Neurons Flashcards
Which part of a Neuron contains the nucleus?
The cell body.
What is a Neuron?
A type of cell that makes up the nervous system and supports, amongst other things, cognitive functions.
Name the branching structures which carry information FROM other neurons.
Dendrites
How many other neurons can one neuron connect with?
Around 10,000
Which cells make up 10% of cells in our brain?
Neurons
Which cells make up 90% of our brain?
Glia cells
What are the functions of glia cells?
Tissue repair and the production of myelin
What is myelin?
A fatty substance which increases conductivity of electrical impulses along the axon
Roughly how many neurons are in the human brain?
100-150 billion
What is the function of the axon?
To carry information TO other neurons
What is action potential?
A sudden change (depolarisation and repolarisation) in the electrical properties of the Neuron membrane in the axon
What are axon terminal buttons?
A neural impulse travels down the axon to axon terminal buttons, a means by which one Neuron can communicate with other neurons
What is the resting potential across the cell membrane?
-70mV
Which part of the Neuron is the only part capable of producing action potentials?
The axon
Where are voltage-gated ion channels situated and what are they for?
In the axon. They are important in the generation of an action potential.
What is cell depolarisation
Negative potential is reduced (at -50mV cell membrane becomes completely permeable and the charge momentarily reverses
What is hyperpolarisation?
K+ channels continue to operate which causes and undershoot. This makes it more difficult for the axon to depolarise again straight away
Which substance blocks normal K+/Na+ transfer and makes the action potential jump down the length of the axon at the nodes of ranvier?
Myelin
What is a synapse?
The small gap between neurons which neurotransmitters are released, permitting signalling between neurons.
What are neurotransmitters?
Chemical signals released by one Neuron that affects the properties of other neurons.
What do neurotransmitters bind to?
Receptors on the dendrites or cell body of the postsynaptic Neuron
What do neurotransmitters do by binding to receptors on the dendrites or cell body?
They create a synaptic potential
How is synaptic potential conducted? Actively or passively?
Passively. Does not create a change in electrical charge.
If passively conducted currents are _______ enough when they reach the beginning of the axon, this leads to _______ __________ and the development of a ________ ___________.
Strong
Active conduction
Action potential
Is active conduction long range or short range?
Long range.
Passive conduction is short range.
What is single cell electrophysiology?
It is an invasive technique that measures the electrical activity of a single Neuron/cell in response to an environmental stimulus.
What are the 3 R’s in animal welfare?
Reduction - less animals used
Replacement - using least sentient species
Refinement - improving experimental design
Is single cell electrophysiology invasive or non invasive?
Invasive
What are the two types of recordings in single cell electrophysiology according the location?
Intracellular recording - inside axon
Extra cellular recording - outside cell membrane
Which units are used for measurement in single cell electrophysiology?
Spikes per second
After single cell electrophysiology anaesthetised surgery, what happens to the animal?
They are euthanised
Does single cell electrophysiology use humans, animals or both?
Animals
What type of animal would be best to use in single cell electrophysiology?
Monkeys because their brains are similar to humans, and monkeys can be trained to perform behaviour tasks.
How are spike recordings obtained?
Using miroelectrodes
What are visual cortex cells selective for?
Orientation
Size
Motion detection
Speed
What did Hubel and Wiesel record in 1959 (single cell electrophysiology)
Recorded from single cells in cats primary visual cortex and found that cells there were vey selective for the orientation, size direction and speed of a stimulus.
What is electroencephalography (EEG) ?
Records electrical signals generated by the brain through electrodes placed at different points on the scalp.
Is EEG invasive or non invasive?
Non-invasive
What does EEG measure?
The amplitude and timing of electrical impulses
How are single cell electrophysiology and EEG different?
Single cell measures axonal currents of single neurons
EEG measures Dendric currents in neuronal populations
For which measure must a whole population of neurons be active in synchrony to generate a large enough electrical field to be detectable?
EEG
For which measure must neurons be aligned into parallel orientation so that their activity summates rather than cancels out?
EEG
Where is the F electrode placed in EEG?
Frontal lobe
Where is the P electrode placed in EEG?
Parietal lobe
Where is the O electrode placed in EEG?
Occipital lobe
Where is the T electrode placed in EEG?
Temporal lobe
Where is the C electrode placed in EEG?
Central lobe
In EEG, which number electrodes are situated on the left side of the midline?
Odd numbers. Right is even.
Remember, it is ODD to be LEFT handed
How can The time-course of an EEG signal be qualified?
Using an event-related potential (ERP)
With what unit is electrode potential measured?
Microvolts
What does structural imaging measure?
The spatial configuration of different types of tissue in the brain
Name two types of structural imaging techniques
MRI
CT
What does MRI stand for?
Magnetic resonance imaging
What does CT scan stand for?
Computerised tomography
Which type of scan is responsible for discovering brain tumour, haemorrhages and gross brain abnormalities?
CT computerised tomography
Most human tissue is ________ based.
Water
What does an MRI scan particularly focus on?
The behaviour of hydrogen atoms in a magnetic field
What is a hydrogen atom made up of?
1 proton, 0 neutrons
Structural imaging techniques are s_______?
Static
