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1.
Proc Natl Acad Sci U S A ; 120(9): e2217011120, 2023 02 28.
Artículo en Inglés | MEDLINE | ID: mdl-36812195

RESUMEN

Subplate neurons are early-born cortical neurons that transiently form neural circuits during perinatal development and guide cortical maturation. Thereafter, most subplate neurons undergo cell death, while some survive and renew their target areas for synaptic connections. However, the functional properties of the surviving subplate neurons remain largely unknown. This study aimed to characterize the visual responses and experience-dependent functional plasticity of layer 6b (L6b) neurons, the remnants of subplate neurons, in the primary visual cortex (V1). Two-photon Ca2+ imaging was performed in V1 of awake juvenile mice. L6b neurons showed broader tunings for orientation, direction, and spatial frequency than did layer 2/3 (L2/3) and L6a neurons. In addition, L6b neurons showed lower matching of preferred orientation between the left and right eyes compared with other layers. Post hoc 3D immunohistochemistry confirmed that the majority of recorded L6b neurons expressed connective tissue growth factor (CTGF), a subplate neuron marker. Moreover, chronic two-photon imaging showed that L6b neurons exhibited ocular dominance (OD) plasticity by monocular deprivation during critical periods. The OD shift to the open eye depended on the response strength to the stimulation of the eye to be deprived before starting monocular deprivation. There were no significant differences in visual response selectivity prior to monocular deprivation between the OD changed and unchanged neuron groups, suggesting that OD plasticity can occur in L6b neurons showing any response features. In conclusion, our results provide strong evidence that surviving subplate neurons exhibit sensory responses and experience-dependent plasticity at a relatively late stage of cortical development.


Asunto(s)
Corteza Visual , Ratones , Animales , Corteza Visual/fisiología , Neuronas/fisiología , Predominio Ocular , Ojo , Plasticidad Neuronal/fisiología
2.
J Neurosci ; 44(36)2024 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-39117456

RESUMEN

Monocular deprivation (MD) causes an initial decrease in synaptic responses to the deprived eye in juvenile mouse primary visual cortex (V1) through Hebbian long-term depression (LTD). This is followed by a homeostatic increase, which has been attributed either to synaptic scaling or to a slide threshold for Hebbian long-term potentiation (LTP) rather than scaling. We therefore asked in mice of all sexes whether the homeostatic increase during MD requires GluN2B-containing NMDA receptor activity, which is required to slide the plasticity threshold but not for synaptic scaling. Selective GluN2B blockade from 2-6 d after monocular lid suture prevented the homeostatic increase in miniature excitatory postsynaptic current (mEPSC) amplitude in monocular V1 of acute slices and prevented the increase in visually evoked responses in binocular V1 in vivo. The decrease in mEPSC amplitude and visually evoked responses during the first 2 d of MD also required GluN2B activity. Together, these results support the idea that GluN2B-containing NMDA receptors first play a role in LTD immediately following eye closure and then promote homeostasis during prolonged MD by sliding the plasticity threshold in favor of LTP.


Asunto(s)
Predominio Ocular , Potenciales Postsinápticos Excitadores , Ratones Endogámicos C57BL , Plasticidad Neuronal , Receptores de N-Metil-D-Aspartato , Animales , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Receptores de N-Metil-D-Aspartato/metabolismo , Ratones , Masculino , Predominio Ocular/fisiología , Femenino , Plasticidad Neuronal/fisiología , Plasticidad Neuronal/efectos de los fármacos , Potenciales Postsinápticos Excitadores/fisiología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Potenciales Evocados Visuales/fisiología , Corteza Visual/fisiología , Corteza Visual/efectos de los fármacos , Antagonistas de Aminoácidos Excitadores/farmacología , Privación Sensorial/fisiología , Potenciación a Largo Plazo/fisiología , Potenciación a Largo Plazo/efectos de los fármacos , Depresión Sináptica a Largo Plazo/fisiología , Depresión Sináptica a Largo Plazo/efectos de los fármacos , Estimulación Luminosa/métodos
3.
Proc Natl Acad Sci U S A ; 119(23): e2203965119, 2022 06 07.
Artículo en Inglés | MEDLINE | ID: mdl-35648829

