Biological Psychology Biological Roots of Behavior How the Brain Governs Behavior Neurotransmitters

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Biological Psychology Biological Roots of
BehaviorHow the Brain Governs BehaviorNeurotrans
mitters
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So why do we have to study biology in a psych
class?

• Let me use Phineas Gage to help answer this
  question

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He was no longer Gage

• Several different angles of where the rod passed
  through his skull

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There is a Phineas Gage display in the Warren
Medical Museum at Harvard University

• This is what went through his brain (see below)

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Biological Roots of Behavior

• Franz Gall (1758-1828) Austrian physicist who
  invented phrenology
• He felt that bumps on the skull could reveal our
  mental abilities and character traits.
• Introduced as being scientific but its use was
  exploited by quacks on gullible individuals

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Biological Roots of Behavior

• Became similar to that of astrology, palm-reading
  and tarot
• Although, ill-fated theory was laughed at by
  scientific community of that day it may have
  had some validity
• Localization of brain functions somehow hit the
  mark

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The Nervous System

• Electrochemical communication system that enables
  us to think, feel, and behave.
• Complex beyond comprehension
• Although, human brains are more complex our
  nervous systems and those of animals operate in a
  similar fashion advantage of this is
  experimentation

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The Nervous System

• Allows researchers to study simple animals such
  as squids and sea slugs to help us better
  understand the organization of our own brains

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Divisions of the Nervous System

• Consists of two systems
• Central Nervous System
• Brain and spinal cord
• Peripheral Nervous System
• Which connects the CNS to the rest of the body

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Organization of the Nervous System
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Peripheral Nervous System

• Two components
• Somatic Nervous System
• Transmits sensory input to the CNS from the
  outside world and directs motor output
• Autonomic Nervous System
• Controls glands and muscles of our internal
  organs automatic pilot

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Autonomic Nervous System

• Dual system
• Sympathetic Nervous System
• Arouses the body
• Parasympathetic Nervous System
• Calms us down

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Neurons

• Nerve cells (building blocks) essentially
  identical to animals
• Small samples of brain tissue from a person and a
  monkey are basically indistinguishable

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Endocrine System Taking the slow lane

• Unlike the speedy nervous system which zips
  messages from eyes to brain to hand in a fraction
  of a second, endocrine messages use the slow lane
• May take several seconds or more as bloodstream
  carries a hormone from an endocrine gland to its
  target tissue

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Endocrine System

• Hormones are chemical messengers
• Influence all aspects of our lives growth,
  metabolism, reproduction, moods, etc.
• Strives for homeostasis (balance) by responding
  to stress, exertion, internal thoughts, etc.

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The Brain

• Studying the brain
• Clinical observations
• Manipulating the brain

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How does the brain govern behavior?

• 3 Principle layers of the brain
• (1) Brainstem
• (2) Limbic System
• Hippocampus
• Amygdala
• Hypothalamus
• (3) Cerebral Cortex
• The Whole Brain Atlas

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What the Brain Controls
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The Lobes of the Brain
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A Positron Emission Tomography Scanner (PET)
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A Pet Scan of a Depressed Patient
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A PET Scan of a Schizophrenic Patient
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Brainstem (or Hindbrain)

• The brains innermost region
• Begins where the spinal cord enters the skull and
  swells slightly forming the medulla
• Towards the rear of the brainstem is the
  cerebellum this is linked to memory and its
  major function is muscular control

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Limbic System

• Hippocampus
• This structure plays a key role in allowing us to
  store new information
• Problems here may cause Alzheimer's these
  individuals have trouble processing declarative
  memories
• Milner (1968) the classic case of H.M.

