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NEUROBIOLOGICAL BASES OF BEHAVIOR

NEUROBIOLOGICAL BASES OF BEHAVIOR. MODULE 1 RNSG 2213. PART I Anatomy and Physiology Review. A & P Review. Three Main Parts of the Brain 1. Forebrain: a. Cerebrum b. Diencephalon 2 . Midbrain 3. Hindbrain or Brain Stem. Cerebral cortex “Gray matter ”. The Forebrain. Cerebrum

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NEUROBIOLOGICAL BASES OF BEHAVIOR

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  1. NEUROBIOLOGICAL BASES OF BEHAVIOR MODULE 1 RNSG 2213

  2. PART IAnatomy and Physiology Review

  3. A & P Review Three Main Parts of the Brain 1. Forebrain: a. Cerebrum b. Diencephalon 2. Midbrain 3.Hindbrain or Brain Stem

  4. Cerebral cortex “Gray matter”

  5. The Forebrain • Cerebrum • Right and left hemispheres connected by the corpus callosum

  6. Lobes of the Cerebrum

  7. The Lobes of the Cerebrum: a Closer Look • Frontal Lobe • “The Executive” or decision maker; regulation of behavior, e.g. planning, adaptation to change, etc. • Reliant on other parts of the brain for data. • Prefrontalarea relates to features of the personality, motivation & goal setting • Motor and Premotor areas: voluntary movement

  8. Lobes of the Cerebrum, cont’d • Parietal Lobe • Perception, interpretation, touch, body perception • Temporal Lobe • Hearing  Occipital Lobe --Vision

  9. The Forebrain: Cerebrum, cont’d Limbic System • “The Emotional Brain:” • Consists of many structures • Controls the “4 F’s”: Feeding, Fighting, Fleeing and Fornicating • Functions include Memory, Pleasure, Emotions, Motivation

  10. Functions of The Limbic System

  11. More Functions of Limbic System • Olfactory Functions • Feeding Functions (consider the relationships between emotions, pleasure, smell, and food intake!)

  12. Some Important Structures Connecting to the Limbic System • Hypothalamus-activates & controls many body functions: endocrine, sleep, appetite, body temp. • Pineal Gland- role in sleep (secretes melatonin) and consciousness

  13. Important Structures Connecting to Limbic System, cont’d • Thalamus-association of sensory inputs with pleasant and unpleasant feelings • Hippocampus-memory processing, and making of new memories • Amygdala-stores feelings relating to memories,

  14. Structures Connecting to Limbic System cont’d • VTA (Ventral Tegmental Area) -midbrain • “Pleasure pathway” or “Reward Center” • Contains many dopaminergic neurons that connect to sites in limbic system • seat of craving in addiction

  15. Basal Ganglia or Extrapyramidal System Regulate motor behavior, appropriate muscle tone and posture Balances excitatory and inhibitory neurotransmitters. Important Structures Connecting to the Limbic System,cont’d

  16. The Forebrain, cont’d Diencephalon • Connects the cerebrum with the lower brain structures • Relays sensory info. to cerebral cortex (thalamus) • Releases and inhibits hormones (hypothalamus) • Regulates fluid, temperature, GI, CV function (hypothalamus)

  17. The Midbrain • Midbrain, or Mesencephalon --Responsible for visual, auditory, and balance reflexes and posture --Substantia Nigra produces Dopamine in this area

  18. The Hindbrain & Brain Stem • Hindbrain/Brain Stem Structures • Pons: regulates respiration and muscle tone • Medulla: reg. heart rate, blood pressure • Cerebellum: muscle tone and coordination

  19. More (Hindbrain) Brainstem Structures • Reticular Formation- Integrates sensory input • Reticular Activating System-regulates alertness and ability to pay attention (tune out some stimuli); allows us to fall asleep as well as wake up

  20. A & P: Systems • Autonomic Nervous System • Sympathetic: Dominates in stressful situations, prepares body for fight or flight • Parasympathic: Dominates when person is relaxed

  21. Neurons: A Review Nerve Tissue • CNS: neurons, composed of: • Cell body contains nucleus (genetic material) • Axon transmits message to next cell • Dendrites receive messages from cell

  22. Neurons: Review, cont’d Three classes of neurons in CNS • Afferent (sensory) • Efferent (motor) • Interneurons

  23. Neurons: Review, cont’d • Synapse: the contact point between two neurons. • Synaptic Cleft: space between neurons • Pre-synaptic neuron: area of axon where neurotransmitters are stored. • Postsynaptic neuron: area of dendrite where receptor sites are located.

