Download Chapter 2 - Neurophysiology

AP Notes, ’15: Chapter 2 – Neuroscience and the Brain
Central principle: ultimate challenge: recency – phrenology…
Neural Communication – bottom up (top down is chapter 6…)
-Neurons – dendrite  (cell body)  axon; myelin sheath, multiple sclerosis;
-action potential details: chemistry to electricity, sodium pump, ions, resting potential, selectively
permeable, depolarization, refractory period; cell body decision -- excitatory versus inhibitory
signals: all-or-none response
-synapse / synaptic gap / synaptic cleft – neurotransmitters, release / reuptake – from vesicles in the
terminal buttons (of axon!)
-major neurotransmitters: acetylcholine, dopamine, serotonin, norepinephrine, GABA, glutamate, endorphins
/morphine – and basics for each
agonists, antagonists: blood-brain barrier; L-dopa
The Nervous System – CNS, PNS (figure 2.7, 2.8)
-Peripheral Nervous System: somatic (AKA voluntary), autonomic composed of sympathetic and
parasympathetic
-composed of sensory (in), motor (out)
-Central Nervous System: interneurons
- reflex (figure 2.9)
-neural networks
-The Endocrine System: hormones – pituitary gland! (versus neurotransmitters…) – others, figure 2.11
-The Brain: what, where, how do we know…
-The Tools of Discovery – clinical observation, lesions, stimulation – EEG (electroencephalogram), CT scan
(computed tomography), PET scan (positron emission tomography, MRI (magnetic resonance imaging), fMRI
(functional magnetic resonance imaging) – what and how for each
Structures: (mostly on the handout…)
-size, complexity
-The Brainstem – medulla, reticular formation (AKA Reticular Activating System), pons, thalamus,
cerebellum
-The Limbic System: hippocampus, amygdala, hypothalamus, pituitary gland
– reward deficiency syndrome
-Cerebrum  Cerebral Cortex: glial cells, lobes – frontal, parietal, occipital, temporal (FPOT); motor
cortex, sensory cortex, neural prosthetics, association areas, Phineas Gage!;
-Neural Networks: reading / language circuit: aphasia; angular gyrus  Wernicke’s area  Broca’s
area  motor cortex
-plasticity, hemispheres – corpus callosum, split brain patients – hemispherectomy
-left hemisphere:
-right hemisphere:
- organization, function, complexity – “Left Brain / Right Brain” article issue; left-handedness
AP Notes, ’15 Chapter 2 – Neuroscience and the Brain – with spaces
Central principle: ultimate challenge: recency – phrenology…
Neural Communication – bottom up (top down is chapter 6…)
-Neurons – dendrite  (cell body)  axon; myelin sheath, multiple sclerosis;
-action potential details: chemistry to electricity, sodium pump, ions, resting potential, selectively
permeable, depolarization, refractory period; cell body decision -- excitatory versus inhibitory
signals: all-or-none response
-synapse / synaptic gap / synaptic cleft – neurotransmitters, release / reuptake – from vesicles in the
terminal buttons (of axon!)
-major neurotransmitters: acetylcholine, dopamine, serotonin, norepinephrine, GABA, glutamate, endorphins
/morphine – and basics for each
agonists, antagonists: blood-brain barrier; L-dopa
The Nervous System – CNS, PNS (figure 2.7, 2.8)
-Peripheral Nervous System: somatic (AKA voluntary), autonomic composed of sympathetic and
parasympathetic
-composed of sensory (in), motor (out)
-Central Nervous System: interneurons
- reflex (figure 2.9)
-neural networks
-The Endocrine System: hormones – pituitary gland! (versus neurotransmitters…) – others, figure 2.11
-The Brain: what, where, how do we know…
-The Tools of Discovery – clinical observation, lesions, stimulation – EEG (electroencephalogram), CT scan
(computed tomography), PET scan (positron emission tomography, MRI (magnetic resonance imaging), fMRI
(functional magnetic resonance imaging) – what and how for each
Structures: (mostly on the handout…)
-size, complexity
-The Brainstem – medulla, reticular formation (AKA Reticular Activating System), pons, thalamus,
cerebellum
-The Limbic System: hippocampus, amygdala, hypothalamus, pituitary gland
– reward deficiency syndrome
-Cerebrum  Cerebral Cortex: glial cells, lobes – frontal, parietal, occipital, temporal (FPOT); motor
cortex, sensory cortex, neural prosthetics, association areas, Phineas Gage!;
-Neural Networks: reading / language circuit: aphasia; angular gyrus  Wernicke’s area  Broca’s
area  motor cortex
-plasticity, hemispheres – corpus callosum, split brain patients – hemispherectomy
-left hemisphere:
-right hemisphere:
- organization, function, complexity – “Left Brain / Right Brain” article issue; left-handedness
Chapter 2 Neuroscience and Behavior – complete notes
 Body composed of cells; nerve cells that conduct electricity
 Biological psychologists are concerned with the links between biology and behavior
Phrenology: bumps on head correspond to personality traits… wrong!
