NEUROBIOLOGICAL BASES OF BEHAVIOR

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 • Consists of right and left hemispheres connected by the corpus callosum = deep band of nerve cell fibers

6. 1. Each cerebral hemisphere is divided into four lobes: Frontal lobes Parietal lobes Temporal lobes Occipital lobes

7. Lobes of the Cerebrum

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

9. Lobes of the Cerebrum, cont’d • Temporal Lobes • Hearing • Occipital Lobes • Vision

10. 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

12. Functions of The Limbic System

13. Other Functions of Limbic System • Olfactory Functions • Feeding Functions (We won’t study these, but consider the relationships between emotions, pleasure, smell, and food intake!)

14. 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; exact function not known

15. Important Structures Connecting to Limbic System, cont’d • Hippocampus-memory processing, and making of new memories • Amygdala-stores feelings relating to memories, i.e.: fear, anger, rage, love, happiness, etc.

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

17. 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

18. The Forebrain, cont’d Diencephalon • The diencephalon connects the cerebrum with the lower brain structures

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

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

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

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

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

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

26. 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.

27. 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

28. Pre-synaptic and postsynaptic neuron interchange

29. Neurotransmission Across the Synapse

30. 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

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

32. 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

33. 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

34. Categories of Neurotransmitters, cont’d • Amino Acids • Gamma Aminobutyric Acid (GABA) functions as an inhibitory neurotransmitter (“brain calmer”) • Neuropeptides: endorphins and enkephlins, modulate pain and reduce peristalsis. Also called “natural or endogenous opiates”

35. 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.

36. 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.

37. PART 2 Neurobiology and Mental Illness

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

39. Which one is the schizophrenic brain?

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

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

42. 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

43. 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

44. Implications for Nursing  • Nature-Nurture dichotomy does not exist. Each affects the other. • Nurses need to take a holistic approach to mental health • Psychiatric/mental health nurses can not “just take care of the mind.” • Medical needs of mental health clients: Physical status, responses to drug effects, and diagnostic/ lab work need to be monitored.