The BrainThe Brain

Structures, Functions, and Structures, Functions, and InjuriesInjuries

Older Brain Structures: Older Brain Structures: BrainstemBrainstem

TheThe Brainstem Brainstem isis the oldest part of the brain, the oldest part of the brain, beginning where the spinal cord swells and beginning where the spinal cord swells and enters the skull. It is responsible for enters the skull. It is responsible for automatic automatic survival functionssurvival functions..

MedullaMedulla

The The Medulla Medulla is the is the base of the base of the brainstem that brainstem that controls controls ______________________ and and ______________________________..

PonsPons

Involved in coordinating Involved in coordinating movement, sleeping, movement, sleeping, waking, and dreamingwaking, and dreaming Brainstem is a crossover Brainstem is a crossover

point, where most nerves point, where most nerves to and from each side of to and from each side of the brain connect with the brain connect with body’s opposite sidebody’s opposite side

Reticular FormationReticular Formation

FiltersFilters incoming incoming stimuli & stimuli & relaysrelays important info important info to other areas to other areas of the brainof the brain ““Netlike” Netlike”

network of network of neuronsneurons

ThalamusThalamus

Sitting atop brainstemSitting atop brainstem Receives information Receives information

from all from all sensessenses (except (except smell) and routes it to smell) and routes it to the higher brain the higher brain regions that deal with regions that deal with seeing, hearing, seeing, hearing, tasting, touchingtasting, touching ““Hub in which traffics Hub in which traffics

passes en route to passes en route to various destinations”various destinations”

Thalamus

ThalamusThalamus Brain’s Brain’s sensory sensory

switchboardswitchboard, , located on top of located on top of the brainstem. the brainstem.

It directs messages It directs messages to the sensory areas to the sensory areas in the cortex and in the cortex and transmits replies to transmits replies to the cerebellum and the cerebellum and medulla.medulla.

The “little brain” The “little brain” attached to the rear attached to the rear of the brainstem. of the brainstem.

It helps coordinate It helps coordinate voluntary voluntary movements movements and and balancebalance.. Also involved in: Also involved in:

nonverbal learning, nonverbal learning, memory memory

CerebellumCerebellum

Older Brain FunctionsOlder Brain Functions

““Older” brain functions all occur Older” brain functions all occur without any conscious effortwithout any conscious effort Brain processes most information Brain processes most information

outsideoutside of our awareness of our awareness

Limbic SystemLimbic System isis a a doughnut-shaped doughnut-shaped system of neural system of neural structures structures at the at the border of the brainstem border of the brainstem and cerebrum and cerebrum

Associated with Associated with emotions such as fear, emotions such as fear, aggression and drives aggression and drives for food and sex. for food and sex.

It includes the It includes the hippocampus, amygdala, hippocampus, amygdala, and hypothalamus.and hypothalamus.

The Limbic SystemThe Limbic System

Limbic SystemLimbic System

HippocampusHippocampus: processes memory: processes memory Injury:Injury:

.. ..

AmygdalaAmygdala

Amygdala:Amygdala: two lima bean-sized two lima bean-sized neural clustersneural clusters Influences aggression and fearInfluences aggression and fear Processes Processes emotionalemotional memories memories Injury or Damage:Injury or Damage:

.. ..

HypothalamusHypothalamus HypothalamusHypothalamus: important link in : important link in

chain of command governing bodily chain of command governing bodily maintenancemaintenance Some neural clusters influence:Some neural clusters influence:

Hunger, Thirst, Body Temp, Sexual Hunger, Thirst, Body Temp, Sexual BehaviorsBehaviors

Monitors both blood chemistry and Monitors both blood chemistry and takes orders from other parts of the brain

Limbic SystemLimbic System Hypothalamu

s - Directs maintenance activities like eating, drinking, body temperature, and control of emotions.

Helps govern the endocrine system via the pituitary gland.

Video of an actual brain

Hypothalamus = Reward Hypothalamus = Reward CenterCenter

Read on page 72 & 73Read on page 72 & 73 Olds 1958: Olds 1958: located other located other

“pleasure centers”“pleasure centers” What rats actually experience we What rats actually experience we

don’t knowdon’t know Allowed to press pedals to trigger Allowed to press pedals to trigger

their own stimulationtheir own stimulation Feverish pace – 7000 times an hour – Feverish pace – 7000 times an hour –

until they dropped from exhaustionuntil they dropped from exhaustion

**Rats cross an **Rats cross an electrified grid for self-electrified grid for self-

stimulation when stimulation when electrodes are placed in electrodes are placed in

the reward the reward (hypothalamus) center (hypothalamus) center

(top picture). (top picture).

**When the limbic **When the limbic system is manipulated, a system is manipulated, a rat will navigate fields or rat will navigate fields or climb up a tree (bottom climb up a tree (bottom

picture).picture).

Reward CenterReward CenterS

anjiv Talw

ar, SU

NY

Dow

nstate

Reward CenterReward Center

Do humans have limbic centers for Do humans have limbic centers for pleasure?pleasure? Neurosurgeon implanted electrodes in such Neurosurgeon implanted electrodes in such

areasareas Stimulated patients reported mild pleasureStimulated patients reported mild pleasure However not driven into a frenzy(rat)However not driven into a frenzy(rat)

Researches believe that _____________ disorders Researches believe that _____________ disorders may stem from a reward deficiency syndromemay stem from a reward deficiency syndrome

Genetically disposed deficiency in natural brain Genetically disposed deficiency in natural brain systems for pleasuresystems for pleasure

People crave whatever provides that missing People crave whatever provides that missing pleasure or relieves negative feelingspleasure or relieves negative feelings

Mind Control?Mind Control?

http://www.learner.org/resources/http://www.learner.org/resources/series142.html?pop=yes&pid=1593series142.html?pop=yes&pid=1593

This video links human aggressive behavior This video links human aggressive behavior with specific regions of the brain. with specific regions of the brain.

Scenes from Scenes from classicclassic experiments show experiments show stimulation of a bull's brain to stop it from stimulation of a bull's brain to stop it from charging and excitation of a cat's charging and excitation of a cat's hypothalamus to trigger aggression. hypothalamus to trigger aggression.

A striking case of violent human behavior is A striking case of violent human behavior is then linked to a brain lesion — the surgical then linked to a brain lesion — the surgical removal of which restored normal emotional removal of which restored normal emotional controlcontrol

70 -- Tickling70 -- Tickling

Midbrain

Forebrain StructuresForebrain Structures

ThalamusThalamus Limbic systemLimbic system

HippocampusHippocampus AmygdalaAmygdala HypothalamuHypothalamu

ss CerebrumCerebrum

Cerebral Cerebral cortexcortex

LobesLobes

Hindbrain StructuresHindbrain Structures

BrainstemBrainstem MedullaMedulla CerebellumCerebellum PonsPons