scholarly journals Cerebellar plasticity and associative memories are controlled by perineuronal nets

2019 ◽  
Author(s):  
Daniela Carulli ◽  
Robin Broersen ◽  
Fred de Winter ◽  
Elizabeth M. Muir ◽  
Maja Mešković ◽  
...  
Keyword(s):  
Neural Plasticity ◽  
Eyeblink Conditioning ◽  
Cerebellar Nuclei ◽  
Enzymatic Digestion ◽  
Perineuronal Nets ◽  
Structural Level ◽  
Memory Retention ◽  
Baseline Activity ◽  
Cerebellar Plasticity

SummaryPerineuronal nets (PNNs) are assemblies of extracellular matrix molecules, which surround the cell body and dendrites of many types of neuron and regulate neural plasticity. PNNs are prominently expressed around neurons of the deep cerebellar nuclei (DCN) but their role in adult cerebellar plasticity and behavior is far from clear. Here we show that PNNs in the DCN are diminished during eyeblink conditioning (EBC), a form of associative motor learning that depends on DCN plasticity. When memories are fully acquired, PNNs are restored. Enzymatic digestion of PNNs in the DCN improves EBC learning, but intact PNNs are necessary for memory retention. At the structural level, PNN removal induces significant synaptic rearrangements in vivo, resulting in increased inhibition of DCN baseline activity in awake behaving mice. Together, these results demonstrate that PNNs are critical players in the regulation of cerebellar circuitry and function.

scholarly journals Cerebellar plasticity and associative memories are controlled by perineuronal nets

2020 ◽  
Vol 117 (12) ◽  
pp. 6855-6865 ◽  
Author(s):  
Daniela Carulli ◽  
Robin Broersen ◽  
Fred de Winter ◽  
Elizabeth M. Muir ◽  
Maja Mešković ◽  
...  
Keyword(s):  
Neural Plasticity ◽  
Eyeblink Conditioning ◽  
Cerebellar Nuclei ◽  
Enzymatic Digestion ◽  
Perineuronal Nets ◽  
Structural Level ◽  
Memory Retention ◽  
Baseline Activity ◽  
Cerebellar Plasticity

Perineuronal nets (PNNs) are assemblies of extracellular matrix molecules, which surround the cell body and dendrites of many types of neuron and regulate neural plasticity. PNNs are prominently expressed around neurons of the deep cerebellar nuclei (DCN), but their role in adult cerebellar plasticity and behavior is far from clear. Here we show that PNNs in the mouse DCN are diminished during eyeblink conditioning (EBC), a form of associative motor learning that depends on DCN plasticity. When memories are fully acquired, PNNs are restored. Enzymatic digestion of PNNs in the DCN improves EBC learning, but intact PNNs are necessary for memory retention. At the structural level, PNN removal induces significant synaptic rearrangements in vivo, resulting in increased inhibition of DCN baseline activity in awake behaving mice. Together, these results demonstrate that PNNs are critical players in the regulation of cerebellar circuitry and function.

scholarly journals Perineuronal Nets in the Deep Cerebellar Nuclei Regulate GABAergic Transmission and Delay Eyeblink Conditioning

2018 ◽  
Vol 38 (27) ◽  
pp. 6130-6144 ◽  
Author(s):  
Moritoshi Hirono ◽  
Satoshi Watanabe ◽  
Fuyuki Karube ◽  
Fumino Fujiyama ◽  
Shigenori Kawahara ◽  
...  
Keyword(s):  
Eyeblink Conditioning ◽  
Cerebellar Nuclei ◽  
Perineuronal Nets ◽  
Deep Cerebellar Nuclei ◽  
Gabaergic Transmission

scholarly journals Distribution of N-Acetylgalactosamine-Positive Perineuronal Nets in the Macaque Brain: Anatomy and Implications

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Adrienne L. Mueller ◽  
Adam Davis ◽  
Samantha Sovich ◽  
Steven S. Carlson ◽  
Farrel R. Robinson
Keyword(s):  
Neural Plasticity ◽  
Neuronal Cell ◽  
Cerebellar Nuclei ◽  
Brain Anatomy ◽  
Perineuronal Nets ◽  
Simple Relationship ◽  
Critical Periods ◽  
Neuronal Cell Bodies ◽  
The Central Nervous System ◽  
Extracellular Molecules

Perineuronal nets (PNNs) are extracellular molecules that form around neurons near the end of critical periods during development. They surround neuronal cell bodies and proximal dendrites. PNNs inhibit the formation of new connections and may concentrate around rapidly firing inhibitory interneurons. Previous work characterized the important role of perineuronal nets in plasticity in the visual system, amygdala, and spinal cord of rats. In this study, we use immunohistochemistry to survey the distribution of perineuronal nets in representative areas of the primate brain. We also document changes in PNN prevalence in these areas in animals of different ages. We found that PNNs are most prevalent in the cerebellar nuclei, surrounding >90% of the neurons there. They are much less prevalent in cerebral cortex, surrounding less than 10% of neurons in every area that we examined. The incidence of perineuronal nets around parvalbumin-positive neurons (putative fast-spiking interneurons) varies considerably between different areas in the brain. Our survey indicates that the presence of PNNs may not have a simple relationship with neural plasticity and may serve multiple functions in the central nervous system.

