Unit 2

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UNIT 2
Neuroscience
& the Brain
BIOLOGICAL PSYCHOLOGY
Study the link between biological activity and psychological events
Branch of psychology concerned with the links between biology and
behavior
Examples – behavioral geneticists, behavioral neuroscientists,
biopsychologists, etc.
NEURAL COMMUNICATION
Neuron – a nerve cell, basic building block of the nervous system
Each consists of a cell body and its branching fibers
Dendrite – neuron’s bushy, branching extensions that receive messages
and conduct impulses toward the cell body
DENDRITES LISTEN – brings info in
Axon – neuron extension that passes messages through its branches to
other neurons or to muscles/glands
AXONS SPEAK – sends message (to other neurons or muscles or glands)
NEURAL COMMUNICATION
Myelin sheath – fatty tissue layer that
insulates some axons
Speeds their impulses
Fully laid down around 25 – neural efficiency,
judgment and self-control grow
Degeneration = multiple sclerosis –
communication to muscles slow – loss of muscle
control
ACTION POTENTIAL
neural impulse – brief electrical charge that travels down axon
Speed varies – 2mph – 180mph
Time to react and take action
Neurons are like batteries – generate electricity
Inside axon = +ions
Outside axon = -ions
Resting potential – even # of + and –
 like a gate – no message sent
Depolarization – unfreezes the axon [gate] allowing the message to send
Refractory period – resting period – when extra atoms are pushed out
THRESHOLD
The level of stimulation required to trigger a neural
impulse – action potential
When excitatory ions minus the inhibitory ions exceed
minimum intensity (threshold), the neuron fires an action
potential.
ALL OR NONE RESPONSE – either fire or don’t (full
strength)
NEURAL FIRING AND A TOILET…
1. Like a neuron, a toilet has an “ action potential ”. When
you flush, an “impulse” is sent down a sewer pipe.
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.
3. Like a neuron, a toilet has a resting potential . The toilet
is “charged” when the tank is full and it is capable of
being flushed again.
NEURAL FIRING AND A TOILET…
Like a neuron, a toilet operates on an all - or - none
principle . It always flushes with the same intensity, no
matter how much force you apply to the handle.
Q: So how can we tell the difference between a love tap
and a punch??
A: Because the NUMBER of neurons that fire depend on
the intensity of the stimulation. So, the intensity is based on
how many neurons fire. They all fire at the same intensity.
SYNAPSE
The junction between the
axon tip of the sending
neuron and the dendrite or
cell body of the receiving
neuron
Synaptic gap – tiny gap
 Air kisses
Neurons send info through
synaptic gap with
neurotransmitters
NEUROTRANSMITTERS
Chemical messengers that cross the synaptic gap between
neurons
 Bind to receptor sites – fit like a lock and key
 Ions flow in - a neuron’s readiness to fire
 Excitatory
 Inhibitory
Reuptake – a neurotransmitter’s reabsorption by the sending
neuron
 Get sucked back up and used in next message
NEUROTRANSMITTERS
Each pathway uses different neurotransmitters, each
neurotransmitter has a different function
===================================
Take 15ish minutes and complete your neurotransmitters
chart with a partner. Explain each neurotransmitter’s
function as well as provide an example for the malfunction
HOW DRUGS EFFECT NEUROTRANSMITTERS
Many drugs mimic the neurotransmitter
Agonist vs. antagonist
Agonist – excitatory – increases effect of
neurotransmitter (mimics)
Opiate drugs
Glutamate
Amphetamines
Antagonist – inhibitory – slow down the effect of
neurotransmitter (destroy connections or block them)
Botox – smooth wrinkles by paralyzing underlying
facial muscles
GABA
Alcohol
Neurotransmitter
molecule
Receptor site on
receiving neuron
Receiving cell
membrane
Agonist mimics
neurotransmitter
Antagonist
blocks
neurotransmitter
THE NERVOUS SYSTEM
Body’s speedy,
electrochemical
communication network
consisting of all nerve
