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Neural Communication and Brain Organization: Understanding the Biological Bases of Behavior

Explore the intricate workings of neurons, synapses, and neurotransmitters in the brain, highlighting neural communication, brain organization, and plasticity. Learn about the structure and function of the nervous system, including important brain regions and functions. Discover the significance of mirror neurons and the brain's adaptability. Delve into how communication within the nervous system influences behavior and mental health.

carolynbradley
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Neural Communication and Brain Organization: Understanding the Biological Bases of Behavior

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  1. Chapter 3: The Biological Bases of Behavior https://www.youtube.com/watch?v=h5f56Ynb01E https://www.youtube.com/watch?v=u-xEhxMZOcs&list=PLxHMOb3leLUEiRNxpG2tRbM5CL37B5BD2

  2. Communication in the Nervous System • Hardware • Glia • structural support and insulation • memory formation • chronic pain • psychological disorders • Neurons – communication • Soma – cell body • Dendrites – receive • Axon – transmit away

  3. Figure 3.1 Structure of the neuron

  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 3.2 The neural impulse

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

  9. Figure 3.3 The synapse

  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

  13. Signals: From Postsynaptic Potentials to Neural Networks • Synaptic connections • Elimination and creation • Synaptic pruning

  14. Figure 3.5 Synaptic pruning

  15. Neurotransmitters • Specific neurotransmitters work at specific synapses • Lock and key mechanism • Agonist – mimics neurotransmitter action • Antagonist – opposes action of a neurotransmitter • 15 – 20 neurotransmitters known at present • Interactions between neurotransmitter circuits https://www.youtube.com/watch?v=90cj4NX87Yk&feature=youtu.be

  16. Table 3.1 Common Neurotransmitters and Some of their Functions

  17. Organization of the Nervous System • Central nervous system (CNS) • Afferent = toward the CNS • Efferent = away from the CNS • Peripheral nervous system • Somatic nervous system • Autonomic nervous system (ANS) • Sympathetic • Parasympathetic

  18. Figure 3.7 The central and peripheral nervous systems

  19. Figure 3.8 The autonomic nervous system (ANS)

  20. Studying the Brain: Research Methods • Electroencephalography (EEG) • Damage studies/lesioning • Electrical stimulation (ESB) • Transcranial magnetic stimulation (TMS) • Brain imaging – • computerized tomography • positron emission tomography • magnetic resonance imaging (MRI) • Functional magnetic resonance imaging (fMRI)

  21. 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

  22. The Cerebrum:Two Hemispheres, Four Lobes • Cerebral Hemispheres – two specialized halves connected by the corpus callosum • Left hemisphere – verbal processing: language, speech, reading, writing • Right hemisphere – nonverbal processing: spatial, musical, visual recognition

  23. The Cerebrum:Two Hemispheres, Four Lobes • Four Lobes: • Occipital – vision • Parietal - somatosensory • Temporal - auditory • Frontal – movement, executive control systems

  24. Figure 3.16 Structures and areas in the human brain

  25. Figure 3.18 The cerebral hemispheres and the corpus callosum

  26. Figure 3.19 The cerebral cortex in humans

  27. Figure 3.20 The primary motor cortex

  28. 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.

  29. 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 • Adult brain can generate new neurons - neurogenesis

  30. Figure 3.21 Language processing in the brain

  31. The Endocrine System: Glands & 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

  32. Genes and Behavior:The Field of Behavioral Genetics • Behavioral genetics = the study of the influence of genetic factors on behavioral traits • 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

  33. Genes and Behavior:The Field of Behavioral Genetics • Dominant, recessive • Homozygous, heterozygous • Genotype/Phenotype and PolygenicInheritance

  34. Figure 3.25 Genetic material

  35. 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

  36. Figure 3.27 Genetic relatedness

  37. Figure 3.28 Family studies of risk for schizophrenic disorders

  38. Figure 3.30 Twin studies of intelligence and personality

  39. Modern Approaches to theNature 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 (2000) – “Genes confer dispositions, not destinies.”

  40. 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

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