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 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 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