scholarly journals CREB Regulates Experience-Dependent Spine Formation and Enlargement in Mouse Barrel Cortex

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Annabella Pignataro ◽  
Antonella Borreca ◽  
Martine Ammassari-Teule ◽  
Silvia Middei
Keyword(s):  
Dendritic Spines ◽  
Dendritic Spine ◽  
Barrel Cortex ◽  
Cortical Plasticity ◽  
Brain Connectivity ◽  
Sensory Deprivation ◽  
Brain Regions ◽  
Camp Response Element Binding ◽  
Synaptic Circuits ◽  
Layer V

Experience modifies synaptic connectivity through processes that involve dendritic spine rearrangements in neuronal circuits. Although cAMP response element binding protein (CREB) has a key function in spines changes, its role in activity-dependent rearrangements in brain regions of rodents interacting with the surrounding environment has received little attention so far. Here we studied the effects of vibrissae trimming, a widely used model of sensory deprivation-induced cortical plasticity, on processes associated with dendritic spine rearrangements in the barrel cortex of a transgenic mouse model of CREB downregulation (mCREB mice). We found that sensory deprivation through prolonged whisker trimming leads to an increased number of thin spines in the layer V of related barrel cortex (Contra) in wild type but not mCREB mice. In the barrel field controlling spared whiskers (Ipsi), the same trimming protocol results in a CREB-dependent enlargement of dendritic spines. Last, we demonstrated that CREB regulates structural rearrangements of synapses that associate with dynamic changes of dendritic spines. Our findings suggest that CREB plays a key role in dendritic spine dynamics and synaptic circuits rearrangements that account for new brain connectivity in response to changes in the environment.

scholarly journals Fear extinction reverses dendritic spine formation induced by fear conditioning in the mouse auditory cortex

2018 ◽  
Vol 115 (37) ◽  
pp. 9306-9311 ◽  
Author(s):  
Cora Sau Wan Lai ◽  
Avital Adler ◽  
Wen-Biao Gan
Keyword(s):  
Auditory Cortex ◽  
Fear Conditioning ◽  
Dendritic Spines ◽  
Dendritic Spine ◽  
Pyramidal Neurons ◽  
Fear Extinction ◽  
Spine Formation ◽  
Synaptic Circuits ◽  
Auditory Cue ◽  
Layer V

Fear conditioning-induced behavioral responses can be extinguished after fear extinction. While fear extinction is generally thought to be a form of new learning, several lines of evidence suggest that neuronal changes associated with fear conditioning could be reversed after fear extinction. To better understand how fear conditioning and extinction modify synaptic circuits, we examined changes of postsynaptic dendritic spines of layer V pyramidal neurons in the mouse auditory cortex over time using transcranial two-photon microscopy. We found that auditory-cued fear conditioning induced the formation of new dendritic spines within 2 days. The survived new spines induced by fear conditioning with one auditory cue were clustered within dendritic branch segments and spatially segregated from new spines induced by fear conditioning with a different auditory cue. Importantly, fear extinction preferentially caused the elimination of newly formed spines induced by fear conditioning in an auditory cue-specific manner. Furthermore, after fear extinction, fear reconditioning induced reformation of new dendritic spines in close proximity to the sites of new spine formation induced by previous fear conditioning. These results show that fear conditioning, extinction, and reconditioning induce cue- and location-specific dendritic spine remodeling in the auditory cortex. They also suggest that changes of synaptic connections induced by fear conditioning are reversed after fear extinction.

scholarly journals Monosynaptic tracing maps brain-wide afferent oligodendrocyte precursor cell connectivity

2019 ◽  
Author(s):  
Christopher W Mount ◽  
Belgin Yalçın ◽  
Kennedy Cunliffe-Koehler ◽  
Michelle Monje
Keyword(s):  
Barrel Cortex ◽  
Sensory Deprivation ◽  
Brain Regions ◽  
Thalamic Nuclei ◽  
Oligodendrocyte Precursor Cell ◽  
Adult Mice ◽  
Bona Fide ◽  
Oligodendrocyte Precursor ◽  
Virus Tracing ◽  
Inhibitory Components

