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33 Cards in this Set
- Front
- Back
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Where does the neuron receive most of its input?
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The neuron receive most of its input on the dendrites?
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Describe the pathway of information flow through the cortical layers?
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Thalamic nuclei->Layer 4->Layers 2-3 (supragranular layers; processing occurs)->Layers 5-6 (infragranular; output)->other areas
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What are the 5 types of synapses?
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Axospinous, axodendritic, axosomatic,
2 kinds of axoaxonic: @ axon hillock, @ presynaptic terminal. (these 2 axoaxonic synapses are mostly inhibitory). |
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On a pyramidal cell, where are the major excitatory inputs? How are these spines further categorized?
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In pyramidal cells, the major excitatory input is on the spines. The spines close the axon hillock are called intrinsic (more potent) and the ones far away are called extrinsic (less potent).
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Describe the properties of pyramidal neurons in layers 2-3.
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Dendrites- only in layers 1-3 (supragranular layer)
Axons- extensive axon collaterals in all layers; axons go across corpus callosum. |
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Describe Layer 5 Medium and Deep Layer 3 pyramidal neurons?
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extensive dendritic trees,
long-range cortico-cortical connections across c. callosum. |
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Describe Layer 5 Large Pyramidal cells?
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extensive dendritic trees,
axons project to sub-cortical regions like pons & striatum. |
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What is salient about Layer 5 pyramidal cell types?
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Layer 5 has Medium Pyramidal cells and Large Pyramidal cells.
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Describe Layer 6 pyramidal neurons.
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dendritic tree restricted to layer 4,
axons target thalamus (feedback) |
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What is the rule of thumb about spiny neurons in cortex?
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They are excitatory.
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What are the 4 types of interneurons? Which is the exception?
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Spiny stellate, double-bouquet, chandelier, and basket cells.
Only spiny stellate cells are excitatory. |
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Describe spiny stellate cells.
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Spiny stellate cells are found in Layer 4. Their dendritic arborization is local, and the axons don't project outside the column. This makes spiny stellate cells the link between the input layer (layer 4) and the output layers (3,5,&6).
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What is the relationship between spine length and maturity?
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Stubbier spines are mature, and longer spines are immature.
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Where are double-bouquet cells found?
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They are only in layers 2-3, and their axons/dendrites stay local.
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What is generally true about the morphology of interneurons? What is the exception?
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They stay local! Except basket cells, which have widespread dendrites and axons.
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What is a chandelier cell?
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Located in layer 3, and stay in same column. Have corkscrew like axons that inhibit excitatory neurons.
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What are basket cells?
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found in layers 3 and 5. Unlike other interneurons, dendrites and axons are non-local and aren't confined to column.
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What happens when mice have their whiskers trimmed during the critical period?
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The mice who have their whiskers trimmed during the critical period show impaired performance on a texture discrimination task
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What is the relationship between interneurons, the perineuronal net, and sensory deprivation?
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Interneurons are sheathed in the perineuronal net. Sensory deprivation during the critical period damages the perineuronal net of these interneurons.
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What is true about how sensory deprivation during the critical period affects Layer 6 pyramidal cells and layer 4 interneurons?
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Sensory deprivation during the critical period differentially affects layer 6 pyramidal cells and layer 4 interneurons. In layer 4 interneurons, it caused more dendritic branching. In layer 6 pyramidal cells, it caused apical dendrites to retract and basilar dendrites the expand
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How does neuronal structure change besides sensory deprivation?
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The dendritic structure changes cyclically depending on where a mouse is in the estrous cycle.
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What are three types of glia?
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Oligodendrocytes- myelinates CNS axons
Microglia- immune cells of CNS Astrocytes- 2 types: (1) maintains blood-brain barrier, and (2) maintains extracellular K+, and thereby aids synaptic transmission. |
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what is the different nomenclature for referring to cell extensions?
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They are called PROCESSES, not dendrites.
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What is the relationship between radial glia and microglia?
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The radial glia become the microglia later in development.
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What are the functional differences between the 2 types of astrocytes?
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(1) Uses its processes (called end-feet) to monitor the blood, and then inform the neuron of the blood contents or transport materials in the blood to the neuron.
(2) ensheathes the synapse to prevent neurotransmitters from leaking outside the region, and also uptake neurotransmitters. There is bi-directional feedback between neurons and glia., and this is important in maintaining synapses. |
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What else do astrocytes do?
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Ion buffering- they have K+ channels that regulate extracellar potassium concentrations.
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What are microglia?
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The cell bodies of microglia increase when they are activated. Microglia density changes across development. Sensory deprivation increases the cell body size of microglia and decreases the length of their processes.
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What cells provide myelin?
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In the CNS, oligodendrocytes provide myelin. In the PNS, Schwann cells provide myelin.
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What is the significance of non-nuclear ribosomes in the myelin-making cells?
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There are ribosomes at the leading edge of the myelin, because transporting mRNA is easier than transporting proteins.
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What is multiple schlerosis?
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An autoimmune disease where your body attacks myelin.
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Why does myelin develop so late?
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Myelin develops late because it inhibits neuronal growth, like the factor NoGo.
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How does trimming affect myelin?
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Trimming decreases myelin, but not the overall cell count.
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What are the behavioral consequences of decreased myelin after trimming?
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Decreased physiological responsiveness to whisker touching.
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