2Nerves Hold out your hand in front of you Now wave at yourself Now, tap your headPut your arms downSay out loud to “Move Arm”…Just tell it to moveDid it move?Why not?
3Nerves How does our arm know when you want it to move? Our experiment shows that your arm does not understand spoken commands.So what does it understand?What tells it to move. If you think it is your brain, you are correct.
4NervesBut wait a moment. Your brain is clear up in your head, while your arm is clear down on your body.How does your brain talk to your arm? Somehow they must be connected.The connection between your brain and your arm, as well as every other part of your body is known as your nervous system.
5Nervous SystemHow are messages transmitted along your nervous system? Interestingly enough, messages travel from your brain to your various body parts via electricity, in much the same way cable television signals travel from the cable company to your house, or in the same way that this web page traveled from our web servers to your computer.
7Are your Synapses Firing? Remember that the cells making up your nervous system are called neurons.Neurons are connected to other neurons, as well as to other tissues within the body via synapses.The location where a neuron connects to another cell is called a synapse.
8Brain neurons firingWhen a message is transferred through a neuron it passes to the next neuron via an amazing fast chemical and electrical reaction.Because of its lightning speed, it is often said that a person’s synapses are firing when they are in deep thought.Regardless of whether you are solving a problem, or taking a nap, your synapses are always busy transporting messages.
9The Central Nervous System (CNS) The Central Nervous System is made up of your brain, and your spinal cord.It is the main control center of your body, and the center of thought. Your Central Nervous System controls most of the actions within your body.
10Peripheral Nervous System 3 kinds of neurons connect CNS to the bodysensorymotorinterneuronsMotor - CNS to muscles and organsSensory - sensory receptors to CNSInterneurons: Connections Within CNSSpinalCordBrainNerveskey words: peripheral nervous system
12Neurons Generate Nerve Impulses A nerve impulse travels along the axon and dendrites as electrical current caused by ions moving in and out of the neuron through voltage-gated channelsthese membrane channels open and close in response to electrical voltage changesThe impulse starts when pressure or other sensory inputs disturb a neuron’s plasma membrane, causing Na+ channels to open
13Neurons Generate Nerve Impulses When Na+ channels open, Na+ floods into the neuron from the outsidefor a brief moment, the inside of the neuron is “depolarized,” becoming more positivethe open Na+ channels in the small patch of depolarized membrane remain open for only a half a millisecondif the voltage change of the depolarization is great enough, it causes nearby voltage-gated Na+ and K+ channels to open
14Neurons Generate Nerve Impulses The Na+ channels open first, which starts a wave of depolarization moving down the neuronthis moving local reversal of voltage is called an action potentialan action potential follows an all-or-none law: a large enough depolarization produces either a full action potential or none at all
15Neurons Generate Nerve Impulses The K+ voltage-gated channels open after a slight delay, causing K+ to flow out of the cellthis makes the interior of the neuron more negative, causing the voltage-gated Na+ channels to closeThe period of time after an action potential has passed but before the resting potential is restored is called the refractory period
16Somatic System Nerves to/from spinal cord control muscle movementssomatosensory inputsBoth Voluntary and reflex movementsSkeletal Reflexessimplest is spinal reflex arcMuscleMotorNeuronInterneuronSkin receptorsSensoryBrain
17Autonomic System Two divisions: Control involuntary functions sympatheticParasympatheiticControl involuntary functionsheartbeatblood pressurerespirationperspirationdigestionCan be influenced by thought and emotion
18Sympathetic “Fight or flight” response CENTRAL NERVOUS SYSTEMBrainSpinalcordSYMPATHETICDilates pupilStimulates salivationRelaxes bronchiAccelerates heartbeatInhibits activityStimulates glucoseSecretion of adrenaline,nonadrenalineRelaxes bladderStimulates ejaculationin maleSympatheticgangliaSalivaryglandsLungsHeartStomachPancreasLiverAdrenalglandKidney“Fight or flight” responseRelease adrenaline and noradrenalineIncreases heart rate and blood pressureIncreases blood flow to skeletal musclesInhibits digestive functionskeywords: sympathetic nervous system; fighlt or flight response
19Parasympathetic “Rest and digest” system CENTRAL NERVOUS SYSTEMBrainPARASYMPATHETICSpinalcordStimulates salivationConstricts bronchiSlows heartbeatStimulates activityContracts bladderStimulates erectionof sex organsStimulates gallbladderGallbladderContracts pupil“Rest and digest” systemCalms body to conserve and maintain energyLowers heartbeat, breathing rate, blood pressurekey words: parasympathetic nervous system; rest and digest system
20Sensory Information sent to opposite hemisphere Left visualfieldRight visualOpticnervesCorpusCallosumLeft VisualCortexRight VisualPrinciple is Contralateral OrganizationSensory data crosses over in pathways leading to the cortexVisual Crossoverleft visual field to right hemisphereright field to leftOther senses similarkey words: left hemisphere; right hemisphere; visual infomation; touch information
21BrainYour mind is a powerful and amazing organ. Its ability to calculate, control and think exceeds that of every computer on Earth put together.Your brain has three main parts.CerebrumCerebellumBrain Stem.