AbstractNeurons form bona fide synapses with oligodendrocyte precursor cells (OPCs), but the circuit context of these neuron to OPC synapses remains incompletely understood. Using monosynaptically-restricted rabies virus tracing of OPC afferents, we identified extensive afferent synaptic inputs to OPCs residing in secondary motor cortex, corpus callosum, and primary somatosensory cortex of adult mice. These inputs primarily arise from functionally-interconnecting cortical areas and thalamic nuclei, demonstrating that OPCs have strikingly comprehensive synaptic access to brain-wide functionally-related projection networks. Quantification of these inputs revealed excitatory and inhibitory components that are consistent in number across brain regions and stable in barrel cortex despite whisker trimming-induced sensory deprivation.

scholarly journals Sex differences in dendritic spine density and morphology in auditory and visual cortices in adolescence and adulthood

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Emily M. Parker ◽  
Nathan L. Kindja ◽  
Claire E. J. Cheetham ◽  
Robert A. Sweet
Keyword(s):  
Sex Differences ◽  
Dendritic Spines ◽  
Dendritic Spine ◽  
Brain Regions ◽  
Spine Density ◽  
Female Mice ◽  
Dendritic Spine Density ◽  
Layer 4 ◽  
Visual Cortices ◽  
Mushroom Spines

AbstractDendritic spines are small protrusions on dendrites that endow neurons with the ability to receive and transform synaptic input. Dendritic spine number and morphology are altered as a consequence of synaptic plasticity and circuit refinement during adolescence. Dendritic spine density (DSD) is significantly different based on sex in subcortical brain regions associated with the generation of sex-specific behaviors. It is largely unknown if sex differences in DSD exist in auditory and visual brain regions and if there are sex-specific changes in DSD in these regions that occur during adolescent development. We analyzed dendritic spines in 4-week-old (P28) and 12-week-old (P84) male and female mice and found that DSD is lower in female mice due in part to fewer short stubby, long stubby and short mushroom spines. We found striking layer-specific patterns including a significant age by layer interaction and significantly decreased DSD in layer 4 from P28 to P84. Together these data support the possibility of developmental sex differences in DSD in visual and auditory regions and provide evidence of layer-specific refinement of DSD over adolescent brain development.

scholarly journals Whisker row deprivation affects the flow of sensory information through rat barrel cortex

2017 ◽  
Vol 117 (1) ◽  
pp. 4-17 ◽  
Author(s):  
Vincent Jacob ◽  
Akinori Mitani ◽  
Taro Toyoizumi ◽  
Kevin Fox
Keyword(s):  
Spontaneous Activity ◽  
Information Content ◽  
Barrel Cortex ◽  
Cortical Plasticity ◽  
Neuronal Response ◽  
Sensory Deprivation ◽  
Sensory Information ◽  
Short Latency ◽  
Characteristic Analysis

Whisker trimming causes substantial reorganization of neuronal response properties in barrel cortex. However, little is known about experience-dependent rerouting of sensory processing following sensory deprivation. To address this, we performed in vivo intracellular recordings from layers 2/3 (L2/3), layer 4 (L4), layer 5 regular-spiking (L5RS), and L5 intrinsically bursting (L5IB) neurons and measured their multiwhisker receptive field at the level of spiking activity, membrane potential, and synaptic conductance before and after sensory deprivation. We used Chernoff information to quantify the “sensory information” contained in the firing patterns of cells in response to spared and deprived whisker stimulation. In the control condition, information for flanking-row and same-row whiskers decreased in the order L4, L2/3, L5IB, L5RS. However, after whisker-row deprivation, spared flanking-row whisker information was reordered to L4, L5RS, L5IB, L2/3. Sensory information from the trimmed whiskers was reduced and delayed in L2/3 and L5IB neurons, whereas sensory information from spared whiskers was increased and advanced in L4 and L5RS neurons. Sensory information from spared whiskers was increased in L5IB neurons without a latency change. L5RS cells exhibited the largest changes in sensory information content through an atypical plasticity combining a significant decrease in spontaneous activity and an increase in a short-latency excitatory conductance. NEW & NOTEWORTHY Sensory cortical plasticity is usually quantified by changes in evoked firing rate. In this study we quantified plasticity by changes in sensory detection performance using Chernoff information and receiver operating characteristic analysis. We found that whisker deprivation causes a change in information flow within the cortical layers and that layer 5 regular-spiking cells, despite showing only a small potentiation of short-latency input, show the greatest increase in information content for the spared input partly by decreasing their spontaneous activity.

