Biological Foundations of Behavior

1
Chapter 2

• Biological Foundations of Behavior

2
Module 2.1

• Neurons The Bodys Wiring
• Its EVOLUTION!

3
What is our advantage?

• What puts us at a major advantage over other
  animals which puts us at the top of the food
  chain?

4
Our Brain!
5
Its Evolution Baby!

• The human brain is a product of generations of
  adaptive mutations and adaptations.
• Homo sapiens-100,000 years old (is this old?)
• What the heck is natural selection?

6
The original Chuck D Charles Darwin

• Evolve To develop gradually.
• Gradual change in the structure of an animal or
  plant as a result of natural selection.
• NS process by which inherited traits that lead
  to a selective advantage increase the likelihood
  of reproduction.

7
The Adaptive Human

• Brain size correlates with intelligence? T or F
• Bigger brainSmarter?

8
Cephalisation Index

• Ratio of brain weight to body weight.
• KE/P
• KCephalisation Index
• EBrain weight in grams
• PBody weight in kilograms

Real Smart Humans .89 Dolphins .64
Chimp.30 Real Dumb Sheep .10
Rabbit .05
9
Neurons!

• The basic building block of the nervous system
• Cells
• Transmit information via an electro-chemical
  process.

10
Chapter 2

• Biological Foundations of Behavior

11
Figure 2.1 The Neuron
soma
12
Cells in the Nervous System

• Three types of neurons
• Sensory neurons (or afferent neurons)
• Motor neurons (or efferent neurons)
• Interneurons (or associative neurons)
• Glial cells (the glue!)
• Account for 90 of cells in adult human brain
• Help hold neurons together
• Provide supports for the nervous system

13
Cells in the Nervous System

• Sensory Neurons
• Afferent nerves
• Information about the outside world to the brain.
• Sensory organs to brain.
• 5 senses
• That stinks!

14
Cells in the Nervous System

• Motor Neurons
• Efferent Nerves
• Sends message from the brain to the muscles and
  glands to cause response/behavior or to regulate
  bodily processes.

15
Cells in the Nervous System

• Interneuron
• Most common neuron in the NS
• Connect neurons to neurons
• Connect sensory to motor, motor to sensory
• More on this laterI promise

16
How do they talk?

• Electro-Chemical process
• Sodium (Na) and Potassium (K)
• A cell at rest 70 (mV).
• Cell begins to let positive ions into the cell,
  changing the polarity to (40 mV)
• This is an action potential (firing or spiking)
• All-or-none Principle
• Must have a full voltage of 40 mv to fire.
• Wont half fire or semi fire.

17
Action Potentials
18
Whats next?

• Neurotransmission!
• When the neuron fires, the axons terminal
  buttons release molecules of NTs into synaptic
  gap.
• They bind to Receptor sites on the dendrites of
  other neurons.
• 2 possible outcomes
• Excitatory
• Inhibitory

19
Module 2.2

• The Nervous System Your Bodys Information
  Superhighway

20
Figure 2.4 Parts of the Nervous System
21
Concept Chart 2.2 Organization of the Nervous
System
22
Spinal Cord

• Column of nerves extending from brain
• Protected by the spine
• Transmits information between the brain and the
  peripheral nervous system
• Controls some spinal reflexes
• Allows quick responses to particular types of
  stimuli (evolution)
• CNS regulates everything in the body.

23
Figure 2.5a The Knee-Jerk Reflex
afferent
efferent
24
Figure 2.5b The Withdrawal Reflex
25
Peripheral Nervous System

• Connects the CNS with other body parts
• Divided into 2 parts
• Somatic Nervous System Transmits messages
  between CNS and the sensory organs, glands, and
  muscles (moves ya around)
• Autonomic Nervous System (ANS) Controls internal
  bodily processes
• BP, Heart Rate, Etcnot aware but may be affected
  by conscious things (stress, anger)

26
Divisions of the ANS

• Sympathetic Nervous System
• Speeds up bodily processes
• Draws energy from stored reserves
• Activation often accompanied by strong emotions
• Parasympathetic Nervous System
• Fosters bodily processes that replenish energy
  stores
• Helps conserve energy by slowing down other
  bodily processes

27
Module 2.3

• The Brain Your Crowning Glory

28
Brain Facts

• Average number of neurons in the brain 100
  billion
• The average brain weighs about 3 pounds.
• 77 of a human brain is dedicated to the cerebral
  cortex.
• 31 is dedicated to a rats.

29
(No Transcript)
30
HindbrainKickin it old school!