22Cerebrum Largest portion of the brain Your cerebrum is responsible for all the voluntary processes that you do each day, including thought.Voluntary means that you want to do something, or that you decide to do something, like hold your hand in the air, wave to yourself, and tap yourself on the head.
23CerebrumAs you do these actions, your cerebrum sends electrical messages out to your body using the neurons of your nervous system.When the message reaches your arm, your muscles obey, and do as they are instructed.
24CerebellumYour cerebellum aids your cerebrum in the task of moving your muscles.It helps to maintain balance, moving the muscles you don’t think to move, as you make your arm wiggle around. This allows you to move about smoothly, with little effort.
25Brain StemYour brain stem sites at the base of the brain, and connects it to the spinal cord.The brain stem controls the flow of information between the brain and the rest of the body, and also controls many of the involuntary movements that your body does, every single day.
26Localization of function FrontalParietalOccipitalTemporalkey words: cerebral cortex; lobes; frontal; parietal; temporal; occipital
27Occipital Lobe Input from Optic nerve Contains primary visual cortex most is on surface inside central fissureOutputs to parietal and temporal lobesOccipitalLobeVisualLobe
28Temporal Lobe Inputs are auditory, visual patterns Contains primary auditory cortexTemporalLobeAuditoryCortexInputs are auditory, visual patternsspeech recognitionface recognitionword recognitionmemory formationOutputs to limbic System, basal Ganglia, and brainstemTemporalLobe
29Parietal Lobe Inputs from multiple senses SomatosensoryCortexParietal LobeInputs from multiple sensescontains primary somatosensory cortexborders visual & auditory cortexParietalLobeOutputs to Frontal lobehand-eye coordinationeye movementsattention
30Frontal Lobe Motor action/behavior Contains primary motor cortex WorkingMemoryMotorCortexBroca’sAreaNo direct sensory inputImportant planning and sequencing areasBroca’s area for organization/speechkey words: cerebral cortex; lobes; frontal; motor functionsFrontal lobe is not directly involved in sensation or perception. Its functions are related to motor action (behavior). The motor cortex is the start of nerves that run through the spinal cord to the muscles.Broca’s area organizes sequences of speech movements. Damage leads to productive aphasiaDorsolateral Prefrontal Cortex is important in working memory. WM is short term memory for information needed to maintain a context, to prepare for the next step in a sequence of thought, and /or to inhibit irrelevant responsesPrefrontal area for working memory
32Frontal Lobe Disorders Broca’s areaproductive aphasia--an acquired language disorder affecting all modalities such as writing, reading, speaking, and listening and results from brain damagePrefrontal arealose track of ongoing contextfail to inhibit inappropriate responseskey words: cerebral cortex; lobes; frontal; motor functions
33The Nervous System: Summary Major structures of the nervousCNS, Somatic, AutonomicTwo hemispheres & 4 lobesOrganizationcontralateral input & outputprimary sensory areasmotor areasCommissureLocalization of functionsCentral Nervous SystemPeripheral Nervous System
34Corpus Callosum What happens when the corpus callosum is cut? Sensory inputs are still crossedMotor outputs are still crossedHemispheres can’t exchange dataEpileptickey words: left hemisphere; right hemisphere; corpus callosum; epilepsyOne method used to treat severely epileptic patients involves cutting the corpus callosum to prevent the spread of seizures acorss the entire brain. The video clip on this slide shows a man who has had such a surgery. Double click on video to start video clip. This clip discusses the types of information processing deficits associated with cutting the corpus callosum and shows a task often used to assess corpus callosum damage. This task is also represented in drawing form on the following slide as well.
