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??