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Jendrichovsky P, Lee HK, Kanold PO. Dark exposure reduces high-frequency hearing loss in C57BL/6J mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.02.592252. [PMID: 38746420 PMCID: PMC11092591 DOI: 10.1101/2024.05.02.592252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Plastic changes in the brain are primarily limited to early postnatal periods. Recovery of adult brain plasticity is critical for the effective development of therapies. A brief (1-2 week) duration of visual deprivation (dark exposure, DE) in adult mice can trigger functional plasticity of thalamocortical and intracortical circuits in the primary auditory cortex suggesting improved sound processing. We tested if DE enhances the ability of adult mice to detect sounds. We trained and continuously evaluated the behavioral performance of mice in control and DE conditions using automated home-cage training. Consistent with age-related peripheral hearing loss present in C57BL/6J mice, we observed decreased performance for high-frequency sounds with age, which was reduced by DE. In CBA mice with preserved peripheral hearing, we also found that DE enhanced auditory performance in low and mid frequencies over time compared to the control.
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Affiliation(s)
- Peter Jendrichovsky
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine; Baltimore, USA
| | - Hey-Kyoung Lee
- Department of Neuroscience, Johns Hopkins University School of Medicine; Baltimore, USA
- Kavli NDI, Johns Hopkins University School of Medicine; Baltimore, USA
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University; Baltimore, USA
| | - Patrick O. Kanold
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine; Baltimore, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine; Baltimore, USA
- Kavli NDI, Johns Hopkins University School of Medicine; Baltimore, USA
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2
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Mittelstadt JK, Shilling-Scrivo KV, Kanold PO. Long-term training alters response dynamics in the aging auditory cortex. Hear Res 2024; 444:108965. [PMID: 38364511 PMCID: PMC11186583 DOI: 10.1016/j.heares.2024.108965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 01/16/2024] [Accepted: 01/20/2024] [Indexed: 02/18/2024]
Abstract
Age-related auditory dysfunction, presbycusis, is caused in part by functional changes in the auditory cortex (ACtx) such as altered response dynamics and increased population correlations. Given the ability of cortical function to be altered by training, we tested if performing auditory tasks might benefit auditory function in old age. We examined this by training adult mice on a low-effort tone-detection task for at least six months and then investigated functional responses in ACtx at an older age (∼18 months). Task performance remained stable well into old age. Comparing sound-evoked responses of thousands of ACtx neurons using in vivo 2-photon Ca2+ imaging, we found that many aspects of youthful neuronal activity, including low activity correlations, lower neural excitability, and a greater proportion of suppressed responses, were preserved in trained old animals as compared to passively-exposed old animals. Thus, consistent training on a low-effort task can benefit age-related functional changes in ACtx and may preserve many aspects of auditory function.
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Affiliation(s)
- Jonah K Mittelstadt
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Kelson V Shilling-Scrivo
- Department of Biology, University of Maryland, College Park, MD 20742, USA; Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21230, USA
| | - Patrick O Kanold
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Biology, University of Maryland, College Park, MD 20742, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, USA.
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3
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Niraula S, Yan SS, Subramanian J. Amyloid Pathology Impairs Experience-Dependent Inhibitory Synaptic Plasticity. J Neurosci 2024; 44:e0702232023. [PMID: 38050105 PMCID: PMC10860629 DOI: 10.1523/jneurosci.0702-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 11/09/2023] [Accepted: 11/14/2023] [Indexed: 12/06/2023] Open
Abstract
Alzheimer's disease patients and mouse models exhibit aberrant neuronal activity and altered excitatory-to-inhibitory synaptic ratio. Using multicolor two-photon microscopy, we test how amyloid pathology alters the structural dynamics of excitatory and inhibitory synapses and their adaptation to altered visual experience in vivo in the visual cortex. We show that the baseline dynamics of mature excitatory synapses and their adaptation to visual deprivation are not altered in amyloidosis. Likewise, the baseline dynamics of inhibitory synapses are not affected. In contrast, visual deprivation fails to induce inhibitory synapse loss in amyloidosis, a phenomenon observed in nonpathological conditions. Intriguingly, inhibitory synapse loss associated with visual deprivation in nonpathological mice is accompanied by subtle broadening of spontaneous but not visually evoked calcium transients. However, such broadening does not manifest in the context of amyloidosis. We also show that excitatory and inhibitory synapse loss is locally clustered under the nonpathological state. In contrast, a fraction of synapse loss is not locally clustered in amyloidosis, indicating an impairment in inhibitory synapse adaptation to changes in excitatory synaptic activity.