I.
Neural Communications
 Body built of neurons (interconnected cells)
 We are biopsychosocial systems
 Similarities in humans and monkeys allow researchers to study relatively simple animals (i.e. squid)
-Animal nervous system and neural systems are similar
Objective: People’s thoughts and emotions interact with their biology and person history to produce a unique
individual. Scientists gain much of their study of neural systems in other mammals because humans and
animals have similar neural systems
A. Neurons
 Body built of neurons nerve cells
 Dendrite; bushy fibers, receive information and conducts it towards the body
 Axon; pass information from dendrite to other neurons sometimes very long
 Motorneurons control muscles
 The myelin sheath fat that insulates the axons of some neurons (protects your brain; fat head, literally)
- Multiple sclerosis is a result of the deteriorating myelin sheath, slows all communication to the muscles
along with loss of muscle control
 Brain activity measured in milliseconds
 A neuron fired (an impulse) when it receives signals from sense receptors stimulated by pressure, heat or
light
 If stimulated by chemical messages from other neurons it is called action potential
 Neurons generate electricity from chemical events
 The fluid below a resting axon has an excess if negatively charged ions
 The fluid outside the axon has positively charged ions
 Positive outside negative inside is called resting potential
 A resting axon has gates that block positive sodium ions
-The axons surface is selectively permeable
 Axons gates open  positive charged sodium ions flood through the membrane
 Depolarizes the axon the axon’s next channel opens
 During resting, pause; (refractory period) neuron pumps positively charged sodium ions back
-Excitatory; pushing a neurons accelerator
-Inhibitory; pushing its break (stopping it)
 Threshold- the level of stimulation required to trigger a neural impulse
 Increasing the stimulus above the threshold does not increase the action potential; it either happens or not –
all-or-none
Objective: Body’s circulatory system consists billions of cells; neurons, they send signals through their axon
(sometimes encased in the myelin sheath). Receive signals through the dendrites and their cell body. If strong
enough, signal fires, transmitting and electrical impulse (action potential).
B. How Neurons Communicate
 Synapse; synaptic gap or cleft
 The junction between the axon tip of the sending neuron and the dendrite receiving neurons
 Synapse is the reason for the pause of electrically charge
 Action potential reaches its end point, triggering neurotransmitters
Objective: When action potential reaches end of the axon, they stimulate the release of neurotransmitters. They
carry messages from the sending neuron across a synapse to a site on a receiving neuron. Again, if strong
enough it generates its own action potential and sends the messages to other cells.
C. How Neurotransmitters Influence Us
 Neural pathway in the brain may only use only one or tow neurotransmitters
 (ACh)Acetylcholine
-Neurotransmitters
Neurotransmitters
Acetylcholine (Ach)
Dopamine
Serotonin
Norpinephrine
GABA
Glutamate
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
Function
Enable muscle action, learning
memory
Influences movements, learning,
attention, emotion
Example
Alzheimer’s disease, ACh neurons deteriorate
Mod, hunger sleep, arousal
depression
Controls alertness and arousal
adrenaline
Major inhibitory neurotransmitter
STOP
Major excitatory neurotransmitter,
memory
Undersupply linked to depression, to raise levels
take Prozac
Not enough can cause depression
Excessive leads to schizophrenia, tremors and
decreased mobility Parkinson’s
Not enough can cause seizures, tremors and
insomnia
Over supply can over stimulate brain, producing
migraines, seizures (people avoid MSG)
Ach: Role of learning and memory
Messenger at every junction between a motor neuron and skeletal muscle (If blocked, muscles cannot
contract.)
