Dendritic spine classification using shape and appearance features based on two-photon microscopy

Ghani, Muhammad Usman; Mesadi, Fitsum; Kanık, Sümeyra Ümmühan Demir; Argunşah, Ali Özgür; Hobbiss, Anna Felicity; Israely, Inbal; Ünay, Devrim; Taşdizen, Tolga; Çetin, Müjdat

doi:10.1016/j.jneumeth.2016.12.006

Cited by 37 publications

(27 citation statements)

References 26 publications

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“…We next investigated whether homeostatic plasticity leads to structural modification of synapses by live, 2-photon imaging of GFP-labeled CA1 dendrites ( Figure 1 E). The volumes of all visible spines within the image were measured using SpineS , a custom in-house-developed MATLAB toolbox ( Erdil et al., 2012 , Ghani et al., 2017 ). We found that spines chronically treated with TTX were significantly bigger than those from control cells beginning at 48 hr ( Figures 1 E and 1F; control = 0.136 ± 0.0062 μm³, TTX = 0.211 ± 0.0123 μm³, p = 1.9e-10).…”

Section: Resultsmentioning

confidence: 99%

Homeostatic Plasticity Scales Dendritic Spine Volumes and Changes the Threshold and Specificity of Hebbian Plasticity

2018

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SummaryInformation is encoded in neural networks through changes in synaptic weights. Synaptic learning rules involve a combination of rapid Hebbian plasticity and slower homeostatic synaptic plasticity that regulates neuronal activity through global synaptic scaling. Hebbian and homeostatic plasticity have been extensively investigated, whereas much less is known about their interaction. Here we investigated structural and functional consequences of homeostatic plasticity at dendritic spines of mouse hippocampal neurons. We found that prolonged activity blockade induced spine growth, paralleling synaptic strength increases. Following activity blockade, glutamate uncaging-mediated stimulation at single spines led to size-dependent structural potentiation: smaller spines underwent robust growth, whereas larger spines remained unchanged. Moreover, spines near the stimulated spine exhibited volume changes following homeostatic plasticity, indicating that there was a breakdown of input specificity following homeostatic plasticity. Overall, these findings demonstrate that Hebbian and homeostatic plasticity interact to shape neural connectivity through non-uniform structural plasticity at inputs.

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Section: Resultsmentioning

confidence: 99%

Homeostatic Plasticity Scales Dendritic Spine Volumes and Changes the Threshold and Specificity of Hebbian Plasticity

2018

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“…Other parameters such as spine morphology and length were also evaluated. Protrusions from dendrites were classified based on predefined parameters as mushroom spines, stubby spines, thin spines, or filopodia (Ghani et al, 2017 ). A total of 527 dendritic spines (283 spines for WT and 244 for KOLPA 1 mice) were analyzed.…”

Section: Methodsmentioning

confidence: 99%

Glutaminase and MMP-9 Downregulation in Cortex and Hippocampus of LPA1 Receptor Null Mice Correlate with Altered Dendritic Spine Plasticity

Peñalver

Campos-Sandoval

Blanco

et al. 2017

Front. Mol. Neurosci.

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Lysophosphatidic acid (LPA) is an extracellular lipid mediator that regulates nervous system development and functions acting through G protein-coupled receptors (GPCRs). Here we explore the crosstalk between LPA1 receptor and glutamatergic transmission by examining expression of glutaminase (GA) isoforms in different brain areas isolated from wild-type (WT) and KOLPA1 mice. Silencing of LPA1 receptor induced a severe down-regulation of Gls-encoded long glutaminase protein variant (KGA) (glutaminase gene encoding the kidney-type isoforms, GLS) protein expression in several brain regions, particularly in brain cortex and hippocampus. Immunohistochemical assessment of protein levels for the second type of glutaminase (GA) isoform, glutaminase gene encoding the liver-type isoforms (GLS2), did not detect substantial differences with regard to WT animals. The regional mRNA levels of GLS were determined by real time RT-PCR and did not show significant variations, except for prefrontal and motor cortex values which clearly diminished in KO mice. Total GA activity was also significantly reduced in prefrontal and motor cortex, but remained essentially unchanged in the hippocampus and rest of brain regions examined, suggesting activation of genetic compensatory mechanisms and/or post-translational modifications to compensate for KGA protein deficit. Remarkably, Golgi staining of hippocampal regions showed an altered morphology of glutamatergic pyramidal cells dendritic spines towards a less mature filopodia-like phenotype, as compared with WT littermates. This structural change correlated with a strong decrease of active matrix-metalloproteinase (MMP) 9 in cerebral cortex and hippocampus of KOLPA1 mice. Taken together, these results demonstrate that LPA signaling through LPA1 influence expression of the main isoenzyme of glutamate biosynthesis with strong repercussions on dendritic spines maturation, which may partially explain the cognitive and learning defects previously reported for this colony of KOLPA1 mice.

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“…Most synapses are formed between the axonal bouton and the dendritic spine, which is a specialized protrusion from the dendritic membrane. Dendritic spines come in a variety of shapes and sizes, differing greatly across brain areas, cell types, and animal species (Ghani et al, 2017 ). During structural analysis dendritic spines are traditionally grouped into four fixed classes according to their morphological features reflecting head and neck properties: mushroom, thin, stubby, and filopodia ( Figure 1 ).…”

Section: Dendritic Spines Shape Classification and Its Limitationsmentioning

confidence: 99%

Dendritic Spines Shape Analysis—Classification or Clusterization? Perspective

Pchitskaya

Bezprozvanny

2020

Front. Synaptic Neurosci.

102

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Dendritic spines are small protrusions from the dendrite membrane, where contact with neighboring axons is formed in order to receive synaptic input. Changes in size, shape, and density of synaptic spines are associated with learning and memory, and observed after drug abuse in a variety of neurodegenerative, neurodevelopmental, and psychiatric disorders. Due to the preeminent importance of synaptic spines, there have been major efforts into developing techniques that enable visualization and analysis of dendritic spines in cultured neurons, in fixed slices and in intact brain tissue. The classification of synaptic spines into predefined morphological groups is a standard approach in neuroscience research, where spines are divided into fixed categories such as thin, mushroom, and stubby subclasses. This study examines accumulated evidence that supports the existence of dendritic spine shapes as a continuum rather than separated classes. Using new approaches and software tools we reflect on complex dendritic spine shapes, positing that understanding of their highly dynamic nature is required to perform analysis of their morphology. The study discusses and compares recently developed algorithms that rely on clusterization rather than classification, therefore enabling new levels of spine shape analysis. We reason that improved methods of analysis may help to investigate a link between dendritic spine shape and its function, facilitating future studies of learning and memory as well as studies of brain disorders.

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Dendritic spine classification using shape and appearance features based on two-photon microscopy

Cited by 37 publications

References 26 publications

Homeostatic Plasticity Scales Dendritic Spine Volumes and Changes the Threshold and Specificity of Hebbian Plasticity

Homeostatic Plasticity Scales Dendritic Spine Volumes and Changes the Threshold and Specificity of Hebbian Plasticity

Glutaminase and MMP-9 Downregulation in Cortex and Hippocampus of LPA1 Receptor Null Mice Correlate with Altered Dendritic Spine Plasticity

Dendritic Spines Shape Analysis—Classification or Clusterization? Perspective

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