neural basis of cognition

How many pounds is the brain?

3

How many neurons (range) does the brain have?

100-200 billion

How many connections does the brain have?

100 trillion (approx.)

Are there more neurons in the brain or stars in the Milky Way?

neurons in brain (100-200 billion vs 100 billion)

Has the brain or the mind been studied for longer?

The mind

How long (approx.) has the brain been studied for?

Several decades

Basic parts of a neuron (3)

dendrites, cell body, axon

dendrites detect incoming signals from other

neurons

The cell body contains the and cellular

nucleus, machinery

The axon transmits to other neurons

signals

How does the axon transmit signals?

through specialized axonal terminals

the specialized axonal terminals form synaptic with follow-up neurons

connections

An action potential is an electrical signal from the ____ ____

cell body

What is an action potential coloquially called?

a "spike"

When an action potential reaches the axon terminals, these terminals release a

neurotransmitter

neurotransmitter

a chemical signal

What does a neurotransmitter act on?

the membrane of the postsynaptic neuron.

How do neurotransmitters change the postsynaptic membrane?

by triggering the flow of charged atoms (ions) through it

Condition needed to produce an action potential

sufficient ionic flow to surpass the neuron's threshold

All-or-none law

an action potential is always of the same magnitude

True or false: signal frequency can vary depending on the stimulus

TRUE

Do action potentials vary in strength or frequency?

frequency

True or false: All neurons will fire the same way towards all stimuli

False (some may only respond (or respond more/less) to particular stimuli)

True or false: In some cases, specific neurons can represent specific stimuli

TRUE

“Pattern coding" (aka distributed representation)

When specific things (like a song) are represented in the brain through patterns of neuron firing

Where are action potentials typically generated?

cell body

Where do action potentials typically travel down?

the axon

An action potential always travels in ____ direction/s along the axon

one

What part of neurons get myelinated?

axons

What does myelination do?

make spike propagations very fast

Speed of myelinated action potentials (per second)

about 100 m/sec

Would you expect longer reaction times to need more or fewer neurons?

More

More than ____ neurotransmitters have been identified so far.

100

Neurotransmitter's functional effect mostly depends on which brain they operate in

circuits

Examples of things neurotransmitters play a role in (3)

mood, anxiety, attention

What does synaptic transmission allow a neuron to do?

receive and integrate information from many neurons

Where do neurons receive info thanks to synaptic transmission?

at dendrites

Where do neurons integrate info thanks to synaptic transmission?

at cell body

What two things can neurons do as per other incoming signals?

"1) compare incoming signals

2) adjust responses to input "

Neural plasticity

strengths of synaptic connections are adjustable

True or false: neural plasticity is crucial for learning and memory

TRUE

What can neural plasticity be altered by? (4)

experience, development, aging, pathology, pharmacologically

Examples of pharamcological changing of neural plasticity

anxiolytic, antidepressant, antipsychotic medication, etc. (mood, anxiety, psychedelic…)

True or false: glia have historically been considered superior to neurons

False (seen as secondary)

Functions of glia (4)

"1) Guide development of nervous system

2) Repair damage in nervous system

3) Control nutrient flow to neurons, including oxygen

4) Electrical insulation (axon myelination)"

Example of a nutrient neurons need

Oxygen (found in blood)

Three main structures of the human brain

hindbrain, midbrain, forebrain

What does the hindbrain contain?

brain stem (pons, medulla), cerebellum

The brain stem is the top of the ___ ___

spinal cord

largest region of the hindbrain

cerebellum

main function of the cerebellum

fine movement coordination

what kind of function is the hindbrain mainly responsible for?

key life functions (like blood pressure)

Oldest part of the brain

hindbrain

Functions of the midbrain (3)

"1) Coordinating precise eye movement

2) Relaying auditory info from ears to forebrain

3) Regulating pain experiences"

What part of the brain surrounds the midbrain and most of the hindbrain?

forebrain

Parts of the forebrain (3)

cerebral cortex (cerebrum), four lobes, subcortical structures

The cortex is the outer surface of the

forebrain

How much of the brain is the cortex? (percent)

80%

What percentage of neurons are from the cortex?

50%

What divides the two cerebral hemispheres?

longitudinal fissure

Newest part of the brain

cortex

True or false: the lobes of the brain are structurally distinct

False: moreso functionally distinct

Subcortical parts of forebrain (3)

thalamus, hypothalamus, limbic system

thalamus

sensory relay station (how senses reach the cerebral cortex)

hypothalamus

controls behaviors that serve specific biological needs (e.g., eating)

limbic system parts (2)

amygdala and hippocampus

the amydgala is responsible for…

emotional processing

the hippocampus is responsible for…

learning and memory

The brain is divided into roughly symmetrical ___ and ___ hemispheres.

left, right

The cortex is organized

contralaterally

contralateral

controlled by the opposite side

Two examples of contralateral organization

Left visual hemifield goes to Right hemisphere; Right hand is controlled by Left hemisphere

The left and right hemispheres are connected by

commissures

commissures

thick bundles of fibers that carry information

What is the largest commissure?

corpus callosum

Split-brain procedure

last-resort treatment for severe epilepsy; severely limits hemisphere communication

Is the split-brain procedure usually still done today?

No

True or false: split-brain patients provide evidence for some hemispheric specializations of functions

TRUE

Language is mostly controlled by the ____ hemisphere

left

"If you ask a split-brain patient to read a word from their left visual field and grab it with their left hand, will they…

1) recognize the word?

2) take the correct object?"

"1) no

2) yes"

From Lab #2

"If you ask a split-brain patient to read a word from their right visual field and grab it with their left hand, will they…

1) recognize the word?

2) take the correct object?"

"1) yes

2) no"

"If you ask a split-brain patient to read a word from their left visual field and grab it with their right hand, will they…

1) recognize the word?

2) take the correct object?"

"1) no

2) no"

"If you ask a split-brain patient to read a word from their right visual field and grab it with their right hand, will they…

1) recognize the word?

2) take the correct object?"

"1) yes