Chapter 2:Neuroscience andBehavior
Neurons and SynapsesTypes of NeuronsSensory Motor Interneurons
SpinalCordBrainSensoryNeuronSensory Neurons• INPUT From sensory organs to thebrain and spinal cordDrawing shows asomatic n...
SpinalCordBrainSensoryNeuronMotorNeuronMotor Neurons• OUTPUT From the brain and spinalcord, to the muscles and glands
SpinalCordBrainSensoryNeuronMotorNeuronInterneurons• Interneuronscarryinformationbetween otherneurons onlyfound in thebrai...
Parts of a Neuron
The Cell Body– round, centrally locatedstructure– contains DNA– controls protein manufacturing– directs metabolism– no rol...
Dendrites• Information collectors• Receive inputs from neighboringneurons• Inputs may number in thousands• If enough input...
Dendritic Growth• Mature neurons generally can’t divide• But new dendrites can grow• Provides room for more connections to...
Axon• The cell’s output structure• One axon per cell, 2 distinct parts– tubelike structure– branches at end that connect t...
Myelin Sheath• White fatty casing on axon• Acts as an electrical insulator• Not present on all cells• When present, increa...
How Neurons Communicate• Neurons communicate by means of anelectrical signal called the actionpotential• Action potentials...
Action Potential Within a Neuron
Resting Potential• At rest, the inside of the cell is at -70 microvolts• With inputs to dendrites, the inside becomes more...
Depolarization Ahead of AP• Action potential opens cell membrane to allow sodium (Na+) in• Inside of cell rapidly becomes ...
Repolarization Follows• After depolarization potassium (K+) moves out restoringthe inside to a negative voltage• This is c...
Finally, Hyperpolarization• Repolarization leads to a voltage below the restingpotential, called hyperpolarization• Now, n...
Neuron to Neuron• Axons branch out and end near dendritesof neighboring cells• Axon terminals are the tips of the axon’sbr...
Neurotransmitter Release• Action potential causes vesicle toopen• Neurotransmitter released intosynapse• Locks onto recept...
Excitatory and InhibitoryMessages• Excitatory message—increases thelikelihood that the postsynapticneuron will activate• I...
Locks and Keys• Neurotransmittermolecules havespecific shapes• When NT binds toreceptor, ions enter• Receptor moleculeshav...
Some Drugs Work on Receptors• Some drugs are shapedlike neurotransmitters• Antagonists: poorly fit thereceptor and block t...
Types of Neurotransmitters• Acetylcholine• Dopamine• Serotonin• Norepinephrine• GABA• Endorphins
Acetylcholine (Ach)• Found in neuromuscularjunctions• Involved in muscle movements• Involved in learning and memory
Disruptions ofAcetylcholine Functioning• Curare—blocks ACh receptors– paralysis results• Nerve gases and black widow spide...
Disruptions ofAcetylcholine Functioning• Cigarettes—nicotine works onACh receptors– can artificially stimulate skeletal mu...
Alzheimer’s Disease• Deterioration of memory,reasoning, and language skills• Symptoms may be due a to lossof ACh neurons
Dopamine• Involved in movement, attention,and learning• Dopamine imbalance alsoinvolved in schizophrenia• Parkinson’s dise...
Parkinson’s Disease• Results from loss of dopamine-producingneurons in the substantia nigra• Symptoms include– difficulty ...
Parkinson’s Disease• Treatments– L-dopa– transplants of fetal dopamine-producingsubstantia nigra cells– adrenal gland tran...
Serotonin• Involved in sleep• Involved in depression–Prozac works by keeping serotoninin the synapse longer, giving itmore...
Norepinephrine• Arousal• “Fight or flight” response
Endorphins• Control pain and pleasure• Released in response to pain• Morphine and codeine work on endorphinreceptors; invo...
GABA• Inhibition of brain activity• Huntington’s disease involvesloss of neurons in striatum thatuse GABA–Symptoms:• jerky...
