Concepts of Neurobiology

1. Concepts of Neurobiology

2. Introduction • The 1990’s was called the “decade of the Brain” with the challenge of studying the biological basis of behavior • In keeping with the “neuro scientific revolution”, greater emphasis is placed on the organic basis of mental illness • Research is ongoing and new discoveries are being made. fMRI and sMRI’s are giving us new information.

3. What makes a brain happy and healthy? • Balanced Neurotransmitters • Brain uses the most glucose • Healthy Diet (serotonin/GABA shake) • Aerobic exercise • Empathic conversation • 8 hours of sleep • Listening to music • Being in nature • Hearing an inspiring speech • Helping others

4. What makes a brain happy?But is not so healthy • Coke, potato chips, and chocolate • A margarita • Going shopping • Driving fast • Cocaine • Nicotine • Rollercoasters/action movies • Gambling • Computer Games

5. Thee Parts of the Brain • 1. Forebrain • A. Cerebrum • B. Diencephalon • 2. Midbrain • 3. Hindbrian or brain stem

6. 1. The Forebrain • A. Cerebrum • Consists of right and left hemisphere connected by a deep groove called the corpus callosum. • Each hemisphere is divided into four lobes: • Frontal lobes • Parietal lobes • Temporal lobes • Occipital lobes

7. Frontal lobes The executive; decision maker, reliant on other parts of the brain for data. Prefrontal is the personality Parietal Lobes Perception, interpertation touch body perception Temporal Lobes Hearing Occipital Lobes Sight The Lobes of the Cerebrum: a closer Look

8. The diencephalon connects the cerebrum with the lower brain structures Limbic System: “the bagel”or the “emotional brain:” Limbic system consists of many structures Contain “4 F’s”-Feeding, fighting, fleeing and fornicating Memory, Pleasure Pathway, emotions, motivation Forebrain: Diencephalon

9. Forebrain: Diencephalon (Limbic System) • Connects the cerebrum with the lower brain structures • Very powerful • Do not underestimate • Pleasure Emotions Cravings Memories • Can overwhelm the Frontal Lobe

10. Other Important Structures in the Limbic System • Hippocampus-Contains memory • Amigdala-stores affect about memories, ie, fear, anger, rage, love, and happiness • Both structures are bilateral, under the temporal lobe • VTA is a pathway in this area of the brain that is the seat of craving in addiction

11. Diencephalon Cont. • Basil Ganglia-Modulates motor behavior; appropriate muscle tone and posture • Balances excitatory (acetylcholine) and inhibitory(dopamine) neurotransmitters in extra-pyramidal system. GABA inhibits also. • Hypothalmus, pituitary gland • Thalmus: integrates sensory input,except smell, which Limbic does

12. The Midbrain and Hindbrain • The midbrain, or mesencephalon, is responsible for visual, auditory, and balance (righting) reflexes. Substantia Nigra Produces Dopamine in this area • Hindbrain or Brain stem • Pons: regulates respiration and muscle tone • Medulla: reg. heart rate, blood pressure, • Cerebellum: muscle tone and coordination

13. Nerve Tissue • CNS: neurons, composed of: • Cell body, contains nucleus • Axon, transmits message to next cell • Dendrites, receives messages from cells • Three classes of neurons in CNS • Afferent, (sensory) • Efferent, (motor) • Interneurons, in CNS

14. Neurons: a reveiw

15. Synapses • The synapse is the junction 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. • Electrical impulses begins the process.

16. Synapse: a review

17. Neurotransmitters • Play an important role in human emotions and behavior • Are the target for the mechanism of action for psychotropic medications • Summary: Neurotransmitters are released into the synaptic cleft from the axon to the dendrite. The substance is either inactivated or returned to the axon.

18. Categories of neurotransmitters • Cholinergics • Acetylcholine: involved in sleep, arousal, movement, MEMORY, • Monoamines • Norepinephrine: effects mood, cognition, perception, locomotion, CV functioning, sleep and arousal

19. Monoamines: • Dopamine: effects movement, coordination, emotions, voluntary judgment, and release of prolactin • Serotonin: effects sleep, arousal, libido, appetite, mood, aggression, pain perception, coordination, and judgment • Histamine: Not sure of influence on mood

20. Amino Acids and Neuropeptides • Amino Acid: gamma aminobutyric acid(GABA) functions as an inhibitor neurotransmitter. Has a calming effect. • Neuropeptides: endorphins and enkephlins, modulates pain and reduces peristalsis. Also called “natural opiates”

21. Autonomic Nervous System • Sympathetic: Dominates in stressful situations, prepares body for fight or flight • Parasympathic: Dominates when person is relaxed

22. Neuroendocrinology • Hypothalamus-has direct control over the pituitary gland, the “master gland” • All these effect health. Our main concerns are: TSH, ACTH, Melatonin • Circadian Rhythms- implications in many mental illness as it effects the ability to sleep.

23. Other factors in Neurobiology • Genetics: research has shown that all major mental illness seem to have a genetic base. • Psychoimmunology: Normal immune responses are decreased with grief, bereavement, and depression.

24. Implications for Nursing • Nature-Nurture dichotomy does not exist. Each effects the other. • A nurse never “Just takes care of the body” even if you want to. • Psychiatric/mental health nurses can not “Just take care of the mind.” • “Pathophysiology” check lab work daily. Listen and observe

25. Goals for the Student Nurse in Psychiatric Nursing • Learn about mental illness • Improve communication • Psychotropic Medication • Decrease your fear of “Mental Patients” • Attend groups

26. Neurobiology The End