 Candace Pert and Solomon Snyder discovery
-Radioactive tracer to morphine, show where it takes up room in brain
 Morphine bound to receptors in areas linked with mood and pain sensations
 Endorphins; “Morphine within”
 Brain contains many neurotransmitters like morphine
Objective: Each neurotransmitter has an effect on behavior and emotions. ACh, affects muscle action, learning
and memory. Endorphins are natural opiates release in repose of pain and exercise (runner’s high).
D. How Drugs and Other Chemicals Alter Neurotransmission
 If the brain is filled with opiate drugs, can stop producing its own opiate
 Agonist  mimics its effect or blocks its reuptake (Excites)
 Antagonists  inhibits a neurotransmitters release (Inhibits)
 Blood brain barrier; enables brain to fence out unwanted chemicals circulating blood.
Objective: drugs and other chemicals affect communication at the synapse. Agonists excite by mimicking
neurotransmitters or block their reuptake. Antagonists (i.e. curare) inhibit neurotransmitters release or block its
effect.
II.
The Nervous System
 Neurons are the elementary components of out nervous system
 Central Nervous system; Brain and spinal cord
 Peripheral Nervous system; Links the central nervous system with the body’s sense receptors muscles and
glands
 Nerves are bundled axons.
 Sensory neurons Sends information from body’s tissues and sensory organs to the central nervous system
(processes information)
 Motor neurons receive the information form the sensory neurons
 Interneurons communicate and intervene between the sensory input and motor output
Objective: Divisions of the nervous system: central nervous system; consists of the brain and spinal cord.
Peripheral nervous system; consists of the neurons that connect the CNS to the rest of the body. Sensory
neurons carry information to the sense receptors in the CNS and motorneurons carry information from the CNS
to muscles and glands.
A. The Peripheral Nervous System
 Two components
 Somatic and autonomic
 Somatic; voluntary control of our muscles
 Autonomic; controls glands and muscles of out internal organs
 Operates on its own (unconsciously)
 Two parts of autonomic  Sympathetic and parasympathetic
 Sympathetic; arousal -- adrenaline
 Parasympathetic; calming – conserves energy
Objective: Somatic- voluntary control of the skeletal muscles. Autonomic sympathetic and parasympathetic
controls involuntary control of skeletal.
B. Central Nervous System
 Tens of bullions neurons, communications with other neurons
C. The Spinal Cord and Reflexes
 An information highway—connects peripheral nervous system to the brain
 Ascendingsends up sensory information
 Descendingsends back motor control information
 Reflexes; automatic responses to stimuli, illustrate the spinal cord work
 Spinal reflex is composed of single sensory neuron and signal neuron
 Pain reflex; interneuron respond by activating motor neurons to the muscles in your arm
 To produce bodily pain or pleasure the sensory information must reach the brain
D. The Brain and Neural Networks
 Brian; receives information, interprets it, decides responses
 Neuron connect with thousands of others (little brains within your big brain)
 Clustered neurons are in groups called neural networks
 Learning occurs as feedback strengthens connections that produce certain results
Objective: Reflex pathways are automatic inborn responses to stimuli and they do not rely on conscious
decisions made in the brain. A neuron can be excited by a stimulus and pass a message to an interneuron in the
spinal cord, then causing a muscle reaction. Neural networks are bundles of neurons that strengthen with use,
learning from experience.
III.
The Endocrine System
 The body’s “slow” chemical communication system
 Glands that secrete hormones into the bloodstream
 Hormones; originate in tissuetravel through blood stream affect tissue/brain
 Very slow system
 Are chemically identical to neurotransmitters
 Hormones influence our interest in food, sex, and aggression
 Hormones influence our growth, reproduction, metabolism, and mood
 Keeps everything in balance while we respond to stress
 Adrenal glandslocated on top of the kidneys
 Releases epinephrine and norepinephrine (Adrenaline and noradrenalin)
 Increase heart rate, blood pressure, blood sugarENERGY
 Pituitary gland; pea-sized structure located in the core of the brain
 Controlled by he hypothalamus
 Brainpituitaryother glands hormonesbrain
 Neurotransmitters can drift in the brain fluid’s to nerve receptors
 Affecting the overall alertness or mood transmitters
Objective: Set of glands the secrete hormones into the bloodstream. Chemical messengers travel through the
body and affect other tissues- the brain. Some hormones are chemically identical to neurotransmitters; the
endocrine system mater gland is the pituitary system which influences the hormones release by other glands.