35The ‘Split Brain’ studies Surgery for epilepsy : cut the corpus callosumRoger Sperry, 1960’sSpecial apparatuspicture input to just one side of brainscreen blocks objects on table from viewNonverbalrighthemisphereVerballeftkey words: left hemisphere; right hemisphere; corpus callosum; epilepsyThis slide is a schematic of the task shown in the video clip on the previous slide
36The ‘Split Brain’ studies I saw anapple.“What didyou see?”NonverbalrighthemisphereVerballeftNonverbalrighthemisphereVerballeft??“What didyou see?”“Using your left hand,Pick up what you saw.”Picture to right braincan’t name the objectleft hand can identify by touchPicture to left braincan name the objectleft hand cannot identify by touch
37Super HighwayLike a powerful broadband Internet connection, your spinal cord can move a lot of data very quickly. Its job is to carry messages to and from the body to the brain.There are 32 different nerves that connect directly into the spinal cord, and that branch outward towards the rest of the body.Reflexes are processed directly in the spinal cord, allowing you to respond very quickly to danger, without wasting time thinking about what you should do.
38Addictive Drugs Act on Chemical Synapses Emotional states (mood, pleasure, pain, etc.) are determined by particular groups of neurons that use special sets of neurotransmitters and neuromodulatorsmany researchers think that depression results from a shortage of serotoninProzac, an anti-depressant, inhibits the reabsorption of serotonin
39Drugs alter transmission of impulses across the synapse
40Addictive Drugs Act on Chemical Synapses Nerve cells are particularly prone to the loss of sensitivity when exposed to a chemical signal for a long timeif receptor proteins within synapses are exposed to high levels of neurotransmitters for prolonged periods, the nerve cell often responds by inserting fewer receptor proteins into the membrane
41Addictive Drugs Act on Chemical Synapses Cocaine acts a neuromodulator, causing abnormal amounts of neurotransmitters to remain in the synapse for long periodsit affect neurons in the brain’s pleasure pathwaysthese cells transmit pleasure messages using the neurotransmitter dopaminecocaine works by blocking transporter proteins on the presynaptic membrane that normally reabsorb dopaminebecause dopamine cannot bind to a transporter, it remains in the synapse and continues to stimulate
42Addictive Drugs Act on Chemical Synapses When receptor proteins in the pleasure pathways of the brain are exposed to high levels of dopamine due to cocaine, the nerve cells respond by lowering the number of receptor proteinswith so few receptors, the drug user needs the drug to maintain even normal nerve activity levelsthis is addiction, the physiological adaptation of the nervous system due to drug abuse
44Addictive Drugs Act on Chemical Synapses Nicotine, also an addictive drug, binds to postsynaptic receptors in the brain that normally bind to AchThe brain responds bymaking fewer receptors to which nicotine can bindaltering the pattern of activation of the nicotine receptors (i.e., their sensitivity to neurotransmitters)This leads to profound changes in the patterns of release of many neurotransmitters, and addiction results
45How the Brain WorksThe cerebrum is the center for thought and association and makes up about 85% of the weight of the brainthe cerebrum is divided into right and left halves, called cerebral hemispheresMuch of the neural activity of the cerebrum occurs within a thin, gray outer layer called the cerebral cortex
46SensesWe use our senses to get information about the world around us into our brains.There are five main senses that most of us use each day.SightHearingTouchTastesmellWithout senses, your brain would have no way of knowing what was going on around you. Life would be a very lonely, dark, and quiet place.
47EyesThe human eye is an amazing and powerful organ. As you read the words on this screen, your eyes see the shapes of the letters, and transmit the information back to your brain.Light travels from the computer screen to your eyes, entering them through a transparent layer of tissue called the cornea.
