Brain Structure Brain Structure and and FunctionFunction

OverviewOverview

Lobes of the brain (Forebrain)Lobes of the brain (Forebrain) Midbrain/HindbrainMidbrain/Hindbrain Protection and Blood supplyProtection and Blood supply Structure and Function of a Structure and Function of a

neuronneuron Synaptic TransmissionSynaptic Transmission NeurotransmittersNeurotransmitters

The brainThe brain

Most complex Most complex organ of the bodyorgan of the body

Only weighs Only weighs 1,300 grams1,300 grams

Contains billions Contains billions of neural of neural networks that networks that interact to create interact to create human behaviourhuman behaviour

ForebrainForebrain Cerebrum and Cerebral cortexCerebrum and Cerebral cortex Left and Right HemispheresLeft and Right Hemispheres Left hemisphere for most people is the Left hemisphere for most people is the

dominant hemisphere- responsible for dominant hemisphere- responsible for production of language, mathematical production of language, mathematical ability, problem solving, logicability, problem solving, logic

Right hemisphere thought to be Right hemisphere thought to be responsible for creativity and spatial responsible for creativity and spatial abilityability

(Barlow and Durand , 2005)

Frontal LobeFrontal Lobe Located at the front of both cerebral Located at the front of both cerebral

hemispheres hemispheres Primary motor cortexPrimary motor cortex Pre-motor cortexPre-motor cortex Broca’s Area- Motor Production of Broca’s Area- Motor Production of

speechspeech Complex Functioning- personality, Complex Functioning- personality,

judgement, insight, reasoning, judgement, insight, reasoning, problem solving, abstract thinking and problem solving, abstract thinking and working memoryworking memory

(http://www.nidcd.nih.gov/health/voice/aphasia.asp)

(Barlow and Durand , 2005)

Parietal lobeParietal lobe

Located behind frontal lobeLocated behind frontal lobe Somatosensory cortexSomatosensory cortex Spatial orientation, perception and Spatial orientation, perception and

comprehension of language function comprehension of language function recognising object by touchrecognising object by touch

Links visual and somatosensory Links visual and somatosensory information togetherinformation together

NeglectNeglect

Temporal LobesTemporal Lobes

Located at each side of the brainLocated at each side of the brain Involved in receiving and Involved in receiving and

processing auditory information , processing auditory information , higher order visual information, higher order visual information, complex aspects of memory and complex aspects of memory and languagelanguage

Wernicke’s Area- Comprehension Wernicke’s Area- Comprehension of speech of speech

(Barlow and Durand , 2005)

Occipital lobesOccipital lobes

Rearmost portion of the brainRearmost portion of the brain Visual processing areaVisual processing area

Corpus Callosum- Fibre bundle in Corpus Callosum- Fibre bundle in the brain that connects the two the brain that connects the two hemispheres together. hemispheres together.

DiencephalonDiencephalon ThalamusThalamus- filters - filters

sensory information, sensory information, controls mood states controls mood states and body movement and body movement associated with associated with emotive statesemotive states

HypothalamusHypothalamus- ‘Central - ‘Central control’ for pituitary control’ for pituitary gland. Regulates gland. Regulates autonomic, emotional, autonomic, emotional, endocrine and somatic endocrine and somatic function. Has a direct function. Has a direct involvement in stress involvement in stress and mood states. and mood states.

(http://training.seer.cancer.gov/module_anatomy/unit5_3_nerve_org1_cns.html)

HindbrainHindbrain

CerebellumCerebellum- regulates equilibrium, - regulates equilibrium, muscle tone, postural control, fine muscle tone, postural control, fine movement and coordination of movement and coordination of voluntary muscle movement.voluntary muscle movement.