Summary• Neuron structure• Action potentials• Synapses• Neurotransmitters• Receptors and ions• Agonists andantagonists
Parts of the Nervous System• Central nervous system (CNS)–Brain and spinal cord• Peripheral nervous system (PNS)–Carries m...
Central nervoussystemPeripheralnervous system
Sympathetic and parasympathetic divisionsof the nervous system
Endocrine System• Pituitary gland—attached to the base ofthe brain, hormones affect the function ofother glands• Adrenal g...
Brain• Images• Brainstem– Hindbrain– Midbrain• Forebrain– Limbic system– Cortex
Hindbrain Structures• Cerebellum• Brainstem– medulla– reticularformation– pons
Cerebellum• Coordinated,rapid voluntarymovements– playing the piano,kicking, throwing,etc.• Lesions tocerebellum– jerky, e...
Medulla• Breathing• Heart rate• Digestion• Other vitalreflexes– swallowing– coughing– vomiting– sneezing
Reticular Formation• Network ofneurons in thebrainstem (andthalamus)• Sleep andarousal• Attention
Pons• Helps coordinatemovements onleft and rightsides of the body– eg, posturalreflexes that helpyou maintainbalance while...
Forebrain Structures• Thalamus• LimbicSystem• Cortex
Thalamus• Relay station inbrain• Processes mostinformation to andfrom higher braincenters
The Limbic System• Hypothalamus• Amygdala• Hippocampus
Hypothalamus• Contains nuclei involved in a varietyof behaviors– sexual behavior– hunger and thirst– sleep– water and salt...
Hypothalamus and HormonesHypothalamusreleaseshormones orreleasing factors,which in turncause pituitarygland to releaseits ...
Amygdala and Emotion• Identify emotion fromfacial expressionsAmygdala damagemakes this taskdifficult.(click on picture to ...
Cortical Specialization• Localization—notion that differentfunctions are located in different areasof the brain• Lateraliz...
Lobes of the Cortex• Frontal lobe—largest lobe, producesvoluntary muscle movements; involved inthinking, planning, and emo...
Language and the Brain• Aphasia—partial orcomplete inability toarticulate ideas orunderstand languagebecause of brain inju...
•Split-brain operation—procedure used to reduce recurrent seizures insevere cases of epilepsy•Corpus callosum—thick band o...
PSYC 1113 Chapter 2
PSYC 1113 Chapter 2
PSYC 1113 Chapter 2
PSYC 1113 Chapter 2
PSYC 1113 Chapter 2
PSYC 1113 Chapter 2
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  • PSYC 1113 Chapter 2

    1. 1. Chapter 2:Neuroscience andBehavior
    2. 2. Neurons and SynapsesTypes of NeuronsSensory Motor Interneurons
    3. 3. SpinalCordBrainSensoryNeuronSensory Neurons• INPUT From sensory organs to thebrain and spinal cordDrawing shows asomatic neuron
    4. 4. SpinalCordBrainSensoryNeuronMotorNeuronMotor Neurons• OUTPUT From the brain and spinalcord, to the muscles and glands
    5. 5. SpinalCordBrainSensoryNeuronMotorNeuronInterneurons• Interneuronscarryinformationbetween otherneurons onlyfound in thebrain andspinal cord
    6. 6. Parts of a Neuron
    7. 7. The Cell Body– round, centrally locatedstructure– contains DNA– controls protein manufacturing– directs metabolism– no role in neural signalingContains the cell’s nucleus
    8. 8. Dendrites• Information collectors• Receive inputs from neighboringneurons• Inputs may number in thousands• If enough inputs, the cell’s AXONmay generate an output
    9. 9. Dendritic Growth• Mature neurons generally can’t divide• But new dendrites can grow• Provides room for more connections toother neurons• New connections are basis for learning
    10. 10. Axon• The cell’s output structure• One axon per cell, 2 distinct parts– tubelike structure– branches at end that connect to dendritesof other cells
    11. 11. Myelin Sheath• White fatty casing on axon• Acts as an electrical insulator• Not present on all cells• When present, increases the speed ofneural signals down the axon