scholarly journals Npas4 Expression in Two Experimental Models of the Barrel Cortex Plasticity

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Aleksandra Kaliszewska ◽  
Malgorzata Kossut
Keyword(s):  
Barrel Cortex ◽  
Cortical Plasticity ◽  
Laser Microdissection ◽  
Aversive Stimulus ◽  
Brain Plasticity ◽  
Sensory Deprivation ◽  
Experimental Models ◽  
Early Gene ◽  
Cortical Circuits ◽  
Stimulation Of

Npas4 has recently been identified as an important factor in brain plasticity, particularly in mechanisms of inhibitory control. Little is known about Npas4 expression in terms of cortical plasticity. In the present study expressions of Npas4 and the archetypal immediate early gene (IEG) c-Fos were investigated in the barrel cortex of mice after sensory deprivation (sparing one row of whiskers for 7 days) or sensory conditioning (pairing stimulation of one row of whiskers with aversive stimulus). Laser microdissection of individual barrel rows allowed for analysis of IEGs expression precisely in deprived and nondeprived barrels (in deprivation study) or stimulated and nonstimulated barrels (in conditioning study). Cortex activation by sensory conditioning was found to upregulate the expression of both Npas4 and c-Fos. Reorganization of cortical circuits triggered by removal of selected rows of whiskers strongly affected c-Fos but not Npas4 expression. We hypothesize that increased inhibitory synaptogenesis observed previously after conditioning may be mediated by Npas4 expression.

Sensory deprivation after focal ischemia in mice accelerates brain remapping and improves functional recovery through Arc-dependent synaptic plasticity

2018 ◽  
Vol 10 (426) ◽  
pp. eaag1328 ◽  
Author(s):  
Andrew W. Kraft ◽  
Adam Q. Bauer ◽  
Joseph P. Culver ◽  
Jin-Moo Lee
Keyword(s):  
Ischemic Stroke ◽  
Synaptic Plasticity ◽  
Molecular Mechanisms ◽  
Barrel Cortex ◽  
Cortical Plasticity ◽  
Sensory Deprivation ◽  
Sensory Loss ◽  
Behavioral Recovery ◽  
Functional Reorganization ◽  
Sensorimotor Recovery

Recovery after stroke, a major cause of adult disability, is often unpredictable and incomplete. Behavioral recovery is associated with functional reorganization (remapping) in perilesional regions, suggesting that promoting this process might be an effective strategy to enhance recovery. However, the molecular mechanisms underlying remapping after brain injury and the consequences of its modulation are poorly understood. Focal sensory loss or deprivation has been shown to induce remapping in the corresponding brain areas through activity-regulated cytoskeleton-associated protein (Arc)–mediated synaptic plasticity. We show that targeted sensory deprivation via whisker trimming in mice after induction of ischemic stroke in the somatosensory cortex representing forepaw accelerates remapping into the whisker barrel cortex and improves sensorimotor recovery. These improvements persisted even after focal sensory deprivation ended (whiskers allowed to regrow). Mice deficient in Arc, a gene critical for activity-dependent synaptic plasticity, failed to remap or recover sensorimotor function. These results indicate that post-stroke remapping occurs through Arc-mediated synaptic plasticity and is required for behavioral recovery. Furthermore, our findings suggest that enhancing perilesional cortical plasticity via focal sensory deprivation improves recovery after ischemic stroke in mice.

scholarly journals Sensory input drives rapid homeostatic scaling of the axon initial segment in mouse barrel cortex