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Affiliation(s)
- Suraj Niraula
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas 66045
| | - Shirley ShiDu Yan
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas 66045
- Department of Surgery, Vagelos College of Physicians and Surgeons of Columbia University, New York, New York 10032
| | - Jaichandar Subramanian
- Department of Pharmacology and Toxicology, School of Pharmacy, University of Kansas, Lawrence, Kansas 66045
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Gay JD, Dangcil E, Nacipucha J, Botrous JE, Suresh N, Tucker A, Carayannopoulos NL, Khan MR, Meng R, Yao JD, Wackym PA, Mowery TM. An Animal Model of Neonatal Intensive Care Unit Exposure to Light and Sound in the Preterm Infant. Integr Comp Biol 2023; 63:585-596. [PMID: 37164937 PMCID: PMC10503467 DOI: 10.1093/icb/icad020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 05/12/2023] Open
Abstract
According to the World Health Organization, ∼15 million children are born prematurely each year. Many of these infants end up spending days to weeks in a neonatal intensive care unit (NICU). Infants who are born prematurely are often exposed to noise and light levels that affect their auditory and visual development. Children often have long-term impairments in cognition, visuospatial processing, hearing, and language. We have developed a rodent model of NICU exposure to light and sound using the Mongolian gerbil (Meriones unguiculatus), which has a low-frequency human-like audiogram and is altricial. To simulate preterm infancy, the eyes and ears were opened prematurely, and animals were exposed to the NICU-like sensory environment throughout the gerbil's cortical critical period of auditory development. After the animals matured into adults, auditory perceptual testing was carried out followed by auditory brainstem response recordings and then histology to assess the white matter morphology of various brain regions. Compared to normal hearing control animals, NICU sensory-exposed animals had significant impairments in learning at later stages of training, increased auditory thresholds reflecting hearing loss, and smaller cerebellar white matter volumes. These have all been reported in longitudinal studies of preterm infants. These preliminary results suggest that this animal model could provide researchers with an ethical way to explore the effects of the sensory environment in the NICU on the preterm infant's brain development.
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Affiliation(s)
- Jennifer D Gay
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
- Rutgers Brain Health Institute, New Brunswick, NJ, USA
| | - Evelynne Dangcil
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Jacqueline Nacipucha
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Jonathon E Botrous
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Nikhil Suresh
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Aaron Tucker
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Nicolas L Carayannopoulos
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Muhammad R Khan
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Raphael Meng
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
| | - Justin D Yao
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
- Rutgers Brain Health Institute, New Brunswick, NJ, USA
| | - P Ashley Wackym
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
- Rutgers Brain Health Institute, New Brunswick, NJ, USA
| | - Todd M Mowery
- Department of Otolaryngology—Head and Neck Surgery, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08854, USA
- Rutgers Brain Health Institute, New Brunswick, NJ, USA
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Whitt JL, Ewall G, Chakraborty D, Adegbesan A, Lee R, Kanold PO, Lee HK. Visual Deprivation Selectively Reduces Thalamic Reticular Nucleus-Mediated Inhibition of the Auditory Thalamus in Adults. J Neurosci 2022; 42:7921-7930. [PMID: 36261269 PMCID: PMC9617613 DOI: 10.1523/jneurosci.2032-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 08/19/2022] [Accepted: 08/24/2022] [Indexed: 11/21/2022] Open
Abstract
Sensory loss leads to widespread cross-modal plasticity across brain areas to allow the remaining senses to guide behavior. While multimodal sensory interactions are often attributed to higher-order sensory areas, cross-modal plasticity has been observed at the level of synaptic changes even across primary sensory cortices. In particular, vision loss leads to widespread circuit adaptation in the primary auditory cortex (A1) even in adults. Here we report using mice of both sexes in which cross-modal plasticity occurs even earlier in the sensory-processing pathway at the level of the thalamus in a modality-selective manner. A week of visual deprivation reduced inhibitory synaptic transmission from the thalamic reticular nucleus (TRN) to the primary auditory thalamus (MGBv) without changes to the primary visual thalamus (dLGN). The plasticity of TRN inhibition to MGBv was observed as a reduction in postsynaptic gain and short-term depression. There was no observable plasticity of the cortical feedback excitatory synaptic transmission from the primary visual cortex to dLGN or TRN and A1 to MGBv, which suggests that the visual deprivation-induced plasticity occurs predominantly at the level of thalamic inhibition. We provide evidence that visual deprivation-induced change in the short-term depression of TRN inhibition to MGBv involves endocannabinoid CB1 receptors. TRN inhibition is considered critical for sensory gating, selective attention, and multimodal performances; hence, its plasticity has implications for sensory processing. Our results suggest that selective disinhibition and altered short-term dynamics of TRN inhibition in the spared thalamic nucleus support cross-modal plasticity in the adult brain.SIGNIFICANCE STATEMENT Losing vision triggers adaptation of the brain to enhance the processing of the remaining senses, which can be observed as better auditory performance in blind subjects. We previously found that depriving vision of adult rodents produces widespread circuit reorganization in the primary auditory cortex and enhances auditory processing at a neural level. Here we report that visual deprivation-induced plasticity in adults occurs much earlier in the auditory pathway, at the level of thalamic inhibition. Sensory processing is largely gated at the level of the thalamus via strong cortical feedback inhibition mediated through the thalamic reticular nucleus (TRN). We found that TRN inhibition of the auditory thalamus is selectively reduced by visual deprivation, thus playing a role in adult cross-modal plasticity.
