Transcript Unit 2
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) ScanX- 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 Brainperforms 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 Areasareas 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