Psychology 398: Biological bases of motivational systems

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Psychology 398 Biological bases of motivational
systems

• Instructor
• Dr. Ming Li, ming.li_at_camhpet.ca
• T.A. Katherine Krpan, katherine_at_psych.utoronto.ca
  
• Office hrs
• Wednesday 400 pm 600 pm (or by appointment)
• Room SE 2040E
• Course Website http//www.utm.utoronto.ca/w3psy/
  index_files/04-05/PSY398
• Discussion group http//groups.yahoo.com/group/ps
  y398/

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The commonly studied motivational systems

• Eating (feeding)
• Drinking (fluid consumption)
• Temperature regulation
• Attacking (aggression)
• Copulating (sexual behavior)
• Caring of the offspring (maternal behavior)
• Escaping/avoiding (fear)
• Exploring (novelty seeking)
• Brain self-stimulating
• Drug seeking (drug abuse)
• Motivation for achievement
• Motivation for learning

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Course overview

• Covers 3 general areas
• Homeostatic behaviors (eating, drinking)
• Social motivations (sexual and maternal
  behaviors)
• Negative emotional behaviors (fear, aggression,
  and drug-seeking)

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Course overview

• Each area consists of 3 components
• Basic behavioral findings
• Relevant neural brain structures
• Relevant neurochemicals
• Course materials are primarily from animal
  research, however, some important human studies
  are also included.

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Readings

• Certain sections from the text Biological
  Psychology by Rosenzweig, Leiman and Breedlove
  that you used in Psych 290.
• Neil Carlsons Physiology of Behavior is also a
  good reference book.
• Journal articles (can be downloaded via UT
  library. I may post them on the group website).
  There are two required readings for each week.

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Evaluation

• Two non-accumulateive mid-term tests (each
  20)------40
• Final exam (25)-----25
• A research paper (APA style)------25
• Oral presentation 10

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Three tests

• Non-cumulative
• 1st test (Jan 26) covers introduction, eating
  and drinking
• 2nd test (Mar 2) covers drug abuse, sexual
  behavior and maternal behavior
• Final exam (Apr. 18-) covers fear and aggression
  and materials presented by students.

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The Format

• Definitions
• Fill the blank
• Short questions (1-2 sentences)
• Long questions (5sentences)

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Research paper

• APA style
• A critical review of one topic with at least 5-10
  original papers as references
• No more than 10 pages (5 10 pg)
• Due by the end of the class
• Examples
• Role of neuropeptide Y in eating behavior
• Is dopamine important for sexual behavior?
• A critical review of the role of medial preoptic
  area in the control of maternal behavior in rats

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Oral presentation

• Select one (1) research article from an
  empirical, peer-reviewed journal that examines a
  question in the study of motivation that is
  related to the topics covered in this class.
• Present to the class (1) background information
  (2) why they did it? (3) how they did it? (4)
  what did they find? (5) what implications could
  be drawn from their work?
• Time limit 10 min presentation followed by 5 min
  Q A.
• Or you can present your research paper.

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Grading criteria

• statement of the background for the paper
• statement of the research question(s)
• presentation of research methods used
• presentation of research findings
• clarity of take-home message
• clarity of responses to questions/discussion.

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Where to find articles?

• Use PubMed at http//www.ncbi.nlm.nih.gov/entrez/q
  uery.fcgi
• Type in keywords (e.g dopamine eating)
• This powerful search engine will list articles
  matching your topic. It will also suggest related
  articles.

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Neuroanatomical bases of motivated behaviors
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A brief review

• Central nervous system (CNS) brain and spinal
  cord.
• Peripheral nervous system outside of the CNS.
• Hindbrain (medulla, pons, cerebellum)
• Midbrain (tectum and tegmentum)
• Forebrain (thalamus, hypothalamus, basal ganglia
  (caudate putamen, nucleus accumbens, globus
  pallidus), limbic system and cerebral cortex).

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The main areas of the human brain
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Major components of the limbic system
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Neurochemical bases of motivated behaviors
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Communication between neurons
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The mesolimbic dopamine system
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Research Methods
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Behavioral methods

• Observation of undisturbed behaviors
• Maternal behaviors
• Sexual behaviors
• Schedule-controlled behavior
• Operant conditioning for food
• Pavlovian fear conditioning

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Experimental ablation

• Lesions destroy the neurons or severs the neural
  pathways leading to and from a given brain
  region. The lesions prevent the cells from
  receiving and sending their normal signals and
  thus prevent the cells from having their normal
  effects.
• Function of an area of the brain can be inferred
  from the behaviors that the animal can no longer
  perform after the area is damaged.

