Concepts of NeurobiologyConcepts of Neurobiology

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IntroductionIntroduction

The 1990’s was called the “decade of The 1990’s was called the “decade of the Brain” with the challenge of the Brain” with the challenge of studying the biological basis of behaviorstudying the biological basis of behavior

In keeping with the “neurobiology In keeping with the “neurobiology scientific revolution”, greater emphasis scientific revolution”, greater emphasis is placed on the organic basis of mental is placed on the organic basis of mental illnessillness

Research is ongoing and new Research is ongoing and new discoveries are being made. discoveries are being made.

What makes a brain happy What makes a brain happy and healthy?and healthy? Balanced NeurotransmittersBalanced Neurotransmitters Brain uses the most glucoseBrain uses the most glucose

– Healthy Diet (serotonin/GABA shake)Healthy Diet (serotonin/GABA shake)– Aerobic exercise Aerobic exercise – Empathic conversationEmpathic conversation– 8 hours of sleep 8 hours of sleep – Listening to musicListening to music– Being in natureBeing in nature– Hearing an inspiring speechHearing an inspiring speech– Helping others Helping others

What makes a brain happy?What makes a brain happy?But is not so healthyBut is not so healthy

Coke, potato chips, and chocolate Coke, potato chips, and chocolate A margaritaA margarita Going shoppingGoing shopping Driving fastDriving fast CocaineCocaine Nicotine Nicotine Rollercoasters/action moviesRollercoasters/action movies GamblingGambling Computer GamesComputer Games

Thee Parts of the BrainThee Parts of the Brain

1. Forebrain1. Forebrain– A. CerebrumA. Cerebrum– B. DiencephalonB. Diencephalon

2. Midbrain2. Midbrain 3. Brain Stem3. Brain Stem

1. The Forebrain1. The Forebrain– A. CerebrumA. Cerebrum

Consists of right and left hemisphere Consists of right and left hemisphere connected by a deep groove called the connected by a deep groove called the corpus callosum.corpus callosum.

Each hemisphere is divided into four lobes:Each hemisphere is divided into four lobes:– Frontal lobesFrontal lobes– Parietal lobesParietal lobes– Temporal lobesTemporal lobes– Occipital lobesOccipital lobes

The Lobes of the Cerebrum: The Lobes of the Cerebrum: a closer Looka closer Look

Frontal lobesFrontal lobes– The executive; The executive;

decision maker, decision maker, reliant on other reliant on other parts of the brain parts of the brain for data. Prefrontal for data. Prefrontal is the personalityis the personality

Parietal LobesParietal Lobes– Perception, Perception,

interpertation interpertation touch body touch body perceptionperception

Temporal LobesTemporal Lobes– HearingHearing

Occipital LobesOccipital Lobes– SightSight

Forebrain: DiencephalonForebrain: Diencephalon

The diencephalon The diencephalon connects the connects the cerebrum with the cerebrum with the lower brain structureslower brain structures– Limbic SystemLimbic System: : “the “the

“emotional brain:”“emotional brain:” – Limbic system consists Limbic system consists

of many structuresof many structures– Contain “4 F’s”-Contain “4 F’s”-

Feeding, fighting, Feeding, fighting, fleeing and fornicatingfleeing and fornicating

– Memory, Pleasure Memory, Pleasure Pathway, emotions, Pathway, emotions, motivationmotivation

Forebrain: Diencephalon Forebrain: Diencephalon (Limbic System)(Limbic System)

Connects the cerebrum with the Connects the cerebrum with the lower brain structureslower brain structures

Very powerfulVery powerful Do not underestimateDo not underestimate Pleasure Emotions Cravings Pleasure Emotions Cravings

MemoriesMemories Can overwhelm the Frontal LobeCan overwhelm the Frontal Lobe

Other Important Structures in Other Important Structures in the Limbic Systemthe Limbic System

