How many neurons are there in the brain?
Who is the father of modern neuroscience?
Ramon y Cajal
Why do we say that neurons are polarized?
Information only goes one way
What is the cytoskeleton of a neuron made out of?
Tubular and filamentous proteins
What is the communication between two nerve cells called?
What is the brief period of silence that occurs right after the membrane starts recharging?
What allows neuroscientists to view the movements of ions through individual ion channels?
How fast are the fastest of myelinated neurons' transmissions?
100 meters per second
How frequently can action potentials be fired?
1000 times per second
Who discovered the mechanism for the transmission of the nerve impulse? What animal did they use?
- Alan Hodgkin & Andrew Huxley
- squid, giant axon
Calcium acts on which presynaptic proteins?
How long does it take for the neurotransmitters to diffuse across the synaptic cleft?
Less than a millisecond
Three ways that neurotransmitters are recycled:
- cleaned up by glial cells with transportersbroken down by other chemicals in the cleft
- nerve cells pump them back into their nerve endings
What type of receptors are associated with neuromodulation?
What does dependence mean?
Craving for the drug.
What is addictionL
unpleasant physical and psychological side-effects
Three most addictive drugs in order:
What are the different touch receptors and their functions?
- Pacinian (large receptive field)/Meissner corpuscles
- --- vibration, flutter (rapidly changing)
- Merkel's disks
- --- pressure (sustained indentations)
- Ruffini endings
- --- slowly changing indentations
How many photoreceptors are there?
125 million on each retina
How many times more sensitive to light are rods than cones?
What is phototransduction?
The conversion of light into electrical signals
What percentage of retinal ganglion cells are small? Large?
90% small, 5% large = M-type = magnocellular
Which scientists discovered that cells in the visual cortex fire according to orientation?
David Hubel & Torsten Wiesel
Who discovered how the visual system develops?
How do you contract a muscle?
Action potential => ntx released => action potential in the muscles fibers => Ca2+ is released => triggers contraction
What are motor neurons also known as?
The final common path
How long before movement occurs do cells in the motor cortex begin to fire?
100 milliseconds (1/10 second)
How is the information stored in the motor cortex?
in a population code
What do the basal ganglia do? Where are their inputs/outputs?
filter through a lot of their inputs (that they receive from the anterior part of the cortex) and feed back to the motor cortex
important in learning, allowing the selection of actions that lead to a reward.
What mechanism is very important for learning skilled movements?
LTD - long-term depression
When is the most dopamine released and what does that have to do with learning?
When it's unexpected. It comes at a time when it's most crucial to learning.
What is a genome? How many genes are there in it?
the set of instructions to make an organ of the body. 40,000
What animals have been studied by neuroscientists and why?
- zebrafish (embryo is transparent)
- frogs, chicks (large embryos)
- mice (breeds rapidly)
What is the first step in brain development?
What next? What is the name of this step?
- cell division
- differentiation. orders things spatially. Pattern formation.
What is it known as when neurons migrate to various locations in the brain?
When is the first major event of pattern formation? What does the embryo look like?
What type of structure is formed?
Where do the signals that determine the destiny of these cells? What happens in this place?
- 3 weeks. 2 connected sheets of dividing cells.
- The cells on the topside will for the brain and spinal chord
- ---these cells form the neural plate
The signals come from the lower layer, which will form the midline skeleton and muscles
When/what is rolling around?
What is happening with the neural plate?
- 4 weeks
- the neural plate closes up and sinks into what will become the epidermis
How do cells figure out their positions in the developing embryo?
the embryo sets up polarizing regions, meaning that there are differing concentrations of signal molecules.
What signaling does the bottom of the bottom of the neural tube secrete? How does it act? What does it make?
Sonic Hedgehog. Doro-vertral axis. When close, Sonic hedgehog makes innerneurons, and farther away, it makes motor neurons
When is the visual system complete in monkeys? Humans?
8 weeks. 1 year.
What is a phoneme, and how many are there in the English language?
Each phoneme is a seperate sound, and there are 44
How many kids have had dyslexia at one point?
What is orthagraphy?
recognize alphabetic visual symbols in the right order
What is phonemic structure?
translating symbols into sound
What type of cells control eye movements?
A network of large neurons known as magnocellular system.
What is different in the lateral geniculate nucleus of somebody with dyslexia?
the parvocellular layers and the magoncellular layers are mixed together.
name 4 people with dyslexia
edison, eistein, da Vinci, Hans Christian Anderson
What is the eletrical response in response to ntx release known as?
What are the four type of glutamate receptors and what type of receptors are they?
- Three ionotropic
- ---AMPA, NMDA, kainate
- one metabotropic
What are the memory molecules?
AMPA and NMDA receptors
When do we learn best?
During happy, sad, or painful experiences and when we pay attention.
Who transformed the study of excitatory trans mission in the brain by developing a drug known as AP5?
What controls the flow of information in the formation of memory? Who helps this system?
- The central executive system is supported by a phonological store
- silent rehearsal loop
- visual sketchpad
Where is working memory located?
How is visual information processed during memory formation?
information entering the visual system passes down a so-called ventral pathway from the striate cortex to the medial temporal lobe through a cascade of networks that work out shape, colour, object dentity, whether the object is familiar or not, until some kind of memory is formed of this particular object and when and where it has been seen.
What is it called when somebody can't remember stuff before an event?
What structures in the midbrain are important for a normal memory? Other places?
For normal memory?
- Mamillary bodies and thalamus. Hippocampus.
- the perirhinal cortex
Who developed the idea of working memory?
What guides damaged cells to the "trash can"?
What is the HPA axis, what hormones are involved, etc?
- the hypothalamus releases corticotrophin releasing factor
- the pitutitary gland releases adrenocorticotrophin
- the adrenal gland to secrete cortisol
What is the function of cortisol? Positive and negative stuffs.
- raises blood sugar and releases fatty acids (by breaking down proteins)
- raises blood pressure
- makes you feel good.
turns off growth, digestion, inflammation, wound-healing
What is the last step of the cortisol feedback system?
Where does cortisol have the greatest effect?
- cortisol feedback to the brain
- hippocampus (and some on the amygdala)
- --- amygdala is activated, hippocampus is shut off
What receptors are active in the hippocampus?
Which one is activating by which?
When is cognative function highest?
- low MR (normal levels of cortisol) and high GR (high levels of cortisol)
- When we're a little stressed
what does excess cortisol cause?
depression (aka long-term stress)
What kills invading cells?
What are cytokines? How many are there?
Respond to injury/disease. over 100. interferons, inter leukins, tumour necrosis factors, and chemokines.
What genes acts as our internal clocks? How do they function?
Per and tim. they synthesize during the day and link up, then daylight degrades the proteins.