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Petit C, Bonnet C, Safieddine S. Deafness: from genetic architecture to gene therapy. Nat Rev Genet 2023; 24:665-686. [PMID: 37173518 DOI: 10.1038/s41576-023-00597-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2023] [Indexed: 05/15/2023]
Abstract
Progress in deciphering the genetic architecture of human sensorineural hearing impairment (SNHI) or loss, and multidisciplinary studies of mouse models, have led to the elucidation of the molecular mechanisms underlying auditory system function, primarily in the cochlea, the mammalian hearing organ. These studies have provided unparalleled insights into the pathophysiological processes involved in SNHI, paving the way for the development of inner-ear gene therapy based on gene replacement, gene augmentation or gene editing. The application of these approaches in preclinical studies over the past decade has highlighted key translational opportunities and challenges for achieving effective, safe and sustained inner-ear gene therapy to prevent or cure monogenic forms of SNHI and associated balance disorders.
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Affiliation(s)
- Christine Petit
- Institut Pasteur, Université Paris Cité, Inserm, Institut de l'Audition, F-75012, Paris, France.
- Collège de France, F-75005, Paris, France.
| | - Crystel Bonnet
- Institut Pasteur, Université Paris Cité, Inserm, Institut de l'Audition, F-75012, Paris, France
| | - Saaïd Safieddine
- Institut Pasteur, Université Paris Cité, Inserm, Institut de l'Audition, F-75012, Paris, France
- Centre National de la Recherche Scientifique, F-75016, Paris, France
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2
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Feldmeyer D. Structure and function of neocortical layer 6b. Front Cell Neurosci 2023; 17:1257803. [PMID: 37744882 PMCID: PMC10516558 DOI: 10.3389/fncel.2023.1257803] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 08/14/2023] [Indexed: 09/26/2023] Open
Abstract
Cortical layer 6b is considered by many to be a remnant of the subplate that forms during early stages of neocortical development, but its role in the adult is not well understood. Its neuronal complement has only recently become the subject of systematic studies, and its axonal projections and synaptic input structures have remained largely unexplored despite decades of research into neocortical function. In recent years, however, layer 6b (L6b) has attracted increasing attention and its functional role is beginning to be elucidated. In this review, I will attempt to provide an overview of what is currently known about the excitatory and inhibitory neurons in this layer, their pre- and postsynaptic connectivity, and their functional implications. Similarities and differences between different cortical areas will be highlighted. Finally, layer 6b neurons are highly responsive to several neuropeptides such as orexin/hypocretin, neurotensin and cholecystokinin, in some cases exclusively. They are also strongly controlled by neurotransmitters such as acetylcholine and norepinephrine. The interaction of these neuromodulators with L6b microcircuitry and its functional consequences will also be discussed.
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Affiliation(s)
- Dirk Feldmeyer
- Research Centre Jülich, Institute of Neuroscience and Medicine 10 (INM-10), Jülich, Germany
- Department of Psychiatry, Psychotherapy, and Psychosomatics, RWTH Aachen University Hospital, Aachen, Germany
- Jülich-Aachen Research Alliance, Translational Brain Medicine (JARA Brain), Aachen, Germany
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3
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Mukherjee D, Xue B, Chen CT, Chang M, Kao JPY, Kanold PO. Early retinal deprivation crossmodally alters nascent subplate circuits and activity in the auditory cortex during the precritical period. Cereb Cortex 2023; 33:9038-9053. [PMID: 37259176 PMCID: PMC10350824 DOI: 10.1093/cercor/bhad180] [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: 02/24/2023] [Revised: 05/03/2023] [Accepted: 05/04/2023] [Indexed: 06/02/2023] Open
Abstract
Sensory perturbation in one modality results in the adaptive reorganization of neural pathways within the spared modalities, a phenomenon known as "crossmodal plasticity," which has been examined during or after the classic "critical period." Because peripheral perturbations can alter the auditory cortex (ACX) activity and functional connectivity of the ACX subplate neurons (SPNs) even before the critical period, called the precritical period, we investigated if retinal deprivation at birth crossmodally alters the ACX activity and SPN circuits during the precritical period. We deprived newborn mice of visual inputs after birth by performing bilateral enucleation. We performed in vivo widefield imaging in the ACX of awake pups during the first two postnatal weeks to investigate cortical activity. We found that enucleation alters spontaneous and sound-evoked activities in the ACX in an age-dependent manner. Next, we performed whole-cell patch clamp recording combined with laser scanning photostimulation in ACX slices to investigate circuit changes in SPNs. We found that enucleation alters the intracortical inhibitory circuits impinging on SPNs, shifting the excitation-inhibition balance toward excitation and this shift persists after ear opening. Together, our results indicate that crossmodal functional changes exist in the developing sensory cortices at early ages before the onset of the classic critical period.
