UNIT 2 BIOLOGICAL BASES OF BEHAVIOR

An  Early  History  of  Biopsychology  

l Plato:  the  mind  is  located  in  the  brain  

l Franz  Gall  and  Phrenology  – Early  1800s  – Read  bumps  on  skull  to  understand  traits  

 

If I was to take your brain out of your body, place it into patient needing brain surgery, where would the new ‘self’ call home? Are you simply the end product of a biological and chemical reaction?

Biopsychology  Today  l Everything  we  do  is  ulFmately  controlled  by  our  body  and  brain  – Body/brain  composed  of  cells  – Brain  cells  called  neurons  communicate  electrically  and  chemically  

– Different  parts  of  the  brain  have  specific  funcFons  – Our  brains  create  meaningful  experiences  from  sensory  informaFon  

– Brain  structure  and  funcFon  is  influenced  by  experience  

AGENDA

1)  Review Text Book Reading 2)  Quiz 3)  Todays Theme: Hemisphere

Dominance 4)  VIDEO: Split Brain Patients 5)  Hand back & Discuss Test

(I WILL NEED 5-7 minutes)

The  Cortex  

l Each  hemisphere  is  divided  into  4  lobes  

Frontal  lobe  Temporal  lobe  Parietal  lobe  Occipital  lobe  

l The  lobes  are  separated  by  deep  

convoluFons  known  as  fissures  

Cortex  Breakdown…  

l  Occipital  Lobes  –  Visual  cortex  –  Damage?  

l  Temporal  Lobes  –  Auditory  cortex  –  Auditory  hallucinaFons?  

l  Parietal  Lobes  –  Primary  sensory  or  

somatosensory  cortex  –  AllocaFon  of  space?  

l  Frontal  Lobes  –  Most  evolved    –  Motor  cortex,  which  allows  

us  to  move  –  AllocaFon  of  space?  

Some  Hemispheric  Strengths  

LeU  Hemisphere  Language  Logic  Right  side  of  body  

Right  Hemisphere  PercepFon  Sense  of  self  Inferences  LeU  side  of  body  

Split-­‐Brain  

Epilepsy,  seizures  and  the  corpus  callosum    ReducFon  in  epilepFc  seizures  Different  abiliFes  in  each  hemisphere    hYps://www.youtube.com/watch?v=lfGwsAdS9Dc    

AGENDA:

1. Map the Brain with the Truine Model

2. COLLABORATION: Map brains parts together

3. VIDEO: Secrets of the Mind

TRUINE MODEL:

REPTILIAN BRAIN

•  Primary focus is survival

•  Instinct •  Internal Functions •  OLDEST

STRUCTURE

TRUE STORY:

TRUINE MODEL:

MAMALIAN BRAIN

•  Contains the Limbic System (Seat of EMOTION)

•  In charge of appetite, sex drives and some vision.

TRUINE MODEL:

HUMAN BRAIN •  Youngest Part •  Counteracts

Emotions •  Information

Processing •  Abstract Complex

Thoughts & Behaviors

STEP  1:  RESEARCH  YOUR  BRAIN  FEATURE  (You  need  to  explain  it  to  other  students  WITHOUT  NOTES.  STEP  2:  Create  a  creaOve  catch  phrase  or  slogan  which  will  help  people  remember  what  your  funcOon  does.  STEP  3:  Come  up  with  a  visual  image  that  illustrates  its  funcOon.  STEP  4:  LOCATE  THE  BRAIN  PART  AND  PUT  YOUR  INFO  ON  THE  BOARD  

THE  MORE  CREATIVE  YOU  ARE,  THE  MORE  YOU  WILL  REMEMBER  

INTERNAL                                                                                                                        EXTERNAL  

PrimiOve  Brain  Structures  “AUTOPILOT”  

Brainstem  Oldest  part  of  brain  Contains  medulla,  controlling  heartbeat,  blood  pressure  and  breathing  Also  contains  pons,  which  helps  regulate  sensory  informaFon  and  facial  expressions  Contains  ReOcular  FormaOon  (RF)  for  alertness/arousal,  sleep/wakefulness  

