Chapter 3. The Biological basis of Behavior 8 th Edition

Transcription

1 Chapter 3 The Biological basis of Behavior 8 th Edition

2 Communication in the Nervous System Hardware: Glia structural support and insulation Neurons communication Soma cell body Dendrites receive Axon transmit away

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4 Neural Communication: Insulation and Information Transfer Myelin sheath speeds up transmission Terminal Button end of axon; secretes neurotransmitters Neurotransmitters chemical messengers Synapse point at which neurons interconnect

5 The Neural Impulse: Electrochemical Beginnings Hodgkin & Huxley (1952) - giant squid Fluids inside and outside neuron Electrically charged particles (ions) Neuron at rest negative charge on inside compared to outside -70 millivolts resting potential

6 The Neural Impulse: The Action Potential Stimulation causes cell membrane to open briefly Positively charged sodium ions flow in Shift in electrical charge travels along neuron The Action Potential All or none law

7 Figure Neural Impluse

8 The Synapse: Chemicals as Signal Couriers Synaptic cleft Presynaptic neuron Synaptic vesicles Neurotransmitters Postsynaptic neuron Receptor sites

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10 When a Neurotransmitter Binds: The Postsynaptic Potential Voltage change at receptor site postsynaptic potential (PSP) Not all-or-none Changes the probability of the postsynaptic neuron firing Positive voltage shift excitatory PSP Negative voltage shift inhibitory PSP

11 Figure 3.4 Overview of synaptic transmission

12 Signals: From Postsynaptic Potentials to Neural Networks One neuron, signals from thousands of other neurons Requires integration of signals PSPs add up, balance out Balance between IPSPs and EPSPs Neural networks Patterns of neural activity Interconnected neurons that fire together or sequentially Synaptic connections Elimination and creation Synaptic pruning Figure 3.5

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14 Neurotransmitters Specific neurotransmitters work at specific synapses Lock and key mechanism Agonist mimics neurotransmitter action Antagonist opposes action of a neurotransmitter neurotransmitters known at present Interactions between neurotransmitter circuits Botox Ach blocker p. 86 Dopamine substantia nigra Parkinson disease p. 87

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16 Organization of the Nervous System Central nervous system (CNS) brain and spinal cord Afferent = toward the CNS/ Efferent = away from the CNS Peripheral nervous system nerves that lie outside the central nervous system Somatic nervous system voluntary muscles and sensory receptors Autonomic nervous system (ANS) controls automatic, involuntary functions Sympathetic Go (fight-or-flight) Parasympathetic Stop

17 Figure 3.6 Organization of the human nervous system

18 Figure 3.7 Peripheral Nervous System Somatic and Autonomic

19 Cranial Nerves

20 The Cranial Nerves and Their Function 1 Olfactory - smell S 2 Optic vision S 3 Occulomotor eye movements, control of pupil and lens, tears MP 4 Trochlear - eye movements M 5 Trigeminal facial sensations, chewing SM 6 Abducens - eye movements M 7 Facial facial muscles, salivary glands, taste SMP 8 Auditory acoustic branch: audition S verstibular branch: balance S 9 Glossopharynegeal throat muscles, salivary glands, taste SMP 10 Vagus parasympathetic control of internal organs, sensation from internal organs, taste SMP 11 Spinal accessory head and neck muscles M 12 Hypoglossal tongue and neck muscles M S, sensory; M, motor; P, parasympatheic function

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22 Studying the Brain: Research Methods Electroencephalography (EEG) F 3.10 Damage studies/lesioning Electrical stimulation (ESB) F 3.11 Transcortical Magnetic Stimulation (TMS) F 3.12 Brain imaging computerized tomography CT F 3.13 positron emission tomography - PET F 3.14 magnetic resonance imaging MRI F 3.15 functional magnetic resonance imaging fmri F 3.15

23 Figure 3-10 Electroencephalography (EEG)

24 XXX 3.13

25 Figure 3.14 PET scan Figure 3.15 MRI and fmri scans

26 Positron Emission Tomography PET scan

27 Magnetic Resonance Imaging - MRI

28 Functional MRI images showing reduced activation of language areas during a linguistic task in patients with schizophrenia