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Affiliation(s)
- Jessica L Whitt
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Gabrielle Ewall
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Darpan Chakraborty
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Ayorinde Adegbesan
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Rachel Lee
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Patrick O Kanold
- Department of Biomedical Engineering, Whiting School of Engineering and Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Hey-Kyoung Lee
- Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, Maryland 21218
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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Kim YH, Schrode KM, Engel J, Vicencio-Jimenez S, Rodriguez G, Lee HK, Lauer AM. Auditory Behavior in Adult-Blinded Mice. J Assoc Res Otolaryngol 2022; 23:225-239. [PMID: 35084628 PMCID: PMC8964904 DOI: 10.1007/s10162-022-00835-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 12/31/2021] [Indexed: 10/19/2022] Open
Abstract
Cross-modal plasticity occurs when the function of remaining senses is enhanced following deprivation or loss of a sensory modality. Auditory neural responses are enhanced in the auditory cortex, including increased sensitivity and frequency selectivity, following short-term visual deprivation in adult mice (Petrus et al. Neuron 81:664-673, 2014). Whether or not these visual deprivation-induced neural changes translate into improved auditory perception and performance remains unclear. As an initial investigation of the effects of adult visual deprivation on auditory behaviors, CBA/CaJ mice underwent binocular enucleation at 3-4 weeks old and were tested on a battery of learned behavioral tasks, acoustic startle response (ASR), and prepulse inhibition (PPI) tests beginning at least 2 weeks after the enucleation procedure. Auditory brain stem responses (ABRs) were also measured to screen for potential effects of visual deprivation on non-behavioral hearing function. Control and enucleated mice showed similar tone detection sensitivity and frequency discrimination in a conditioned lick suppression test. Both groups showed normal reactivity to sound as measured by ASR in a quiet background. However, when startle-eliciting stimuli were presented in noise, enucleated mice showed decreased ASR amplitude relative to controls. Control and enucleated mice displayed no significant differences in ASR habituation, PPI tests, or ABR thresholds, or wave morphology. Our findings suggest that while adult-onset visual deprivation induces cross-modal plasticity at the synaptic and circuit levels, it does not substantially influence simple auditory behavioral performance.
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Affiliation(s)
- Ye-Hyun Kim
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Katrina M Schrode
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - James Engel
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Sergio Vicencio-Jimenez
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Gabriela Rodriguez
- Cell, Molecular, Developmental Biology, and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD, USA
| | - Hey-Kyoung Lee
- Cell, Molecular, Developmental Biology, and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA.,Zanvyl-Krieger Mind/Brain Institute and Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Amanda M Lauer
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, 21205, USA. .,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA.
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7
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Pospisil DA, Bair W. Accounting for Biases in the Estimation of Neuronal Signal Correlation. J Neurosci 2021; 41:5638-5651. [PMID: 34001625 PMCID: PMC8244973 DOI: 10.1523/jneurosci.2775-20.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 02/10/2021] [Accepted: 05/02/2021] [Indexed: 11/21/2022] Open
Abstract
Signal correlation (rs) is commonly defined as the correlation between the tuning curves of two neurons and is widely used as a metric of tuning similarity. It is fundamental to how populations of neurons represent stimuli and has been central to many studies of neural coding. Yet the classic estimate, Pearson's correlation coefficient, [Formula: see text], between the average responses of two neurons to a set of stimuli suffers from confounding biases. The estimate [Formula: see text] can be downwardly biased by trial-to-trial variability and also upwardly biased by trial-to-trial correlation between neurons, and these biases can hide important aspects of neural coding. Here we provide analytic results on the source of these biases and explore them for ranges of parameters that are relevant for electrophysiological experiments. We then provide corrections for these biases that we validate in simulation. Furthermore, we apply these corrected estimators to make the following novel experimental observation in cortical area MT: pairs of nearby neurons that are strongly tuned for motion direction tend to have high signal correlation, and pairs that are weakly tuned tend to have low signal correlation. We dismiss a trivial explanation for this and find that an analogous trend holds for orientation tuning in the primary visual cortex. We also consider the potential consequences for encoding whereby the association of signal correlation and tuning strength naturally regularizes the dimensionality of downstream computations.SIGNIFICANCE STATEMENT Fundamental to how cortical neurons encode information about the environment is their functional similarity, that is, the redundancy in what they encode and their shared noise. These properties have been extensively studied theoretically and experimentally throughout the nervous system, but here we show that a common estimator of functional similarity has confounding biases. We characterize these biases and provide estimators that do not suffer from them. Using our improved estimators, we demonstrate a novel result, that is, there is a positive relationship between tuning curve similarity and amplitude for nearby neurons in the visual cortical motion area MT. We provide a simple stochastic model explaining this relationship and discuss how it would naturally regularize the dimensionality of neural encoding.
