Transcript Brain & Behavior

Brain & Behavior
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Goals for Lecture & Readings
• Understand the mechanisms of
neural communication
• Understand the form and function of
the nervous system
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Phineas Gage
• 1848
• Railway worker
• Tamping iron blew
through his head
• Memory and movement
intact, could learn new
things
• But, personality changed
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Phineas Gage
• 1980s
• Computer modelling
shows path of rod
• Damaged ventromedial
frontal lobe
• Brain region linked to
personality
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“Biopsychology”
• Biological approach to the study of
psychology
• Various approaches to understand
links between nervous system and
behavior
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Characteristics of Biopsychology
• Humans & nonhumans subjects
• Experiments and case studies
• Basic and applied research
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Divisions of Biopsychology
1. Physiological Psychology
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Manipulate nervous system (surgery,
chemicals); theories of neural control of
behavior
2. Psychopharmacology
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Effects of drugs on neural activity and
behavior
3. Neuropsychology
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Study behavioral deficits produced by brain
damage; often applied
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Divisions of Biopsychology
4. Psychophysiology
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Record physiological responses to
understand relation between physiology and
psychology
5. Comparative Psychology
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Behavior of different species; focus on
genetics, evolution, function
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Building Blocks of Nervous
System
• Neurons
• Specialized nerve cells
• Send/receive nerve impulses
• Sensory, motor, interneurons
• Neurons have a right-hand man, called
glial cells
• hold neurons in place and provide
nutrients
• Outnumber neurons 10:1
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Neurons
• Three basic parts:
• Cell body (soma)
• Metabolic centre, genetic material,
etc…
• Dendrites
• Specialized fibres for receiving info
• Axon
• Conducts messages away from cell
body
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Also, Node of Ranvier
Terminal buttons
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Neurons
• Neuron fires when stimulated
– Heat
– Light
– Pressure
– Other neurons
• The impulse is called an action potential
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Electrical Activity of a Resting
Neuron
• Membrane Potential:
• Difference in electrical charge between
inside and outside of cell
• Resting Potential:
• -70 mV
• Lots of Na(+) ions outside cell
• Lots of protein(-) molecules inside cell
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When a Neuron is
Stimulated…
• Stimulation causes
distribution of
particles to change
• Na(+) flows in
• Attracted to
protein(-)
• Inside now (+)
relative to outside
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Neural Conduction
• Action Potential:
• Massive, brief reversal of membrane
potential from –70 to +50 mV
• After an action potential, neuron has to
recharge, so to speak
• K(+) pumped out of cell, (-) charge
restored
• Refractory period – neuron cannot fire
again during this process
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Myelinated Axons
• Myelin is fatty tissue
• Faster conduction
• Action potential
“jump” from one Node
of Ranvier to the next
• Multiple Sclerosis –
myelin sheath
destroyed
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From One Neuron to the
Next
• Synapse:
• The site of adjacent neurons
• “Synapse” - Greek word for “gap”
• (Every mall in Athens has a store called
“The Synapse”)
• Action potentials at terminal buttons
cause release of chemical
neurotransmitters
• Neurotransmitters bind to sites on
adjacent neurons and thereby induce
electrochemical changes in them
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Neurotransmitters
• When they bind to an adjacent
neuron, they cause chemical
reactions
• Excitatory neurotransmitters
• Cause Na(+) to enter cell
• Makes action potential more likely
• Makes it more likely the cell will
send signals to other neurons
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Neurotransmitters
• Inhibitory neurotransmitters
• May cause K(+) to leave the cell, or
Chloride(-) to enter
• This makes an action potential less
likely
• makes it less likely the cell will
send signals to other neurons
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Some Neurotransmitters
• Acetylcholine
• Excitatory at synapses involved in
memory and movements
• Dopamine
• Excitatory; movement, emotional
arousal
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Effects of Drugs
• Drugs affect behavior and thought by
influencing the activity of neurons
• Agonists
• Mimic a particular neurotransmitter
• Increase activity of neurotransmitter
• Antagonists
• Inhibits activity of a neurotransmitter
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Effects of Drugs
• Nicotine is an agonist for Dopamine
• Reward and pleasure
• Amphetamines and Cocaine:
agonists for Dopamine and
Norepinephrine
• Reward, pleasure, arousal
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Major Divisions of Nervous
System
• Central Nervous System
(CNS):
• Brain
• Spinal cord
• Peripheral Nervous
System (PNS):
• Somatic Nervous System
• Autonomic Nervous
System
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Peripheral Nervous System
• Somatic Nervous System:
• Interacts with external environment
• Sensory info from receptors (in
skin, joints, eyes, ears, etc.) to CNS
• Signals sent back from CNS to
skeletal muscles
• Deals largely with voluntary
actions
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Peripheral Nervous System
• Autonomic Nervous System:
• Involved in regulation of internal
environment
• Deals largely with involuntary functions
• Signals from organs to CNS
• Signals from CNS to organs
• Sympathetic nerves
• Prepare for action
• Parasympathetic nerves
• Conserve energy
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Central Nervous System
• Spinal Cord
• Highway for most nerves
• H-shaped core of gray matter
• Cell bodies, unmyelinated
interneurons
• Surrounding white matter
• Ascending & descending myelinated
axons
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The Brain
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The Brain
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One More Brain Diagram
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EEG
Measures electrical activity
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CAT Scan
Computerized Axial
Tomography
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PET Scan
Positron Emission
Tomography
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MRI
Magnetic Resonance
Imaging
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The Brain, Function & Form
• Brainstem
• Medulla:
• Tracts that carry signals between
brain and rest of body
• Reticular formation:
• Involved in sleep, attention,
movement, and various autonomic
functions
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The Brain, Function & Form
• Cerebellum
• “Little brain”
• Walking
• Balance
• Timing and coordination of
movements
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The Brain, Function & Form
• Thalamus
• Sensory relay station
• Info from sensory receptors processed
and sent to sensory cortex
• Basal Ganglia
• Surrounds thalamus
• Deliberate movements
• Parkinson’s disease
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The Brain, Function & Form
• Limbic System
• Hippocampus
• memory
• Amygdala
• emotion
• Hypothalamus
• Motivation; biological drives
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The Brain
• Cerebral Cortex:
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Outermost layer of brain
Wrinkled
Many connections to other areas
Frontal cortex complex cognition
Temporal  auditory, language
Occipital  visual
Parietal  sensory stuff
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