Biology and Behavior

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Biology and Behavior

• Biological Psychology

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What is Biological Psychology?

• The study of how biological processes are linked
  to psychological processes and behavior
• Biological psychologists study how parts of the
  body communicate with the brain and send/receive
  information
• They focus on the nervous system, the brain, the
  endocrine system, and DNA/heredity

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The Nervous System
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Two Main Nervous Systems

• Central Nervous System (CNS) consists of the
  brain and the spinal cord
• Peripheral Nervous System (PNS) made up of
  nerves that send messages between the CNS and all
  other parts of the body
• Messages are transmitted around the body by
  neurons, nerve cells that use chemicals to
  communicate

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The Neuron

• There are billions of neurons in the body, shaped
  like a tree
• Dendrites branch-like structures that receive
  chemical messages and pass them to the cell body
• Cell body produces energy that fuels the cells
  activity
• Axon carries messages away from the cell body
  to the axon terminals
• Axon terminals the small branches at the end of
  the axon that send a chemical message to a nearby
  neuron
• Synapse the gap between the axon terminals of
  one neuron and the dendrites of another

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How Neurons Send Information

• The dendrites receive a chemical message from
  another neuron
• The chemical message is turned into an electrical
  impulse by the cell body
• The impulse is fired down the axon to the
  synapses at 200 mph
• The axon terminals read the electrical impulse
  and translate it into a chemical, called a
  neurotransmitter
• The neurotransmitter leaves the synapse and
  travels toward the dendrites of another neuron
• Messages can only travel in one direction

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(synaptic cleft)
Presynaptic neuron
Terminal button
Postsynaptic neuron
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Types of Neurons

• Sensory neurons send messages from parts of the
  body to the brain (think 5 senses)
• Motor neurons send messages from the brain to
  parts of the body

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Neurotransmitters

• Chemicals stored in sacs inside the axon
  terminals
• They are fired out of the axon terminal like
  droplets out of a windex bottle they travel
  toward receptors on nearby dendrites
• Receptors are shaped to fit only certain
  neurotransmitters (like a lock and key)
• There are several types of neurotransmitters
• Neurotransmitters are involved in EVERY activity
  we do throughout our life

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Acetylcholine

• Used by both the CNS and PNS
• Controls muscles by stimulating them in the PNS
• Controls excitability and affects memory in the
  CNS
• When the brain runs low on acetylcholine, it is
  harder to form memories

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Dopamine

• Controls motor behaviors
• Too little dopamine can cause Parkinsons disease
• Too much dopamine can cause Schizophrenia
• Makes people feel good, acts like a reward system
  for the body

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Serotonin

• Used by the CNS to regulate moods and some bodily
  functions
• anger, aggression, body temperature, mood, sleep,
  sexuality, appetite, and metabolism
• Many anti-depressants and anti-anxiety
  medications work like serotonin

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Epinephrine

• Also called adrenaline
• Prepares the body for emergency situations
  fight or flight
• Makes heart rate and breathing increase, causes
  higher state of alertness, helps body respond
  quicker to sensory messages

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CNS

• The spinal cord a column of nerves that run
  from the brain down the back (about as thick as a
  thumb)
• Transmits messages from the brain to glands and
  muscles throughout the body
• Spinal reflexes an automatic response to
  certain messages (removing a hand from a hot
  stove, blinking, knee-jerk reflex)

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PNS

• Has two main parts somatic nervous system and
  autonomic nervous system
• Somatic transmits messages to the central
  nervous system (hot, cold, soft, sharp, pain,
  pressure)
• Autonomic controls involuntary functions like
  those of our internal organs
• This nervous system also has 2 parts sympathetic
  and parasympathetic
• Sympathetic involved when a person is going
  into action, like entering a stressful event
  causes fight or flight
• Parasympathetic brings the body back to normal
  after being in fight or flight mode
• S stress P - peace

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The Brain
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The Brain

• Essential to understanding biological psychology
  psychologists have placed more importance on
  the brain over time
• Controls and regulates other body systems and our
  body chemistry
• Stores memories and information, controls
  consciousness
• Gives meaning to the information collected from
  our five senses
• Extremely complex organ, we still have a lot to
  learn about it

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The Three Brains of a Human

• Hindbrain the lower portion of the brain,
  controls functions that keep us alive
• Midbrain area above the hindbrain, controls
  vision and hearing
• Forebrain front area of the brain, controls
  thought and emotion

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Hindbrain

• Medulla controls heart rate, blood pressure and
  breathing
• Pons regulates body movement, attention, sleep,
  and alertness
• Cerebellum little brain connected with
  balance and coordination

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Midbrain

• Reticular activating system (RAS) begins in the
  hindbrain and runs into the midbrain controls
  attention, sleep, and arousal when stimulated by
  vision and sight
• What part of the hindbrain works with the RAS?

