Brain Basics Flashcards
who was phineas gage?
what are we missing from his story?
the man who got a spike through his prefrontal cortex.
How was he actually assessed?
To what extent did he recover?
were his symptoms exagerated?
Turns out he wasn’t followed up on much, reports came in from 2nd/3rd hand sources,
speculation that he was always a “get rich quick” guy
What were mechanisms/analogies limited by?
Scientific knowledge.
Time has gone through periods where metaphors for the brain have directly related to our science at the time.
“the brain is like a computer” - now
“the brain was like wires/electricity” -19th century
“the brain is like a hydraulic system” - 18th century (i.e. fluid moving through a tube to get somewhere.
-rome: the 4 humors (blood phlegm, yellow/black bile)
What did some doctors refer to the brain as? (hippocrates)
the seat of the mind
What were early investigations hampered by?
ethics/morality (didn’t want to cut open people)
Who is “the roman who got clever” and why?
Galen decided to cut up animals because they are similar to us.
Which era allowed scientists to cut people open?
The renaissance and the “hydraulic era” and Vesalius was one of the first people to dissect a brain (noticed big and little brain)
What was descartes legacy?
Dualism: the thought that the mind and body are separate entities. Noticed that the brain controlled the body, so the soul was in the PINEAL gland
who were Galvani and Raymond?
they used frog legs and electric signals to make the dead legs move!
ask becca/tallinn
who were bell and magendie?
organized the spinal chord dorsally and ventrally. They cut the selective parts of the nervous system and found…
cut dorsal: lose sensation
cut ventral: lose motor skills
who were fluorens and broca?
they localized function and had “tan” patient. founded “broca’s area”
Specialized function in the brain (localization)
who was schwann?
he invented the cell theory: everything is made of cells, the brain isn’t one mass but many many cells
when was the debate between golgi and ramon going down?
19/20th century
what was golgi’s stain?
what did he deduce from this?
silver nitrate staining of a subset of cells. saw the processes and thought it looked like a mesh/net and thought liquid could flow through it.
THE RETICULAR THEORY
what did ramon cajal do?
he drew the neurons from golgi’s stain. very systematic, came up with the idea that the base unit of all things are neurons.
NEURON DOCTRINE: base unit of the nervous system is the neuron (idea of the synapse)
who was right? golgi or ramon?
ramon, after years of being enemies and sharing the nobel prize, he won!
early microscopes couldn’t tell who was right! synapses were too small
what is neuroscience?
study of the nervous system
study of human nature
what it means to be you, how its related to mind and how the NS functions
what are the levels of analysis?
molecular cellular systems behavioural cognitive (using mri to study active brain)
what are the types of research?
basic applied (how do we cure/fix etc)
its very hard to treat a problem without understanding it first
what are some FACTS about the human brain?
2-3% of your body weight
consumes 20% of your energy (blood/oxygen/glucose)
slightly larger in men than women
huge variation
composed of neurons/glia/stem cells/blood vessels
100 billion neurons, more than half are cerebellum (soft tofu little brain)
its convoluted (related to intelligence)
cells are not replaced!!
whats the analogy for the tectum?
the “boston pizza” of your brain - your eyes getting drawn somewhere without you trying to
what is the pattern for different types of brains (animal/insect/human)
bigger developed cerebrum, more wrinkles = smarter
larger and larger brains
what are some exceptions to the “rules” when it comes to brain types?
Dolphin brains! they have huge cerebellums (for motor coordination) but they don’t really have “digits” or fine motor movements? so it doen’st really make sense
Parrots!
their brains are smooth - but they are incredibly smart and can understand things like counting and categorization etc.
what is the best gross level mechanism for determining intelligence?
BRAIN CELL DENSITY
- size doesn’t really matter (even relative size)
Intelligence also coorelates with sophisication of cellular connections (connectivity between neurons is a good predictor of intelligence)
what are the types of matter?
white: myelinated
Grey: cell bodies and unmyelinated axons
what are nissel and fiber stains?
nissel: stains cell bodies (not the branches)
you can see the grey matter because they stain the cell body
“pressel violet stain”
fiber: another word for white matter, shows you where the white matter is and where axons “come to an end”
it stains the insulating glial cells
what are the 2 basic cell types?
neurons
glia
what is the design of a neuron?
input (dendrites)
flow of signal (through cell body)
output (axon terminals)
what are the purkinje cells?
part of your cerebellum that has the most dendritic branching. it gathers a lot of information and conflomerates out to a single output
what are the two basic types of neurons?
projection neurons and interneurons
what is the structure/purpose of an interneuron?
shaped like a star, very short axons
- modifying and shaping long distance signals
purpose: influence and shape neurons when they pass through stopping/pausing
i.e. the thalamus does a lot of this!
what is the purpose /structure of projection neurons?
really long axons, some from spine all the way to toes!
some paths need reshaping/stoping and others just need the one axon.
what is the advantage of having interneurons?
they synchronize activity between neural circuits.
