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29 Cards in this Set
- Front
- Back
Why do Receptive Fields have Center surrounded organization?
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Do to lateral inhibition
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What is center surrounded orginzation?
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In the somtosensory neurons in the somtocortex are selectively stimulated, while the surrounding neuros are inhibited to do lateral inhibition
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Where does center surrounded orginization commonly occur?
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the somotcortex
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What is directionally selective?
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some neurons respond best to stimuli in moving in a specific direction
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What is a receptive field?
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•The receptive field of a sensory neuron is a region of space in which the presence of a stimulus will alter the firing of that neuron.
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What are the 4 distinct regions of the S1?
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1, 2 3a, and 3b
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Lesion in area 1 distrupt?
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texture discrimination
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Lesions in area 2 distrupt
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size and shape discrimination
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Lesions in area 3b distrupt?
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Size, shape and texture disctrimination
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3a and 2 receive inputs from? carrying what info? from where (specific)?
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Inputs from the VP of the thalamas. carrying proiception information from the muscle spindles(3a) and the golgi tendon organs(2)
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3b and 1 receive inputs from? carrying what info?
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receive inputs frm the VP of the thalamus carrying information from the cutaneous receptors which include mechanorecepts thermoreceptors and nociceptors
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How is the somatocortex organized? Vertically (column)? horizontally (somato mapping)?
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each column receive inputs from a single region of the body, and each column receives that same type of input (fast, slow).
The body is laid across the the somatocortex in an ordely fashion creating the humunculus. Not by size of of body but rather how many neurons occupy that space. |
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How many layers in the somatocortex? is it more or less layers than others?
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6 layers, No.
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What layer of the somatocortex do inputs from the VP enter?
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Layer 4
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What type of cells do inputs from the VP synapes on in the somatocortex?
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Stellate cells.
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stellate cells in somatocortex recieve inputs from where? are located in what layer? and synapes on?
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VP of the thalamus, layer 4, pyrimdal cells in other cortical areas
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What layers are the pyrimdal cells in?
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layers 2, 3, 5, 6
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Pyrimdal cells synapes on what parts of the brain?(each layer is different)
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layer 2 and 3 on motor areas
5 sends inputs to non motor areas, including the basal ganglion 6 sends inputs to thalamus, relay |
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area 6 pyridmal cells send inputs too?
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feedback connections to the thalamus
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Pryimdal Cells of layer 2 and 3 send synapes send information too?
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coritcal motor areas
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pyrimdal cells from layer 5 send synapes and information to?
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non cortical motor areas, including the basal ganglion
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How does opium and opiate derivatives effect the brain(act on)? what does the pathway do?
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they act on opinoid receptors in the brain, the pathway leads to the release of endorphins, endorphins lead to analgesia
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Naturally released endorphins are?
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enkephalins
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where is the PAG located and what is it?
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medulla and the periaqueductal gray matter
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How does enkepalin get released?
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serotinin is released from the dorsal gray matter which activates local interneurons which release enkepalin.
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How and what does enkepalin do? Be specific, inhibit or excite what.
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produces analgesia by activating local interneurons, both presynaptically and post synaptically inhititing noiceptor transmission.
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What does the activation of the PAG produce? does it excite or inhibit and what?
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analgesia. excites the ralphe nuclei
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PAG and ralphe nuclei are located? Are connected with what pathway?
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PAG in the midbrain and the ralphe nuclei the medulla. PAG excites ralphe nuclei
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ralphei nuclei are excited by? release what neurotransmiiter? to where? doing what?
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PAG, serotin (HT-5), to the dorsal gray matter, indirectly inhibiting noiception
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