MyersPsy02神经科学与行为.ppt.ppt

Myers PSYCHOLOGY Chapter 2 Neuroscienceand BehaviorNeural CommunicationBiological Psychologybranch of psychology concerned with the links between biology and behaviorsome biological psychologists call themselves behavioral neuroscientists,neuropsychologists,behavior geneticists,physiological psychologists,or biopsychologistsNeurona nerve cellthe basic building block of the nervous systemNeural CommunicationDendritethe bushy,branching extensions of a neuron that receive messages and conduct impulses toward the cell bodyAxonthe extension of a neuron,ending in branching terminal fibers,through which messages are sent to other neurons or to muscles or glandsMyelin MY-uh-lin Sheath a layer of fatty cells segmentally encasing the fibers of many neuronsenables vastly greater transmission speed of neutral impulsesNeural CommunicationNeural CommunicationAction Potential a neural impulse;a brief electrical charge that travels down an axongenerated by the movement of positively charged atoms in and out of channels in the axons membraneThreshold the level of stimulation required to trigger a neural impulseNeural CommunicationCell body end of axonDirection of neural impulse:toward axon terminalsNeural CommunicationSynapse SIN-apsjunction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neurontiny gap at this junction is called the synaptic gap or cleftNeurotransmitterschemical messengers that traverse the synaptic gaps between neuronswhen released by the sending neuron,neuro-transmitters travel across the synapse and bind to receptor sites on the receiving neuron,thereby influencing whether it will generate a neural impulseNeural CommunicationNeural CommunicationSerotonin PathwaysDopamine PathwaysNeural CommunicationNeural CommunicationAcetylcholine ah-seat-el-KO-leen a neurotransmitter that,among its functions,triggers muscle contractionEndorphins en-DOR-fins“morphine within”natural,opiatelike neurotransmitters linked to pain control and to pleasureNeural CommunicationNeurotransmitter moleculeReceiving cellmembraneReceptor site onreceiving neuronAgonist mimicsneurotransmitterAntagonistblocksneurotransmitterThe Nervous SystemNervous System the bodys speedy,electrochemical communication system consists of all the nerve cells of the peripheral and central nervous systemsCentral Nervous System(CNS)the brain and spinal cordPeripheral Nervous System(PNS)the sensory and motor neurons that connect the central nervous system(CNS)to the rest of the bodyThe Nervous SystemCentral(brain andspinal cord)NervoussystemAutonomic(controlsself-regulated action ofinternal organs and glands)Skeletal(controlsvoluntary movements ofskeletal muscles)Sympathetic(arousing)Parasympathetic(calming)PeripheralThe Nervous SystemNerves neural“cables”containing many axonspart of the peripheral nervous systemconnect the central nervous system with muscles,glands,and sense organsSensory Neurons neurons that carry incoming information from the sense receptors to the central nervous systemThe Nervous SystemInterneurons CNS neurons that internally communicate and intervene between the sensory inputs and motor outputsMotor Neuronscarry outgoing information from the CNS to muscles and glandsSomatic Nervous Systemthe division of the peripheral nervous system that controls the bodys skeletal musclesThe Nervous SystemAutonomic Nervous System the part of the peripheral nervous system that controls the glands and the muscles of the internal organs(such as the heart)Sympathetic Nervous System division of the autonomic nervous system that arouses the body,mobilizing its energy in stressful situationsParasympathetic Nervous System division of the autonomic nervous system that calms the body,conserving its energyThe Nervous SystemThe Nervous SystemThe Nervous SystemReflexa simple,automatic,inborn response to a sensory stimulusSkinreceptorsMuscleSensory neuron(incoming information)Motor neuron(outgoing information)BrainInterneuronSpinal cordThe Nervous SystemNeural Networksinterconnected neural cells with experience,networks can learn,as feedback strengthens or inhibits connections that produce certain results computer simulations of neural networks show analogous learningInputsOutputsNeurons in the brain connect with oneanother to form networksThe brain learns by modifyingcertain connections in response to feedbackThe BrainLesiontissue destruction a brain lesion is a naturally or experimentally caused destruction of brain tissueElectroencephalogram(EEG)an amplified recording of the waves of electrical activity that sweep across the brains surfacethese waves are measured by electrodes placed on the scalpThe BrainCT(computed tomography)Scana series of x-ray photographs taken from different angles and combined by computer into a composite representation of a slice through the