Interneurons can control when the output happens (diaphragm, heartbeat, attention span, perceptions)
some signals need to be depressed and others boosted
- competing pathways are supported in one and suppressed in the other
what is fundamentally different in people with learning disabilities like dsylexia?
- their white matter!
what are the two general categories of GLIA?
- microglia
2. macroglia
what are the categories of macroglia?
schwann cells, oligodentrocytes, astrocytes
what are microglia?
immune system of your brain.
- very small until they sense a threat: they get ‘primed’
- when they find what is causing trouble in the brain they ENGULF it and digest it (they become huge)
why does your brain need its own immune system?
due to the blood brain barrier, lots of things can’t get in (good and bad)
what are schwann cells and oligodendrocytes?
they myelinate axons to speed up transmission
Schwann: entire cell wraps one axon, in the PNS
Oligo: several axons in the CNS
what are astrocytes?
they are part of the blood brain barrier, and the synapse!
they get oxygen, glucose, ions (in and out) and distribute them accordingly.
they maintain the environment of the synapse
- i.e. if there is a surge of sodium in your body the astrocytes are there to save the day and buffer away ions
what is a gap junction and who thought the brain worked like this?
each glia has a 1/2 projection on another cell, a continuous pore form one to another (instant electrical or buffering activity)
like golgi’s reticular theory of a net/mesh system
what is the tripartite system?
neurotransmission and glialtransmission (pre + post + astrocyte)
how does the astrocyte relate to the synapse?
it surrounds the synapse
glia are releasing transmitters and have receptors!
- astrocytes receive signals to know how much to provide/take away
-influence on transmission of info
- WHAT THEY RELEASE increases/decreases likelihood of transmission/receptor bindings and whatnot
-this determines whether you are susceptible to stress!!
what is the central dogma of biology?
the body is cells and the cells are proteins
DNA is replicated and transcripted into RNA which is then translated into PROTEINS
-RNA can sometimes be reverse transcribed
how do viruses make more of themselves?
they use the machinery in your brain when RNA reverse transcribes
what is the story of the mitochondria!
- powerhouse of the cell
- was once a bacteria (they create energy for us - they chill in our bodies)
- they have their own DNA
- any issues with mitochondria will come from your mother because they are only passed down through those genes!! (cool!)
how is energy produced in the mitochondria?
protein/sugar/fat } pyruvic acid + 0xygen = atp + c02
what does the cytoskeleton do?
what disorders does it effect?
it creates structural integrity inside the cell in alzeimers (neurogenrative disorders) the cytoskeleon is effeced because tau proteins start clumping together and the skeleton begins to fall apart?
made of microtubles and some smaller ones*
- constantly growing/shrinking
- lots of room to go nuts
what is kinesin and dynein?
kinesin: anterograde
dynein: retrograde transport
what is the main way to move up/down the axon?
the cytoskeleton!
- new proteins made have to be shuttled down to the terminal button, some things that walk down the axon and carry big vesicles of stuff you might need
(other molecules walk back the other way)
what does the terminal button need a lot of?
mitochondria and NT! (lots of energy is needed)
what are the types of synapses?
- axosecretory
- axoaxonic
- axodendritic
- axoextracellular
- axosomatic
- axosynaptic
what are the different types of spines on neurons?
spines: release gluatmate
non spiney: releases gaba
what is the purpose of a spine?
whats the story of as spine?
more opprotuninty to modify the synapse
- it can widow away if its not an important synapse
- can grow if it is really important
- YOU ARE YOUR SYNAPSES
what is the relationship between number of spines and disorders?
too many: autism
too few: schizophrenia
*is this for negative symptoms only? ask becca
a loss of spines: alzehimers
shapes of the spines is really important and we need better technology for viewing them