The Biology of The Biology of Mind and Behavior:Mind and Behavior:The Brain in ActionThe Brain in Action

The NeuronThe Neuron

The basic unit of the nervous systemThe basic unit of the nervous system– Receives signals from neurons or sense Receives signals from neurons or sense

organsorgans– Processes signalsProcesses signals– Sends signals to other neurons, muscles, Sends signals to other neurons, muscles,

or organsor organs The brain contains 100 billion The brain contains 100 billion

neuronsneurons

Complexity of the BrainComplexity of the Brain

Complexity of the brain!Complexity of the brain!– 100,000,000,000 (100 billion) neurons100,000,000,000 (100 billion) neurons– Average of 10,000 connections for each Average of 10,000 connections for each

neuronneuron– 10,000,000,000,000 (10 trillion) neural 10,000,000,000,000 (10 trillion) neural

connections!connections!

The Neuron: StructureThe Neuron: Structure

Neural ImpulsesNeural Impulses

Resting potentialResting potential– More positively charged ions outside than insideMore positively charged ions outside than inside

Action potential: “Firing”Action potential: “Firing”– Threshold exceededThreshold exceeded– All-or-none lawAll-or-none law– Flow of ions through channels in membraneFlow of ions through channels in membrane– Saltatory conductionSaltatory conduction

MyelinMyelin– Acts as an insulatorActs as an insulator– Allows signal to travel more efficientlyAllows signal to travel more efficiently– Multiple sclerosis (MS): deteriorated myelinMultiple sclerosis (MS): deteriorated myelin

Action PotentialAction Potential

Neuron Firing

Neurotransmitters and Neurotransmitters and NeuromodulatorsNeuromodulators

SynapseSynapse Synaptic cleftSynaptic cleft NeurotransmitterNeurotransmitter VesiclesVesicles ReuptakeReuptake ExcitatoryExcitatory InhibitoryInhibitory Synaptic Transmission

Drugs and the BrainDrugs and the Brain

AgonistAgonist AntagonistAntagonist Serotonin, dopamine, acetylcholine, Serotonin, dopamine, acetylcholine,

norepinephrinenorepinephrine Agonist Example: Selective Agonist Example: Selective

serotonin-reuptake inhibitor (SSRI)serotonin-reuptake inhibitor (SSRI)– Prozac, Zoloft, and Paxil block the Prozac, Zoloft, and Paxil block the

reuptake of serotoninreuptake of serotonin

The Central Nervous SystemThe Central Nervous System

BrainBrain Spinal cordSpinal cord

– ReflexReflex

Spinal CordSpinal Cord

The Brain: StructuresThe Brain: Structures

Cerebral Cerebral cortexcortex

Cerebral Cerebral hemispherehemisphere

LobesLobes Corpus Corpus

callosumcallosum

The Brain: LobesThe Brain: Lobes

Occipital lobesOccipital lobes Temporal lobesTemporal lobes Parietal lobesParietal lobes Frontal lobesFrontal lobes

SulciSulci– Central sulcusCentral sulcus– Lateral sulcusLateral sulcus

The Frontal LobesThe Frontal Lobes

Front of the brain Front of the brain Functions includeFunctions include

– PlanningPlanning– Memory searchMemory search– Motor processingMotor processing– ReasoningReasoning– Emotional Emotional

regulationregulation Phineas Gage

The Occipital LobesThe Occipital Lobes

At the back of At the back of the headthe head

Functions Functions includeinclude– Visual Visual

processingprocessing

The Temporal LobesThe Temporal Lobes

In front of the earsIn front of the ears Functions includeFunctions include

– Language Language comprehensioncomprehension

– Sound processingSound processing– "Entering new "Entering new

information in information in memory"memory"

– "Storing visual "Storing visual memories"memories"

The Parietal LobesThe Parietal Lobes

Top, rear of the Top, rear of the brainbrain

Functions Functions includeinclude– AttentionAttention– Spatial locationSpatial location– Somatosensory Somatosensory

processingprocessing

The “Strips”The “Strips”

Subcortical Brain AreasSubcortical Brain Areas

Subcortical Brain AreasSubcortical Brain Areas

Thalamus: CrossroadsThalamus: Crossroads Hypothalamus: Hypothalamus:

ThermostatThermostat Hippocampus: RememberHippocampus: Remember Amygdala: Inner feelingsAmygdala: Inner feelings Basal ganglia: Planning Basal ganglia: Planning

and producing movementand producing movement Brainstem (medulla and Brainstem (medulla and

pons): sleep and arousalpons): sleep and arousal Cerebellum: coordinationCerebellum: coordination

Hippocampal DamageHippocampal Damage

Hippocampal Damage

Probing the BrainProbing the Brain Detecting electrical activityDetecting electrical activity

– Electroencephalograph (EEG)Electroencephalograph (EEG)– Magnetoencephalography (MEG)Magnetoencephalography (MEG)– Single-cell recordingSingle-cell recording

Visualizing structureVisualizing structure– Computer-assisted tomography (CT scan)Computer-assisted tomography (CT scan)– Magnetic resonance imaging (MRI)Magnetic resonance imaging (MRI)

Visualizing functionVisualizing function– Positron emission tomography (PET)Positron emission tomography (PET)– Functional magnetic resonance imaging Functional magnetic resonance imaging

(fMRI)(fMRI)

Observing the BrainObserving the Brain

Brain damageBrain damage– LesionLesion– StrokeStroke

Stimulating the brainStimulating the brain– Transcranial magnetic stimulation (TMS)Transcranial magnetic stimulation (TMS)

DNADNA DNA (Deoxyribonucleic acid ) resides in the DNA (Deoxyribonucleic acid ) resides in the

nucleus of each of the body's trillions of nucleus of each of the body's trillions of cells. cells.