Thalamus  Pair  of  egg-­‐shaped  structures  on  top  of  brainstem  Routes  all  incoming  sensory  informaFon  except  for  smell  to  appropriate  areas  of  brain  

Cerebellum  “liYle  brain”  at  read  of  brainstem  Controls  coordinaFon,  balance,  and    muscle  tone  

These  parts  of  the  brain  are  our  “autopilot” so  other  regions  can  deal  with  higher-­‐level  “human” funcFons  

The  Limbic  System  Located  in  between  the    primiFve  parts  of  the  brain  and  the  cerebral  hemispheres  

Hippocampus  processes  new  memories  Amygdala  controls  emoFons  such  as  aggression  and  fear  –  in  animals,  the  “aYack”  response    Hypothalamus  regulates  hunger,  thirst,  body  temperature  and  sex  drive  –  also  controls  pituitary  gland  

PRIMARILY,  the  limbic  system  processes  drives,  smell  and  various  emoOonal  responses  

The  Cortex  

•  Most  highly  evolved  part  of  the  human  brain  

•  Body’s  ulFmate  control  and  informaFon-­‐processing  center  

•  Reasoning  Center  

Limbic  System  vs.  Cortex    hYps://www.youtube.com/watch?v=u76jBk59RFk    

AGENDA:

1. QUIZ (Be ready to go at the bell) 2. GET FIRED UP ABOUT NEUROSCIENCE! 3. How does our body communicate with itself? 4. Labeling the Neuron 5. ACTING OUT NEURAL COMMUNICATION!

NEURONS and SYNAPSES

Types  of  Neurons  

Sensory   Motor   Interneurons  

Sensory Neurons

From sensory organs to the brain and spinal cord.

Drawing  shows  a  somatosensory  neuron    Vision,    hearing,    taste  and  smell  nerves  are  cranial,  not  spinal    

Spinal Cord

Brain Sensory Neuron

Motor Neurons

From the brain and spinal cord to the muscles and glands.

Spinal Cord

Brain Sensory Neuron

Motor Neuron

Interneurons Interneurons carry information

between other neurons only found in the brain and spinal cord.

HOW LONG DOES THIS TAKE WITH NORMAL STIMULI?

BUT HOW EXACTLY DO THESE CELLS

COMMUNICATE??!?!?!

AcFon  potenFals  

•  Brief  Electrical  charge  that  travels  down  an  axon  (Myelin  Sheath  helps  speed  things  up!)  

•  NeurotransmiYers:  Chemicals  that  transmit  messages  between  neurons  

STRUCTURES OF THE NEURON

PLEASE DRAW THIS ON A BLANK SHEET OF PAPER

THE CELL BODY

•  CONTAINS  THE  CELL’S  NUCLEUS  

•  Round,  centrally  located  structure  

•  Contains  DNA  •  Controls  protein  manufacturing  

•  Directs  metabolism  

•  No  role  in  neural  signaling  

DENDRITES •  InformaFon  collectors  

•  Receive  inputs  from  neighboring  neurons  

•  Inputs  may  number  in  thousands  

•  If  enough  inputs  the  cell’s  AXON  may  generate  output.  

DENDRITIC GROWH •  Mature  neurons  generally  can’t  divide….  

•  BUT  new  dendrites  can  grow.  

•  Provides  room  for  more  connecFons  to  other  neurons.  

•  NEW  CONNECTIONS  ARE  THE  BASIS  FOR  LEARNING  

AXON

•  The  cell’s  output  structure  •  One  axon  per  cell,  2  disFnct  parts:  

AXON  AXON  TERMINAL  

Myelin Sheath • White  faYy  casing  on  axon  •  Acts  as  an  electrical  insulator  •  Not  present  on  all  cells  • When  present  increases  the  speed  of  neural  signals  

Myelin  Sheath  

Neuron on Neuron

Axons  branch  out  and  end  near  dendrites  of  neighboring  cells.    

