The BrainThe Brain

Structures, Functions, and Structures, Functions, and InjuriesInjuries

The BrainThe Brain ““Older” brain networks sustain Older” brain networks sustain

______________ functions, and enable ______________ functions, and enable memory emotions, and basic drivesmemory emotions, and basic drives

Newer neural networks within the Newer neural networks within the cerebrum cerebrum – the – the two large two large hemispheres hemispheres that contribute 85% of that contribute 85% of brain’s weight brain’s weight are associated are associated with: Perceptions, Thinking, with: Perceptions, Thinking, SpeakingSpeaking

The Cerebral CortexThe Cerebral Cortex

Cerebral Cortex:Cerebral Cortex: a thin surface a thin surface layer of interconnected neural cells, layer of interconnected neural cells, covers cerebrumcovers cerebrum ““Brain’s Thinking Crown”Brain’s Thinking Crown” Ultimate control and information-Ultimate control and information-

processing centerprocessing center How does our cerebral cortex separate us How does our cerebral cortex separate us

from other animals?from other animals?

Structure of the CortexStructure of the Cortex

Cerebral CortexCerebral Cortex: contains 20-23 : contains 20-23 billion nerve cells – 300 trillion billion nerve cells – 300 trillion synaptic connectionssynaptic connections Glial CellsGlial Cells: cells that support, nourish, : cells that support, nourish,

and protect neuronsand protect neurons Neurons = Queen BeesNeurons = Queen Bees Glial Cells = __________Glial Cells = __________

Structure of the CortexStructure of the Cortex

Each brain Each brain hemisphere is hemisphere is divided into four divided into four lobes that are lobes that are separated by separated by prominent fissures.prominent fissures. These lobes are the:These lobes are the:

___________ lobe___________ lobe (forehead)(forehead)

__________lobe__________lobe (top to (top to rear head)rear head)

________ lobe________ lobe (back of (back of head)head)

__________ lobe__________ lobe (side (side of head).of head).

The Cerebrum:The Cerebrum:Two Hemispheres, Four Two Hemispheres, Four

LobesLobes Four LobesFour Lobes: each lobe carries out : each lobe carries out

many functions and many functions many functions and many functions require require interplayinterplay of several lobes of several lobes OccipitalOccipital – associated with – associated with visual visual

processes processes ParietalParietal –associated with –associated with sensory input sensory input

for touch and body position for touch and body position TemporalTemporal – – hearing and balancehearing and balance FrontalFrontal – – muscle movement, decision-muscle movement, decision-

making, planning, & speaking making, planning, & speaking Responsible for the ability to “see” or be aware Responsible for the ability to “see” or be aware

of ourselves, re-experience past events, come up of ourselves, re-experience past events, come up with strategies or plans, interpret what is going with strategies or plans, interpret what is going on in the world around us, and tell us what to do on in the world around us, and tell us what to do and feel. and feel.

Motor FunctionsMotor Functions

1870, Fritsch & 1870, Fritsch & HitzigHitzig Electrical Electrical

stimulation to stimulation to parts of a dog’s parts of a dog’s cortexcortex

Could make Could make parts of body parts of body movemove

Stimulating parts of Stimulating parts of this region in left or this region in left or right hemisphere right hemisphere caused movements caused movements of body parts on of body parts on opposite side opposite side of the of the bodybody

Discovered Discovered motor motor cortex: cortex: area at rear of area at rear of frontal lobes that frontal lobes that control voluntary control voluntary movementsmovements

Functions of the CortexFunctions of the Cortex TheThe Motor Cortex Motor Cortex is the area at the is the area at the rear of the rear of the

frontal lobesfrontal lobes that control voluntary movements. that control voluntary movements. ___________ messages ___________ messages outout to the body to the body

The The Sensory CortexSensory Cortex (parietal lobe) (parietal lobe) ____________________ information from skin surface and sense organs.information from skin surface and sense organs.

Sensory CortexSensory Cortex

Sensory cortex: Sensory cortex: Area at the _______ of the parietal Area at the _______ of the parietal

lobeslobes Registers and processes body touch and Registers and processes body touch and

movement sensationsmovement sensations If neurosurgeons stimulate point: If neurosurgeons stimulate point:

On On toptop of this band of tissue, a person may of this band of tissue, a person may report being touched on the ____________report being touched on the ____________

On On sideside of this band of tissue, a person may of this band of tissue, a person may report being touched on their ___________report being touched on their ___________

Sensory CortexSensory Cortex

Sensory cortex:Sensory cortex: There are various areas in brain There are various areas in brain

where cortex receives input fromwhere cortex receives input from Visual information in visual cortex in Visual information in visual cortex in

occipital lobes, at the _________ of your occipital lobes, at the _________ of your brainbrain

Bash in the back of your head can make you Bash in the back of your head can make you ___________or stimulating it you might see ___________or stimulating it you might see flashes of colorflashes of color

Association AreasAssociation Areas

Association Areas:Association Areas: areas of areas of cerebral cortex, involved in cerebral cortex, involved in higher higher mental functionsmental functions such as: such as: .. .. .. ..

