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A DISINHIBITORY MICROCIRCUIT FOR GATED CEREBELLAR LEARNING
Title
A DISINHIBITORY MICROCIRCUIT FOR GATED CEREBELLAR LEARNING.
Creator
Zhang, Ke, Christie, Jason, Dawson-Scully, Ken, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
Performance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to...
Show morePerformance motor errors trigger animals’ adaptive learning behaviors to improve the accuracy and efficiency of the movement. The cerebellum is one of the key brain centers for encoding motor performance and motor learning. Climbing fibers relay information related to motor errors to the cerebellar cortex, evoking elevation of intracellular Ca2+ signals at Purkinje cell dendrites and inducing plasticity at coactive parallel fiber synapses, ultimately recalibrating sensorimotor associations to alter behavior. Molecular layer interneurons (MLIs) inhibit Purkinje cells to modulate dendritic excitability and action potential output. How MLIs contribute to the regulation and encoding of climbing fiber-evoked adaptive movements remains poorly understood. In this dissertation, I used genetic tools to manipulate the activity of MLIs while monitoring Purkinje cell dendritic activity during a cerebellum-dependent motor learning task with different contexts to evaluate how MLIs are involved in this process. The results show that by suppressing dendritic Ca2+ signals in Purkinje cells, MLI activity coincident with climbing fiber-mediated excitation prevents the occurrence of learning when adaptation is not necessary. On the other hand, with error signals present, disinhibition onto Purkinje cells, mediated by MLI-MLI microcircuit, unlocked the ability of climbing fibers to induce plasticity and motor learning.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013526
Subject Headings
Cerebellum, Interneurons, Purkinje cells, Dendrites, Sensorimotor integration, Neuroplasticity
Format
Document (PDF)
Function of glycinergic interplexiform cells in rod synaptic transmission
Title
Function of glycinergic interplexiform cells in rod synaptic transmission.
Creator
Jiang, Zheng., Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
The interplexiform cells(IP cells) are the most recently discovered neurons in the retina and their function is to provide centrifugal feedback in retina. The anatomical structure of the IP cells has been well studied, but the function of these neurons is largely unknown. I systematically studied the excitatory and inhibitory inputs from IP cells in salamander retina. I found that L-EPSCs in IP cells are mediated by AMPA and NMDA receptors; in addition, L-IPSCs are mediated by glycine...
Show moreThe interplexiform cells(IP cells) are the most recently discovered neurons in the retina and their function is to provide centrifugal feedback in retina. The anatomical structure of the IP cells has been well studied, but the function of these neurons is largely unknown. I systematically studied the excitatory and inhibitory inputs from IP cells in salamander retina. I found that L-EPSCs in IP cells are mediated by AMPA and NMDA receptors; in addition, L-IPSCs are mediated by glycine receptors and GABAC receptors. In response to light, IP cells reaction potentials transiently at the onset and onset of light stimulation. The major neural transmitter of IP cells in salamander retina is glycine. We also studied the distribution and function of glycine transporters. Our result indicates that GlyT1- and GlyT2-like transporters were present in Muller cells and neurons. The glycine feedback at outer plexiform layer (OPL) has effects on both the bipolar cell dendrites and rod photoreceptor terminals. At bipolar cell dendrites, glycine selectively depolarizes rod-dominant On-bipolar cells, and hyperpolarizes Off- bipolar cells. At rod photoreceptor terminals, 10 M glycine activates voltage-gated Ca2+ channels. These effects facilitated glutamate vesicle release in photoreceptors. It increases the sEPSC in OFF bipolar cells. The combined effect of glycine at rod terminals and bipolar cell dendrites leads to enhanced dim light signal transduction in the rod photoreceptor to ganglion cell pathway. This study provides a model that displays the function of centrifugal feedback through IP cells in the retina.