Hypothalamuspituitaryother glandsinfluences the brain.
IV.
The Brain
 Enables the mind—seeing, hearing, smelling, feeling, remembering, thinking, speaking, dreaming
A. Tools of Discovery
 Lesion; tissue destruction
 Usually naturally or experimentally cause by destruction of brain tissue
1. Clinical Observations
 Right side of the body is weird to the left side of the brain, the left side of the brain is weird to the right side
of the brain.
 Back of the brain vision
 Left frontal part of the brain speech
2. Manipulating the brain
 Scientists can chemically or magnetically stimulate carious parts of the brain and note the effects.
3. Recording the Brains Electrical Activity
 The electroencephalogram (EEG) reads the electrical activity waves.
 Able to filter out brain activity unrelated to the stimulus people can identify the electrical wave evoked by
the stimulus
 Used for epilepsy
4. Neuroimaging Techniques
 PET (position emission tomography) scan; visual display of brain activity that detect a brains area of
glucose consumption
 Active neurons are glucose hogs
 MRI (Magnetic resonance imaging) scans; using magnetic fields and radio waves generates images
distinguishing different types of soft tissue
 Can reveal enlarges fluid filled brain areas in some patients who have a disabling psychological disorder
(Schizophrenia).
 fMRI (Functional MRI)
 Can reveal the brains functioning as well as its structure
 Can detect blood rushing to the back of the brain as a person performs different mental functions such as
looking at a persons face
 Snapshots are taken showing the brains changing activity
 CT scans-computed topography; photograph of the brain
Objective: EEG, MRI and fMRI all reveal general effects of damage to various parts of the brain. Lesioning or
electrically simulating specific brain areas, by recording the brains surface electrical activity by neural activity
with brain scans, neuroscientist are now able to make connections between the brain, mind and behavior.
B. Older Brain Structures
1. The Brainstem
 The brainstem is the oldest and innermost region
 Begins where the spinal cord enters the skull; slightly swelling to the medulla
 Brainstem is responsible for automatic survival functions
 If the brainstem is cut off the animal will still be able to breath and live.
 Above he medulla sits the pons; helps coordinate movements
 Brainstem is also the crossover point
 Between the ear lies the reticular “netlike” formation; a network of neurons that extend from the spinal
cord to the thalamus
 Controls arousal
 Giuseppe Moruzzi and Horace Magoun; discovered that electrically stimulating the reticular formation of a
sleeping cat instantly produced an awake alert animal
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2.
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3.
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Our brains are not idle when we sleep
The Thalamus
Egg shaped structure that sits on top of the brainstem
Directs messages to the sensory receiving areas in the cortex and transmits to the cerebellum and medulla
Receives information from all the senses except smell
The Cerebellum
Extends from the rear of the brainstem
“little brain”
Coordinates movements, nonverbal learning and movements, judge time, alter our emotions and tell apart
sounds and textures.
 “Our brain processes most information outside of our awareness”
Objective: brainstem survival functions. Medulla (heartbeat, breathing), pons (coordinate movements),
reticular formation (arousal). The thalamus is the brain’s sensory switchboard. Cerebellumcoordinates
muscle movements, help process sensory information
C. The Limbic System
 Doughnut shape, borders the brainstem and cerebral hemisphere
 Associated with emotions; fear and aggression and drives for food and sex
1. The Amygdala
 Influence aggression and fear both involve neural activity in all levels of the brain
 Lesions of the amygdala can change a mammal from calm to violent
2. The Hypothalamus
 A neural system lying below the thalamus
 Directs several maintenance activities (eating, drinking, body temperature)
 Helps govern the endocrine system- pituitary gland is linked to emotion
 Monitors blood chemistry and takes orders from other parts of the brain
 Cerebral cortex; can stimulate hormones
 James Olds and Peter Milnerrat experiment; stimulate upon a brain center that provides a pleasurable.
 Addictive disorders ma stem from reward deficiency syndrome; genetically disposed efficiency in the
neural brain systems for pleasure
Objective: Located between the brainstem and cerebral cortex. Linked to emotions, memory, and drives.
Amygdala, the hypothalamus; pleasurable rewards, hormonal system. Pituitary gland “master gland”
controls it by stimulating it to trigger the release of hormones. Hippocampusmemory (Hippo on campus
thinking).