Association AreasAssociation Areas

Association Areas:Association Areas: Not involved in primary motor or sensory Not involved in primary motor or sensory

function function Account for _____ of cerebral cortexAccount for _____ of cerebral cortex Link sensory inputs with stored Link sensory inputs with stored

memoriesmemories Interpret, integrate, and act on Interpret, integrate, and act on

information processed by sensory information processed by sensory areasareas

Association AreasAssociation Areas

Association Areas:Association Areas: Found in all four lobes:Found in all four lobes: Frontal Lobes: Frontal Lobes: association areas association areas

enable judgment, planning, and enable judgment, planning, and processing of new memoriesprocessing of new memories Which of these would damage to frontal Which of these would damage to frontal

lobe affect?lobe affect? Intact Memories Intact Memories Planning ahead to bake a cake Planning ahead to bake a cake High Scores on IQ tests High Scores on IQ tests Cake baking skillsCake baking skills

Association AreasAssociation Areas

Frontal lobe damage can also alter Frontal lobe damage can also alter personality:personality: Removing inhibitionsRemoving inhibitions Moral judgments unrestrainedMoral judgments unrestrained

Phineas GagePhineas Gage

Effects of Other Brain Effects of Other Brain Injuries: Phineas GageInjuries: Phineas Gage

Gage was a railroad Gage was a railroad construction foremanconstruction foremanAn 1848 explosion An 1848 explosion forced a steel tamping forced a steel tamping rod through his headrod through his headOthers said he was Others said he was “no longer Gage”“no longer Gage”Lost his job, worked Lost his job, worked as a sideshow exhibitas a sideshow exhibit

Gage’s Injuries and Gage’s Injuries and SymptomsSymptoms

The rod pierced through his frontal lobe and The rod pierced through his frontal lobe and exited out the top of his skull. exited out the top of his skull.

Remarkably enough, he survived because none Remarkably enough, he survived because none of the vital parts that control breathing, of the vital parts that control breathing, movement or physical control had been movement or physical control had been damaged. damaged.

However, other However, other majormajor changes were noticed as changes were noticed as a result of the accident. Gage, a usually friendly a result of the accident. Gage, a usually friendly and normal person, and normal person, suddenly began to swear suddenly began to swear frequently, undress whenever he felt like frequently, undress whenever he felt like it, urinate in public, and have temper it, urinate in public, and have temper tantrumstantrums. .

The case of Phineas Gage suggests that our The case of Phineas Gage suggests that our frontal lobe plays a large part in social frontal lobe plays a large part in social control and personalitycontrol and personality, and demonstrates , and demonstrates the severe effect any type of brain injury can the severe effect any type of brain injury can have. have.

Figure 2.28 Phineas Gage reconsideredMyers: Psychology, Ninth EditionCopyright © 2010 by Worth Publishers

Phineas Gage video link (#25):

http://www.learner.org/resources/series142.

html

Association AreasAssociation Areas Must be Must be warywary of using pictures of brain of using pictures of brain

“hot spots” that locate complex functions “hot spots” that locate complex functions in precise brain areasin precise brain areas

Parietal Lobes: enable mathematical & spatial Parietal Lobes: enable mathematical & spatial reasoningreasoning

Temporal Lobes: facial recognitionTemporal Lobes: facial recognition ProsopagnosiaProsopagnosia

Very Very complexcomplex mental functions DO NOT mental functions DO NOT reside in any one placereside in any one place

Memory, language, attention result from Memory, language, attention result from synchronizedsynchronized activity among distinct activity among distinct brain areasbrain areas

LanguageLanguage• AphasiaAphasia is an is an impairment of languageimpairment of language, ,

usually caused by left hemisphere usually caused by left hemisphere damage either to damage either to Broca’s areaBroca’s area (impaired (impaired speaking) or to speaking) or to Wernicke’s areaWernicke’s area (impaired understanding).(impaired understanding).

Broca’s Area Broca’s Area Receives impulse from Receives impulse from

Wernicke’s Area and Wernicke’s Area and converts it into motor converts it into motor commands. commands.

Damage: disrupts Damage: disrupts speakingspeaking

Person Person can understand can understand languagelanguage

Words may not be properly Words may not be properly formed formed

Speech is slow and slurred.Speech is slow and slurred. Patients may get frustrated Patients may get frustrated

because because they know they know that that something is wrong.something is wrong.

Wernicke’s AreaWernicke’s Area The area in our brain that allows The area in our brain that allows

understandingunderstanding of spoken and written of spoken and written language. language.

It is the It is the part that enables a person part that enables a person to interpret languageto interpret language, so damage to , so damage to this part causes the person to become this part causes the person to become unaware of his own speech and the unaware of his own speech and the speech of others.speech of others.

Sometimes the person can speak Sometimes the person can speak clearly, but the words that are put clearly, but the words that are put together make no sense. This way of together make no sense. This way of speaking has been called speaking has been called "word salad" "word salad" because it appears that the words are because it appears that the words are all mixed up like the vegetables in a all mixed up like the vegetables in a salad.salad.

Might use complete nonsense words.Might use complete nonsense words. Often Often not aware not aware of their problem.of their problem.