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Date Issued
2009
PURL
http://purl.flvc.org/FAU/2708369
Subject Headings
Cellular signal transduction, Neurochemistry, Neuroplasticity, Synapses, Retina, Cytology, Visual pathways
Format
Document (PDF)
VISUALIZING NANO-SCALE SYNAPTIC CHANGES DURING SINGLE DENDRITIC SPINE LONG-TERM POTENTIATION BY CORRELATIVE LIGHT AND ELECTRON MICROSCOPY
Title
VISUALIZING NANO-SCALE SYNAPTIC CHANGES DURING SINGLE DENDRITIC SPINE LONG-TERM POTENTIATION BY CORRELATIVE LIGHT AND ELECTRON MICROSCOPY.
Creator
Sun, Ye, Yasuda, Ryohei, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
Dendritic spines are the major sites for receiving excitatory synaptic inputs and play important roles in neuronal signal transduction, memory storage and neuronal circuit organization. Structural plasticity of dendritic spines is correlated with functional plasticity, and is critical for learning and memory. Visualization of the changes of dendritic spines at the ultrastructural level that specifically correlated with their function changes in high throughput would shed light on detailed...
Show moreDendritic spines are the major sites for receiving excitatory synaptic inputs and play important roles in neuronal signal transduction, memory storage and neuronal circuit organization. Structural plasticity of dendritic spines is correlated with functional plasticity, and is critical for learning and memory. Visualization of the changes of dendritic spines at the ultrastructural level that specifically correlated with their function changes in high throughput would shed light on detailed mechanisms of synaptic plasticity. Here we developed a correlative light and electron microscopy workflow which combines two-photon MNI-glutamate uncaging, pre-embedding immunolabeling, Automatic Tape-collecting Ultramicrotome sectioning and scanning electron microscopy imaging. This method bridges two different visualization platforms, directly linking ultrastructure and function at the level of individual synapses. With this method, we successfully relocated single dendritic spines that underwent long-term potentiation (LTP) induced by two-photon MNI-glutamate uncaging, and visualized their ultrastructures and AMPA receptors distribution at different phases of LTP in high throughput.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013433
Subject Headings
Dendritic Spines, Neuroplasticity, Visualization, Microscopy, Long-Term Potentiation--physiology, Neurons--ultrastructure
Format
Document (PDF)
Over-Expression of BDNF Does Not Rescue Sensory Deprivation-Induced Death of Adult-Born Olfactory Granule Cells
Title
Over-Expression of BDNF Does Not Rescue Sensory Deprivation-Induced Death of Adult-Born Olfactory Granule Cells.
Creator
Berger, Rachel A., Guthrie, Kathleen M., Florida Atlantic University, Charles E. Schmidt College of Medicine, Department of Biomedical Science
Abstract/Description
It is of interest to understand how new neurons incorporate themselves into the existing circuitry of certain neuronal populations. One such population of neurons is that which are born in the subventricular zone (SVZ) and migrate to the olfactory bulb where they differentiate into granule cells. Another area of interest is the role of brain-derived neurotrophic factor (BDNF) on the survival and overall health of these neurons. This study aimed to test whether or not BDNF is a survival factor...
Show moreIt is of interest to understand how new neurons incorporate themselves into the existing circuitry of certain neuronal populations. One such population of neurons is that which are born in the subventricular zone (SVZ) and migrate to the olfactory bulb where they differentiate into granule cells. Another area of interest is the role of brain-derived neurotrophic factor (BDNF) on the survival and overall health of these neurons. This study aimed to test whether or not BDNF is a survival factor for adult-born granule cells. Here were utilized a transgenic mouse model over-expressing BDNF under the α- calcium/calmodulin-dependent protein kinase II (CAMKIIα) promoter, and tested its effect on olfactory granule cells under sensory deprived conditions. Results from this experiment indicated that there was no significant difference in cell death or cell survival when comparing transgenic and wild type animals. We concluded that BDNF is not a survival factor for adult-born granule cells.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004722, http://purl.flvc.org/fau/fd/FA00004722
Subject Headings
Cellular control mechanisms, Mice as laboratory animals, Nervous system -- Diseases -- Gene therapy, Neural circuitry, Neuroplasticity, Neurotransmitter receptors, Sensory deprivation, Sensory neurons -- Testing
Format
Document (PDF)