• Lowest, oldest part of the brain
• Includes the
• Medulla (heart beat etc.)
• Pons (time for bedwake up!)
• Cerebellum (dont trip dont forget to breathe)

31
Figure 2.6 The Brainstem
32
Midbrain

• Contains nerve pathways that connect the
  hindbrain with the forebrain
• Midbrain structures perform important roles
• e.g., control of automatic movements of the eye
  muscles
• Reticular formation plays key role in regulating
  states of attention, alertness, and arousal.

33
Major Structures of the Forebrain

• Thalamus
• Relays sensory information to appropriate parts
  of the cerebral cortex
• Receives input from the basal ganglia
• Hypothalamus
• Regulates many vital bodily functions as well as
  emotional states, aggressive behavior, and
  response to stress
• (The 3 Fs)

34
The Limbic System

• Group of interconnected structures
• Amygdala Helps regulate states of emotional
  arousal
• Hippocampus Plays important role in the
  formation of memories
• Why cant you remember when you were born?
• Parts of the thalamus
• Parts of the hypothalamus

35
The Cerebral Cortex

• Thin, outer layer of the largest part of the
  forebrain which is called the cerebrum
• Cerebrum consists of the right and left cerebral
  hemispheres.
• Hemispheres connected by the corpus callosum

36
Figure 2.7 The Size of the Cerebral Cortex in
Humans and Other Animals
37
Figure 2.8 Lobes of the Cerebral Cortex
38
Table 2.1 The Lobes of the Cerebral Cortex
39
Figure 2.9 Somatosensory Cortex and Motor Cortex
40
Module 2.4

• Methods of Studying the Brain

41
Methodology

• Postmortem studies
• Animal Studies
• Electrical Recordings
• Static Imaging Techniques
• Metabolic Imaging

42
Recording and Imaging Techniques

• EEG (electroencephalograph)
• CT (computed tomography) scan
• PET (positron emission tomography) scan
• MRI (magnetic resonance imaging)
• fMRI (functional MRI)

43
Experimental Methods

• Lesioning
• Electrical recording
• Electrical stimulation

44
Static Magnetic Resonance Imaging

• Strong magnetic field passed through the skull
• Uses the detection of radio frequency signals
  produced by displaced radio waves in a magnetic
  field
• Creates a detailed anatomical image of the brain

45
(No Transcript)
46
Metabolic Positron Emission Tomography (PET)

• Radioactive material is injected or inhaled
• Participant is then scanned to produce an image
  of the brains activity

47
(No Transcript)
48
Metabolic fMRI

• fMRI imaging takes a series of images of the
  brain in quick succession and then statistically
  analyzes the images for differences among them
• Brain areas with more blood flow have been shown
  to have better visibility on fMRI images ?BOLD
• Better visibility is correlated with brain
  activation

49
What might this person be doing?
50
Module 2.5

• The Divided Brain
• Specialization of Function

51
Lateralization of Brain Functions

• Refers to division of functions between right and
  left hemispheres
• Left hemisphere dominant for language abilities,
  logical reasoning, and problem solving
• Right hemisphere dominant in nonverbal processing
• People are not left-brained or right-brained.

52
Figure 2.15 Brocas and Wernickes Area
Production
Comprehension
53
Brocas and Wernickes Area

• Brocas Aphasia
• Me How are you today?
• BA Ah ah ah ah ah ah ga ga ga ga ga ga ga ga
  gmmmmmmmpppfffffffffffgood thanks
• Wernickes Aphasia
• Me How are you today?
• WA Kangaroos can box you know!

54
Split-Brain Research

• Severing corpus callosum as treatment for severe
  epilepsy
• Split-brain patients retain intellect and
  personality
• But differences in perception, language evident
  in special testing circumstances

55
Brain Damage and Psychological Functioning

• Case of Phineas Gage Prefrontal cortex damage
• Plasticity Ability of the brain to adapt and
  reorganize itself following trauma or surgical
  alteration

56
What happened to Gage?

• indulging at times in the grossest profanity
  (which was not previously his custom),
  manifesting but little deference for his fellows,
  impatient of restraint or advice when it
  conflicts with his desires
• CONCLUSION?
• Gage's case is cited as among the first evidence
  suggesting that damage to the frontal lobes could
  alter aspects of personality and affect socially
  appropriate interaction

57
Module 2.7

• Genes and Behavior A Case of Nature and Nurture

58
Genetic Influences on Behavior

• Nature-nurture problem
• Genotype An organisms genetic code
• Phenotype The observable physical and behavioral
  characteristics of the organism
• Genetic and environmental influences interact in
  complex ways to shape our personality.

59
Kinship Studies

• Familial association studies
• Twin studies
• Identical (MZ) vs. fraternal (DZ) twins
• Concordance rates
• Adoptee studies

Continue
60
Figure 2.19 Genetic Overlap Among Family Members