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Limbic System

• Amygdala
• Emotional control center of the brain major
  influence on aggression and fear
• Emotional memories as well
• Alzheimers ???
• Kluver and Bucy (1939)
• Demasio (1994)

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Limbic System

• Hypothalamus
• Major influence on hunger, thirst, body
  temperature, and sexual behavior
• Olds and Milner (1954)

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Cerebral Cortex

• Makes us distinctively human much higher
  developed than in animals
• Motor Cortex involved in the conscious
  initiation of voluntary movements in specific
  parts of the body including hand, knee, foot and
  head
• Fritsch and Hitzig (1870)
• Delgado (1969a)
• Delgado (1969b)
• Penfield (1975)

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Cerebral Cortex

• Sensory Cortex receives information from our
  senses
• Visual cortex
• visual info
• Auditory cortex
• auditory info
• Somatosensory cortex
• info from skin
• Association cortex
• involved in complex cognitive tasks associating
  words with images
• Brocas area (aphasia)
• Wernickes area (aphasia)

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Neurons
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More Neurons
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And just one more!!
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Neurotransmitters

• Neurotransmitters are chemicals made by neurons
  and used by them to transmit signals to the other
  neurons
• A chemical message telling the next cell to fire
  or not to fire its own action potential
• More than 200 in our body all with different
  functions
• Lets briefly discuss some of the most important
  ones

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Serotonin

• Facilitates a relaxed, sleepy feeling
• Tryptophan which is an amino acid found in dairy
  products and turkey is converted into serotonin
  in the body
• So, insomnia sufferers may be smart to listen to
  grandmothers suggestion to drink a warm glass of
  milk before going to bed

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Some Illnesses Associated With Serotonin

• Too low levels in depression and anxiety
  sufferers
• Obesity may also be associated with low levels
• Linked to aggression as well -- low levels in the
  brains of suicide victims

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Dopamine

• High levels lead to pleasure
• Makes person feel happy and active
• Dopamine raises the body's temperature and
  increases metabolic rate
• Gives you euphoric feelings and allows you to be
  active
• Drug and alcohol abuse will block dopamine
  receptors and therefore a person needs to take
  more to get the same effect

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Illnesses Associated With Dopamine

• Parkinsons Disease too low levels
• Schizophrenia too high levels
• Tourettes disorder too high levels
• Huntingtons disease too high levels

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Norepinephrine

• Plays a role in attention and arousal
• Used by sympathetic nervous system to prepare us
  for action

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Illnesses Associated With Norepinephrine

• Depression
• chronic stress depletes this neurotransmitter and
  can lead to depression
• Note
• Aerobic Exercise is found to protect the brain
  from this depletion so go out and run a mile or
  two if your down in the dumps

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Epinephrine

• Involved in energy and glucose metabolism

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Illnesses Associated With Epinephrine

• Depression too low levels

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Acetylcholine

• Involved in voluntary movement, learning, memory,
  and sleep
• Helps parasympathetic nervous system to slow our
  heart rate

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Illnesses Associated With Acetylcholine

• Alzheimers disease too low levels
• Note
• Unfortunately, drugs used to increase
  acetylcholine to help restore normal levels
  appear to have small effects on improving memory

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GABA

• Inhibits excitation and anxiety
• Appears directly related to anxiety reduction

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Illnesses Associated With GABA

• Anxiety disorders too low levels
• Huntingtons Disease too low levels
• GABA systems arent working and this allows
  dopamine systems to run wild
• Huntington's disease is a hereditary disorder
  characterized by memory loss, abnormal movement
  and premature death
• It affects 1 in 10,000 people, and children with
  an affected parent have a 50 percent chance of
  developing the disease
• Epilepsy too low levels

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Glutamate

• Main excitatory neurotransmitter in the brain
• Very important in learning and memory

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Illnesses Associated With Glutamate

• Alzheimers disease too low levels in
  hippocampus
• Strokes too high levels can cause neurons to
  die
• ALS (Lou Gehrigs Disease) causes death in
  neurons in the spinal cord and brainstem

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Endorphins

• Involved in pain reduction and pleasure
• They enhance the release of dopamine
• These natural opiates are released in response to
  pain and vigorous exercise

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Illnesses Associated With Endorphins

• Use of artificial opiates can cause body to stop
  manufacturing its own this can lead to drug
  addiction