Module 2: The brain and neurons Flashcards
what are the 3 major parts of the brain?
cerebrum
cerebellum
brainstem
what is the biggest part of the brain?
the cerebrum
Talk about the features of the cerebrum
It is the biggest part of the brain.
splits into the 2 cerebral hemispheres.
how are the cerebral hemispheres connected from the surface?
through the longitudinal fissure/interhemispheric fissure
internally, how are the hemispheres connected?
through the corpus callosum, a thick layer of axons
is there any contact between the cerebral hemispheres?
on the surface, NO. they ONLY communicate through the corpus callosum.
define cortex.
The cortex is basically the grey matter and it is the surface of the brain.
It is 2.4 mm thick and contains the major neurons that compose the functioning of the brain
what is found in the cortex?
the cell bodies of neurons
why is the surface folding pattern important?
Because we want to fit all billions of millions of neurons into this very small organ (the brain in the skull) and so it needs to be condensed and folded to fit everything in it.
what is below the grey matter?
the white matter. contains axons and dendrites of neurons
What is the main role of the white matter?
connects the neurons from the cortex to the spinal cord which diffuses the messages to the targeted organs
what are the four lobes and the location?
1) occipital lobe, to the back of the head
2) temporal lobe, above the brainstem close to the ears
3) frontal lobe, to the front of the head
4) parietal lobe, central line of the brain; anterior to the frontal and posterior to the occipital
What is Broca’s region?
the region in the frontal lobe that is essential for speech production. People with damage to this region can understand language perfectly but cannot produce speech; slow sentences that make 0 sense.
what is Wernicke’s area?
Region in the temporal lobe responsible for speech understanding.
Any damage to this area will cause the individual to not understand language and speech, but can produce it well.
what are the function of the occipital lobe?
- Shelters the primary visual cortex.
- Responsible for all perception.
- Modular system/regions in the occipital lobe to detect different aspects of the visualized thing: edges, colors, shape, orientation.
what kind of system reigns in the occipital lobe?
A modular system
what is a modular system?
when different regions of the brain/the lobe have different groups of neurons with different functions each, to detect different aspects.
what are the functions of the frontal lobe?
-Shelters the primary motor cortex.
-Responsible for all movements/muscle contractions in our body.
-Responsible for executive functions: decision making, analytical thinking, planning, inhibitory control.
Important in speech production.
What are the function of the parietal lobe?
- Shelters the primary somatosensory cortex.
- takes input from the occipital lobe (visual perception) and helps build a representation of space and orientation.
- what we see is a very messy “video” that the parietal lobe organizes and makes clear. detects objects from backgrounds, moving objects from still objects, etc…
- most important function is that it links action to vision and helps fine controlled movement based on what we see.
What are the functions of the tempral lobe?
- Shelters the primary auditory cortex.
- Perception of sounds.
- Understanding language and speech
- Limbic system
What is a particular region of the temporal lobe?
The limbic system;
it is made up of
1) the amygdala: activates the alert system in the face of danger. Very quick to activate and alert us from incoming threats.
2) the hippocampus: important in learning and memory. Any damage to the hippocampus -> cannot form new memories.
what is the corpus callosum made up? and what use is it to destroy it?
Made of axons of neurons.
It is the ONLY mode of communication between the 2 cerebral hemispheres.
With epileptic patients, cutting the corpus callosum stops the spreading of the seizure from one hemisphere to the other, and makes it more bearable.
also it is important to evaluate each hemisphere functioning independently.
what did we rely on to evaluate brain functions before MRI existed?
case studies
what is the most poplar case study?
that of Phineas Cage in 1848
what year did Paul Broca identify the Broca region in the left side of the frontal lobe?
1861
what do we call disorders of language and speech?
Aphasias
Define aphasia.
Disorder of language and speech
What are the two popular aphasias in the brain and where are they located?
- Broca’s aphasia ; left side frontal lobe
- Wernicke’s aphasia ; left posterior temporal lobe
how long did Phineas Cage survive after his accident in 1848?
