IV.IV. NeuroscienceNeuroscience

The relationship between The relationship between brain and behavior.brain and behavior.

A. Earliest work...A. Earliest work...

Brain/body and behavior Brain/body and behavior connection.connection.– Hippocrates: brain injury and Hippocrates: brain injury and

behaviorbehavior– Phrenology (Franz Gall – 1800’s)Phrenology (Franz Gall – 1800’s)

What does your skull say about you?What does your skull say about you?

B. The body’s basic communication B. The body’s basic communication network.network.

The nervous system:The nervous system: 1. “Communication system”. 1. “Communication system”.

Encounter a bear in the woods.....Encounter a bear in the woods..... Coordinates the body and Coordinates the body and

environment.environment.– ““Electrochemical”Electrochemical”

receives messagesreceives messages organizes messagesorganizes messages sends out messagessends out messages

B. The body’s basic communication B. The body’s basic communication network.network.

2. Two components:2. Two components:– a. Central Nervous System (CNS)a. Central Nervous System (CNS)

Brain and spinal cord.Brain and spinal cord.

B. The body’s basic B. The body’s basic communication networkcommunication network

2. Two components:2. Two components:– b. Peripheral Nervous System.b. Peripheral Nervous System.

Connects CNS with rest of body.Connects CNS with rest of body. Controls skeletal movement and internal Controls skeletal movement and internal

organs.organs.

Nervous System

Central(brain and

spinal cord)

Nervoussystem

Autonomic (controlsself-regulated action of

internal organs and glands)

Skeletal (controlsvoluntary movements of

skeletal muscles)

Sympathetic (arousing)

Parasympathetic (calming)

Peripheral

C. Basic Building Blocks of C. Basic Building Blocks of Neural CommunicationNeural Communication

THE NEURON THE NEURON – Nerve or Neuron?Nerve or Neuron?– A A neuron neuron is a single nerve cellis a single nerve cell– A nerve is a bundle of neuronsA nerve is a bundle of neurons

Nerve cell - most basic component.Nerve cell - most basic component.Information carrier and integrator.Information carrier and integrator.

“ “Talks” to other cells, muscles, etc.Talks” to other cells, muscles, etc. 1. 1. 3 different kinds of neurons3 different kinds of neurons::

– Sensory: Sensory: receivingreceiving– Interneuron: Interneuron: organizingorganizing– Motor:Motor: sendingsending

2. Structure of a Neuron2. Structure of a Neuron

C. Basic Building Blocks of C. Basic Building Blocks of Neural CommunicationNeural Communication

2. Structure of neuron:2. Structure of neuron:– DendritesDendrites receive signals. receive signals.

Carry info to Carry info to cell bodycell body..

– Cell bodyCell body synthesizes these signals. synthesizes these signals.– Signal travels down Signal travels down axonaxon..

Away from Away from cell bodycell body..

– Helped along by Helped along by myelin sheathmyelin sheath.. Made up of Made up of glial cellsglial cells..

C. Basic Building Blocks of C. Basic Building Blocks of Neural CommunicationNeural Communication

3. How neurons communicate.3. How neurons communicate. a. Chemistry-to-electricity process.a. Chemistry-to-electricity process.

– WithinWithin neuron part: neuron part:– Neuron at rest – electrically charged.Neuron at rest – electrically charged.

Resting potential. Resting potential. Ions exist outside/inside of cell membrane.Ions exist outside/inside of cell membrane. More negative ions inside of membrane.More negative ions inside of membrane.

– Gets stimulated (by light, heat, Gets stimulated (by light, heat, pressure, chemicals from other pressure, chemicals from other neurons).neurons).

C. Basic Building Blocks of C. Basic Building Blocks of Neural CommunicationNeural Communication

3. How neurons communicate (with 3. How neurons communicate (with neuron).neuron).

a. Chemistry-to-electricity process.a. Chemistry-to-electricity process.– Positive ions move into cell – if strong enough Positive ions move into cell – if strong enough

– causes depolarization– causes depolarization FIRES!FIRES!

– But – strong enough means must reach:But – strong enough means must reach:– ThresholdThreshold – Fires signal/electric impulse down axon Fires signal/electric impulse down axon

called called Action potentialAction potential.. ““All-or-none process”All-or-none process”

C. Basic Building Blocks of C. Basic Building Blocks of Neural CommunicationNeural Communication

3. How neurons communicate.3. How neurons communicate. b. Importance of neurotransmitters.b. Importance of neurotransmitters.

((BetweenBetween neuron communication). neuron communication). Synapse: Synapse: Junction between axon tip of sending Junction between axon tip of sending

neuron and dendrites of receiving neuron. neuron and dendrites of receiving neuron.

Synaptic GapSynaptic Gap - tiny gap between neurons. - tiny gap between neurons. Action potential fires, travels down axon – Action potential fires, travels down axon –

releases releases NeurotransmittersNeurotransmitters - chemical messengers - chemical messengers

cross the synaptic gap, binds to sites on cross the synaptic gap, binds to sites on receiving neuron.receiving neuron.

3. How neurons 3. How neurons communicatecommunicate

a. Importance of Neurotransmitters.a. Importance of Neurotransmitters.

Found in different places, do different jobs.Found in different places, do different jobs.