2020 ◽  
Author(s):  
Nora Jamann ◽  
Dominik Dannehl ◽  
Robin Wagener ◽  
Corinna Corcelli ◽  
Christian Schultz ◽  
...  
Keyword(s):  
Action Potential ◽  
Initial Segment ◽  
Neuronal Excitability ◽  
Barrel Cortex ◽  
Cortical Plasticity ◽  
Sensory Deprivation ◽  
Axon Initial Segment ◽  
Electrophysiological Recordings ◽  
Network States

SummaryThe axon initial segment (AIS) is an important axonal microdomain for action potential initiation and implicated in the regulation of neuronal excitability during activity-dependent cortical plasticity. While structural AIS plasticity has been suggested to fine-tune neuronal activity when network states change, whether it acts as a homeostatic regulatory mechanism in behaviorally relevant contexts remains poorly understood. Using an in vivo model of the mouse whisker-to-barrel pathway in combination with immunofluorescence, confocal analysis and patch-clamp electrophysiological recordings, we observed bidirectional AIS plasticity. Furthermore, we find that structural and functional AIS remodeling occurs in distinct temporal domains: long-term sensory deprivation elicits an AIS length increase, accompanied with an increase in neuronal excitability, while sensory enrichment results in a rapid AIS shortening, accompanied by a decrease in action potential generation. Our findings highlight a central role of the AIS in the homeostatic regulation of neuronal input-output relations.

scholarly journals Monosynaptic tracing maps brain-wide afferent oligodendrocyte precursor cell connectivity

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Christopher W Mount ◽  
Belgin Yalçın ◽  
Kennedy Cunliffe-Koehler ◽  
Shree Sundaresh ◽  
Michelle Monje
Keyword(s):  
Barrel Cortex ◽  
Sensory Deprivation ◽  
Brain Regions ◽  
Thalamic Nuclei ◽  
Oligodendrocyte Precursor Cell ◽  
Adult Mice ◽  
Bona Fide ◽  
Oligodendrocyte Precursor ◽  
Virus Tracing ◽  
Inhibitory Components

Neurons form bona fide synapses with oligodendrocyte precursor cells (OPCs), but the circuit context of these neuron to OPC synapses remains incompletely understood. Using monosynaptically-restricted rabies virus tracing of OPC afferents, we identified extensive afferent synaptic inputs to OPCs residing in secondary motor cortex, corpus callosum, and primary somatosensory cortex of adult mice. These inputs primarily arise from functionally-interconnecting cortical areas and thalamic nuclei, illustrating that OPCs have strikingly comprehensive synaptic access to brain-wide projection networks. Quantification of these inputs revealed excitatory and inhibitory components that are consistent in number across brain regions and stable in barrel cortex despite whisker trimming-induced sensory deprivation.

Synaptic organization of the gustatory NST

1994 ◽  
Vol 52 ◽  
pp. 150-151
Author(s):  
M. C. Whitehead
Keyword(s):  
Central Nervous System ◽  
Dendritic Spines ◽  
Fundamental Problem ◽  
Cell Types ◽  
Brain Regions ◽  
Excitatory Synapses ◽  
Solitary Tract ◽  
Synaptic Organization ◽  
Synaptic Junctions ◽  
Afferent Terminals

A fundamental problem in taste research is to determine how gustatory signals are processed and disseminated in the mammalian central nervous system. An important first step toward understanding information processing is the identification of cell types in the nucleus of the solitary tract (NST) and their synaptic relationships with oral primary afferent terminals. Facial and glossopharyngeal (LIX) terminals in the hamster were labelled with HRP, examined with EM, and characterized as containing moderate concentrations of medium-sized round vesicles, and engaging in asymmetrical synaptic junctions. Ultrastructurally the endings resemble excitatory synapses in other brain regions.Labelled facial afferent endings in the RC subdivision synapse almost exclusively with distal dendrites and dendritic spines of NST cells. Most synaptic relationships between the facial synapses and the dendrites are simple. However, 40% of facial endings engage in complex synaptic relationships within glomeruli containing unlabelled axon endings particularly ones termed "SP" endings. SP endings are densely packed with small, pleomorphic vesicles and synapse with both the facial endings and their postsynaptic dendrites by means of nearly symmetrical junctions.

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