you are, the more “plastic” your brain is

The Endocrine System

a system of glands that secrete

hormones into the bloodstream

similar to nervous system, except

hormones work a lot slower than

neurotransmitters

Neurotransmitters

Hormones

Endocrine System

• System of glands that secrete hormones.

• Controlled by the hypothalamus.

• Ovaries and Testes.

• Adrenal Gland

• Epinephrine-energy boast (adrenaline)

• hold your stomach!

So what’s the REAL significance of this chapter??