cells of PNS and CNS
o2 parts
oCentral Nervous System
oPeripheral Nervous System
oThe nervous system uses 3
types of neurons
o1. sensory
o2. interneurons
o3. motor neurons
THE NERVOUS SYSTEM
Nerves – bundled axons that form neural “cables” connecting the CNS with
muscles, glands, and sense organs
3 types of neurons
 1. sensory – carry incoming info from body’s tissues and sensory receptors to
brain and spinal cord
 MILLIONS
 AFFERENT
 2. interneurons – communication that takes place internally and intervene between
sensory input and motor output
 BILLIONS
 3. motor neurons – carry outgoing info from brain and spinal cord (CNS) –
muscles/glands
 MILLIONS
 EFFERENT
THE NERVOUS SYSTEM – CNS & PNS
CNS – brain and spinal cord
Body’s decision maker
Spine connects PNS to brain
Reflex – simple, automatic response to a sensory stimulus, such as
the knee-jerk response
PNS – the sensory and motor neurons that connect
the CNS to the rest of the body
Responsible for gathering info and sending CNS decisions
PERIPHERAL NERVOUS SYSTEM
SOMATIC NERVOUS SYSTEM
AUTONOMIC NERVOUS SYSTEM
Control’s the body’s skeletal
muscles - voluntary
Controls our glands and the
muscles of our internal organs,
influencing such functions as
heartbeat, digestion, and
hormones
aka skeletal nervous system
Bell rings at the end of class –
SNS reports to brain – carries
instructions back – triggering
your body to rise from your seat
Autopilot – operates on its own –
autonomously
AUTONOMIC NERVOUS SYSTEM
SYMPATHETIC NERVOUS SYSTEM
*arouses the body
*mobilizes its energy in stressful
situations
*accelerated heartbeat
PARASYMPATHETIC NERVOUS SYSTEM
*raise blood pressure
*calms the body
*slows digestion
*conserves its energy
*decreased heartbeat
*lowering blood sugar
TOOLS OF DISCOVERY
THE BRAIN
TOOLS OF DISCOVERY
Manipulating the brain –
Lesions
electromagnetic charges
 chemical and magnetic stimulation
Clinical Observations
- looking at damaged brains
Recording Electrical Activity EEG (
electroencephslogram)
an amplified recording of the waves of electrical activity
that sweep across the brain’s surface
TOOLS OF DISCOVERY
Neuroimaging-
CT (Computed tomography) ScanX- Ray photographs
PET (Positron emission tomography) Scan
Looks at sugar glucose to determine brain activity
“HOT SPOTS”
MRI- (Magnetic Resonance Imaging)
generated images that distinguish among different types of soft
tissue; allows us to see structures within the brain.
PET SCAN
LOWER LEVEL BRAIN STRUCTURE
LOWER BRAIN
Lower Brainperforms life saving operations freeing the higher
brain regions to think, dream, memorize..
We are unaware of most of its functions
LOWER LEVEL BRAIN STRUCTURE
THE BRAINSTEM
1. Brainstem where spinal cord enters the skull
 Crossover point for nerves
 responsible for automatic survival functions
2. Medulla- Heartbeat and breathing
LOWER LEVEL BRAIN STRUCTURE
THE BRAINSTEM
3. Reticular Formation-
 Filter and relay station
 Controls arousal
4. Thalamus-
 Sensory input station, except
smell
 Receives higher brains replies
 Controls electrical cycles. Slows
during sleep; speeds up while
awake
LOWER LEVEL BRAIN STRUCTURE
THE BRAINSTEM
5. The Cerebellum
Coordinates voluntary movements
Balancing, walking……….
Nonverbal voluntary movement
6. Pons
Regulates sleep
THE LIMBIC SYSTEM
THE LIMBIC SYSTEM
associated with emotions such as fear and
aggression and drives such as those for food
and sex
includes the hippocampus, amygdala, and
hypothalamus.
THE LIMBIC SYSTEM
1. Hippocampus-
Processes memory
Forms new memories
2.
Amygdala-
Aggression and fear
THE LIMBIC SYSTEM
3. Hypothalamus-
Controls pituitary gland (hormones)
directs several maintenance activities
eating
drinking
body temperature
Triggers autonomic nervous system
Pleasure Center
Reward Deficiency Syndrome- alcoholism, binge
drinking, drug abuse
THE CEREBRAL CORTEX
Thin layer covering your cerebral
hemispheres- wrinkly thing
Neural cells
Controls body and info
The bigger the better
THE CEREBRAL CORTEX
Structure and Functions
1. Each hemisphere is divided up into 4 lobes




2.