12 years
how long did Phineas Cage survive after his accident in 1848?
12 years
what happened to Phineas Cage in 1848?
A 1 m long rod whet up through his skull and landed on the floor on the other side of the road.
He remained conscious during and after the accident.
what areas were damaged in Phineas Cage’s brain?
His frontal lobe
Who identified the importance of the frontal lobe for executive control of behavior?
John Harlow after observing changes in personality in Phineas after his accident
what is phrenology?
Mapping out the bumps on the skull to determine the functions of each brain region.
how did John Harlow describe Phineas Gage after the accident?
“A man who was no longer a man”
When was the Broca region identified first? (before Broca named it and researched it)
mid 1800’s
When was the Broca region identified first? (before Broca named it and researched it)
mid 1800’s
define anomia?
the difficulty to find appropriate words.
What are the consequences of damages to the Wernicke’s area?
Can speak fluently with normal rhythm.
Can’t understand a thing.
Their speech sounds normal but makes 0 sense.
Deficits of Wernicke aphasia are….
- Deficit in connecting meaning to language.
- Deficit in understanding people’s speech.
a) In the mid 1950s, how did we map out the brain functions?
b) Who was the scientists?
c) According to which 2 lobes?
d) And what was the name of the resulting map?
a) Through electrical simulations to specific areas of the brain during surgery.
b) Wilder Penfield
c) according to the primary somatosensory cortex and the primary motor cortex. (frontal and parietal lobes)
d) the homonculus
What was the size of the different cortexes on the map proportional to?
- The level of fine motor control with that part of the body.
- The level of sensory discrimination we have with that part of the body.
what are the most important areas/largest areas on the homunculus and why?
a) finger and hands -> sensory and fine movements
b) lips, tongue and mouth -> speech requires very fine controlled movements.
what are the 3 roles of the brainstem?
1) connects the cerebral hemispheres to the spinal cord.
2) carries information between cerebral hemispheres and cerebellum, cerebral hemispheres and spinal cord.
3) drives the autonomic nervous system.
split the nervous system into its diff components.
CNS - PNS
PNS -> Autonomic and somatic
autonomic -> parasympathetic and sympathetic.
what is the CNS made of?
brain + spinal cord
what is the PNS made of?
all the neurons scattered around the body, outside brain and spinal cord
What are the functions of the somatic nervous system?
Domain of physiology
1) control voluntary movement.
2) Motor + sensory
nerves go from somatic nervous system to….
muscles
what are the function of the autonomic nervous system?
Domain of biology
1) controls involuntary movement.
heart rate and respiratory rate.
2)Fight or flight / Rest and digest
What is the sympathetic nervous system part of and what are its functions?
Part of the autonomic NS -> PNS
responsible for the fight or flight response: when subject to danger, a survival mechanism activates everything in the body to face the danger.
increased heart rate, increased respiratory rate, sweaty palms, high adrenaline, etc…
What is the parasympathetic nervous system part of and what are its functions?
Autonomic NS -> PNS
“Rest and digest”
in times of calmness and no danger, calms the body down
processes for digestion continue and are enforced, steady heart rate, etc…
what drives the autonomic NS?
The brainstem and the medulla/ medulla oblongata.
What is the main function of the brainstem?
Maintain Homeostasis in the body.
keep the central core warm to keep the vital organs functioning and healthy.
What is the medulla?
- The center of control of heart rate, respiration, blood pressure regulation, and body temperature.
- The center of reflexes. the messages that are controlled from the spinal cord and only make it to the brain after the response movements is done.
Give an example of how the medulla keeps us alive through reflexes.
When we are coughing or vomiting -> these are reflexes to keep our airways open and keep us alive.
what is the scientific term for “coma”?
And what is it characterized by?
- Persistent Vegetative State
- loss of conscious awareness
what causes a persistent vegetative state?
Severe damage to the upper brain
upper brain = hemispheres and cortexes
how come patients in a persistent vegetative state can maintain a steady heart rate and respiration, along with facial and eye movements?