Hippocampus-Contains memoryHippocampus-Contains memory Amigdala-stores affect about Amigdala-stores affect about

memories, ie, fear, anger, rage, love, memories, ie, fear, anger, rage, love, and happinessand happiness

Both structures are bilateral, under Both structures are bilateral, under the temporal lobethe temporal lobe

VTA is a pathway in this VTA is a pathway in this area of the brain that is the area of the brain that is the seat of craving in addiction seat of craving in addiction

Basil GangliaBasil Ganglia

controls starting and stopping controls starting and stopping movementsmovements– Balances excitatory (Balances excitatory (acetylcholineacetylcholine) )

and inhibitory(and inhibitory(dopaminedopamine) ) neurotransmitters in extra-pyramidal neurotransmitters in extra-pyramidal system (EPS). GABA inhibits also.system (EPS). GABA inhibits also.

– If there are changes in the balance If there are changes in the balance between acetylcholine and dopamine between acetylcholine and dopamine motor function will abnormal.motor function will abnormal.

CerebellumCerebellum

Second largest structureSecond largest structure Dependent on the balance between Dependent on the balance between

acetylcholine acetylcholine and and dopaminedopamine for normal for normal movementmovement

Function (highly specialized)Function (highly specialized)– Movement Movement – Posture Posture – BalanceBalance– Sensory motor coordinationSensory motor coordination– Hand eye coordinationHand eye coordination

The Midbrain and Brian The Midbrain and Brian StemStem

The midbrain contorls visual, auditory, and balance (righting) The midbrain contorls visual, auditory, and balance (righting) reflexes. Substantia Nigra Produces reflexes. Substantia Nigra Produces DopamineDopamine in this areain this area

Brain stemBrain stem– Pons: regulates respiration and muscle tonePons: regulates respiration and muscle tone– Medulla: reg. heart rate, blood pressure,Medulla: reg. heart rate, blood pressure,– Cerebellum: muscle tone and coordination Cerebellum: muscle tone and coordination

Reticular Activating Reticular Activating System System (not on test)(not on test)

Responsible for Responsible for regulation of arousal regulation of arousal and sleep-wake and sleep-wake transitions.transitions.

Nerve TissueNerve Tissue

Neurons are composed of: Neurons are composed of: – Cell body, contains nucleus Cell body, contains nucleus – Axon, transmits message to next cellAxon, transmits message to next cell– Dendrites, receives messages from cellsDendrites, receives messages from cells– Myelin sheath: insulates and promotes conductionMyelin sheath: insulates and promotes conduction

Three classes of neurons in CNSThree classes of neurons in CNS– Afferent: (sensory)Afferent: (sensory)

Send messages to the brainSend messages to the brain– Efferent: (motor)Efferent: (motor)

Send messages away from the brainSend messages away from the brain

– Interneurons, in CNSInterneurons, in CNS

Neurons: a reveiwNeurons: a reveiw

SynapsesSynapses

The synapse is the junction between The synapse is the junction between two neurons .two neurons .

Synaptic Cleft: space between Synaptic Cleft: space between neuronsneurons

Pre-synaptic neuron: area of axon Pre-synaptic neuron: area of axon where neurotransmitters are stored.where neurotransmitters are stored.

Postsynaptic neuron: area of dendrite Postsynaptic neuron: area of dendrite where receptor sites are located.where receptor sites are located.

Synapse: a reviewSynapse: a review

NeurotransmittersNeurotransmitters

Play an important role in human Play an important role in human emotions and behavior emotions and behavior

Are the target for the mechanism of Are the target for the mechanism of action for action for psychotropic medicationspsychotropic medications

Summary: Neurotransmitters are Summary: Neurotransmitters are released into the synaptic cleft from released into the synaptic cleft from the axon to the dendrite. The the axon to the dendrite. The substance is either inactivated or substance is either inactivated or returned to the axon.returned to the axon.