Frontal
Occipital
Temporal
Parietal
Glial Cells- -


neural nannies
Support the 22 billion nerve cells
THE CEREBRAL CORTEX
1. Frontal Lobespeaking, muscle
movement, making plans,
judgments
Motor Cortexoutgoing messages
to the body
THE CEREBRAL CORTEX
2.Parietal Lobe- sensory cortex
Sensory Cortex-registers and processes
body sensations
Receives info from skin receptors
More sensitive= bigger area
3.Occipital Lobe- receives visual from opposite sides
THE CEREBRAL CORTEX
4.Temporal Lobes- receive auditory simulation
from opposite sides
Don’t need real sounds
Functional MRI
scan of the
visual cortex
activated by
light shown in
the subject’s
eyes
Visual
cortex
Auditory
cortex
THE CEREBRAL CORTEX
Association Areasareas of the
cerebral cortex that
are not involved in
primary motor or
sensory functions
involved in higher
mental functions
such as learning,
remembering,
thinking, and
speaking
ASSOCIATION AREAS
Aphasia
 impairment of language, usually caused by left hemisphere damage either to Broca’s
area (impairing speaking) or to Wernicke’s area (impairing understanding)
Broca’s Area
 an area of the left frontal lobe that directs the muscle movements involved in speech
Wernicke’s Area
 an area of the left temporal lobe involved in language comprehension
Angular Gyrus-auditory sounds
THE CEREBRAL CORTEX
Brain activity when hearing,
seeing, and speaking words
BRAIN REORGANIZATION
Plasticity- neural tissue can reorganize
in response to damage
Orgasm in foot
Most plastic when young
OUR DIVIDED BRAIN
Corpus callosum
Corpus Callosum
largest bundle of
neural fibers
connects the two brain
hemispheres
carries messages
between the
hemispheres
SPLIT BRAIN
a condition in which the two hemispheres of the
brain are isolated by cutting the connecting
fibers (mainly those of the corpus callosum)
between them
“alien hand syndrome”
HEMISPHERIC DIFFERENCES
Specialization
Each hemisphere has its own specialties
Most people are stronger in one
hemisphere
Left- logical, verbal, sequential
Right- emotional, expressive, better at
spatial relations
HANDEDNESS
90% right handed
Percentage of 14%
left-handedness
12
The percentage of
lefties sharply
declines with age
10
8
6
4
2
0
10
20
30
40
50
Age in years
60
70
80
90
NEURAL AND HORMONAL SYSTEMS
Endocrine System
the body’s “slow”
chemical communication
system
a set of glands that
secrete hormones into the
bloodstream
ENDOCRINE SYSTEM
Hormones
chemical messengers, mostly those manufactured by
the endocrine glands, that are produced in one
tissue and affect another
Growth, reproduction, metabolism, mood………
ENDOCRINE SYSTEM
Adrenal Glands
a pair of endocrine glands just above the
kidneys
secrete the hormones epinephrine
(adrenaline) and norepinephrine
(noradrenaline), which help to arouse the
body in times of stress
Increases heart beat, blood pressure, blood
sugar….. Gives us energy
ENDOCRINE SYSTEM
Pituitary Gland
under the influence of the hypothalamus, the
pituitary regulates growth and controls other
endocrine glands
Master gland
OTHER HORMONES/GLANDS
1. Pineal Gland


Produces melatonin
regulates circadian rhythms
Seasonal Affective disorder
2. Thyroid-
 Maintains metabolic activities
 Lack of thyronixe= mental retardation in
children
3. Pancreas-
releases insulin and glucagon which regulates blood sugar
OTHER HORMONES /GLANDS
4. Gonads-
Testis and Ovaries
Release estrogen and testosterone
Half a brain
http://www.youtube.com/watch?v=2MKNsI5CWoU&safety_mode=true&persist_safety_mode=1&safe=active
Pituitary Gland
http://www.cnn.com/video/?hpt=hp_c2#/video/health/2012/09/01/dnt-nv-woman-gigantism-disease.ktnv
Split brain
http://www.youtube.com/watch?v=aCv4K5aStdU&safety_mode=true&persist_safety_mode=1&safe=active
Left or right
http://www.youtube.com/watch?v=feAikjPqOq8
Concussions
http://espn.go.com/espn/otl/story/_/id/9931754/former-nfl-stars-tony-dorsett-leonard-marshall-joe-delameilleure-show-indicators-cte-resultingfootball-concussions
http://content.time.com/time/video/player/0,32068,64253995001_1957921,00.html
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