If the brainstem is intact, all the autonomic functions remain.
As for the eyes and facial expression, cranial nerves stem from the brainstem to those organs and control their movements.
what is the diseases that results in locked in syndrome?
ALS = amyotrophic lateral sclerosis or motor nueron disease
what causes ALS?
Loss of motor neurons or loss of connection between the cerebral hemispheres and the spinal cord or brain injury
Can everything be intact and a person still suffer from ALS?
YES.
even if both the cerebrum AND the spinal cord are intact, if they are not connected, THERE IS NO MOTRICITY.
in this case, cognitive functions are still intact, mental health is perfect, there just is NO RESPONSIVENESS
What did Owen Adrian find in patients in a persistent vegetative state?
Through MRI, he found that people in a persistent vegetative state could still follow instructions and activate certain areas of their brain upon demand.
they have conscious intentions and exerience.
what do people in a persistent vegetative state and locked in patients have in common?
their cortex is fully functionnal
they can still activate regions of their brain upon commands.
Low level and High level functions of the brain.
-Low level = brainstem.
Critical for survival, not unique to us as humans.
-high level = cerebrum
unique to us as humans
highly evolved and complex in our language and problem solving and reasoning.
why can’t we tickle ourselves?
because of the feedback loop between the action and the sensory information we get as the action is performed.
When I’m about to tickle myself, my brain makes a prediction of wat it’s going to feel like. when I do it, it matches my prediction -> I’m not tickled.
when someone else tries tot tickle me, my brain has no access to the motor plan of the other person (It happens in their own brain) so my brain cannot make predictions -> no feedback loop.
what does our control and coordination of skilled movements rely on?
on the feedback loop between the movemetn we make and the senation we get as we are performing the movement.
what does the feeback loop give us?
the sense of agency over our own actions and the ability to identify if the things happening around us are CAUSED by us.
what are the functions of the cerebellum?
- adjust posture and balance in an involuntary fashion, constantly. (autonomic N.S)
- Involved in motor learning of skilled fine movements (movement adjustment)
What are the adjustments done by the cerebellum based on?
on the feedback loop
what is the basis of balance?
the center of mass should be adjusted above our feet at all time.
unconscious and no-concentration required for the posture adjustments.
where is this feedback loop the highest in?
the primary motor cortex and the primary sensory cortex.
what is meant by movemetn sequencing?
Each signal sent by the motor cortex will contract A SINGLE MUSCLE. However, complex movements require the contraction of multiple muscles at one; the brain sets out a sequence of signals that are sent out sequentially, in order to perform the higher complexity movement.
Main criteria for the brain sequencing of motor signals is __
it is SEQUENTIAL.
different muscles contracted at different times (milliseconds apart)
what happens to a skill when we learn it?
it is stored in our memory/hippocampus
The brain will either creat a program ___(1)___ or ___(2)___ like a signature
1) right before the movement
2) retrieve a program of a learned skill than perform it
why is the feedback loop important in learning new complex skills?
it helps us fixe our mistakes
why are skilled movements considered so complex?
Because the program is created immediately before the performance and DURING the program, sensory info is being sent back to the brain to give a feedback
what is proprioception?
all our muscles are covered in sensors to inform us of how stretched our muscles are. gives us a sense of where our limbs are compared to our body.
what is proprioception?
all our muscles are covered in sensors to inform us of how stretched our muscles are. gives us a sense of where our limbs are compared to our body.
what was Raymond Cajals doctrine on neurons in the late 1800’s?
the brain and the nervous system are made of individual discrete cells, the neurons.
what are neurons made of?
1) cell body englobing the nucleus.
2) the axon
3) axon terminal
what makes neurons so special? (one structure only found in neurons)
- The cell body of neurons is covered with dendrites that receive input signals.
- > 1 neuron has many dendrites and each dendrite receives signals from thousands of other neurons.
what is the longest axon in our body?
axon from toes to base of spine = 1 meter long
Describe axons and their function.