DNA exists as two long, paired strands DNA exists as two long, paired strands spiraled into the famous double helix. spiraled into the famous double helix.

DNA in each cell contains 3 billion base DNA in each cell contains 3 billion base pairs of proteins pairs of proteins (adenine, guanine, cytosine, thymine).(adenine, guanine, cytosine, thymine).

The 3 billion base pairs are organized into The 3 billion base pairs are organized into 23 pairs of chromosomes (one set of pair 23 pairs of chromosomes (one set of pair inherited from the mother and one from the inherited from the mother and one from the father). father).

GenesGenes

The DNA in each chromosome The DNA in each chromosome contains many genes. contains many genes.

Each gene is a stretch of DNA that Each gene is a stretch of DNA that contains a particular set of contains a particular set of instructions, usually coding for a instructions, usually coding for a particular protein. particular protein.

There are between 30,000 – 50,000 There are between 30,000 – 50,000 human genes.human genes.

How Genetically Complex are How Genetically Complex are Humans Relative to Other Humans Relative to Other

Species?Species?

Number of Genes:Number of Genes:

Human - Human - ~30,000 ~30,000

Mouse - Mouse - ~30,000 ~30,000

Fruit Fly - 13,600 Fruit Fly - 13,600

Plant - 25,500 Plant - 25,500

How Genetically Diverse are How Genetically Diverse are Humans from other Species?Humans from other Species?

Genetically identical to Humans:Genetically identical to Humans: Chimpanzees Chimpanzees ~ 98.5%~ 98.5% Mice Mice ~ 85.0% ~ 85.0%

Genes and the BrainGenes and the Brain Genotype: Sum total of your particular set of Genotype: Sum total of your particular set of

genes.genes. Phenotype: The observable structure of behavior Phenotype: The observable structure of behavior

of an organism.of an organism.

Mutations (physical changes to genes can Mutations (physical changes to genes can produce different behaviors)produce different behaviors)– Fat miceFat mice

The environment mattersThe environment matters– Pruning (losing unused neural connections)Pruning (losing unused neural connections)– Plasticity (the brains ability to change with Plasticity (the brains ability to change with

experience: pruning or neural growth)experience: pruning or neural growth)

Three Ways Genes and the Three Ways Genes and the Environment InteractEnvironment Interact

Passive interaction: Passive interaction: Genetically shaped Genetically shaped tendencies of parents or siblings produce tendencies of parents or siblings produce an environment that is passively received an environment that is passively received by the child.by the child.

Evocative Evocative (or (or reactivereactive) ) interaction: interaction: Genetically influenced characteristics draw Genetically influenced characteristics draw out behaviors from other people.out behaviors from other people.

Active interaction: Active interaction: People choose, partly People choose, partly based on genetic tendencies, to put based on genetic tendencies, to put themselves in specific situations and to themselves in specific situations and to avoid others.avoid others.

Behavioral GeneticsBehavioral Genetics

DNADNA HeritabilityHeritability Twin studiesTwin studies

– Monozygotic (identical)Monozygotic (identical)– Dizygotic (fraternal)Dizygotic (fraternal)– Adoption studiesAdoption studies

Evolution and the BrainEvolution and the Brain

EvolutionEvolution Natural selectionNatural selection AdaptationAdaptation Reproduction of the Reproduction of the

fittestfittest

Genetic TestingGenetic Testing

DNA testing is useful DNA testing is useful – innocence or guilt; disease risk; preventive treatment or innocence or guilt; disease risk; preventive treatment or

adjust their lifestyle; paternity.adjust their lifestyle; paternity. Genetic “blueprints” cost as little as $985 Genetic “blueprints” cost as little as $985

– find out if your risk for 18 diseases, including find out if your risk for 18 diseases, including Alzheimers.Alzheimers.

Soon it may be economically possible to construct Soon it may be economically possible to construct a complete genetic map for every individual in a complete genetic map for every individual in the United States. the United States.

Potential uses and abuse Potential uses and abuse

More Questions on GeneticsMore Questions on Genetics Would you want to know about your risk for a disease that has no current Would you want to know about your risk for a disease that has no current

preventive treatment or cure? Why?preventive treatment or cure? Why?

Would the information improve or diminish your quality of life? Why?Would the information improve or diminish your quality of life? Why?

Should potential employers, insurance companies, or the government have Should potential employers, insurance companies, or the government have access to this information? Why?access to this information? Why?

Should potential employers, insurance companies, or the government be able to Should potential employers, insurance companies, or the government be able to administer these tests prior to you being hired or insured? Why?administer these tests prior to you being hired or insured? Why?

Because it is clear that the ability to gather this information is rapidly Because it is clear that the ability to gather this information is rapidly approaching, should steps be taken to limit who has access to this information or approaching, should steps be taken to limit who has access to this information or to limit how it is used? What kind of steps?to limit how it is used? What kind of steps?

Do the potential benefits of having this information outweigh the drawbacks? Do the potential benefits of having this information outweigh the drawbacks? Why?Why?