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Affiliation(s)
- Didhiti Mukherjee
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Binghan Xue
- Department of Biology, University of Maryland, College Park, MD 20742, United States
| | - Chih-Ting Chen
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Minzi Chang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Joseph P Y Kao
- Department of Physiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, United States
| | - Patrick O Kanold
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, United States
- Department of Biology, University of Maryland, College Park, MD 20742, United States
- Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21205, United States
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4
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Mukherjee D, Xue B, Chen CT, Chang M, Kao JPY, Kanold PO. Early retinal deprivation crossmodally alters nascent subplate circuits and activity in the auditory cortex during the precritical period. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.21.529453. [PMID: 36865142 PMCID: PMC9980129 DOI: 10.1101/2023.02.21.529453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Sensory perturbation in one modality results in adaptive reorganization of neural pathways within the spared modalities, a phenomenon known as "crossmodal plasticity", which has been examined during or after the classic 'critical period'. Because peripheral perturbations can alter auditory cortex (ACX) activity and functional connectivity of the ACX subplate neurons (SPNs) even before the classic critical period, called the precritical period, we investigated if retinal deprivation at birth crossmodally alters ACX activity and SPN circuits during the precritical period. We deprived newborn mice of visual inputs after birth by performing bilateral enucleation. We performed in vivo imaging in the ACX of awake pups during the first two postnatal weeks to investigate cortical activity. We found that enucleation alters spontaneous and sound-evoked activity in the ACX in an age-dependent manner. Next, we performed whole-cell patch clamp recording combined with laser scanning photostimulation in ACX slices to investigate circuit changes in SPNs. We found that enucleation alters the intracortical inhibitory circuits impinging on SPNs shifting the excitation-inhibition balance towards excitation and this shift persists after ear opening. Together, our results indicate that crossmodal functional changes exist in the developing sensory cortices at early ages before the onset of the classic critical period.
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5
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Tabuena DR, Huynh R, Metcalf J, Richner T, Stroh A, Brunton BW, Moody WJ, Easton CR. Large-scale waves of activity in the neonatal mouse brain in vivo occur almost exclusively during sleep cycles. Dev Neurobiol 2022; 82:596-612. [PMID: 36250606 PMCID: PMC10166374 DOI: 10.1002/dneu.22901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 09/09/2022] [Accepted: 10/06/2022] [Indexed: 01/30/2023]
Abstract
Spontaneous electrical activity plays major roles in the development of cortical circuitry. This activity can occur highly localized regions or can propagate over the entire cortex. Both types of activity coexist during early development. To investigate how different forms of spontaneous activity might be temporally segregated, we used wide-field trans-cranial calcium imaging over an entire hemisphere in P1-P8 mouse pups. We found that spontaneous waves of activity that propagate to cover the majority of the cortex (large-scale waves; LSWs) are generated at the end of the first postnatal week, along with several other forms of more localized activity. We further found that LSWs are segregated into sleep cycles. In contrast, cortical activity during wake states is more spatially restricted and the few large-scale forms of activity that occur during wake can be distinguished from LSWs in sleep based on their initiation in the motor cortex and their correlation with body movements. This change in functional cortical circuitry to a state that is permissive for large-scale activity may temporally segregate different forms of activity during critical stages when activity-dependent circuit development occurs over many spatial scales. Our data also suggest that LSWs in early development may be a functional precursor to slow sleep waves in the adult, which play critical roles in memory consolidation and synaptic rescaling.
