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29 Cards in this Set
- Front
- Back
What happens in single cell recording? |
The electrode picks up activity of a single neuron Electrical activity of single cells can be monitored by an electrode placed outside of the cell membrane and inside the cell membrane |
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Recording outside the cell |
extracellular recording |
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Recording inside of the cell |
intrracellular |
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What does the electrode do? |
An electrode is introduced into the brain of a living animal Detects action potentials Generated by the neurons adjacent to the electrode tip |
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Microelectrodes are used for |
extra cellular single unit recordings |
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The wires used are |
made from tungsten or platinum-iridium alloys they are insulated except at their extreme tip often glass micropipettes willed with a weak electrolyte solution similar in composition to extra cellular fluid |
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Microelectrodes have a tip size of |
3 to 10 micrometers |
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Single cell recording is performed on |
nonhuman primates cats rodents |
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During the procedure, the animal is |
anaesthetized, held in a stereotaxic frame, intubated (to help breathing), body temperature monitored |
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What does the procedure involve? |
A craniotoomy is conducted Electrode inserted Visual stimulation Recording |
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To confirm the site of recording |
Dye ejected from microelectrode Animal sacrificed Dye mark recovered |
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Brain cells in the right visual cortex are only driven by stimulation of |
the left visual field, but only a very specific area of the visual field. This is the receptive field for that particular brain cell |
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Bars and gratings are used to |
work out the orientation of stimuli and direction of movement preferred by a cell |
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Receptive field |
The receptive field of asensory neuron is a region of space in which the presence of a stimulus willalter the firing of that neuron(increase/excite or decrease/suppress) |
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ganglion cells ---> |
geniculate cells ---> single cortical cells ---> V1, V2, V3 cells |
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Simple cells |
areactivated by features such as edges |
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Complex cells |
combineinformation from several simple cells and detect the position and orientationof the stimuli1 |
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Hypercomplex cells |
detectend points and crossing lines from the positional and orientation information. |
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Critical period for the development of binocular sensitive cells in cats and humans: |
12 weeks in cats 36 months in humans |
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Place cells |
only fire when an animal enters a specific location in a given enrionment different place cells could be active in different places the combination of activity in many lace cells creates an internal neural map of their surroundings The hippocampus can contain multiple maps represented by combinations of activity in different environments A specific combination of active place cells may therefore represent a unique environment |
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Place cells are found in |
the hippocampus |
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The hippocampus is larger in a |
rat than a primate |
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Associative spatial memory is stored in the |
place cells |
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Taxi drivers have a significantly larger |
posterior hippocampus than controlls |
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Single cell recording does not allow neuropsychologists to simultaneouslyanalyse |
patterns of activity at multiple locations in the brain |
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fMRI scanning of adolescents and adults when doing allocentric or memory guided navigation |
showed that lots of different areas of the brain are activated, and this is not shown by single cell recording |
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Single cell recording provides little information about |
the relative timing of neural events at different brain locations |
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However, simultaneous measurement of the onset and offset of neural activity can provide valuable information about |
cause and effect relationships between cognitive structures as cognitive operations unfold |
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Single cell recording provides little information about the inputs and outputs of |
any given neuron |