Axons carry the information received through the dendrites and relay it either to another neuron, a muscle, the spinal cord or other body parts.
they are wrapped in a myelin sheath.
what is the importance of the myelin sheath?
the myelin sheath acts as an insulator to make the signal propagation fast and to minimize/erase any loss of electrical current.
(signal = electrical signal)
describe axon terminals and their role.
they are at the end of the axon and through these, synapses happen.
the axon terminals secrete neurotransmitters to make synapses possible.
what are glial cells?
they are cells, other than neurons, that are implicated in the support of the nervous system and the brain funcionning
what are glial cells?
they are cells, other than neurons, that are implicated in the support of the nervous system and the brain funcionning
how many types of glial cells are there?
and what is each’s role?
3 types.
1) oligodendrocites:
produce the myelin sheath that wraps around the axon; essential for signal propagation across the neuron.
2) microglia.
They are the immune system of the brain.
3) Astrocytes.
They connect to axons and act as a brain-blood barrier, preventing certain substances from entering the brain and causing potential damage.
PLUS, the provide nutrients to the neurons.
why does the brain need specific immune cells?
the blood-brain barrier prevents immune cells common to the rest of the body from entering , and so microglia take that job in the brain.
what cells surrond the axon of neurons?
oligodendrocytes which produce the myelin sheath are wrapped around the axon
and
astrocytes connect to the axons to provide them with nutrients from the blood and support the neuron.
what is the one characteristic of neuron to neuron communication?
it happens in ONE WAY. Unidirectional, from cell body to axon terminal.
what is the one characteristic of neuron to neuron communication?
it happens in ONE WAY. Unidirectional, from cell body to axon terminal.
what is the cause of multiple sclerosis?
it is an autoimmune disease where the immune cells of the body attack and destroy the myelin sheath of axons.
evolution of Multiple clerosis symptoms.
loss of movement control then changes in cognitive processes.
pre-synaptic neuron: from __(1)__ to __(2)__
post-synaptic neuron: from __(3)__ to __(4)__
1) cell body
2) axon terminal
3) dendrite
4) cell body
true or false
The action potential depends on NA+ channels.
True.
either the threshold is reached and the NA+ channels open for depolarization, or no action potential is created.
what is the axon hillock?
It is the connection of the axon to the cell body.
Place of initiation of the action potential.
Why is the axon hillock the place of initiation of the action potentials?
- has the lowest threshold
- is the easiest to trigger
- the first place where the NA+ channels open
how does the signal propagate in the axon?
The first NA+ channel opens at the axon hillock, (+) charges flow in. They attract negative charges and repulse the positive charges which will agglomerate near the next NA+ channel, threshold reached -> those channels open and so on… until we reach the axon terminal.
what is a membrane potential?
it is the difference in electrical charges across the cell membrane
what is the resting membrane potential?
-70 mV ; inside is less positive than outside by 70 mV
What are the 3 critical ions channels?
- NA+/K+ pumo -> active transport
- voltage dependent channels (NA+ and K+)
- ligand gated channels
describe the events of an Action Potential
Depolarization: NA+ channels open, inside becomes more (+) than outside
Repolarization: at the peak of the depolarization, NA+ channels close and K+ channels open until inside less (+) than outside
Undershoot: the refractory period where NA+ channels don’t open (no threshold reached) and K+ channels keep leaking. (below -70 mV)
Then the pump reinstates the resting membrane potential.
How long is the depolarization-repolarization process?
0.002 seconds
how much energy goes into the functioning of the NA+/K+ pump?
70% of brain energy
25% of body energy
where do ions bathe?
in the intracellular fluid (cytoplasm) and extracellular fluid
70% of the brain = water
do all the drugs act by replacing the neurotransmitter?
No. some act on the ways of removing those neurotransmitters from the synaptic cleft
what are the 2 ways to remove neurotransmitters from the synaptic cleft after a synapse?
1- recycled through a reuptake pump into new synaptic vesicles
2- enzymes break them down
what is the major way of neurotransmitter removal?
Reuptake - recycling
what is the role of serotonin?