RESUMEN

During developmental critical periods, circuits are sculpted by a process of activity-dependent competition. The molecular machinery involved in regulating the complex process of responding to different levels of activity is now beginning to be identified. Here, we show that the nonclassical major histocompatibility class I (MHCI) molecule Qa-1 is expressed in the healthy brain in layer 6 corticothalamic neurons. In the visual cortex, Qa-1 expression begins during the critical period for ocular dominance (OD) plasticity and is regulated by neuronal activity, suggesting a role in regulating activity-dependent competition. Indeed, in mice lacking Qa-1, OD plasticity is perturbed. Moreover, signaling through CD94/NKG2, a known cognate Qa-1 heterodimeric receptor in the immune system, is implicated: selectively targeting this interaction phenocopies the plasticity perturbation observed in Qa-1 knockouts. In the cortex, CD94/NKG2 is expressed by microglial cells, which undergo activity-dependent changes in their morphology in a Qa-1­dependent manner. Our study thus reveals a neuron­microglial interaction dependent upon a nonclassical MHCI molecule expressed in L6 neurons, which regulates plasticity in the visual cortex. These results also point to an unexpected function for the Qa-1/HLA-E (ligand) and CD94/NKG2 (receptor) interaction in the nervous system, in addition to that described in the immune system.


Asunto(s)
Corteza Cerebral , Antígenos de Histocompatibilidad Clase I , Microglía , Subfamília C de Receptores Similares a Lectina de Células NK , Subfamília D de Receptores Similares a Lectina de las Células NK , Plasticidad Neuronal , Animales , Corteza Cerebral/metabolismo , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/metabolismo , Ratones , Ratones Noqueados , Microglía/metabolismo , Subfamília C de Receptores Similares a Lectina de Células NK/metabolismo , Subfamília D de Receptores Similares a Lectina de las Células NK/metabolismo , Plasticidad Neuronal/genética , Plasticidad Neuronal/fisiología , Neuronas/metabolismo
4.
Cereb Cortex ; 33(4): 983-996, 2023 02 07.
Artículo en Inglés | MEDLINE | ID: mdl-35332915

RESUMEN

It is well known how selective attention biases information processing in real time, but few work investigates the aftereffects of prolonged attention, let alone the underlying neural mechanisms. To examine perceptual aftereffect after prolonged attention to a monocular pathway, movie images played normally were presented to normal adult's one eye (attended eye), while movie images of the same episode but played backwards were presented to the opposite eye (unattended eye). One hour of watching this dichoptic movie caused a shift of perceptual ocular dominance towards the unattended eye. Interestingly, the aftereffect positively correlated with the advantage of neural activity for the attended-eye over unattended-eye signals at the frontal electrodes measured with steady-state visual evoked potentials. Moreover, the aftereffect disappeared when interocular competition was minimized during adaptation. These results suggest that top-down eye-specific attention can induce ocular dominance plasticity through binocular rivalry mechanisms. The present study opens the route to explain at least part of short-term ocular dominance plasticity with the ocular-opponency-neuron model, which may be an interesting complement to the homeostatic compensation theory.


Asunto(s)
Predominio Ocular , Potenciales Evocados Visuales , Adulto , Humanos , Percepción Visual/fisiología , Visión Ocular , Cognición , Progresión de la Enfermedad , Visión Binocular/fisiología , Estimulación Luminosa , Plasticidad Neuronal/fisiología
5.
Cereb Cortex ; 33(16): 9599-9615, 2023 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-37415460

RESUMEN

We previously revealed the presence of ocular dominance columns (ODCs) in the primary visual cortex (V1) of pigmented rats. On the other hand, previous studies have shown that the ipsilateral-eye domains of the dorsal lateral geniculate nucleus (dLGN) are segregated into a handful of patches in pigmented rats. To investigate the three-dimensional (3D) topography of the eye-specific patches of the dLGN and its relationship with ODCs, we injected different tracers into the right and left eyes and examined strain difference, development, and plasticity of the patches. Furthermore, we applied the tissue clearing technique to reveal the 3D morphology of the LGN and were able to observe entire retinotopic map of the rat dLGN at a certain angle. Our results show that the ipsilateral domains of the dLGN appear mesh-like at any angle and are developed at around time of eye-opening. Their development was moderately affected by abnormal visual experience, but the patch formation was not disrupted. In albino Wistar rats, ipsilateral patches were observed in the dLGN, but they were much fewer, especially near the central visual field. These results provide insights into how ipsilateral patches of the dLGN arise, and how the geniculo-cortical arrangement is different between rodents and primates.