  24. Neurotransmission = Chemical Signalling

  25. Neurotransmission (Physiology) • Neurotransmitters are released into the synaptic cleft (space) from the axon to the dendrite. (--Calcium ions facilitate NT release) • NTs bind with receptors on post-synaptic neuron (dendrite) and activate it • Then NT substance is either deactivated or returned to the axon (“reuptake”). • Nerve cells can release more than one type of neurotransmitter

  26. Pre-synaptic and postsynaptic neuron interchange

  27. Neurotransmission Across the Synapse

  28. Role of Neurotransmitters in Mental Health • Neurotransmitters • Play an important role in human emotions and behavior • Influence motor activity and hormone levels • Are the target for the mechanism of action for psychotropic medications

  29. Categories of Neurotransmitters Cholinergics • Acetylcholine (ACh): involved in sleep, arousal, movement, memory

  30. Categoriesof Neurotransmitters, cont’d MONOAMINES • Norepinephrine: affects mood, cognition, perception, locomotion, CV functioning, sleep and arousal • Dopamine: effects movement, coordination, emotions, voluntary judgment, and release of prolactin

  31. Monoamines, cont’d • Serotonin: effects sleep, arousal, libido, appetite, mood, aggression, pain perception, coordination, and judgment • Histamine (role not well understood): involved in the immune/inflammatory response appears to be involved in mood

  32. Categories of Neurotransmitters, cont’d • Amino Acids • Gamma Aminobutyric Acid (GABA)functions as an inhibitory neurotransmitter (“brain calmer”) • Glutamate excitatory

  33. Categories of NTs, cont’d • Neuropeptides: endorphins and enkephlins, modulate pain and reduce peristalsis. Also called “natural or endogenous opiates”

  34. Neuroendocrinology • Hypothalamus- the “master gland,” has direct control over the pituitary • Hormones: all of these affect health. Our main focus in this course = TSH, Melatonin, ACTH • Circadian Rhythms- implications in many mental illnesses: affect sleep cycles and regulate hormones which influence mood and emotions.

  35. Other Factors in Neurobiology • Genetics: research has shown that all major mental illness seem to have genetic markers. (Increases “risk for”) • Psychoimmunology: Normal immune responses are decreased with acute and chronic stress, grief, bereavement, and depression.

  36. PART 2 Neurobiology and Mental Illness

  37. Neurobiology and Mental Illness • Neuroanatomical Changes (examples) -Enlargement of ventricles: schizophrenia, alcoholism-Atrophy of hippocampus: trauma or severe stress in early life

  38. Which one is the schizophrenic brain?

  39. Neurobiology and Mental Illness, cont’d • Decreased Cerebral Blood Flow (Some examples:) -In Prefrontal cortex: Schizophrenia -In Frontal lobe: Attention-Deficit Hyperactivity Disorder (ADHD)

  40. Which one is the schizophrenic brain? Cerebral blood flow (CBF) levels in middle cerebral artery of gray matter Source: Romanian Journal of Psychopharmacology, 2008

  41. Neurobiology and Mental Illness, cont’d • Neurotransmitter Dysfunction Lack of availability or lack of secretion (Some examples:) • Too much dopamine: Schizophrenia • Insufficient serotonin: Depression • Insufficient norepinephrine: Depression • Insufficient GABA: Anxiety disorders • Too much norepinephrine: Anxiety Disorders

  42. NB and MI, cont’d • Neuroendocrine Dysfunction (examples) -Altered Hypothalamic regulatory mechanisms: Anorexia Nervosa -Increased Hypothalamic-Pituitary-Adrenal Axis (HPA) activity causing elevated cortisol (stress hormone) levels: Caused by early life deprivation, trauma or stress -Thyroid dysfunction: (Hyper-)Anxiety, (Hypo-) Depression

  43. Implications for Nursing  • MI must be seen as interaction of biological-interpersonal- environmental factors • Psychiatric/mental health nurses can not “just take care of the mind.” • Medical needs of mental health clients need equal attention

  44. Psychopharmacology • Metabolism of Psychotropic Drugs Involves 2 Enzyme Systems • Cytochrome P-450 (CYP) System • controls 75% of all drug metabolism • Monamine oxidase (MAO)-inactivates monoamines • dysfunction in this system causes serious sympathetic SEs

  45. Psychopharmacology: Drug Interactions and Adverse Effects • Synergism and opposition are common problems • The “right” prescription: how do you know? • Ethical and legal implications

  46. Implications for Nursing: Client Teaching • Must have patient Consent in order to teach • Client and Family Attitudes: What are the issues? • Side Effects: What are the issues? • Culture and Personal Beliefs: What are your attitudes about these drugs? How do they compare to your client’s?

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