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Forebrain

• Thalamus acts as a relay station for sensory
  messages by telling them where to go
• Hypothalamus regulates body temperature, tells
  the body how to store important nutrients,
  involved with motivation and emotion, controls
  primal urges
• Limbic system involved with learning, emotions,
  memory, sex, and aggression
• Cerebrum makes up about 70 of brain, contains
  the cerebral cortex, the wrinkled surface of the
  brain with ridges and valleys

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The Cerebral Cortex

• This is where thinking occurs, it is what makes
  humans unique the cerebral cortex is divided
  into two hemispheres
• Corpus callosum the structure that connects the
  two hemispheres, helps transmit messages from one
  side to the other
• Information that is collected by one side of the
  body is transmitted to the hemisphere on the
  opposite side
• Each hemisphere is divided into two lobes, the
  brain has four lobes

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Lobes of the Brain
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Lobes of the Brain (4)

• Frontal
• Parietal
• Occipital
• Temporal

http//www.bioon.com/book/biology/whole/image/1/1-
8.tif.jpg
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Lobes of the Brain - Frontal

• The Frontal Lobe of the brain is located deep to
  the Frontal Bone of the skull.

• It plays an integral role in the following
  functions/actions

- Memory Formation
- Emotions
- Decision Making/Reasoning
- Personality
(Investigation Phineas Gage)
Investigation (Phineas Gage)
Modified from http//www.bioon.com/book/biolog
y/whole/image/1/1-8.tif.jpg
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Lobes of the Brain - Parietal Lobe

• The Parietal Lobe of the brain is located deep to
  the Parietal Bone of the skull.

• It plays a major role in the following
  functions/actions

- Senses and integrates sensation(s)

• Spatial awareness and perception
• (Proprioception - Awareness of body/ body parts
  in space and in relation to each other)

Modified from http//www.bioon.com/book/biology
/whole/image/1/1-8.tif.jpg
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Lobes of the Brain Occipital Lobe

• The Occipital Lobe of the Brain is located deep
  to the Occipital Bone of the Skull.

• Its primary function is the processing,
  integration, interpretation, etc. of VISION and
  visual stimuli.

Modified from http//www.bioon.com/book/biology
/whole/image/1/1-8.tif.jpg
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Lobes of the Brain Temporal Lobe

• The Temporal Lobes are located on the sides of
  the brain, deep to the Temporal Bones of the
  skull.

• They play an integral role in the following
  functions

• Hearing

• Organization/Comprehension of language

• Information Retrieval (Memory and Memory
  Formation)

Modified from http//www.bioon.com/book/biology
/whole/image/1/1-8.tif.jpg
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Further Investigation
Phineas Gage Phineas Gage was a railroad worker
in the 19th century living in Cavendish, Vermont.
One of his jobs was to set off explosive charges
in large rock in order to break them into smaller
pieces. On one of these instances, the
detonation occurred prior to his expectations,
resulting in a 42 inch long, 1.2 inch wide, metal
rod to be blown right up through his skull and
out the top. The rod entered his skull below his
left cheek bone and exited after passing through
the anterior frontal lobe of his brain.
Frontal
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Remarkably, Gage never lost consciousness, or
quickly regained it (there is still some debate),
suffered little to no pain, and was awake and
alert when he reached a doctor approximately 45
minutes later. He had a normal pulse and normal
vision, and following a short period of rest,
returned to work several days later. However, he
was not unaffected by this accident.
http//www.sruweb.com/walsh/gage5.jpg
Learn more about Phineas Gage http//en.wikipedia
.org/wiki/Phineas_Gage
Frontal
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Studying the Brain

• Accidents how does the brain respond to and
  recover from damage? What functions did the
  damaged areas control?
• Electrical stimulation using an electrode to
  activate certain parts of the brain, used in
  brain mapping
• Electroencephalogram (EEG) measures electrical
  activity in the brain
• Scans create a picture of the brain using
  magnetic energy (MRI), X-Ray beams (CAT), or
  radioactive sugar (PET)