Asunto(s)
Cuerpos Geniculados , Corteza Visual , Ratas , Animales , Cuerpos Geniculados/anatomía & histología , Corteza Visual/anatomía & histología , Vías Visuales/anatomía & histología , Campos Visuales , Ratas Wistar
6.
Cereb Cortex ; 33(15): 9303-9312, 2023 07 24.
Artículo en Inglés | MEDLINE | ID: mdl-37279562

RESUMEN

Experience dependent plasticity in the visual cortex is a key paradigm for the study of mechanisms underpinning learning and memory. Despite this, studies involving manipulating visual experience have largely been limited to the primary visual cortex, V1, across various species. Here we investigated the effects of monocular deprivation (MD) on the ocular dominance (OD) and orientation selectivity of neurons in four visual cortical areas in the mouse: the binocular zone of V1 (V1b), the putative "ventral stream" area LM and the putative "dorsal stream" areas AL and PM. We employed two-photon calcium imaging to record neuronal responses in young adult mice before MD, immediately after MD, and following binocular recovery. OD shifts following MD were greatest in LM and smallest in AL and PM; in LM and AL, these shifts were mediated primarily through a reduction of deprived-eye responses, in V1b and LM through an increase in response through the non-deprived eye. The OD index recovered to pre-MD levels within 2 weeks in V1 only. MD caused a reduction in orientation selectivity of deprived-eye responses in V1b and LM only. Our results suggest that changes in OD in higher visual areas are not uniformly inherited from V1.


Asunto(s)
Plasticidad Neuronal , Corteza Visual , Ratones , Animales , Plasticidad Neuronal/fisiología , Ratones Endogámicos C57BL , Corteza Visual/fisiología , Predominio Ocular , Aprendizaje , Privación Sensorial/fisiología
7.
Cereb Cortex ; 33(16): 9450-9464, 2023 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-37415464

RESUMEN

Despite previous agreement of the absence of cortical column structure in the rodent visual cortex, we have recently revealed a presence of ocular dominance columns (ODCs) in the primary visual cortex (V1) of adult Long-Evans rats. In this study, we deepened understanding of characteristics of rat ODCs. We found that this structure was conserved in Brown Norway rats, but not in albino rats; therefore, it could be a structure generally present in pigmented wild rats. Activity-dependent gene expression indicated that maturation of eye-dominant patches takes more than 2 weeks after eye-opening, and this process is visual experience dependent. Monocular deprivation during classical critical period strongly influenced size of ODCs, shifting ocular dominance from the deprived eye to the opened eye. On the other hand, transneuronal anterograde tracer showed a presence of eye-dominant patchy innervation from the ipsilateral V1 even before eye-opening, suggesting the presence of visual activity-independent genetic components of developing ODCs. Pigmented C57BL/6J mice also showed minor clusters of ocular dominance neurons. These results provide insights into how visual experience-dependent and experience-independent components both contribute to develop cortical columns during early postnatal stages, and indicate that rats and mice can be excellent models to study them.


