Chapters 1-4 Midterm Flashcards
What are the 10 brain imaging techniques?
Lesioning, transcranial magnetic stimulation (TMD), brain mapping, electroencephalograms (EEG), CT or CAT scans, magnetic resonance imaging (MRI), functional MRIs (fMRI), position emission tomography (PET scan), diffusion tensor imaging (DTI), Magneto-encephalograohy (MEG)
What is lesioning?
by lesioning (cutting off/killing) certain areas of the brain and seeing what behavior changes result
What is transcranial magnetic stimulation?
where you temporarily tamp down or booth the function in specific cortical areas
TMS is not so much of a _______ tool as a _______ one.
brain mapping, therapeutic
When is brain mapping used?
to guide the most delicate of brain surgeries
During brain surgery, the patient is ______, _______, and ______ to the touch of an ________ on various parts of the brain
awake, conscious, responding, electrical probe
What do EEgs do?
Read the electrical impulses of the brain (brain wave activity) via electrodes attached to the scalp
How to CT and CAT scans take pictures?
take a bunch of cross sectional x-rays of the brain to see structures
What are CT an CAT scans great for locating? (3)
gross abnormalities, tumors, injury
How do MRIs take pictures?
using super strong magnets
____ provide pictures with greater resolution and clarity than do _____
MRIs, CAT
MRIs have no risks associated with _____
x-rays
____ are much fatser than _____, can take pictures with astonishing detail and clarity, and display the brain’s structure and ______
fMRIs, MRIs, function
fMRIs show brain function by taking pictures of what?
relative blood flow and oxygenation (whats using up most blood)
MRIs take advantage of the body’s natural ______ field, measuring changes in the field’s ____ as patients are exposed to different ______ frequencies
magnetic, energy, radio
MRIs can be rendered in 3D because the MRI machine slices along 3 or more ____ instead of 1, like CT scans.
planes
How are fMRIs able to display function?
They use immense magnetic feilds to temporary displace hydrogen atoms in our tissue, and when they are released they wobble back to their original orientation and emit signals indicating the relative oxygenation of the blood at that site. This information can then be used to determine tumors, areas of high/low neural activity, and tissue density
What does a PET scan show us?
shows us which areas of the brain are more active than others by measuring glucose and oxygen levels.
How does a PET scan track glucose?
first you inject a glucose substance traced with radioactive isotopes, and then scan and the isotopes will cause areas of the brain to “light up” where glucose is really being used, and come up dark where there is brain damage.
What do DTI look at in the brain?
looks specifically at how different regions of the brain are wired together
What do DTI machines track?
tracks how water flows through white matter, and flows its route like the path of a river.
DTI are useful in diagnosing?
brain function diseased like Alzheimer’s
What doe MEGs measure?
the firing of neurons
How to MEGs rack the firing of neurons?
by detecting minute changes in tiny magnetic signals produced by active neurons
What are MEGs ideal for tracing?
the order in which different brain regions are activated during various tasks
What are the 2 basic types of neural cells?
neurons and glial cells
What do glia (glial cells) do?
they are basically life support for neurons; they absorb nutrients to feed neurons, clean up chemical waste and toxins, and make protective coverings for parts of neurons.
Glia can ____ and ____ neural signals over long distances
boost, inhibit
What do glia determine about new synapses?
where they are formed and how many are formed
Glia can repair damage to _____.
neural pathways
What are neurons responsible for?
receiving, transferring, and storing information
Can neurons regenerate?
yes, very much so in children
Where is a hotbed of neural stem cells creation?
the olfactory bulb and the hippocampus
What are the 3 main structures of a neuron?
soma, dendrite, axon
What is the structure and function of the soma?
structure: body of the neuron; contains DNA
function: produced chemical manufacturing for the transmission of messages
What is the structure and function of dendrites?
structure: smaller branches off the soma
function: handle incoming messages from surrounding sister cells (receiver)
What is the structure and function of the axon?
Structure: large, single, insulated branch off the soma
function: transmits outgoing messages (sender)
What is the myelin sheath and what is its purpose?
insulation along the axon of a neuron, its purpose is to speed up messages and make sure the messages dont get scrambled
What is the myelin sheath made of?
white fatty tissue
What autoimmune disease destroys the myelin sheath of motor neurons?
multiple sclerosis
When is a neuron polarized?
when it is at rest
What does it mean for a neuron to be polarized?
it means there is a slightly greater negative electrical charge inside the cell and a slightly greater positive charge outside the cell
How are nerons stimulated by other cells?
graded potentials
What 2 things can happen when a neuron is strongly stimulated by other cells?
hyperpolarization or depolarization
What happens when a cell is hyperpolarized?
polarization increases making the inside and outside electrical difference even greater.
A neuron is even more at ____ when it is hyperpolarized, and less likely to ____.
rest, fire
How does a neuron become hyperpolarized?
Doesn’t allow ions come in; it makes it even more difficult for ions to pass into the cell
hyperpolarization is the result of ____ messages from surrounding neurons, so the action is ____
inhibitory, inhibited
What happens when a neuron becomes depolarized?
the electrical difference between the inside and outside of the cell is reduced because ions are allowed in
depolarization preps the cell for _____, and makes it ready to _____.
action, fire
depolarization is the result of ______ messages from surrounding neurons
excitatory
graded potential cause brief ____ changes in the dendrites, then spread down the ____ ______.
voltage, cell membrane
effects from graded potentials are cumulative, so stimulation that depolarizes one section of the cell can be ________ by stimulation from another cell that hyperpolarizes, OR the same type of stimulation can add up causing a ripple all the way down to the ___,
cancelled out, axon
If an excitatory/depolarizing cumulative ripple reaches the axon, what will happen?
the cell membrane will become temporarily permeable, allowing ion channels to open letting positive ions into the cell. This momentarily reverses the original charges (now they’re positive inside, negative outside), but then reverts to its original state, and this happens all the way down the axon.
The brief reversal and subsequent restoration of charges is referred to as what?
action potential
How does the action potential from one neuron get sent to another neuron?
By changing the electrical message to chemical messages using neurotransmitters. The electrical action potential forces synaptic vesicles to pop and release neurotransmitters, which leave the pre-synaptic neuron across the synaptic cleft and bind to the receptor sites on the receiving/post-synaptic neuron’s surface. This causes ion channels to open causing graded potentials on the receiving neuron.
Where are neurotransmitters stored in the pre-synaptic neuron?
in synaptic vesicles
The sum total of all such graded potential messages received by a neuron will determine what?
the type of message sent (inhibitory, or excitation)
Inhibitory neuron account for ___% of all our neurons
10-20%
Inhibitory neurons work exclusively to do what?
calm the brain down
Inhibitory neurons are key to brain ____, ____, and _____. They also play a role in many _______ disorders by _____ the level of activity in neighboring neurons.
development, learning, memory, neurological, repressing
inhibitory neurons prevent the brain from spinning out of control into _____ or _____.
hyper-excited states, full-blown epilepsy
After an excitatory message, what remains of the neurotransmitters need to become _____ so that the cell can be ready to pick up the next message coming its way
deactivated
How is a neurtransmitter deactivated?
An enzyme in the synapse made by glial cells break the neurotransmitter down, or the chemical return to the pre-synaptic neuron’s terminal buttons through re-uptake.
Why is deactivation necessary?
because the post-synaptic cells might keep firing on and on causing seizures or even death
What are mirror neurons?
neurons that fire when we see something else preform an action
Where are mirror neurons mostly located?
in areas related to understanding others actions, intentions, emotions, feelings, and language
What are mirror neurons essential for?
modelling, observational learning, and development of empathy