Axon  terminals  are  the  Fps  of  the  axon’s  branches    

Gap  is  the  Synapse   Cell Body

Dendrite

Axon

Synapse Axon  terminals  contain  small  storage  sacks  called  synapFc  vesicles      

 Vesicles  contain  neurotransmiYer    molecules  

Sending  Neuron  

Synapse  Axon  Terminal  

THE  MESSAGE  IS  SENT  DOWN  THE  AXON  IN  WHAT  WE  CALL  AN:  

ACTION  POTENTIAL  

•  Domino  Effect  of  electrical  current.  

TIME  TO  APPLY!      

LAB  TIME!        

LETS  MAKE  IT  VISUAL!  

A.  ResFng  State  1.  Outside  of  the  neuron  membrane  is  posiOve  2.  Inside  of  the  membrane  is  negaOve  (-­‐70  mV)  3.  More  Na+  outside,  more  K+  inside  Why  don’t  the  charges  escape?  4.  The  membrane  is  selecOvely  permeable  

Cell membrane is Semi-Permeable

Cell Membrane at rest

Na+ Cl- K+

Na+ Cl- K+ A-

Outside  of  Cell  

Inside  of  Cell  Potassium  (K+)  can  pass  through  to  equalize  its  concentraOon  

Sodium  and  Chlorine  cannot  pass  through  

Result  -­‐  inside  is  negaOve  relaOve  to  outside  

- 70 mv

RESTING POTENTIAL

•  At  rest  inside  of  the  cell  is  at  -­‐70  microvolts  •  With  inputs  to  dendrites  inside  becomes  more  posiFve  •  If  resFng  potenFal  rises  above  threshold  and  acFon  potenFal  starts  to  travel  from  cell  body  down  the  axon.  

•  Figure  shows  resFng  axon  being  approached  by  an  AP  

Depolarization ahead of AP

•  AP  opens  cell  membrane  to  allow  sodium  (NA+)  in  •  Inside  of  cell  rapidly  becomes  more  posiFve  than  outside  •  This  depolarizaFon  travels  down  the  axon  as  leading  edge  of  the  AP.  

B.  DepolarizaFon  (Rising  Phase)        Causes  the  inside  of  the  membrane  to  become  posiFvely  charged  (depolarized)  

2)  RepolarizaFon  (Falling  Phase  of  AcFon  PotenFal)  

3)  Refractory  Period  •  Short  amount  of  Fme    when  no  new  acFon  potenFals  can  be  fired    ResFng  potenFal  (-­‐70  mV)  must  

Be  restored  

Nerve  Cell  Membrane  

• Each  level  contains  about  10%  o  the  energy  in  the  previous  level.  

ResFng  State  

hYp://www.youtube.com/watch?v=90cj4NX87Yk&feature=related  

Neurotransmitter Release •  AcFon  PotenFal  Causes  vesicle  to  open  •  NeurotransmiYer  released  into  synapse  •  Locks  onto  receptor  molecule  in  postsynapFc  

membrane.  

NeurotransmiYer  molecules  have  specific  shapes  

Binding  sites  for  NT’s  

When  NT  binds  to  receptor,  ions  enter…  Starts  AP  again…  

What  happens  when  the  acFon  potenFal  reaches  the  terminal  branch?  

 •  Vesicles  containing  neurotransmiYers  are  released  into  the  synapse  

•  NeurotransmiYers  bind  to  postsynapFc  receptors  

•  Cause  excitatory  or  inhibitory  effects    hYp://www.youtube.com/watch?v=Ntenaz7Sf4k    

Neuron Firing: Electro Chemical Process

1.  Neuron  at  rest  is  polarized  2.  Neuron  receives  signals  from  neighboring  

neurons  3.  Total  excitatory  input  exceeds  absolute  

threshold  4.  Neuron  fires  according  to  all  or  none  principle  –  

acFon  potenFal  shoots  down  the  axon  5.  NeurotransmiYers  are  released  across  synapse.  6.  Refractory  period  

NeurotransmiYers  bind  receptors  in  a  lock-­‐and-­‐key  model