    12. 12. How Neurons Communicate• Neurons communicate by means of anelectrical signal called the actionpotential• Action potentials are based on themovements of ions between the outsideand inside of the cell• When an action potential occurs, amolecular message is sent to neighboringneurons
    13. 13. Action Potential Within a Neuron
    14. 14. Resting Potential• At rest, the inside of the cell is at -70 microvolts• With inputs to dendrites, the inside becomes more positive• If resting potential rises above threshold, an action potentialstarts to travel from cell body down the axon• Figure shows resting axon being approached by an actionpotential
    15. 15. Depolarization Ahead of AP• Action potential opens cell membrane to allow sodium (Na+) in• Inside of cell rapidly becomes more positive than outside• This depolarization travels down the axon as leading edgeof the action potential
    16. 16. Repolarization Follows• After depolarization potassium (K+) moves out restoringthe inside to a negative voltage• This is called repolarization• The rapid depolarization and repolarization produce apattern called a spike discharge
    17. 17. Finally, Hyperpolarization• Repolarization leads to a voltage below the restingpotential, called hyperpolarization• Now, neuron cannot produce a new action potential• This is the refractory period
    18. 18. Neuron to Neuron• Axons branch out and end near dendritesof neighboring cells• Axon terminals are the tips of the axon’sbranches• A gap separates the axon terminals fromdendrites• Gap is called the synapse
    19. 19. Neurotransmitter Release• Action potential causes vesicle toopen• Neurotransmitter released intosynapse• Locks onto receptor molecule inpostsynaptic membrane
    20. 20. Excitatory and InhibitoryMessages• Excitatory message—increases thelikelihood that the postsynapticneuron will activate• Inhibitory message—decreases thelikelihood that the postsynapticneuron will activate
    21. 21. Locks and Keys• Neurotransmittermolecules havespecific shapes• When NT binds toreceptor, ions enter• Receptor moleculeshave binding sites
    22. 22. Some Drugs Work on Receptors• Some drugs are shapedlike neurotransmitters• Antagonists: poorly fit thereceptor and block theNT– eg, beta blockers• Agonists: fit receptorwell and act like the NT– eg, nicotine
    23. 23. Types of Neurotransmitters• Acetylcholine• Dopamine• Serotonin• Norepinephrine• GABA• Endorphins
    24. 24. Acetylcholine (Ach)• Found in neuromuscularjunctions• Involved in muscle movements• Involved in learning and memory
    25. 25. Disruptions ofAcetylcholine Functioning• Curare—blocks ACh receptors– paralysis results• Nerve gases and black widow spidervenom; too much ACh leads to severemuscle spasms and possible death
    26. 26. Disruptions ofAcetylcholine Functioning• Cigarettes—nicotine works onACh receptors– can artificially stimulate skeletal muscles,leading to slight trembling movements
    27. 27. Alzheimer’s Disease• Deterioration of memory,reasoning, and language skills• Symptoms may be due a to lossof ACh neurons
    28. 28. Dopamine• Involved in movement, attention,and learning• Dopamine imbalance alsoinvolved in schizophrenia• Parkinson’s disease is caused bya loss of dopamine-producingneurons
    29. 29. Parkinson’s Disease• Results from loss of dopamine-producingneurons in the substantia nigra• Symptoms include– difficulty starting and stopping voluntarymovements– tremors at rest– stooped posture– rigidity– poor balance
    30. 30. Parkinson’s Disease• Treatments– L-dopa– transplants of fetal dopamine-producingsubstantia nigra cells– adrenal gland transplants– electrical stimulation of the thalamus hasbeen used to stop tremors
    31. 31. Serotonin• Involved in sleep• Involved in depression–Prozac works by keeping serotoninin the synapse longer, giving itmore time to exert an effect