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Types of lesions

• Electrolytic lesion passing electrical current
  through a stainless steel wire that is coated
  with an insulating varnish except for the very
  tip. This type of lesions destroys neurons and
  the axons of neurons that pass through the
  region.
• Excitotoxic lesion an excitatory amino acid such
  as kainic acid is infused into the target area.
  KA produces lesions by stimulating neurons to
  death, which spares the axons of passage.
• Reversible lesion injecting a local anesthetic
  (lidocaine) into the targeted area.
• NT-specific lesion 6-hydroxydopamine destroys
  dopamine and noradrenergic neurons or terminals.

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Stereotaxic surgery
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Electrical stimulation

• Electrical stimulation of specific cells or areas
  in the brain can be produced with very fine
  electrodes and very low voltage. This type of
  stimulation mimics the cells natural (neural)
  firing and causes the cells to become active.
  Researchers then observe what behavioral or
  neurochemical effects occur as a result of the
  activity of that brain area.

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Recording of single cell activity

• Electrodes can be used to provide recordings of
  activity of cells in specific areas of the brain.
  Implanted electrodes can record neural pulses
  when the cells fire.

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Microinfusions

• Chemicals acting on the neurons are injected into
  the targeted area of the brain via an apparatus
  permanently attached to the skull (called a guide
  cannula).

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Microdialysis

• Microdialysis is a procedure for analyzing
  chemicals present in the interstitial fluid
  through a small piece of tubing made of a
  semipermeable membrane that is implanted in the
  brain.

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Immunocytochemistry

• This technique utilizes antibodies to bind to
  specific areas of a protein. By incubating tissue
  in a series of different chemical containing
  solutions, the targeted protein is labeled and
  can be visualized under the microscope.

Fos-protein
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Tracing neural connections

• Anterograde (moving forward) tracing chemicals
  (PHA-L) are injected in one brain site that are
  taken up by dendrites or cell bodies and are then
  transported through the axons toward the terminal
  buttons.
• Retrograde (moving backward) tracing chemicals
  (fluorogold) are taken up by terminal buttons and
  carried back through the axons toward the cell
  bodies.

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Human brain imaging

• Computerized tomography (CT) re-construct brain
  images by measuring the amount of X-ray
  radioactivity that passes through the subjects
  head.

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Human brain imaging

• Magnetic resonance imaging (MRI) brain images
  are reconstructed by measuring the radio
  frequency wave in the magnetic field.

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Functional Magnetic Resonance Imaging

• fMRI is based on the increase in blood flow to
  the local vasculature that accompanies neural
  activity in the brain. It is a technique for
  determining which parts of the brain are
  activated by different types of physical
  sensation or activity,

Activations in the Ventral Striatum and Anterior
Insula by aversive CS
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Positron Emission Tomography (PET)

• PET scan, is a examination that involves the
  acquisition of physiologic images based on the
  detection of positrons. Positrons are tiny
  particles emitted from a radioactive substance
  administered to the subjects.

                                              
                                              
PET Scan of Alzheimer's Disease Brain
PET Scan of Normal Brain
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Basic concepts of motivational systems
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Appetitive vs. consummatory phase

• A motivated behavior is generally divided into
  two sequential phases
• (1) appetitive phase the flexible approach or
  avoidance behavior that an animal or person emits
  before the motivational goal is achieved
• (2) consummatory phase the stereotyped and
  species-typical pattern of movements elicited by
  the goal stimulus chewing and swallowing food,
  licking and drinking water, copulation, nursing
  pups, etc.

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What is a motivational system?

• Motivation is an intervening variable used to
  explain the drive behind a behavior and the
  direction of it.
• Motivation is concerned with goal-directed
  behavior. Motivation refers to the internal
  states of the organism that lead to the
  instigation, persistence, energy and direction of
  behavior towards a goal (Klinger and Cox, 2004).
• A motivational system is the one that has
  responsibility for giving not only instigation
  and momentum, but also goal direction, to
  behavior (Toates, 1989).
• A hungry rat looking for food

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The general use of drive

• To identify the underlying causes of behaviors
  lacking apparent instigators (drive).