PonsPons- Relay station between - Relay station between cerebrum and cerebellumcerebrum and cerebellum

(http://training.seer.cancer.gov/module_anatomy/unit6_3_endo_glnds1_pituitary.html )

Medulla oblongata-Medulla oblongata- Conscious control Conscious control of skeletal muscles, balance, co-of skeletal muscles, balance, co-ordination regulating sound impulses ordination regulating sound impulses in the inner ear, regulation of in the inner ear, regulation of automatic responses such as heart automatic responses such as heart rate, swallowing, vomiting, coughing rate, swallowing, vomiting, coughing and sneezingand sneezing

Reticular Formation- Reticular Formation- Important in Important in arousal and maintaining arousal and maintaining consciousness, alertness attention and consciousness, alertness attention and Reticular Activating System which Reticular Activating System which controls all cyclic functions i.e. controls all cyclic functions i.e. respiration, circadian rhythm. respiration, circadian rhythm.

Basal Ganglia-Basal Ganglia- Control of muscle Control of muscle tone, activity, tone, activity, posture, large posture, large muscle movements muscle movements and inhibit unwanted and inhibit unwanted muscle movements. muscle movements.

Substatia Nigra-Substatia Nigra- Produces dopamine Produces dopamine is connected to the is connected to the basal ganglia. – basal ganglia. – EPSE’sEPSE’s

(Barlow and Durand , 2005)

The Limbic systemThe Limbic system

AmygdalaAmygdala- mediates - mediates and controls major and controls major affective mood states affective mood states such as friendship , such as friendship , love, affection, fear, love, affection, fear, rage and aggression.rage and aggression.

HippocampusHippocampus- - Memory, particularly Memory, particularly the ability to turn the ability to turn short term memory short term memory into long term into long term memory. Alzheimer's memory. Alzheimer's disease.disease. (Barlow and Durand , 2005)

Protection and Blood Protection and Blood SupplySupply

MeningesMeninges- Dura mater and Pia - Dura mater and Pia matermater

CSFCSF- 2 main functions ; shock - 2 main functions ; shock absorption and mediation of absorption and mediation of blood vessels and brain tissue in blood vessels and brain tissue in exchange of nutrients.exchange of nutrients.

Circle of Willis –Circle of Willis –carotid arteries carotid arteries and baliser arteries.and baliser arteries.

Blood brain Barrier-Blood brain Barrier- Protect the Protect the brain from chemicals in the brain from chemicals in the blood. Made up of tightly packed blood. Made up of tightly packed Endothelial cells/capillaries Endothelial cells/capillaries making it difficult to penetrate. making it difficult to penetrate.

(http://training.seer.cancer.gov/module_anatomy/unit5_3_nerve_org1_cns.html)

Structure of a NeuronStructure of a Neuron

(This image has been released into the public domain by its author, LadyofHats. This applies worldwide.)

Function of a NeuronFunction of a Neuron

Resting potentialResting potential- -

positive/negative chargepositive/negative charge- voltage - voltage

gated channelsgated channels-sodium/-sodium/

potassium pumppotassium pump Action potentialAction potential

- - thresholdthreshold

--depolarisationdepolarisation (This image has been released into the public domain by its author)

Action potentialAction potential

(Rosenweig, Breedlove and Leiman ,2005 pg 64 )

Synaptic transmissionSynaptic transmission

Calcium ion Calcium ion channelschannels

SynapseSynapse Lock and Lock and

key effectkey effect reuptakereuptake

(This image has been released into the public domain by its author)

NeurotransmittersNeurotransmitters

- Acetylcholine Acetylcholine (ACh(ACh))Release through the brain Release through the brain

via cholinergic pathways. via cholinergic pathways. Plays role in:Plays role in:

- cognition - cognition (memory)(memory)

- sleep/wake cycle- sleep/wake cycle- parasympathetic - parasympathetic

nervous systemnervous system- regulation of - regulation of

heart rate, digestion, heart rate, digestion, production of production of

saliva,bladder function.saliva,bladder function.- smooth muscle - smooth muscle

contractioncontraction ( Boyd, 2002 )

MonoaminesMonoamines

NorepinephrineNorepinephrine (NE)(NE)

Found mainly in 3 Found mainly in 3 areas of the brain; areas of the brain; the locus coeruleous, the locus coeruleous, the pons and the pons and reticular formation. reticular formation. Main role;Main role;- attention, alertness, - attention, alertness, arousalarousal-sleep/wake cycle-sleep/wake cycle- regulating - regulating mood/anxietymood/anxiety

(Barlow and Durand ,2005)

Dopamine (DA)Dopamine (DA)Almost a million nerve cells Almost a million nerve cells

in the brain contain in the brain contain dopamine. Role in ;dopamine. Role in ;

- complex - complex movementmovement-cognition-cognition- motor control- motor control- emotional - emotional

responses such as responses such as euphoria or pleasure.euphoria or pleasure.