scholarly journals Hippocampal Interneurons are Required for Trace Eyeblink Conditioning in Mice

2021 ◽  
Author(s):  
Wei-Wei Zhang ◽  
Rong-Rong Li ◽  
Jie Zhang ◽  
Jie Yan ◽  
Qian-Hui Zhang ◽  
...  
Keyword(s):  
Eyeblink Conditioning ◽  
Pyramidal Cells ◽  
Conditioned Eyeblink ◽  
Cellular Mechanisms ◽  
Sustained Activity ◽  
Early Acquisition ◽  
Freely Moving ◽  
Trace Eyeblink Conditioning

AbstractWhile the hippocampus has been implicated in supporting the association among time-separated events, the underlying cellular mechanisms have not been fully clarified. Here, we combined in vivo multi-channel recording and optogenetics to investigate the activity of hippocampal interneurons in freely-moving mice performing a trace eyeblink conditioning (tEBC) task. We found that the hippocampal interneurons exhibited conditioned stimulus (CS)-evoked sustained activity, which predicted the performance of conditioned eyeblink responses (CRs) in the early acquisition of the tEBC. Consistent with this, greater proportions of hippocampal pyramidal cells showed CS-evoked decreased activity in the early acquisition of the tEBC. Moreover, optogenetic suppression of the sustained activity in hippocampal interneurons severely impaired acquisition of the tEBC. In contrast, suppression of the sustained activity of hippocampal interneurons had no effect on the performance of well-learned CRs. Our findings highlight the role of hippocampal interneurons in the tEBC, and point to a potential cellular mechanism subserving associative learning.

In vitro assessment of food-derived-glucose bioaccessibility and bioavailability in bicameral cell culture system

2020 ◽  
Vol 45 (5) ◽  
pp. 631-637
Author(s):  
Cansu Ozel-Tasci ◽  
Gozde Pilatin ◽  
Ozgur Edeer ◽  
Sukru Gulec
Keyword(s):  
Cell Culture ◽  
Culture System ◽  
Metabolic Diseases ◽  
Enzymatic Digestion ◽  
Cell Culture System ◽  
Culture Studies ◽  
Experimental Approaches ◽  
In Vitro Assessment

AbstractBackgroundFunctional foods can help prevent metabolic diseases, and it is essential to evaluate functional characteristics of foods through in vitro and in vivo experimental approaches.ObjectiveWe aimed to use the bicameral cell culture system combined with the in vitro digestion to evaluate glucose bioavailability.Materials and methodsCake, almond paste, and pudding were modified by adding fiber and replacing sugar with sweeteners and polyols. Digestion process was modeled in test tubes. Rat enterocyte cells (IEC-6) were grown in a bicameral cell culture system to mimic the physiological characteristics of the human intestine. The glucose bioaccessibility and cellular glucose efflux were measured by glucose oxidase assay.Results and discussionThe glucose bioaccessibilities of modified foods were significantly lower (cake: 2.6 fold, almond paste: 9.2 fold, pudding 2.8 fold) than the controls. Cellular glucose effluxes also decreased in the modified cake, almond paste, and pudding by 2.2, 4, and 2 fold respectively compared to their controls.ConclusionOur results suggest that combining in vitro enzymatic digestion with cell culture studies can be a practical way to test in vitro glucose bioaccessibility and bioavailability in functional food development.

scholarly journals A Collagen-Based Scaffold for Promoting Neural Plasticity in a Rat Model of Spinal Cord Injury

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2245
Author(s):  
Jue-Zong Yeh ◽  
Ding-Han Wang ◽  
Juin-Hong Cherng ◽  
Yi-Wen Wang ◽  
Gang-Yi Fan ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Rat Model ◽  
Neural Plasticity ◽  
Collagen Scaffold ◽  
Glial Scar ◽  
Beneficial Effects ◽  
Cord Injury

In spinal cord injury (SCI) therapy, glial scarring formed by activated astrocytes is a primary problem that needs to be solved to enhance axonal regeneration. In this study, we developed and used a collagen scaffold for glial scar replacement to create an appropriate environment in an SCI rat model and determined whether neural plasticity can be manipulated using this approach. We used four experimental groups, as follows: SCI-collagen scaffold, SCI control, normal spinal cord-collagen scaffold, and normal control. The collagen scaffold showed excellent in vitro and in vivo biocompatibility. Immunofluorescence staining revealed increased expression of neurofilament and fibronectin and reduced expression of glial fibrillary acidic protein and anti-chondroitin sulfate in the collagen scaffold-treated SCI rats at 1 and 4 weeks post-implantation compared with that in untreated SCI control. This indicates that the collagen scaffold implantation promoted neuronal survival and axonal growth within the injured site and prevented glial scar formation by controlling astrocyte production for their normal functioning. Our study highlights the feasibility of using the collagen scaffold in SCI repair. The collagen scaffold was found to exert beneficial effects on neuronal activity and may help in manipulating synaptic plasticity, implying its great potential for clinical application in SCI.