-crucial in mood regulation
what happens if there are low levels of serotonin?
depression
What are the 2 drugs used when there are low levels of serotonin?
-SSRI and MAOI
SSRI acts on inhibiting the activity of the reuptake pump
MAOI inhibit the activity of enzymes that break down the serotonin
what does SSRI stand for?
specific serotonin reuptake inhibitor
what does MAOI stand for?
monoamine oxidase inhibitor
give examples of SSRI.
prozac, lexepro, zoloft
give examples of MAOI
Nardil and parnate
what is the nature of the channels that open when neurotransmitters bind to the receptors?
Ligand gated channel
how do the ligand-gated channels close?
The neurotransmitters are no longer in the synaptic cleft, they close
what does the loss of dopamine result in?
and what are the symptoms?
Parkinson’s disease
loss of motor activity
where is dopamine stored
in the basal ganglia
wat drug is used for the treatment of Parkinson’s disease? what does it do?
L-DOPA
crosses the blood-brain barrier and once in the brain, transformed into dopamine
do reflexes go to the brain?
if not, how are they managed?
no. reflexes are managed by the spinal cord and only go to the brain after the response is done
depict the trajectory of a signal from sense to contraction
stimulus -> sensory neuron -> nervous system (brain or spinal cord) -> interneuron -> motor neuron -> muscle -> muscle contraction
what do ligand gated channels cause?
the opening of channels -> either excitation or inhibition
what are excitatory signals called?
EPSP - excitatory post synaptic potential
what are inhibitory signals called?
IPSP - inhibitory post synaptic potential
What happens during an EPSP?
The channels that open trigger DEPOLARIZATION. (flow of NA+ ions in)
What happens during an IPSP?
The channels that open trigger REPOLARIZATION. (flow of K+ ions in, CL- ions in)
what do EPSP and IPSP do relative to the threshold?
EPSP -> closer to the threshold for an action potential
IPSP -> further from the threshold for an action potential
what determines the strength of the synapse?
the strength of the stimulus.
The synapses are either weak or small, IPSP or EPSP, and when they arrive at the dendrites of the post-synaptic neuron, integration will take place.
All these potentials will add up until we reach the threshold or not.
threshold reached -> AP triggered, or else, No AP triggered.
what do we call the EPSP and IPSP?
Graded potentials
Does each of the million of synapses activate an action potential?
No.
We have many inputs but only ONE output.
the summation of the inputs will determine whether the output will happen or not.
what are the different inputs?
stimuli, mental states, neurons,…
What are descending signals? and what generates them?
descending signals are generated by the higher brain, making it less likely for the reflex to occur.
What are highe signals? and what generates them?
Generated by the higher brain, to boost the reflexes.
What is the most common excitatory neurotransmitter in the brain?
Glutamate
What is the most common inhibitory neurotransmitter in the brain?
GABBA
What are the 2 types of sumation/integration?
spacial sumation and temporal sumation
how do we use lesion studies to detect the functions of different brain areas?
we compare.
the behavior that is lost after damage to a particular area is controlled by that area
what is the most accurate technique to detect the location and timing of brain activity?
single neuron recording.
how does single neuron recording work?
we enter an electrode inside the brain and measure the action potential triggered by individual neurons.
this method is highly invasive and only done on animals.
on which animals what single neuron recording done on and what were we testing?
cats -> vision research
monkeys -> motor research
what is the goal of single neuron recording?
the only signal a neuron can fire is an action potential. we want to figure out WHAT is the action potential encoding, and WHAT is CAUSING it. (the stimulus)
who conducted the first single neuron recordings? and for what purposes?
Hubel and Wiesel in 1959
research on the visual cortex of cats
what did Hubel and Wiesel find out from their visual research?
neurons act as detectors of edges in the primary visual cortex. edges as in contrasts, colors and shapes.
Also detects orientation and build visual scenes from that.
how did we learn about neuroplasticity through the single neuron recordings?