    32. 32. Norepinephrine• Arousal• “Fight or flight” response
    33. 33. Endorphins• Control pain and pleasure• Released in response to pain• Morphine and codeine work on endorphinreceptors; involved in healing effects ofacupuncture• Runner’s high— feeling of pleasure aftera long run is due to heavy endorphinrelease
    34. 34. GABA• Inhibition of brain activity• Huntington’s disease involvesloss of neurons in striatum thatuse GABA–Symptoms:• jerky, involuntary movements• mental deterioration
    35. 35. Summary• Neuron structure• Action potentials• Synapses• Neurotransmitters• Receptors and ions• Agonists andantagonists
    36. 36. Parts of the Nervous System• Central nervous system (CNS)–Brain and spinal cord• Peripheral nervous system (PNS)–Carries messages to and from CNS
    37. 37. Central nervoussystemPeripheralnervous system
    38. 38. Sympathetic and parasympathetic divisionsof the nervous system
    39. 39. Endocrine System• Pituitary gland—attached to the base ofthe brain, hormones affect the function ofother glands• Adrenal glands—hormones involved inhuman stress response• Gonads—hormones regulate sexualcharacteristics and reproductiveprocesses; testes in males, ovaries infemales
    40. 40. Brain• Images• Brainstem– Hindbrain– Midbrain• Forebrain– Limbic system– Cortex
    41. 41. Hindbrain Structures• Cerebellum• Brainstem– medulla– reticularformation– pons
    42. 42. Cerebellum• Coordinated,rapid voluntarymovements– playing the piano,kicking, throwing,etc.• Lesions tocerebellum– jerky, exaggeratedmovements– difficulty walking– loss of balance– shaky hands
    43. 43. Medulla• Breathing• Heart rate• Digestion• Other vitalreflexes– swallowing– coughing– vomiting– sneezing
    44. 44. Reticular Formation• Network ofneurons in thebrainstem (andthalamus)• Sleep andarousal• Attention
    45. 45. Pons• Helps coordinatemovements onleft and rightsides of the body– eg, posturalreflexes that helpyou maintainbalance whilestanding ormoving
    46. 46. Forebrain Structures• Thalamus• LimbicSystem• Cortex
    47. 47. Thalamus• Relay station inbrain• Processes mostinformation to andfrom higher braincenters
    48. 48. The Limbic System• Hypothalamus• Amygdala• Hippocampus
    49. 49. Hypothalamus• Contains nuclei involved in a varietyof behaviors– sexual behavior– hunger and thirst– sleep– water and salt balance– body temperature regulation– circadian rhythms– role in hormone secretion
    50. 50. Hypothalamus and HormonesHypothalamusreleaseshormones orreleasing factors,which in turncause pituitarygland to releaseits hormones
    51. 51. Amygdala and Emotion• Identify emotion fromfacial expressionsAmygdala damagemakes this taskdifficult.(click on picture to advance photos)
    52. 52. Cortical Specialization• Localization—notion that differentfunctions are located in different areasof the brain• Lateralization—notion that differentfunctions are processed primarily onone side of the brain or the other
    53. 53. Lobes of the Cortex• Frontal lobe—largest lobe, producesvoluntary muscle movements; involved inthinking, planning, and emotional control• Temporal lobe—primary receiving area forauditory information• Occipital lobe—primary receiving area forvisual information• Parietal lobe—processes somaticinformation
    54. 54. Language and the Brain• Aphasia—partial orcomplete inability toarticulate ideas orunderstand languagebecause of brain injury ordamage• Broca’s area—plays role inspeech production• Wernicke’s area—playsrole in understanding andmeaningful speech
    55. 55. •Split-brain operation—procedure used to reduce recurrent seizures insevere cases of epilepsy•Corpus callosum—thick band of axons that connects the two cerebralhemispheres

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