Asunto(s)
Predominio Ocular , Corteza Visual , Animales , Ratas , Ratones , Ratas Long-Evans , Ratones Endogámicos C57BL , Corteza Visual/fisiología , Neuronas/fisiología
8.
Cereb Cortex ; 33(9): 5636-5645, 2023 04 25.
Artículo en Inglés | MEDLINE | ID: mdl-36396729

RESUMEN

Neural dynamics are altered in the primary visual cortex (V1) during critical period monocular deprivation (MD). Synchronization of neural oscillations is pertinent to physiological functioning of the brain. Previous studies have reported chronic disruption of V1 functional properties such as ocular dominance, spatial acuity, and binocular matching after long-term monocular deprivation (LTMD). However, the possible neuromodulation and neural synchrony has been less explored. Here, we investigated the difference between juvenile and adult experience-dependent plasticity in mice from intracellular calcium signals with fluorescent indicators. We also studied alterations in local field potentials power bands and phase-amplitude coupling (PAC) of specific brain oscillations. Our results showed that LTMD in juveniles causes higher neuromodulatory changes as seen by high-intensity fluorescent signals from the non-deprived eye (NDE). Meanwhile, adult mice showed a greater response from the deprived eye (DE). LTMD in juvenile mice triggered alterations in the power of delta, theta, and gamma oscillations, followed by enhancement of delta-gamma PAC in the NDE. However, LTMD in adult mice caused alterations in the power of delta oscillations and enhancement of delta-gamma PAC in the DE. These markers are intrinsic to cortical neuronal processing during LTMD and apply to a wide range of nested oscillatory markers.


Asunto(s)
Visión Monocular , Corteza Visual , Animales , Ratones , Visión Monocular/fisiología , Privación Sensorial/fisiología , Corteza Visual/fisiología , Predominio Ocular , Neuronas/fisiología , Plasticidad Neuronal/fisiología
9.
Graefes Arch Clin Exp Ophthalmol ; 262(1): 33-41, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37644327

RESUMEN

Ocular dominance (OD), a commonly used concept in clinical practice, plays an important role in optometry and refractive surgery. With the development of refractive cataract surgery, the refractive function of the intraocular lens determines the achievement of the postoperative full range of vision based on the retinal defocus blur suppression and binocular monovision principle. Therefore, OD plays an important role in cataract surgery. OD is related to the visual formation of the cerebral cortex, and its plasticity suggests that visual experience can influence the visual system. Cataract surgery changes the visual experience and transforms the dominant eye, which confirms the plasticity of the visual system. Based on the concept and mechanism of OD, this review summarizes the application of OD in cataract surgery.


Asunto(s)
Extracción de Catarata , Catarata , Cristalino , Humanos , Agudeza Visual , Predominio Ocular , Catarata/complicaciones
10.
Ophthalmic Physiol Opt ; 44(3): 564-575, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38317572

RESUMEN

Short-term monocular deprivation (MD) shifts sensory eye balance in favour of the previously deprived eye. The effect of MD on eye balance is significant but brief in adult humans. Recently, researchers and clinicians have attempted to implement MD in clinical settings for adults with impaired binocular vision. Although the effect of MD has been studied in detail in single-session protocols, what is not known is whether the effect of MD on eye balance deteriorates after repeated periods of MD (termed 'perceptual deterioration'). An answer to this question is relevant for two reasons. Firstly, the effect of MD (i.e., dose-response) should not decrease with repeated use if MD is to be used therapeutically (e.g., daily for weeks). Second, it bears upon the question of whether the neural basis of the effects of MD and contrast adaptation, a closely related phenomenon, is the same. The sensory change from contrast adaptation depends on recent experience. If the observer has recently experienced the same adaptation multiple times for consecutive days, then the adaptation effect will be smaller because contrast adaptation exhibits perceptual deterioration, so it is of interest to know if the effects of MD follow suit. This study measured the effect of 2-h MD for seven consecutive days on binocular balance of 15 normally sighted adults. We found that the shift in eye balance from MD stayed consistent, showing no signs of deterioration after subjects experienced multiple periods of MD. This finding shows no loss of effectiveness of repeated daily doses of MD if used therapeutically to rebalance binocular vision in otherwise normal individuals. Furthermore, ocular dominance plasticity, which is the basis of the effects of short-term MD, does not seem to share the property of 'perceptual deterioration' with contrast adaptation, suggesting different neural bases for these two related phenomena.