body;also called CAT scanPET(positron emission tomography)Scan a visual display of brain activity that detects where a radioactive form of glucose goes while the brain performs a given taskMRI(magnetic resonance imaging)a technique that uses magnetic fields and radio waves to produce computer-generated images that distinguish among different types of soft tissue;allows us to see structures within the brainPET ScanMRI ScanThe BrainBrainstem the oldest part and central core of the brain,beginning where the spinal cord swells as it enters the skullresponsible for automatic survival functionsMedulla muh-DUL-uh base of the brainstemcontrols heartbeat and breathingThe BrainThe BrainReticular Formationa nerve network in the brainstem that plays an important role in controlling arousalThalamus THAL-uh-muss the brains sensory switchboard,located on top of the brainstemit directs messages to the sensory receiving areas in the cortex and transmits replies to the cerebellum and medullaThe BrainCerebellum sehr-uh-BELL-um the“little brain”attached to the rear of the brainstemit helps coordinate voluntary movement and balanceThe BrainLimbic Systema doughnut-shaped system of neural structures at the border of the brainstem and cerebral hemispheresassociated with emotions such as fear and aggression and drives such as those for food and sex includes the hippocampus,amygdala,and hypothalamus.Amygdala ah-MIG-dah-la two almond-shaped neural clusters that are components of the limbic system and are linked to emotionThe BrainHypothalamusneural structure lying below(hypo)the thalamus;directs several maintenance activitieseatingdrinkingbody temperaturehelps govern the endocrine system via the pituitary glandis linked to emotionThe Limbic SystemThe Limbic SystemElectrode implanted in reward centerThe Cerebral CortexCerebral Cortex the intricate fabric of interconnected neural cells that covers the cerebral hemispheresthe bodys ultimate control and information processing centerGlial Cells cells in the nervous system that support,nourish,and protect neuronsThe Cerebral CortexFrontal Lobes involved in speaking and muscle movements and in making plans and judgmentsParietal Lobes include the sensory cortexOccipital Lobes include the visual areas,which receive visual information from the opposite visual fieldTemporal Lobes include the auditory areasThe Cerebral CortexThe Cerebral CortexMotor Cortexarea at the rear of the frontal lobes that controls voluntary movementsSensory Cortexarea at the front of the parietal lobes that registers and processes body sensationsThe Cerebral CortexThe Cerebral CortexFunctional MRI scan shows the visual cortex activated as the subject looks at facesVisual and Auditory CortexAssociation AreasMore intelligent animals have increased“uncommitted”or association areas of the cortexThe Cerebral CortexAphasiaimpairment of language,usually caused by left hemisphere damage either to Brocas area(impairing speaking)or to Wernickes area(impairing understanding)Brocas Area an area of the left frontal lobe that directs the muscle movements involved in speechWernickes Area an area of the left temporal lobe involved in language comprehension and expressionSpecialization and IntegrationSpecialization and IntegrationBrain activity when hearing,seeing,and speaking wordsBrain ReorganizationPlasticitythe brains capacity for modification,as evident in brain reorganization following damage(especially in children)and in experiments on the effects of experience on brain developmentOur Divided BrainCorpus Callosumlarge band of neural fibersconnects the two brain hemispheres carries messages between the hemispheresCorpus callosumOur Divided BrainThe information highway from the eye to the brainSplit Braina condition in which the two hemispheres of the brain are isolated by cutting the connecting fibers(mainly those of the corpus callosum)between themSplit Brain“Look at the dot.”Two words separatedby a dot are momentarily projected.“What worddid you see?”or“Point withyour left hand to theword you saw.”Disappearing SouthpawsThe percentage of left-handers decreases sharply in samples of older people(adapted from Coren,1993).The percentage of lefties sharplydeclines with age10 20 30 40 50 60 70 80 90Age in years14%12 10 8 6 4 2 0Percentage ofleft-handednessBrain Structures and their FunctionsThe Endocrine SystemEndocrine Systemthe bodys“slow”chemical communication systema set of glands that secrete hormones into the bloodstreamNeural and Hormonal SystemsHormoneschemical messengers,mostly those manufactured by the endocrine glands,that are produced in one tissue and affect anotherAdrenal ah-DREEN-el 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 stressPituitary Glandunder the influence of the hypothalamus,the pituitary regulates growth and controls other endocrine glands