Transcript ppt file

First, some philosophy
• I see, I hear, I feel…
• Who is I - Do you mean my brain sees,
hears, and feels or do you mean something
else?
First, some philosophy
• Brains and Minds - Are they the same
thing?
• If not, what is the difference? What is a
good analogy?
Philosophy of Mind
• Monism -
Philosophy of Mind
• Monism - mind and brain (body and soul)
are not different things
Philosophy of Mind
• Monism - mind and brain (body and soul)
are not different things
• Dualism -
Philosophy of Mind
• Monism - mind and brain (body and soul)
are not different things
• Dualism - mind and brain are fundamentally
different
Philosophy of Mind
• What might constitute evidence for or
against either of these two alternatives?
What are Brains Made Of?
• About one
trillion neurons
(1,000,000,000,000)
• Assorted other
cells called “glial
cells”
Neurons Have Three Parts
(Usually)
Neurons Relay Signals From
Other Neurons to Other Neurons
Neurons are Cells with
Electrically Charged Membranes
channels
membrane
Neurons Carry Information as
Electrochemical Signals
Axon
--------------------------+++++++++++++++++++
- at rest, charges balance each other
Neurons Carry Information as
Electrochemical Signals
+--------------------------++++++++++++++++++
- when stimulated, membrane briefly lets charges switch sides
Neurons Carry Information as
Electrochemical Signals
-+------------------------+-+++++++++++++++++
- “depolarization” opens channels nearby that allow more
charges to switch
Neurons Carry Information as
Electrochemical Signals
--+-----------------------++-++++++++++++++++
- Chain-reaction, called an action potential, propagates
along the axon.
Neurons Carry Information as
Electrochemical Signals
---+----------------------+++-+++++++++++++++
- Chain-reaction, called an action potential, propagates
along the axon.
Neurons Carry Information as
Electrochemical Signals
-----+--------------------++++-++++++++++++++
- Chain-reaction, called an action potential, propagates
along the axon.
Neurons Carry Information as
Electrochemical Signals
------+------------------+++++-+++++++++++++
- Chain-reaction, called an action potential, propagates
along the axon.
Neurons Carry Information as
Electrochemical Signals
• Action potential can travel very fast - on the
order of 100 meters per second (360 km/hr !)
Signals Jump from Neuron to
Neuron Across Synapses
Signals Jump from Neuron to
Neuron Across Synapses
Neurotransmitter molecules carry
signal across synapse
What does this have to do with
cognition ?
Signals Jump from Neuron to
Neuron Across Synapses
Neurotransmitter molecules carry
signal across synapse
The synapse is the site of
action of the vast majority
of psychoactive drugs!
Neurons are linked Together to
Form “Pathways”
Visual
Cortex
eye
Optic Nerve
Neurons are Linked Together to
Form “Pathways”
• Different regions
are specialized for
different functions
Neurons are Linked Together to
Form “Pathways”
• Different regions
are specialized for
different functions
• Regions are
reciprocally
connected
Philosophy of Mind
• The Hard Problem - How does the
movement of sodium and potassium ions
across a membrane generate an experience?
Sensation
• What is sensation?
Sensation
• What is sensation?
• Sensation is acquiring information about
the outside world.
Perception
• What is perception?
Perception
• What is perception?
• Perception is interpreting information about
the outside world.
The Senses
• Name the “senses”
The Senses
• Vision
• Hearing
• Taste
• Smell
• Touch
•Temperature
•Balance
•Body Position
“Conscious Senses”
“Subconscious Senses (sometimes)”
The Senses
• All of these senses are really just systems
that extract information about how you and
the rest of the universe are interacting
The Senses
• All of these senses are really just systems
that extract information about how you and
the rest of the universe are interacting
What IS sensory information?
Information is Contained in
Energy
• Hearing is the perception of vibrations in
the air
Information is Contained in
Energy
• Hearing is the perception of vibrations in
the air
• Vision is the perception of electromagnetic
radiation
Information is Contained in
Energy
• Hearing is the perception of vibrations in
the air
• Vision is the perception of electromagnetic
radiation
• Taste and smell are the perceptions of
chemicals
Information is Contained in
Energy
• Hearing is the perception of vibrations in
the air
• Vision is the perception of electromagnetic
radiation
• Taste and smell are the perceptions of
chemicals
• Touch is the perception of force on your skin
Sensation Starts with “Receptors”
• Receptors transduce incoming signals into
neural signals to be sent along axons to the
brain
• transduction - converting one type of
energy into another type of energy (e.g.
mechanical sound energy into
electrochemical neural signals)
Next Time: Hearing