Asunto(s)
Corteza Visual , Adulto , Humanos , Corteza Visual/fisiología , Privación Sensorial/fisiología , Visión Ocular , Visión Binocular/fisiología , Predominio Ocular , Visión Monocular/fisiología
11.
J Neurosci ; 42(1): 16-32, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34764155

RESUMEN

A fundamental regulator of neuronal network development and plasticity is the extracellular matrix (ECM) of the brain. The ECM provides a scaffold stabilizing synaptic circuits, while the proteolytic cleavage of its components and cell surface proteins are thought to have permissive roles in the regulation of plasticity. The enzymatic proteolysis is thought to be crucial for homeostasis between stability and reorganizational plasticity and facilitated largely by a family of proteinases named matrix metalloproteinases (MMPs). Here, we investigated whether MMP2 and MMP9 play a role in mediating adult primary visual cortex (V1) plasticity as well as stroke-induced impairments of visual cortex plasticity in mice. In healthy adult mice, selective inhibition of MMP2/9 for 7 d suppressed ocular dominance plasticity. In contrast, brief inhibition of MMP2/9 after a cortical stroke rescued compromised plasticity. Our data indicate that the proteolytic activity of MMP2 and MMP9 is critical and required to be within a narrow range to allow adult visual plasticity.SIGNIFICANCE STATEMENT Learning and recovery from injuries depend on the plasticity of neuronal connections. The brain's extracellular matrix (ECM) provides a scaffold for stabilizing synaptic circuits, while its enzymatic proteolysis is hypothesized to regulate homeostasis between stability and reorganizational plasticity. ECM digestion is facilitated by a family of matrix metalloproteinases (MMPs). Here, we show that treatments that inhibit MMP2/9 can either inhibit or rescue cortical plasticity depending on cortical state: in the visual cortex of healthy adult mice, inhibition of MMP2/9 suppressed cortical plasticity. In contrast, brief inhibition of MMP2/9 after a stroke rescued compromised plasticity. Our data provide strong evidence that an optimal level of MMP2/9 proteolytic activity is crucial for adult visual plasticity.


Asunto(s)
Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Plasticidad Neuronal/fisiología , Corteza Visual Primaria/enzimología , Accidente Cerebrovascular/fisiopatología , Animales , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Accidente Cerebrovascular/enzimología
12.
Neuroimage ; 274: 120122, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-37080344

RESUMEN

Long term monocular deprivation is considered to be necessary for the induction of significant ocular dominance plasticity in the adult visual cortex. In this study, we subjected adult mice to monocular deprivation for various durations and screened for changes in ocular dominance using dual-wavelength intrinsic signal optical imaging. We found that short-term deprivation was sufficient to cause a shift in ocular dominance and that these early-stage changes were detected only by near-infrared illumination. In addition, single-unit recordings showed that these early-stage changes primarily occurred in deep cortical layers. This early-stage ocular dominance shift was abolished by the blockade of NMDA receptors. In summary, our findings reveal an early phase of adult ocular dominance plasticity and provide the dynamics of adult plasticity.


Asunto(s)
Predominio Ocular , Corteza Visual , Ratones , Animales , Plasticidad Neuronal , Visión Ocular , Corteza Visual/diagnóstico por imagen , Imagen Óptica , Privación Sensorial
13.
Eur J Neurosci ; 57(6): 940-950, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36740723

RESUMEN

Ketamine has been described as a fast-acting antidepressant, exerting effects in depressed patients and in preclinical models with a rapid onset of action. The typical antidepressant fluoxetine is known to induce plasticity in the adult rodent visual cortex, as assessed by a shift in ocular dominance, a classical model of brain plasticity, and a similar effect has been described for ketamine and its metabolite 2R,6R-hydroxynorketamine (R,R-HNK). Here, we demonstrate that ketamine (at 3 or 20 mg/kg) and R,R-HNK facilitated the shift in ocular dominance in monocularly deprived mice, after three injections, throughout the 7-day monocular deprivation regimen. Notably, the comparison between the treatments indicates a higher effect size of R,R-HNK compared with ketamine. Treatment with ketamine or R,R-HNK failed to influence the levels of perineuronal nets (PNNs) surrounding parvalbumin-positive interneurons. However, we observed in vitro that both ketamine and R,R-HNK are able to disrupt the tropomyosin-related kinase B (TRKB) interaction with the protein tyrosine phosphatase sigma (PTPσ), which upon binding to PNNs dephosphorylates TRKB. These results support a model where diverse drugs promote the reinstatement of juvenile-like plasticity by directly binding TRKB and releasing it from PTPσ regulation, without necessarily reducing PNNs deposits.