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Affiliation(s)
- Dean A Pospisil
- Department of Biological Structure, Washington National Primate Research Center, University of Washington, Seattle, Washington 98195
| | - Wyeth Bair
- Department of Biological Structure, Washington National Primate Research Center, University of Washington, Seattle, Washington 98195
- Institute for Neuroengineering, University of Washington, Seattle, Washington 98194
- Computational Neuroscience Center, University of Washington, Seattle, Washington 98194
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8
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Ewall G, Parkins S, Lin A, Jaoui Y, Lee HK. Cortical and Subcortical Circuits for Cross-Modal Plasticity Induced by Loss of Vision. Front Neural Circuits 2021; 15:665009. [PMID: 34113240 PMCID: PMC8185208 DOI: 10.3389/fncir.2021.665009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/14/2021] [Indexed: 11/29/2022] Open
Abstract
Cortical areas are highly interconnected both via cortical and subcortical pathways, and primary sensory cortices are not isolated from this general structure. In primary sensory cortical areas, these pre-existing functional connections serve to provide contextual information for sensory processing and can mediate adaptation when a sensory modality is lost. Cross-modal plasticity in broad terms refers to widespread plasticity across the brain in response to losing a sensory modality, and largely involves two distinct changes: cross-modal recruitment and compensatory plasticity. The former involves recruitment of the deprived sensory area, which includes the deprived primary sensory cortex, for processing the remaining senses. Compensatory plasticity refers to plasticity in the remaining sensory areas, including the spared primary sensory cortices, to enhance the processing of its own sensory inputs. Here, we will summarize potential cellular plasticity mechanisms involved in cross-modal recruitment and compensatory plasticity, and review cortical and subcortical circuits to the primary sensory cortices which can mediate cross-modal plasticity upon loss of vision.
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Affiliation(s)
- Gabrielle Ewall
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Samuel Parkins
- Cell, Molecular, Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD, United States
| | - Amy Lin
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Yanis Jaoui
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Hey-Kyoung Lee
- Solomon H. Snyder Department of Neuroscience, Zanvyl-Krieger Mind/Brain Institute, Johns Hopkins School of Medicine, Baltimore, MD, United States.,Cell, Molecular, Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD, United States.,Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, United States
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9
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Development of Auditory Cortex Circuits. J Assoc Res Otolaryngol 2021; 22:237-259. [PMID: 33909161 DOI: 10.1007/s10162-021-00794-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 03/03/2021] [Indexed: 02/03/2023] Open
Abstract
The ability to process and perceive sensory stimuli is an essential function for animals. Among the sensory modalities, audition is crucial for communication, pleasure, care for the young, and perceiving threats. The auditory cortex (ACtx) is a key sound processing region that combines ascending signals from the auditory periphery and inputs from other sensory and non-sensory regions. The development of ACtx is a protracted process starting prenatally and requires the complex interplay of molecular programs, spontaneous activity, and sensory experience. Here, we review the development of thalamic and cortical auditory circuits during pre- and early post-natal periods.
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Cheyne JE, Montgomery JM. The cellular and molecular basis of in vivo synaptic plasticity in rodents. Am J Physiol Cell Physiol 2020; 318:C1264-C1283. [PMID: 32320288 DOI: 10.1152/ajpcell.00416.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Plasticity within the neuronal networks of the brain underlies the ability to learn and retain new information. The initial discovery of synaptic plasticity occurred by measuring synaptic strength in vivo, applying external stimulation and observing an increase in synaptic strength termed long-term potentiation (LTP). Many of the molecular pathways involved in LTP and other forms of synaptic plasticity were subsequently uncovered in vitro. Over the last few decades, technological advances in recording and imaging in live animals have seen many of these molecular mechanisms confirmed in vivo, including structural changes both pre- and postsynaptically, changes in synaptic strength, and changes in neuronal excitability. A well-studied aspect of neuronal plasticity is the capacity of the brain to adapt to its environment, gained by comparing the brains of deprived and experienced animals in vivo, and in direct response to sensory stimuli. Multiple in vivo studies have also strongly linked plastic changes to memory by interfering with the expression of plasticity and by manipulating memory engrams. Plasticity in vivo also occurs in the absence of any form of external stimulation, i.e., during spontaneous network activity occurring with brain development. However, there is still much to learn about how plasticity is induced during natural learning and how this is altered in neurological disorders.
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Affiliation(s)
- Juliette E Cheyne
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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