We record action potentials fired from singled out neurons, and we see that the neurons used to fire prosthetic limb in monkeys, is different than the one used to control the natural limbs.
this shows that through trial and error and learning, the motor cortex learns new patterns in order to control the prosthetic.
what are the problems posed by single neuron recording?
it is very invasive (electrode in the brain directly)
only done on animals (nowadays on humans through surgery simulation)
what does EEG stand for?
electroencephalography
what does MRI stand for?
Magnetic resonance imaging
what are the 2 techniques used for brain measurement in humans?
EEG and MRI/fMRI
How does an EEG work?
we put a cap on the head and implant it with electrodes. each electrode sensor is going to pick up the summed activity of all the neurons in that region under the electrode sensor.
why do we call it ongoing EEG?
because it measure the oscillatory brain activity
-> brain waves
and each line represents one brainwave
how do the waves differ?
from one mental state to the other, the frequency and amplitude of the brain waves vary enormously.
dependent on the level of sleep, of arousal and alertness
what are the 2 important EEG bands that we look at?
the alpha activity and the delta activity
what are the 2 important EEG bands that we look at?
the alpha activity and the delta activity
describe the alpha activity.
the wave frequency goes from 8-12 Hz (12 is the peak)
-measures the level of alertness and cognitive load.
-represents the idling activity of the brain; large when the person is sleepy/relaxed, especially when eyes are closed.
when eyes are open and, a person is alert, becomes smaller.
what state does the alpha activity represent?
when a person is relaxing. normal alert state.
what state does the delta activity represent?
the person is in deep sleep
describe the delta activity.
- high amplitude
- frequency 1-3 Hz (peak at 3Hz)
- measures brain activity and disturbance
how can we detect epilepsy through EEG?
we take a person and put them to deep sleep, and monitor their brain activity while they are in that state. the delta bands should have low frequency and high amplitude -> any unexpected spike/peak is a sign of seizure activity in the brain.
what are ERPs?
event-related potentials
represent the brain activity following a certain stimulus/event
what are ERPs used for most commonly?
detecting deafness in babies/
what’s a very well-known peak in ERP EEGs?
Face recognition. 170 ms after seeing the face
-> Large negative peak on the EEG -> area for face recognition
what do the peaks and troughs represent on an ERP?
the first few small ones represent the short latency, the beginning of the signal in the sensory organs.
these are the earliest stages of neuron firing.
then we have the larger peaks and throughs related to major brain activity
what do the peaks and troughs represent on an EEG?
the first few small ones represent the short latency, the beginning of the signal in the sensory organs.
these are the earliest stages of neuron firing.
then we have the larger peaks and throughs related to major brain activity
does an EEG determine the specific localization of brain activity?
no, it gives a broad range. (the entire region under the electrode.
When were PET scans first introduced?
1980 - late 1990s
how do pet scans work?
we inject glucose or water with radioactive chemicals into the bloodstream, and we follow the blood flow in the brain, then with specific radioactive labels, we can detect the areas of the brain that are active.
In general, PET scans and EEGs rely on ____
blood flow measurements in the brain
what does an fMRI rely on?
the blood oxygen levels
The difference between MRI and fMRI is ___
MRI gives a clear picture of the brain anatomy whereas an fMRI maps out the changes in blood oxygen levels in the brain in response to a particular task. (color coding)
does an MRI and an fMRI require different tools?
no. same machine, different technique
how do we make conclusions based on ERPs?
we average 100 trials and see where the peaks are happening in the same location after the same stimulus.
how do we make conclusions based on ERPs?
we average 100 trials and see where the peaks are happening in the same location after the same stimulus.
how to use MRI and fMRI?
the fMRI is a statistical map in colors
we put the MRI and fMRI scans on top of each other and relate the color codings to the different areas of the brain.
where will the blood-oxygen levels be the highest?
the neurons that are active need energy and that energy is provided through oxygen, transported in the blood. so the highest levels of blood oxygen will be in the functional area.
what do we call EEG data windows?
epochs
what do ERPs provide(timing and spatial)
the perfectly precise timing of brain activity, poor spatial resolution. (broad region)
how do the electrode sensors connect to the skin to pick up brain activity?
we use conductive electrolyte gel
what does each line on the EEG represent?
