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The brain:The source of mind and self

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OverviewThe central nervous system

The peripheral nervous system

Communication in the nervous system

Chemical messengers in the nervous system

Mapping the brain

A tour through the brain

Two stubborn issues in brain research

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The central nervous

systemBrain

Spinal cordA collection of neurons and

supportive tissue running from thebase of the brain down the center

of the back

Protected by spinal column

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The withdrawal reflex4

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Organization of the

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Structure of a neuronDendrites

Receive information from other

neurons and transmit toward the

cell body

Cell body

Keeps the neuron alive and

determines whether it will fire

AxonExtending fiber that conducts

impulses away from the cell body

and transmits to other cells.

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Types of neurons4

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4Structure of a neuron

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Your turnWhich part of a neuron is tree-like or branchy?

1. Dendrites

2. The axon

3. The cell body

4. The nucleus

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Your turnWhich part of a neuron is tree-like or branchy?

1. Dendrites

2. The axon

3. The cell body

4. The nucleus

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Neurons in the newsNeurogenesis

The production of new neurons

from immature stem cellsStem cells

Immature cells that renew

themselves and have the

potential to develop into maturecells

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Stem-cell researchEmbryonic stem cells appear most useful yet federalfunding faces resistance from some advocates.

In 2001, President Bush signed executive orderpreventing creation of new cell lines.

Some scientists advocate for ban to be lifted because

stem cell research shows promise in helping thosesuffering from diseases of the brain.

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How neurons

communicateAxon terminals releaseneurotransmitter.

Neurotransmitter enterssynapse.

Neurotransmitter binds to

receptors that it fits.

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Action potentialA brief change in electrical voltage thatoccurs between the inside and outside of anaxon when a neuron is stimulated.

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NeurotransmitterChemical released by a transmittingneuron at the synapse and capableof affecting the activity of a receiving

neuron

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Major neurotransmitterSerotonin

Dopamine

Acetylcholine (Ach)

Norepinephrine

Gamma aminobutyric acid (GABA)

Glutamate

Endorphins

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Opioids and Substance P4

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The endocrine systemEndocrine glandsrelease hormonesinto the

bloodstream

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Hormones regulate

growth, metabolism,

sexual developmentand behavior, and otherfunctions.

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The endocrine system

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HormonesMelatoninRegulates daily biological rhythms

Adrenal hormonesInvolved in emotions and stress

Cortisol, epinephrine, and norepinephrine

Sex hormonesRegulate development and functioning of reproductive organs

Androgens, estrogens, and progesterone

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Mapping the brainLesioningInvolves damaging and removing sections of brain in

animals, then observing their effects.

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ElectroencephalogramA recording of neural activity detected byelectrodes

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Transcranial magnetic

stimulation (TMS)

Involves delivering a large current througha wire coil on a persons head

Can be used toProduce motor responses

Temporarily inactivate an area of the brain

Treat depression

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Positron emission

tomography

Active areas have increasedblood flow.

Sensors detect radioactivity.

Different tasks show distinctactivity patterns.

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A method for analyzing biochemical activity in the brain, usinginjections of a glucose-like substance containing a radioactiveelement

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Magnetic resonance

imaging (MRI)

Magnetic fields align certainions and compounds.

When field is removed, thesemolecules release energy asradio waves.

Computer calculates tissuedensity from radio waves.

Provides clear 3D images

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Method for studying body and brain tissue

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A tour through the brainBrain stem

Cerebellum

ThalamusHypothalamus and pituitary gland

Amygdala

Hippocampus

Cerebrum and lobes of the cerebral cortex

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The brain stemPonsInvolved in sleeping, waking,and dreaming

MedullaResponsible for certainautomatic functions such asbreathing and heart rate

Reticular activatingsystemArouses cortex and screensincoming information

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The cerebellumRegulates movement andbalance

Involved in rememberingsimple skills and acquiredreflexes

Plays a part in

Analyzing sensory informationSolving problems

Understanding words

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The thalamusRelays sensory messagesto the cerebral cortex

Includes all sensorymessages except thosefrom olfactory bulb

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Hypothalamus and

pituitary gland

Involved in emotions anddrives vital to survivalFear, hunger, thirst, and reproduction

Regulates autonomicnervous system

Pituitary gland

Small endocrine gland which releases

hormones and regulates otherendocrine glands

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The amygdalaResponsible forArousal

Regulation of emotion

Initial emotional response to sensory

information

Plays important role inMediating anxiety and depression

Emotional memory

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The hippocampusResponsible forStorage of new information in memory

Comparing sensory information with

what the brain expects about the world

Enabling us to form spatial memories

for navigating the environment

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The cerebrumLargest brain structure

Two cerebral hemispheres connected by the

corpus callosum.

In charge of most sensory, motor, andcognitive processes

Surrounded by cerebral cortex, a collection ofseveral thin layers of cells (gray matter)

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Lobes of the cerebral

cortex

Occipital lobes (visual cortex)

Parietal lobes (somatosensory cortex)

Temporal lobesMemory, perception, emotion, and auditory cortex

Left lobe: Wernickes area

Frontal lobes

Emotion, planning, creative thinking, and motor cortexLeft lobe: Brocas area

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Lobes of the cerebral

cortex

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Your turnJenny bumps her head and is suddenly unable to see,

although the doctor says there is nothing wrong with her

eyes? Which part of her brain did Jenny damage?

1. The amygdala

2. The hippocampus

3. The occipital lobe of the cerebral cortex

4. The parietal lobe of the cerebral cortex

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Your turnJenny bumps her head and is suddenly unable to see,

although the doctor says there is nothing wrong with her

eyes? Which part of her brain did Jenny damage?

1. The amygdala

2. The hippocampus

3. The occipital lobe of the cerebral cortex

4. The parietal lobe of the cerebral cortex

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Phineas GageGage was a railroadconstruction foreman

An 1848 explosionforced a steel tampingrod through his head

Others said he wasno longer Gage

Lost his job, workedas a sideshow exhibit

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The corpus callosumMillions of myelinatedaxons connecting thebrains hemispheres

Provides a pathway forcommunication

If surgically severed to

treat epilepsy,hemispheres cannotcommunicate directly

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Split-brain experiment 4

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Split-brain experiment

Subjects were presented information toone or the other side of their brains.

Patients identified verbally the pictures tothe right (e.g., boy).

When patients were asked to point to theface seen, the patients pointed to the leftpicture.

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Allies or opposites?Research on split-brain patientsshows us. . .

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Nearly all right-handed and the majority of left-handed

individuals process language mainly in the lefthemisphere.

Many researchers believe in left-hemisphere dominance.

Others insist right-hemisphere is important for spatialvisual problem solving, comprehending non-verbalsounds, and some language abilities.

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Where is the Self?Modern brain scientists explain the mind orsoul in physical terms as a product of thecerebral cortex.Mind is a series of independent brain parts dealing with different

aspects of thoughts (Dennett 1991).Mind is a loose confederation of mental systems all workingwithout conscious awareness (Gazzaniga, 1998; Roser &Gazzaniga, 2004).

Frontal lobes may play a critical role.

Many still question the relationship betweensubjective experience and physicalprocesses of the brain.

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What do differences

mean for behavior?

Supposed differences are stereotypes.

Brain difference does not necessarilyexplain behavior or performance.

Sex differences in the brain could be the

result rather than the cause of behavioraldifferences.

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