D. The Cerebral Cortex
 Intricate covering of interconnected neural cells that form a thin layer on your cerebral hemisphere
 Body’s ultimate control and information processing center
 Larger cortexincreased capacities for learning and thinking, more acceptable.
1. Structure of the Cortex
 Eighty percent of the brain’s weight lies in the left and right cerebral hemispheres- filled with axon
connections
 Glila cells are cell in the nervous system that support, nourish and protect neurons “glue cells”
 FPOT “Flower pot” as Mr. Craig would say
 Frontal lobe; lying above the forehead speaking and muscle movements
 Parietal lobes; at the top and to the rearreceives sensory input for touch and body positions
 Occipital lobes; at the back of your head visual areas
 Temporal lobes; on the sides above the earsauditory
2. Functions of the Cortex
 Partially paralyzed/speechlessdamaged cortical areas
3. Motor Functions
 Stimulation caused movement only when applied to an arch-shaped region at the back of the motor cortex
 An area at the rear of the frontal lobes that controls voluntary movements

Fritch and Hitzig mapped the motor cortex according to the body parts they controlledThe fingers and
the mouth occupy the greatest amount of cortical space
4. Sensory Functions
 Parallel to the motor cortex is the sensory cortex; registers and processes body touch and movement
sensations
 More sensitive a body regionthe larger area of sensory cortex devoted to it
5. Association Areas
 Neurons in the association areas integrate information
 Associate various sensory inputs with stored memories; very important part of thinking
 Damage to frontal lobe can result in altered personality, unable to plan ahead to begin tasks
6. Language
 Aphasia impaired use of language
 Speak fluently- cannot read
 Comprehend what they read-cannot speak
 Can write but not read... ect.
 Broca’s area; controls language expression, an area of the frontal lobe
 Directs the muscle movement involved in speech
 Wernicke’s area; speaking only meaningless words
 Reading aloud involves a third brain area; angular gyrus
 Read aloud; register in the visual area relayed to second brainunderstood by Wernicke’s areasent to
Broca’s areacontrols the motor cortex; creates pronounced word
 Damage to the angular gyrus-unable to read but can understand
 Wernicke’s area-disrupts understanding
 Broca’s area- disrupts speaking
Objective: Language read aloud; visual cortex, angular gyrus; transforms visual representation into auditory
codes, Wernicke’s area; interprets codes sends to Broca’s area; controls motor cortexpronounced word.
7. The Brain’s Plasticity
 Plasticity; ability to modify itself after some types of damage
 Some neural tissue can reorganize in response to damage
 If one hemisphere is damaged in early life, others will pick up many of its functions
 Neurons transfer to other areas
V.
Our Brain Divided
A. Splitting the Brain
 Corpus callousum; large brand of neural fibers connecting the two brain hemispheres and carrying fibers
between them
 Vogel and Bogen; reduce patients seizures; with uncontrollable epilepsy
 Spilt brain; two hemisphere of the brain are isolated by cutting the connecting fibers between them
 Each hemisphere reports only what it sees
 Split brain patients report seeing portions of the word transmitted
 If pictures is flashed in the middle patients are not able to describe the object
 “two separate minds”
 Both hemispheres can comprehend and follow an instructions
 Left hemisphere is the interpreter
B. Studying Hemispheric Differences in the Intact Brain
 Person performs a perceptual talkbrain waves, blood flow and glucose consumption reveal increased
activity in the right hemisphere
 Hemispheric specialization, called lateralization
 People tend to recognize a picture faster when flashed to the right hemisphere
 People tend to recognize a word faster when flashed to the left hemisphere

Stroke in the left hemisphere will disrupt a deaf persons signing just as it would disrupt a hearing person’s
speaking
 Broca’s area spoken and signed speech
Objective: left cerebral hemisphere is crucial for language. Research of split brain have confirmed that in most
people the left hemisphere is the more verbal and the right excels in the visual perception and recognition of
emotion. People who are healthy show that each hemisphere makes unique contributions to the integrated
functioning of the brain.
C. Brain Organization and Handedness
 About 10 percent of us are left-handed; they tend to die younger!!!
 Right-handers process speech process speech in the left hemisphere
 So do left-handers
 The remainder of left-handers split evenly the processing language in the right hemisphere