scholarly journals Exposure to cyclic intermittent hypoxia increases expression of functional NMDA receptors in the rat carotid body

2009 ◽  
Vol 106 (1) ◽  
pp. 259-267 ◽  
Author(s):  
Yuzhen Liu ◽  
En-Sheng Ji ◽  
Shuanglin Xiang ◽  
Renaud Tamisier ◽  
Jingli Tong ◽  
...  
Keyword(s):  
Nmda Receptors ◽  
Carotid Body ◽  
Intermittent Hypoxia ◽  
Acute Hypoxia ◽  
Sprague Dawley ◽  
Excitatory Neurotransmitter ◽  
Mk 801 ◽  
Baseline Activity ◽  
Nmda Receptor Blocker

Although large quantities of glutamate are found in the carotid body, to date this excitatory neurotransmitter has not been assigned a role in chemoreception. To examine the possibility that glutamate and its N-methyl-d-aspartate (NMDA) receptors play a role in acclimatization after exposure to cyclic intermittent hypoxia (CIH), we exposed male Sprague-Dawley rats to cyclic hypoxia or to room air sham (Sham) for 8 h/day for 3 wk. Using RT-PCR, Western blot analysis, and immunohistochemistry, we found that ionotropic NMDA receptors, including NMDAR1, NMDAR2A, NMDAR2A/2B, are strongly expressed in the carotid body and colocalize with tyrosine hydroxylase in glomus cells. CIH exposure enhanced the expression of NMDAR1 and NMDAR2A/2B but did not substantially change the level of NMDAR2A. We assessed in vivo carotid sinus nerve activity (CSNA) at baseline, in response to acute hypoxia, in response to infused NMDA, and in response to infused endothelin-1 (ET-1) with and without MK-801, an NMDA receptor blocker. Infusion of NMDA augmented CSNA in CIH rats (124.61 ± 2.64% of baseline) but not in sham-exposed rats. Administration of MK-801 did not alter baseline activity or response to acute hypoxia, in either CIH or sham animals but did reduce the effect of ET-1 infusion on CSNA (CSNA after ET-1 = 160.96 ± 8.05% of baseline; ET-1 after MK-801 = 118.56 ± 9.12%). We conclude that 3-wk CIH exposure increases expression of NMDA functional receptors in rats, suggesting glutamate and its receptors may play a role in hypoxic acclimatization to CIH.

scholarly journals Subanesthetic ketamine reactivates adult cortical plasticity to restore vision from amblyopia

2020 ◽  
Author(s):  
Steven F. Grieco ◽  
Xin Qiao ◽  
Xiaoting Zheng ◽  
Yongjun Liu ◽  
Lujia Chen ◽  
...  
Keyword(s):  
Functional Recovery ◽  
Neural Plasticity ◽  
Cortical Plasticity ◽  
Brain Plasticity ◽  
Excitatory Input ◽  
Inhibitory Neurons ◽  
List Type ◽  
Visual Cortical

SummarySubanesthetic ketamine evokes rapid and long-lasting antidepressant effects in human patients. The mechanism for ketamine’s effects remains elusive, but ketamine may broadly modulate brain plasticity processes. We show that single-dose ketamine reactivates adult mouse visual cortical plasticity and promotes functional recovery of visual acuity defects from amblyopia. Ketamine specifically induces down-regulation of neuregulin-1 (NRG1) expression in parvalbumin-expressing (PV) inhibitory neurons in mouse visual cortex. NRG1 downregulation in PV neurons co-tracks both the fast onset and sustained decreases in synaptic inhibition to excitatory neurons, along with reduced synaptic excitation to PV neurons in vitro and in vivo following a single ketamine treatment. These effects are blocked by exogenous NRG1 as well as PV targeted receptor knockout. Thus ketamine reactivation of adult visual cortical plasticity is mediated through rapid and sustained cortical disinhibition via downregulation of PV-specific NRG1 signaling. Our findings reveal the neural plasticity-based mechanism for ketamine-mediated functional recovery from adult amblyopia.Highlights○ Disinhibition of excitatory cells by ketamine occurs in a fast and sustained manner○ Ketamine evokes NRG1 downregulation and excitatory input loss to PV cells○ Ketamine induced plasticity is blocked by exogenous NRG1 or its receptor knockout○ PV inhibitory cells are the initial functional locus underlying ketamine’s effects

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