Newer antipsychotic Newer antipsychotic medication focus on medication focus on particular dopaminergic particular dopaminergic pathways in the brain. pathways in the brain. Lessening EPSE’s. Lessening EPSE’s.

(Barlow and Durand ,2005)

SerotoninSerotonin (5HT (5HT))Believed to be one of the Believed to be one of the great influences on great influences on behaviour. Complex behaviour. Complex neurotransmitter. neurotransmitter. Surprisingly only 2% of Surprisingly only 2% of serotonin is found in CNS. serotonin is found in CNS. Roles includeRoles include

- - Vasoconstriction, Vasoconstriction, gastrointestinal regulation. gastrointestinal regulation.

- Low serotonin - Low serotonin associated with aggression, associated with aggression, suicide, impulsive eating, suicide, impulsive eating, anxiety and low mood. anxiety and low mood.

- regulates - regulates general activity of the CNS, general activity of the CNS, particularly sleep.particularly sleep.

- Delusions, - Delusions, hallucinations and some of hallucinations and some of the negative symptoms of the negative symptoms of schizophrenia.schizophrenia.

(Barlow and Durand ,2005)

Amino AcidsAmino Acids GlutamateGlutamate

- found in all cells- found in all cells- controls opening of ion channels- controls opening of ion channels- blocking glutamate produces - blocking glutamate produces

psychotic psychotic symptomssymptoms- Over exposure to glutamate causes - Over exposure to glutamate causes

cell cell deathdeath GABAGABA( Gamma-aminobutyric acid)( Gamma-aminobutyric acid)

- Only found in CNS- Only found in CNS- Inhibitory neurotransmitter- Inhibitory neurotransmitter- controls excitatory - controls excitatory

neurotransmittersneurotransmitters- Implicated in anxiety disorders- Implicated in anxiety disorders

ReferencesReferences

Boyd (2002). Boyd (2002). Psychiatric Nursing , contemporary Psychiatric Nursing , contemporary practice .practice .Lippincott, USALippincott, USA

Rosenweig, Breedlove and Leiman (2002) Rosenweig, Breedlove and Leiman (2002) Biological Psychology: an Biological Psychology: an introduction to cognitive, behavioural and clinical neuroscience 3rd introduction to cognitive, behavioural and clinical neuroscience 3rd Edition.Edition.Sineur Associates , Inc USA.Sineur Associates , Inc USA.

Stuart and Laraia (2005) Stuart and Laraia (2005) Prinicples and Practice of Psychiatric Prinicples and Practice of Psychiatric Nursing. Nursing. Mosby, USA.Mosby, USA.

Barlow and Durand (2005). Barlow and Durand (2005). Abnormal Psychology, and intergrated Abnormal Psychology, and intergrated approach.approach.Thompson/Wadsworth, Australia.Thompson/Wadsworth, Australia.

Leonard BE (1997). Leonard BE (1997). Fundamentals in PsychopharmacologyFundamentals in Psychopharmacology. 2nd ed. . 2nd ed. Chichester: Wiley & Sons.Chichester: Wiley & Sons.

Purves DE, Augustine GJ, Fitzpatrick D, et al. (eds). Purves DE, Augustine GJ, Fitzpatrick D, et al. (eds). NeuroscienceNeuroscience. . Sunderland, MA: Sinauer Associates, Inc; 1997.Sunderland, MA: Sinauer Associates, Inc; 1997.

Lundbeck Institute, www.brainexplorer.comLundbeck Institute, www.brainexplorer.com Blakemore & Frith (2005). Blakemore & Frith (2005). The Learning BrainThe Learning Brain. Blackwell Publishing. Blackwell Publishing Begley (2005). The blood brain Barrier. Begley (2005). The blood brain Barrier. Gauchers NewsGauchers News May 2005c May 2005c