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The general use of motivation

• To explain behavioral variability for which
  variability in internal state is responsible

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Motivation, drive, stimulus incentive

• Drive is an internal state, often referring
  to the energy level. It is not motivation, but
  could provide motivation.
• Stimulus incentive is an external factor that
  plays a role in stimulating motivation.
• Motivation arises as a function of both internal
  state (drive) and incentive.

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An example

• Two animals are food deprived for 24 hrs. Each
  might be said to have the same hunger drive.
• If one is given normal food, which it eats,
  whereas the other is given quinine-adulterated
  food, and declines it.
• We would say the motivation differs between the
  two animals.

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Behavioral theories
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Humanistic Approach Hierarchy of Needs (Abraham
Maslow)
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The homeostatic drive model

• Homeostasis. The process through which a stable
  internal environment is maintained. The body is
  designed to maintain a constant internal state (a
  setpoint) with regard to body fluid composition,
  temperature, blood pressure, blood glucose level,
  etc.
• Three mechanisms
• A setpoint (body water level, neuronal glucose
  level, nutrient storage level, hormonal level)
• An error detector
• An error correction
• Good to account for hunger, thirst, salt
  appetite less to sex, aggression, or drug
  addiction.

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Homeostatic mechanism
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Bindras theory (Bindra, 1969)

• A motivational action depends upon an interaction
  between certain environmental incentive objects
  and a particular type of physiological state or
  organismic condition of the animal (Bindra,
  1969).
• Each interaction creates in the animal a central
  motive state (CMS). CMS is a neural functional
  change that occurs through an interaction of
  physiological state and incentive stimuli.
• It is the CMS that produce motivated
  species-typical behaviors.

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How does a CMS organize a motivated response?

• Selective-attention function CMS alters the
  effectiveness of sensory input in such a way as
  to increase the probability that a response in
  relation to certain incentive objects will be
  made
• Response-bias function (motor facilitation) CMS
  modifies neural discharge to particular sets of
  autonomic and somatic motor sites involved in a
  species-typical action.

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Schematic diagram of CMS functions
Autonomic discharge
Observed responses
Central Motive State (CMS)
Postural adjustments
Enviromentally organized motor output
Selective attention
Drive
Other situational stimuli
Incentive stimuli
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The conditioning of central motive states

• CMS can be conditioned to neutral stimuli.
• CS and US (incentive stimulus) occur in a certain
  contingent way.
• CS alone will lead to the occurrence of certain
  autonomic and postural reactions as well as to
  the operation of selective attention and
  response-bias mechanisms.
• In the absence of US, CS can elicit spontaneous
  behavior. Thus CS is said to acquire some of the
  incentive properties that are normally possessed
  by US.

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Conditioned CMS
Autonomic discharge
Spontaneous responses
Central Motive State (CMS)
Postural adjustments
Enviromentally organized motor output
Selective attention
Conditioned stimulus
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A tone (CS) paired with the intracranial
stimulation is capable of eliciting
hyperactivity. The CS created a CMS.
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The efficacy of a CS depends on the levels of
drive, the mere presence of the CS is not
sufficient to create the CMS
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Summary

• A CMS is a set of neural processes arising from
  an interaction of a certain type of physiological
  state and a certain class of incentive stimuli.
• The CMS directs behaviors by two mechanisms (1)
  selective attention paid to a certain class of
  incentive stimuli (2) response bias in favor of
  a certain class of species-typical actions.
• CMS can be conditioned.

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Ethical Issues in Research with Animals

• Animals have been traditionally hunted by humans
  for food and clothing, and domesticated for many
  purposes.
• Modern man uses animals for more purposes than
  ever before.
• Modern societies differ in their use of animals.

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Benefits of using animals in research

• Characterization of normal physiological and
  psychological processes
• Pain, stress, maternal care, development...
• Characterization of abnormal functioning
• Addiction/Recovery, schizophrenia, depression,
  Parkinsons disease, brain / spinal injury...
• Screening drugs for efficacy / toxicity
• Parkinsons disease L-DOPA Depression
  imipramine, fluoxetine
• Schizophrenia clozapine, haloperidol
• Interest in animals for their own sake
• Procedures or medicine used by veterinarians

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