Introduction to Psychology

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Introduction to Psychology

• Brain and Behavior

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Nervous System

• CNS Brain and Spinal Cord
• Peripheral Nervous System network of nerves that
  carries information to and from the nervous
  system

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Peripheral Nervous System

• Somatic System carries messages to and from
  sense organs and skeletal muscles
• Controls voluntary behavior

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Peripheral Nervous System

• Autonomic Nervous System glands and organs
  automatic functions
• Heartbeat, digestion

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Peripheral Nervous System

• Sympathetic fight or flight prepares for action
• Parasympathetic quiets the body lowers arousal

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Neurons

• Nerve cells in the brain
• Carry messages activate muscles and glands
• 100 billion neurons in the brain

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The Neuron
Fig. 3.8
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Parts of the Neuron

• Dendrites receives messages from other neurons
• Soma receives messages sends nerve impulse down
  the axon

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Parts of the Neuron

• Axon thin fiber leading to the terminal buttons
  nerve impulses travel down the axon carries
  messages
• Myelin sheath fatty layer covering the axon
  that helps nerve impulses move faster

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Parts of the Neuron

• Synapse the microscopic space between the
  neurons over which messages pass
• Neurotransmitters travel across the axon
• Ions electrically charged molecules found inside
  and outside the neuron, with or - charges

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Resting Potential

• Electrical charge of an inactive neuron
• -70 mv
• Messages from other neurons raise or lower the
  resting potential

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Threshold

• If the charge raises to -50 mv, the neuron
  reaches its threshold
• Thresholdtrigger point for firing
• Ready to fire

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Neural Firing

• An action potential (nerve impulse) sweeps down
  the axon
• Ion channels open and sodium ions rush in

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After the action potential....

• Positive ions flow back out the neuron becomes
  negatively charged again
• Resting state is restored
• After firing, the neuron dips below resting level
  and is less willing to fire

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Firing...

• Firing is an all or nothing event
• The neuron either fires, or doesnt fire
• It take 1/1000 of a second for a neuron to fire
  on average, they fire between 1-400 times per
  second

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Neurotransmitters

• Chemicals that alter activity in the neurons
• Neurotransmitters travel from the terminal
  buttons across the synapse, and connect to
  special receptors sites on the dendrites and soma
  of the next neuron

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Neurotransmitters

• Neurotransmitters can excite or inhibit firing

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Types of Neurotransmitters

• Dopamine too littleParkinsons, too
  muchschizophrenia
• Acetylcholine activates muscles
• Serotonin deficiency associated with
  depression/anxiety
• Neuropeptides influence memory, pain, emotion,
  and mood
• Endorphins released by the pituitary glad
  lessens pain

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The Brain

• Right and Left hemispheres
• Lateralization
• Divided by the corpus callosum

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Left and Right Hemispheres

• Left
• Detail oriented
• Speech and language
• Calculating
• Understands one word at a time, not the big
  picture

• Right
• Non-verbal
• Face recognition
• Express/detect emotion
• Understanding speech context/nuances of language

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The Brains Four Lobes
Fig. 3.7
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Functions of Lobes of the Cortex
Involved in voluntary movement, thinking,
personality, and intentionality or purpose
Frontal lobes
Occipital lobes
Function in vision
Active role in hearing, language processing, and
memory
Temporal lobes
Roles in registering spatial location, attention,
and motor control
Parietal lobes
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The Brain

• Recent research
• Both heredity and environment shape the brain
• The role of experience and brain plasticity

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Dendritic Spreading
Fig. 3.11
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Pruning

• Changes to the dendrites and synapses
• Connections are formed and terminated

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Experience and the Brain

• Exposure to trauma
• PTSD reduced size of the hippocampus
• Depression
• Parts of the brain atrophy over time
• Addiction
• Changes in neurotransmitters

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Experience and the Brain

• Mice in deprived vs. enriched environments
  differences in brain weight, neural connections
  and activity
• Children reared in deprived environments have
  depressed brain activity (i.e. Romanian orphans)
• Can be reversed brain plasticity/resilience

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The Brain in Adolescence

• Adolescent emotions
• Areas of the brain involved in emotional
  regulation are still growing/changing
• Poor self-control seek rewards and pleasure
• Risk taking
• Lack of practical experiences immature judgment

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Alcoholism

• Alcohol doesnt kill neurons, but damages the
  dendrites
• Affects communication between neurons
• Frontal lobe and limbic system
• Brain may atrophy