48EyesThe light of your computer screen then travels onward through the lens. The lens of your eye focuses the light onto a special tissue called the retina.The retina is lined with special photoreceptors called rods and cones.Rods are more sensitive to light, but cannot distinguish between colors.While cones are less sensitive, but can differentiate the different colors, giving us color vision.Not all animals have cones. What does this mean? It means that many animals see in black and white.
49EyesAs light lands on the rods and cones it is converted into electrical impulses and is transmitted to the brain, where it is interpreted as the beautiful images all around us.
50Sensing Light: VisionColor blindness occurs when individuals are not able to perceive all three colorsit typically occurs due to an inherited lack of one or more types of conesit is a sex-linked trait, so men are more likely to be colorblind than women
53Optical IllusionThe brain also uses information learned in the past to help it perceive the images that the eyes sendthe brain can have a tendency to “force” an image into something that the image is not, just so the image looks more familiar. These are called cognitive illusionsoptical illusion isn’t “real,” although the brain interprets the illusion as being true
62HearingHow do we hear?As objects move, or interact with other objects, they cause the air to vibrate. Think of a swimming pool.What happens if you jump in?First you make a big splash, followed by a series of ripples. The harder you jump, the bigger your ripples will be.
63HearingThe air of our atmosphere works in much the same way as a swimming pool.Even though we cannot see the ripples, every time, we move they go traveling through the air.Some of these ripples, or vibrations reach our ears. Inside of your ear is a thin tissue known as the tympanum, or eardrum.
64HearingThe vibrations in the air cause your eardrum to begin vibrating.Behind your eardrum are three tiny bones calledHammerAnvilStirrup
65Hearing As your eardrum begins to vibrate, so do these tiny bones. The last of these bones, the stirrup transmits these vibrations into the fluid filled cochlea.This causes tiny hairs within the cochlea to vibrate.The vibration of these hairs is converted into electrical impulses, which are then transmitted to the brain for interpretation.
66Taste and SmellThe senses of taste and smell are interpreted from tiny objects on your tongue, and in your nose.Receptors within your nose detect and transmit smells to your brain, while your taste buds detect and transmit flavors to your brain
67Taste and SmellMuch of what we think we are tasting is actually smell.Try an experiment. Next time you are eating something, plug your nose. What happens?Much of the flavor disappears.
68TouchThe senses we have discussed so far have been located in one specific location, such as the eye, or nose.However, your sense of touch is not restricted to one small area, but covers your entire body.Your skin is sensitive to heat, to pressure, and to pain.Within your body, there are also many nerve endings that are sensitive to touch.
69Things to keep your mind moving… Leave your comfort zone. Getting good at sudoku? Time to move on. Brain teasers don't form new neural connections once you've mastered them. So try something that's opposite your natural skills: If you like numbers, learn to draw. If you love language, try logic puzzles.
70Curry up. The active ingredient in Indian curry, turmeric, contains resveratrol, the same powerful antioxidant that makes red wine good for brain health. Eat curry once a week, or sprinkle it on salads, to protect brain cells from harmful free radicals.
71Redecorate and redesign your environment Redecorate and redesign your environment. Plant new flowers in front of your house. Redecorate the kitchen. Rearrange your closets and drawers. Replace the candles in your living room with some that have a different scent. Making such changes can alter motor pathways in the brain and encourage new cell growth.
72Sleep. Shut-eye isn't a luxury Sleep. Shut-eye isn't a luxury. It's when your brain consolidates memories. Poor sleep, caused by medical conditions, worry, depression, or insomnia, can interfere with your rest. So treat yourself to relaxing scents like vanilla before bed. They raise the chemical dopamine and reduce cortisol, a stress hormone.
73Play Games Whether you choose Risk, Pictionary, Scrabble, Sudouku, Wii, XBOX or Boggle, games are associated with a lower risk of developing dementia.They activate strategic, spatial, and memory parts of the brain, and require you to socialize, which can help form new neural pathways.
74Switch hands. It may be uncomfortable, but writing with your nondominant hand or operating a computer mouse with that hand can activate parts of the brain that aren't easily triggered otherwise.Anything that requires the brain to pay close attention to a formerly automatic behavior will stimulate brain-cell growth.