- Acetylcholine (learning, memory, muscle - Acetylcholine (learning, memory, muscle contraction,)contraction,)

- Endorphins (mood/pain)- Endorphins (mood/pain)

- Dopamine (smooth movement)- Dopamine (smooth movement)

- - Norepinephrine (alertness, arousal)- Serotonin (mood, hunger, sleep)

3. How neurons 3. How neurons communicatecommunicate

c. Neurotransmitters and drugs.c. Neurotransmitters and drugs. Agonist: EXCITES.

Drug/toxin mimics the effects of neurotransmitter, or heightens activity of neurotransmitters.

Antagonists: INHIBITSDrug/toxin that inhibits or blocks release of neurotransmitters.

Examples:

Influence of drugs on Influence of drugs on neurotransmitters:neurotransmitters:

Importance of Importance of REUPTAKEREUPTAKE..– Agonists heighten neurotransmitter Agonists heighten neurotransmitter

activity by blocking reuptake of the activity by blocking reuptake of the chemical.chemical.

Examples: CocaineExamples: Cocaine

COCAINECOCAINE

D. BrainD. Brain 2. Structure2. Structure a. Lower Level a. Lower Level

– BrainstemBrainstem: oldest, innermost region: oldest, innermost region controls arousal.controls arousal.

– ThalamusThalamus: “switchboard”: “switchboard”– CerebellumCerebellum: little brain: little brain

coordinates movement and balancecoordinates movement and balance

The Brain

2a. Lower level brain 2a. Lower level brain structurestructure

– Limbic systemLimbic system: : amygdala - aggression, fearamygdala - aggression, fear hypothalamus - hunger, thirst, sexual hypothalamus - hunger, thirst, sexual

behavior.behavior.– ““reward center”reward center”

hippocampus - memory.hippocampus - memory.

The Limbic System

2. Structure of brain:2. Structure of brain: a. Lower Level a. Lower Level

2. Structure of Brain:2. Structure of Brain:b. Cerebral Cortexb. Cerebral Cortex

1. “Bark” of the brain1. “Bark” of the brain

2. Structure of Brain:2. Structure of Brain:b. Cerebral Cortexb. Cerebral Cortex

2. Function of 4 Lobes:2. Function of 4 Lobes:

FrontaFrontal: Motor Cortexl: Motor Cortex

Specific areas stimulate movement.Specific areas stimulate movement.

ParietalParietal: Sensory Cortex: Sensory Cortex

Receives information from skin and Receives information from skin and body parts (touch/movement).body parts (touch/movement).

2. Structure of Brain:2. Structure of Brain:b. Cerebral Cortexb. Cerebral Cortex

2. Functions of 4 Lobes, cont’d.2. Functions of 4 Lobes, cont’d.

OccipitalOccipital: processes visual information, : processes visual information, sends it elsewhere to be decoded.sends it elsewhere to be decoded.

TemporalTemporal: processes sound.: processes sound.

Sensory and motor cortex, and visual Sensory and motor cortex, and visual and auditory areas take up 1/4 of and auditory areas take up 1/4 of brain.brain.

2. Structure of Brain:2. Structure of Brain:b. Cerebral Cortexb. Cerebral Cortex

Association AreasAssociation Areas::Other “3/4” of cerebral cortex.Other “3/4” of cerebral cortex.Integrates, interprets, acts on information.Integrates, interprets, acts on information.

(i.e. important to communication).(i.e. important to communication).Areas and their associated behaviors have Areas and their associated behaviors have

been identified based on what happens been identified based on what happens when those areas are damaged.when those areas are damaged.

B. Association AreasB. Association Areas

Frontal Lobe:Frontal Lobe:

- cannot plan or judge.- cannot plan or judge.

- alters personality - Phinneas Gage- alters personality - Phinneas Gage

- speech production- - speech production- Broca’s AreaBroca’s Area

Temporal Lobe:Temporal Lobe:

- can’t recognize faces.- can’t recognize faces.

- speech understanding - - speech understanding - Wernicke’s Wernicke’s AreaArea

C. Two Hemispheres of C. Two Hemispheres of BrainBrain

Brain’s sides (left and right) serve Brain’s sides (left and right) serve different purposes.different purposes.

Stroke? Damage to left side - reading,

writing, speaking, understanding. - considered “major”, verbal hemisphere

Damage to right side - not as dramatic

C. Two Hemispheres of C. Two Hemispheres of BrainBrain

Important - how sides Important - how sides communicate with each communicate with each other.other.– Corpus CallosumCorpus Callosum: :

bundle of neural fibers bundle of neural fibers connecting both sides, connecting both sides, carries messages carries messages between them. between them.

– If severed, If severed, demonstrates how demonstrates how both sides work both sides work together.together.

Corpus callosum

c. Two Hemispheres of c. Two Hemispheres of BrainBrain

Talents of each hemisphere.Talents of each hemisphere.

Right: Right: perceptualperceptual

picture recognitionpicture recognition

emotion, expression, creativityemotion, expression, creativity

Left: Left: speaking, calculating numbersspeaking, calculating numbers

word recognitionword recognition

analytical, logicalanalytical, logical

ConclusionsConclusions

There is no psychology without There is no psychology without biology.biology.

From the neuron to the brain:From the neuron to the brain:– How information/stimuli are taken in, How information/stimuli are taken in,

integrated, and responses (behavior) integrated, and responses (behavior) are generated based on the body’s are generated based on the body’s communication system – nervous communication system – nervous system.system.

Neural Systems

Neural Networks interconnected neural

cells with experience,

networks can learn

Neurons in the brain connect with one

another to form networks

The brain learns by modifyingcertain connections in response to feedback