Categories of Categories of neurotransmittersneurotransmitters

CholinergicsCholinergics– AcetylcholineAcetylcholine: involved in sleep, : involved in sleep,

arousal, movement, MEMORY, arousal, movement, MEMORY, MonoaminesMonoamines

– NorepinephrineNorepinephrine: effects mood, : effects mood, cognition, perception, locomotion, CV cognition, perception, locomotion, CV functioning, sleep and arousalfunctioning, sleep and arousal

Monoamines:Monoamines:

Dopamine:Dopamine: effects movement, effects movement, coordination, emotions, voluntary coordination, emotions, voluntary judgment, and release of prolactinjudgment, and release of prolactin

Serotonin:Serotonin: effects sleep, arousal, effects sleep, arousal, libido, appetite, mood, aggression, libido, appetite, mood, aggression, pain perception, coordination, and pain perception, coordination, and judgmentjudgment

Histamine: Not sure of influence on Histamine: Not sure of influence on mood mood

Amino Acids and Amino Acids and NeuropeptidesNeuropeptides Amino Acid: gamma aminobutyric Amino Acid: gamma aminobutyric

acid(acid(GABAGABA) functions as an ) functions as an inhibitor neurotransmitter. Has a inhibitor neurotransmitter. Has a calming effect. calming effect.

Neuropeptides: endorphins and Neuropeptides: endorphins and enkephlins, modulates pain and enkephlins, modulates pain and reduces peristalsis. Also called reduces peristalsis. Also called “natural opiates” “natural opiates”

Autonomic Nervous Autonomic Nervous SystemSystem

Sympathetic: Dominates in Sympathetic: Dominates in stressful situations, prepares body stressful situations, prepares body for fight or flightfor fight or flight

Parasympathic: Dominates when Parasympathic: Dominates when person is relaxedperson is relaxed

Endocrine System: Endocrine System: a communication systema communication system

Neurochemical Messengers called hormones:Neurochemical Messengers called hormones: Hypothalamus- instructs the pituitary glandHypothalamus- instructs the pituitary gland

– The pituitary gland: The pituitary gland: secretes secretes TSHTSH (Thyroid stimulation Hormone) stimulates (Thyroid stimulation Hormone) stimulates

target cells in:target cells in:– The thyroidThe thyroid (energy level) (energy level)

– The pituitary gland also stimulates target cells in the:The pituitary gland also stimulates target cells in the:– The pituitary gland can monitors The pituitary gland can monitors

The release The release ACTHACTH (adrenal corticotropic (adrenal corticotropic hormone) stimulates the adrenals hormone) stimulates the adrenals (response to stress cortisol)(response to stress cortisol) The gonads (testosterone and estrogen)The gonads (testosterone and estrogen)

The Stress Response to The Stress Response to CortisolCortisol

Other factors in Other factors in NeurobiologyNeurobiology Genetics: research has shown that Genetics: research has shown that

all major mental illness seem to all major mental illness seem to have a genetic base.have a genetic base.

Psychoimmunology: Normal Psychoimmunology: Normal immune responses are decreased immune responses are decreased with grief, bereavement, and with grief, bereavement, and depression.depression.

Implications for NursingImplications for Nursing

Nature-Nurture: Each effects the other.Nature-Nurture: Each effects the other. A nurse never “Just takes care of the body” even if you want to.A nurse never “Just takes care of the body” even if you want to. Mental health nurses can not “Just take care of the mind.”Mental health nurses can not “Just take care of the mind.” ““Pathophysiology” check lab work daily. Listen and observe Pathophysiology” check lab work daily. Listen and observe

Goals for the Student Nurse Goals for the Student Nurse in Mental Health Nursingin Mental Health Nursing

Learn about mental illnessLearn about mental illness Improve communicationImprove communication Psychotropic MedicationPsychotropic Medication Decrease your fear of “Mental Decrease your fear of “Mental

Patients”Patients” Attend groupsAttend groups

NeurobiologyNeurobiology

The EndThe End