1 line = activity detected from one sensor = summed up activity of 1,000 neurons in that region
what does PET scan stand for and what does it map?
maps out neurotransmitters or receptors in the brain
PET = positron emission tomography
when was the first fMRI done?
1992
pros and cons of fMRI?
pros: good LOCALISATION of brain activity
cons: very expensive
the oxygen blood measures are delayed compared to the neural activity.
lines of the ERP
almost flat line = onset of the stimulus
first peak = early stages of sensory processing in the primary cortex
large peak = higher order processing in the cortex
lines of the EEG
almost flat line = onset of the stimulus
first peak = early stages of sensory processing in the primary cortex
large peak = higher order processing in the cortex
what is the reverse inference?
inferring what people are thinking based on their brain activity.
BAD
SEE PDF d of 2.3 module
what 2 processes drive neuroplasticity?
synaptogenesis: new and changes in synapse connexions
neurogenesis: generation of new neurons from stem cells in the brain
if i want to remember a certain thing/person, what input is excitatory in this memory?
all sensory inputs that share traits with the thing I want to remember
what is semantic memory?
when billions of neurons code for billion of different concepts
what experiment did Jerry Lettvin conduct in 1969?
the thought experiment
what is the spreading activation model theory?
when one neuron fires, it spreads out and fires other neurons.
what were Jerry Lettvin’s findings?
there are groups of neurons for each concept that store that concept’s info.
Concepts that are related frequently, those neuron groups are fired together most times.
how does a neuron-neuron connection strengthen?
the more the 2 concepts are mentioned together, the stronger the connection.
Raymond Cajal’ theories were __(1)__ and __(2)__
were they true?
1) neurons do not regenerate -> TRUE
2) during adulthood, nothing new forms, the number of neurons we have is fixed -> FALSE
Where do we find the stem cells in our brain?
the hippocampus and the olfactory bulb
how do we identify the areas that are changing?
we look for new connections or for changes in existing connexions (weaker or stronger)
Donald Hebb observed differences in synapse connections across rats raised in different environments. what did he conclude?
pet rats smarter than lab rats -> living in enriched conditions creates more simulation and more dendrites grow -> strengthen synapses.
What is Long term potentiation?
LTP is when the synapses change structure to become either weaker or stronger.
(stronger -> this happens through learning and memory)
what becomes weaker and what becomes stronger?
the connections that are repeatedly activated grow stronger whereas the connexions used rarely wear out and become weaker.
what was Hebb’s law, or the Hebbian learning?
“neurons that fire together wire together.”
2 neurons sharing a synapse connexion, every time they fire together, that connection strengthens.
is the link between visual perception and motor functions innate? does it require concentration?
it is not innate, we learn it during the early stages of our development.
It happens with 0 effort -> automatic
when does brain re-organization happen? and what does it mean?
it is when we remap our patterns and relearn how to do something and adapt to things. relearn skills. the basis of rehab.
after an injury what is adaptive plasticity vs. maladaptive plasticity?
-Adaptive plasticity: rehabilitation after injury.
when we train and relearn the function of the injured limb. this creates new patterns in the brain and can expand to areas that were not in control of this behavior before the injury. the person is better off.
-Maladaptive plasticity: after an injury, no rehabilitation.
the conditions worsen and the person’s brain area responsible for the behavior shrinks further.
What areas of the brain activate when blind people read brail?
their visual cortex still activates, but their somatosensory cortex is the main actor.
give an example of brain reorganization through experience.
people who play string instruments will learn more skills at their fingertips to have better fine controlled movements on the instrument.
the areas of their brain controlling their fingertips expand in the sensory and motor cortexes.
where do we find the amygdala and the hippocampus?
in the medial temporal lobe -> limbic system
functions of the frontal lobe are____
processing short term memories movement concentration emotional control center executive function inhibitory control center
