Presentation on theme: "The brain: The source of mind and self"— Presentation transcript:
1 The brain: The source of mind and self 4The brain: The source of mind and self
2 4 Overview The central nervous system The peripheral nervous system Communication in the nervous systemChemical messengers in the nervous systemMapping the brainA tour through the brainTwo stubborn issues in brain research
3 The central nervous system 4The central nervous systemBrainSpinal cordA collection of neurons and supportive tissue running from the base of the brain down the center of the backProtected by spinal column
5 Organization of the nervous system 4Organization of the nervous system
6 4 Structure of a neuron Dendrites Cell body Axon Receive information from other neurons and transmit toward the cell bodyCell bodyKeeps the neuron alive and determines whether it will fireAxonExtending fiber that conducts impulses away from the cell body and transmits to other cells.
9 4 Your turn Which part of a neuron is tree-like or “branchy”? 1. Dendrites2. The axon3. The cell body4. The nucleus
10 4 Your turn Which part of a neuron is tree-like or “branchy”? 1. Dendrites2. The axon3. The cell body4. The nucleus
11 4 Neurons in the news Neurogenesis Stem cells The production of new neurons from immature stem cellsStem cellsImmature cells that renew themselves and have the potential to develop into mature cells
12 4Stem-cell researchEmbryonic stem cells appear most useful yet federal funding faces resistance from some advocates.In 2001, President Bush signed executive order preventing creation of new cell lines.Some scientists advocate for ban to be lifted because stem cell research shows promise in helping those suffering from diseases of the brain.
13 How neurons communicate 4How neurons communicateAxon terminals release neurotransmitter.Neurotransmitter enters synapse.Neurotransmitter binds to receptors that it fits.
14 4Action potentialA brief change in electrical voltage that occurs between the inside and outside of an axon when a neuron is stimulated.
15 4NeurotransmitterChemical released by a transmitting neuron at the synapse and capable of affecting the activity of a receiving neuron
16 Major neurotransmitter 4Major neurotransmitterSerotoninDopamineAcetylcholine (Ach)NorepinephrineGamma aminobutyric acid (GABA)GlutamateEndorphins
17 Opioids and Substance P 4Opioids and Substance P
18 4The endocrine systemEndocrine glands release hormones into the bloodstream……Hormones regulate growth, metabolism, sexual development and behavior, and other functions.
20 4 Hormones Melatonin Adrenal hormones Sex hormones Regulates daily biological rhythmsAdrenal hormonesInvolved in emotions and stressCortisol, epinephrine, and norepinephrineSex hormonesRegulate development and functioning of reproductive organsAndrogens, estrogens, and progesterone
21 4 Mapping the brain Lesioning Involves damaging and removing sections of brain in animals, then observing their effects.
22 Electroencephalogram 4ElectroencephalogramA recording of neural activity detected by electrodes
23 Transcranial magnetic stimulation (TMS) 4Transcranial magnetic stimulation (TMS)Involves delivering a large current through a wire coil on a person’s headCan be used toProduce motor responsesTemporarily inactivate an area of the brainTreat depression
24 Positron emission tomography 4Positron emission tomographyA method for analyzing biochemical activity in the brain, using injections of a glucose-like substance containing a radioactive elementActive areas have increased blood flow.Sensors detect radioactivity.Different tasks show distinct activity patterns.