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Affiliation(s)
- Dennis R Tabuena
- Department of Biology, University of Washington, Seattle, Washington, USA.,Graduate Program in Neuroscience, University of Washington, Seattle, Washington, USA
| | - Randy Huynh
- Department of Biology, University of Washington, Seattle, Washington, USA
| | - Jenna Metcalf
- Department of Biology, University of Washington, Seattle, Washington, USA
| | - Thomas Richner
- Institute for Neuroengineering, University of Washington, Seattle, Washington, USA
| | - Albrecht Stroh
- Institute of Pathophysiology, University Medical Center Mainz, Mainz, Germany.,Leibniz Institute for Resilience Research, University Medical Center Mainz, Mainz, Germany
| | - Bingni W Brunton
- Department of Biology, University of Washington, Seattle, Washington, USA.,Institute for Neuroengineering, University of Washington, Seattle, Washington, USA
| | - William J Moody
- Department of Biology, University of Washington, Seattle, Washington, USA.,Institute for Neuroengineering, University of Washington, Seattle, Washington, USA
| | - Curtis R Easton
- Department of Biology, University of Washington, Seattle, Washington, USA
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6
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Inhibition in the auditory cortex. Neurosci Biobehav Rev 2021; 132:61-75. [PMID: 34822879 DOI: 10.1016/j.neubiorev.2021.11.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 10/20/2021] [Accepted: 11/15/2021] [Indexed: 02/05/2023]
Abstract
The auditory system provides us with extremely rich and precise information about the outside world. Once a sound reaches our ears, the acoustic information it carries travels from the cochlea all the way to the auditory cortex, where its complexity and nuances are integrated. In the auditory cortex, functional circuits are formed by subpopulations of intermingled excitatory and inhibitory cells. In this review, we discuss recent evidence of the specific contributions of inhibitory neurons in sound processing and integration. We first examine intrinsic properties of three main classes of inhibitory interneurons in the auditory cortex. Then, we describe how inhibition shapes the responsiveness of the auditory cortex to sound. Finally, we discuss how inhibitory interneurons contribute to the sensation and perception of sounds. Altogether, this review points out the crucial role of cortical inhibitory interneurons in integrating information about the context, history, or meaning of a sound. It also highlights open questions to be addressed for increasing our understanding of the staggering complexity leading to the subtlest auditory perception.
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Sheikh A, Meng X, Kao JPY, Kanold PO. Neonatal Hypoxia-Ischemia Causes Persistent Intracortical Circuit Changes in Layer 4 of Rat Auditory Cortex. Cereb Cortex 2021; 32:2575-2589. [PMID: 34729599 DOI: 10.1093/cercor/bhab365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/12/2022] Open
Abstract
The connection between early brain injury and subsequent development of disorders is unknown. Neonatal hypoxia-ischemia (HI) alters circuits associated with subplate neurons (SPNs). SPNs are among the first maturing cortical neurons, project to thalamorecipient layer 4 (L4), and are required for the development of thalamocortical connections. Thus, early HI might influence L4 and such influence might persist. We investigated functional circuits to L4 neurons in neonatal rat HI models of different severities (mild and moderate) shortly after injury and at adolescence. We used laser-scanning photostimulation in slices of auditory cortex during P5-10 and P18-23. Mild injuries did not initially (P6/P7) alter the convergence of excitatory inputs from L2/3, but hyperconnectivity emerged by P8-10. Inputs from L4 showed initial hypoconnectivity which resolved by P8-10. Moderate injuries resulted in initial hypoconnectivity from both layers which resolved by P8-10 and led to persistent strengthening of connections. Inhibitory inputs to L4 cells showed similar changes. Functional changes were mirrored by reduced dendritic complexity. We also observed a persistent increase in similarity of L4 circuits, suggesting that HI interferes with developmental circuit refinement and diversification. Altogether, our results show that neonatal HI injuries lead to persistent changes in intracortical connections.
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Affiliation(s)
- Aminah Sheikh
- Department of Biology, University of Maryland, College Park, MD 20742, USA.,Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD 20742, USA
| | - Xiangying Meng
- Department of Biology, University of Maryland, College Park, MD 20742, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Joseph P Y Kao
- Center for Biomedical Engineering and Technology, and Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Patrick O Kanold
- Department of Biology, University of Maryland, College Park, MD 20742, USA.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA
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