29 Functional MRI images

30 Brain Regions and Functions Hindbrain vital functions medulla, pons, and cerebellum Midbrain sensory functions dopaminergic projections, reticular activating system Forebrain emotion, complex thought thalamus, hypothalamus, limbic system, cerebrum, cerebral cortex

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32 The Cerebrum: Two Hemispheres, Four Lobes Cerebral Hemispheres two specialized halves connected by the corpus collosum F 3.18 Left hemisphere verbal processing: language, speech, reading, writing, sequential Right hemisphere nonverbal processing: spatial, musical, visual recognition, parallel Four Lobes: - F 3.19 Occipital vision Parietal somatosensory phantom limb - V. S. Ramachandran - Phantoms in the Brain Temporal - auditory Frontal movement, executive control systems F 3.20 Primary functions and associated functions Language Broca s and Wernicke s areas loss of language aphasia F 3.21

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34 Figure 3.19 The cerebral cortex in humans

35 Figure 3.20 Primary motor cortex with homunculus

36 Mirror Neurons An area just forward of the primary motor cortex is where mirror neurons were first discovered accidentally in the mid-1990s. May play a role in the acquisition of new motor skills, the imitation of others, the ability to feel empathy for others, and dysfunctions in mirror neuron circuits may underlie the social deficits seen in autistic disorders.

37 The Plasticity of the Brain The brain is more plastic or malleable than widely assumed Aspects of experience can sculpt features of brain structure Damage to incoming sensory pathways or tissue can lead to neural reorganization Jill Bolte Taylor, Ph.D. My Stroke of Insight a neuroscientist story of her stroke and recovery Adult brain can generate new neurons neurogenesis

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39 Figure 3.22 Visual input with split-brain Roger Sperry and others Figure 3.23 Split-brain research

40 The Endocrine System: Glands and Hormones Hormones chemical messengers in the bloodstream Pulsatile release by endocrine glands Negative feedback system Endocrine glands Pituitary master gland, growth hormone Thyroid - metabolic rate Adrenal - salt and carbohydrate metabolism Pancreas - sugar metabolism Gonads - sex hormones Use of steroids

41 Figure 3.24 The endocrine system

42 Genes and Behavior: The Interdisciplinary Field of Behavioral Genetics Behavioral genetics = the study of the influence of genetic factors on behavioral traits Basic terminology: Chromosomes strands of DNA carrying genetic information Human cells contain 46 chromosomes in pairs (sex-cells 23 single) Each chromosome thousands of genes, also in pairs Dominant, recessive Homozygous, heterozygous Genotype/Phenotype and Polygenic Inheritance

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44 Research Methods in Behavioral Genetics Family studies does it run in the family? Twin studies compare resemblance of identical (monozygotic) and fraternal (dizygotic) twins on a trait Adoption studies examine resemblance between adopted children and their biological and adoptive parents

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48 Modern Approaches to the Nature vs. Nurture Debate Molecular Genetics = the study of the biochemical bases of genetic inheritance Genetic mapping locating specific genes - The Human Genome Project Behavioral Genetics The interactionist model Richard Rose (1995) We inherit dispositions, not destinies.

49 Evolutionary Psychology: Behavior in Terms of Adaptive Significance Based on Darwin s ideas of natural selection Reproductive success key Adaptations behavioral as well as physical Fight-or-flight response Taste preferences Parental investment and mating

50 Parental Investment and Mating Systems - sociobiology Polygyny high female, low male based on a study by Buss (1994) found in 84 % of human cultures Polyandry high male, low female rare but examples have been found for example in the Pahari of Nepal and India, and Tibet and other limited places in the world. The system in Tibet was based on class and land considerations. Monogamy shared parental investment but not always equal. There are few exclusively monogamous species 15 % of human cultures (Buss, 1994) Polygynadry group parental investment and very rare in chimpanzees mating is promiscuous for males and females Incest universal taboo increased genetic diversity

51 Figures 3.32 & 3.33 brain asymmetry and speech localization use of Wadi technique and TMS