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

membranechannels

Neurons Carry Information as Electrochemical Signals

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- at rest, charges balance each other

Axon

Neurons Carry Information as Electrochemical Signals

- when stimulated, membrane briefly lets charges switch sides

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Neurons Carry Information as Electrochemical Signals

- “depolarization” opens channels nearby that allow more charges to switch

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Neurons Carry Information as Electrochemical Signals

- Chain-reaction, called an action potential, propagates along the axon.

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Neurons Carry Information as Electrochemical Signals

- Chain-reaction, called an action potential, propagates along the axon.

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Neurons Carry Information as Electrochemical Signals

- Chain-reaction, called an action potential, propagates along the axon.

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Neurons Carry Information as Electrochemical Signals

- Chain-reaction, called an action potential, propagates along the axon.

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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 ofaction of the vast majorityof psychoactive drugs!

Optic Nerve

VisualCortex

Neurons are linked Together to Form “Pathways”

eye

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

“Conscious Senses”

•Temperature•Balance•Body Position

“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