25 Magnetic resonance imaging (MRI) 4Magnetic resonance imaging (MRI)Method for studying body and brain tissueMagnetic fields align certain ions and compounds.When field is removed, these molecules release energy as radio waves.Computer calculates tissue density from radio waves.Provides clear 3D images
26 A tour through the brain 4A tour through the brainBrain stemCerebellumThalamusHypothalamus and pituitary glandAmygdalaHippocampusCerebrum and lobes of the cerebral cortex
27 4 The brain stem Pons Medulla Reticular activating system Involved in sleeping, waking, and dreamingMedullaResponsible for certain automatic functions such as breathing and heart rateReticular activating systemArouses cortex and screens incoming information
28 4 The cerebellum Regulates movement and balance Involved in remembering simple skills and acquired reflexesPlays a part inAnalyzing sensory informationSolving problemsUnderstanding words
29 4 The thalamus Relays sensory messages to the cerebral cortex Includes all sensory messages except those from olfactory bulb
30 Hypothalamus and pituitary gland 4Hypothalamus and pituitary glandInvolved in emotions and drives vital to survivalFear, hunger, thirst, and reproductionRegulates autonomic nervous systemPituitary glandSmall endocrine gland which releases hormones and regulates other endocrine glands
31 4 The amygdala Responsible for Plays important role in Arousal Regulation of emotionInitial emotional response to sensory informationPlays important role inMediating anxiety and depressionEmotional memory
32 4 The hippocampus Responsible for Storage of new information in memory Comparing sensory information with what the brain expects about the worldEnabling us to form spatial memories for navigating the environment
33 4 The cerebrum Largest brain structure Two cerebral hemispheres connected by the corpus callosum.In charge of most sensory, motor, and cognitive processesSurrounded by cerebral cortex, a collection of several thin layers of cells (gray matter)
34 Lobes of the cerebral cortex 4Lobes of the cerebral cortexOccipital lobes (visual cortex)Parietal lobes (somatosensory cortex)Temporal lobesMemory, perception, emotion, and auditory cortexLeft lobe: Wernicke’s areaFrontal lobesEmotion, planning, creative thinking, and motor cortexLeft lobe: Broca’s area
35 Lobes of the cerebral cortex 4Lobes of the cerebral cortex
36 4Your turnJenny bumps her head and is suddenly unable to see, although the doctor says there is nothing wrong with her eyes? Which part of her brain did Jenny damage?1. The amygdala2. The hippocampus3. The occipital lobe of the cerebral cortex4. The parietal lobe of the cerebral cortex
37 4Your turnJenny bumps her head and is suddenly unable to see, although the doctor says there is nothing wrong with her eyes? Which part of her brain did Jenny damage?1. The amygdala2. The hippocampus3. The occipital lobe of the cerebral cortex4. The parietal lobe of the cerebral cortex
38 4 Phineas Gage Gage was a railroad construction foreman An 1848 explosion forced a steel tamping rod through his headOthers said he was “no longer Gage”Lost his job, worked as a sideshow exhibit
39 4The corpus callosumMillions of myelinated axons connecting the brain’s hemispheresProvides a pathway for communicationIf surgically severed to treat epilepsy, hemispheres cannot communicate directly
41 Split-brain experiment 4Split-brain experimentSubjects were presented information to one or the other side of their brains.Patients identified verbally the pictures to the right (e.g., boy).When patients were asked to point to the face seen, the patients pointed to the left picture.
42 4 Allies or opposites? Research on split-brain patients shows us. . . Nearly all right-handed and the majority of left-handed individuals process language mainly in the left hemisphere.Many researchers believe in left-hemisphere dominance.Others insist right-hemisphere is important for spatial visual problem solving, comprehending non-verbal sounds, and some language abilities.
43 4Where is the Self?Modern brain scientists explain the mind or soul in physical terms as a product of the cerebral cortex.Mind is a series of independent brain parts dealing with different aspects of thoughts (Dennett 1991).Mind is a loose confederation of mental systems all working without conscious awareness (Gazzaniga, 1998; Roser & Gazzaniga, 2004).Frontal lobes may play a critical role.Many still question the relationship between subjective experience and physical processes of the brain.
44 4“His” and “her” brains?After analyzing 49 studies of sex differences in brain anatomy, researchers found small differences between the two groups and larger differences within groups.There do appear to be sex differences in lateralization of language.Males show left hemisphere activation only.Females show left and right hemisphere activation.Females have more gray matter.
45 What do differences mean for behavior? 4What do differences mean for behavior?Supposed differences are stereotypes.Brain difference does not necessarily explain behavior or performance.Sex differences in the brain could be the result rather than the cause of behavioral differences.