unit 2 neuroscience & the brain. biological psychology study the link between biological...
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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 systemEach consists of a cell body and its branching fibers
Dendrite – neuron’s bushy, branching extensions that receive messages and conduct impulses toward the cell bodyDENDRITES LISTEN – brings info in
Axon – neuron extension that passes messages through its branches to other neurons or to muscles/glandsAXONS 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 POTENTIALneural impulse – brief electrical charge that travels down axonSpeed varies – 2mph – 180mph Time to react and take actionNeurons are like batteries – generate electricityInside axon = +ionsOutside axon = -ions Resting potential – even # of + and –
like a gate – no message sentDepolarization – 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 gapAir kisses
Neurons send info through synaptic gap with neurotransmitters
NEUROTRANSMITTERS
Chemical messengers that cross the synaptic gap between neuronsBind to receptor sites – fit like a lock and keyIons flow in - a neuron’s readiness to fire Excitatory Inhibitory
Reuptake – a neurotransmitter’s reabsorption by the sending neuronGet sucked back up and used in next message
NEUROTRANSMITTERS
Each pathway uses different neurotransmitters, each neurotransmitter has a different function
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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 neurotransmitterAgonist vs. antagonist
Agonist – excitatory – increases effect of neurotransmitter (mimics)Opiate drugsGlutamateAmphetamines
Antagonist – inhibitory – slow down the effect of neurotransmitter (destroy connections or block them)Botox – smooth wrinkles by paralyzing underlying facial muscles
GABAAlcohol
Neurotransmitter molecule
Receiving cellmembrane
Receptor site onreceiving neuron
Agonist mimicsneurotransmitter
Antagonistblocksneurotransmitter
THE NERVOUS SYSTEM
Body’s speedy, electrochemical communication network consisting of all nerve cells of PNS and CNS
o2 partsoCentral Nervous SystemoPeripheral Nervous System
oThe nervous system uses 3 types of neuronso1. sensoryo2. interneuronso3. motor neurons
THE NERVOUS SYSTEM Nerves – bundled axons that form neural “cables” connecting the CNS with muscles, glands, and sense organs
3 types of neurons1. sensory – carry incoming info from body’s tissues and sensory receptors to brain and spinal cord MILLIONSAFFERENT
2. interneurons – communication that takes place internally and intervene between sensory input and motor outputBILLIONS
3. motor neurons – carry outgoing info from brain and spinal cord (CNS) – muscles/glandsMILLIONSEFFERENT
THE NERVOUS SYSTEM – CNS & PNS CNS – brain and spinal cord
Body’s decision makerSpine connects PNS to brainReflex – 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 bodyResponsible for gathering info and sending CNS decisions
PERIPHERAL NERVOUS SYSTEM
SOMATIC NERVOUS SYSTEMControl’s the body’s skeletal muscles - voluntaryaka 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
AUTONOMIC NERVOUS SYSTEMControls our glands and the muscles of our internal organs, influencing such functions as heartbeat, digestion, and hormonesAutopilot – operates on its own – autonomously
AUTONOMIC NERVOUS SYSTEM SYMPATHETIC NERVOUS SYSTEM
*arouses the body
*mobilizes its energy in stressful situations
*accelerated heartbeat
*raise blood pressure
*slows digestion
PARASYMPATHETIC NERVOUS SYSTEM
*calms the body
*conserves its energy
*decreased heartbeat
*lowering blood sugar
TOOLS OF DISCOVERY THE BRAIN
TOOLS OF DISCOVERY Manipulating the brain –
Lesionselectromagnetic 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) ScanLooks 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 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 STRUCTURETHE 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 STRUCTURETHE 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 STRUCTURETHE BRAINSTEM
5. The CerebellumCoordinates voluntary movements Balancing, walking……….Nonverbal voluntary movement
6. PonsRegulates 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 memoryForms new memories
2. Amygdala-Aggression and fear
THE LIMBIC SYSTEM
3. Hypothalamus- Controls pituitary gland (hormones)directs several maintenance activitieseatingdrinkingbody temperature
Triggers autonomic nervous systemPleasure CenterReward 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
Frontal Occipital Temporal Parietal
2. Glial Cells- - neural nannies Support the 22 billion nerve cells
THE CEREBRAL CORTEX
1. Frontal Lobe- speaking, muscle movement, making plans, judgmentsMotor Cortex- outgoing messages to the body
THE CEREBRAL CORTEX
2.Parietal Lobe- sensory cortexSensory Cortex-registers and processes body sensationsReceives info from skin receptorsMore sensitive= bigger area
3.Occipital Lobe- receives visual from opposite sides
THE CEREBRAL CORTEX
4.Temporal Lobes- receive auditory simulation from opposite sidesDon’t need real sounds
Functional MRI scan of the visual cortex activated by light shown in the subject’s eyes
Auditorycortex
Visualcortex
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 footMost plastic when young
OUR DIVIDED BRAIN Corpus Callosumlargest bundle of neural fibersconnects the two brain hemispheres carries messages between the hemispheres
Corpus callosum
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 specialtiesMost people are stronger in one hemisphere Left- logical, verbal, sequential Right- emotional, expressive, better at spatial relations
HANDEDNESS
90% right handed
The percentage of lefties sharplydeclines with age
10 20 30 40 50 60 70 80 90Age in years
14%
12
10
8
6
4
2
0
Percentage ofleft-handedness
NEURAL AND HORMONAL SYSTEMS
Endocrine Systemthe body’s “slow” chemical communication systema set of glands that secrete hormones into the bloodstream
ENDOCRINE SYSTEM
Hormoneschemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect anotherGrowth, reproduction, metabolism, mood………
ENDOCRINE SYSTEM
Adrenal Glands a pair of endocrine glands just above the kidneyssecrete the hormones epinephrine (adrenaline) and norepinephrine (noradrenaline), which help to arouse the body in times of stressIncreases heart beat, blood pressure, blood sugar….. Gives us energy
ENDOCRINE SYSTEM
Pituitary Glandunder the influence of the hypothalamus, the pituitary regulates growth and controls other endocrine glandsMaster 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 OvariesRelease 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-resulting-football-concussions
http://content.time.com/time/video/player/0,32068,64253995001_1957921,00.html