Asunto(s)
Ketamina , Animales , Ratones , Antidepresivos/farmacología , Depresión/metabolismo , Predominio Ocular , Interneuronas/metabolismo , Ketamina/farmacología , Parvalbúminas , Proteínas Tirosina Fosfatasas Clase 2 Similares a Receptores , Tropomiosina
14.
Eur J Neurosci ; 57(1): 148-162, 2023 01.
Artículo en Inglés | MEDLINE | ID: mdl-36437778

RESUMEN

Brain plasticity and function is impaired in conditions of metabolic dysregulation, such as obesity. Less is known on whether brain function is also affected by transient and physiological metabolic changes, such as the alternation between fasting and fed state. Here we asked whether these changes affect the transient shift of ocular dominance that follows short-term monocular deprivation, a form of homeostatic plasticity. We further asked whether variations in three of the main metabolic and hormonal pathways affected in obesity (glucose metabolism, leptin signalling and fatty acid metabolism) correlate with plasticity changes. We measured the effects of 2 h monocular deprivation in three conditions: post-absorptive state (fasting), after ingestion of a standardised meal and during infusion of glucagon-like peptide-1 (GLP-1), an incretin physiologically released upon meal ingestion that plays a key role in glucose metabolism. We found that short-term plasticity was less manifest in fasting than in fed state, whereas GLP-1 infusion did not elicit reliable changes compared to fasting. Although we confirmed a positive association between plasticity and supraphysiological GLP-1 levels, achieved by GLP-1 infusion, we found that none of the parameters linked to glucose metabolism could predict the plasticity reduction in the fasting versus fed state. Instead, this was selectively associated with the increase in plasma beta-hydroxybutyrate (B-OH) levels during fasting, which suggests a link between neural function and energy substrates alternative to glucose. These results reveal a previously unexplored link between homeostatic brain plasticity and the physiological changes associated with the daily fast-fed cycle.


Asunto(s)
Péptido 1 Similar al Glucagón , Glucosa , Humanos , Adulto , Glucosa/metabolismo , Obesidad , Ayuno , Insulina
15.
J Theor Biol ; 572: 111588, 2023 09 07.
Artículo en Inglés | MEDLINE | ID: mdl-37507004

RESUMEN

In this paper, we present a multi-layer, activity-dependent model for the joint development of ocular dominance (OD) columns and cytochrome oxidase (CO) blobs in primate V1. For simplicity, we focus on layers 4C and 2/3 with both layers receiving direct thalamic inputs and layer 4C sending vertical projections to layer 2/3. Both the thalamic and the vertical connections are taken to be modifiable by activity. Using a correlation-based Hebbian learning rule with subtractive normalization, we show how the formation of an OD map in layer 4C is inherited by layer 2/3 via the vertical projections. Competition between these feedforward projections and the direct thalamic input to layer 2/3 then results in the formation of CO blobs superimposed upon the ocular dominance map. The spacing of the OD columns is determined by the spatial profile of the intralaminar connections within layer 4, while the spacing of CO blobs depends both on the width of the OD columns inherited from layer 4 and the spatial distribution of intralaminar connections within the superficial layer. The resulting CO blob distribution is shown to be consistent with experimental data. In addition, we numerically simulate monocular deprivation and find that while the CO blob distribution is unaltered, the OD pattern undergoes modification. The OD stripes of the deprived eye narrow, whereas the OD stripes for the remaining open eye widen.


Asunto(s)
Predominio Ocular , Corteza Visual , Animales , Corteza Visual/metabolismo , Complejo IV de Transporte de Electrones/metabolismo , Corteza Visual Primaria , Tálamo
16.
BMC Ophthalmol ; 23(1): 290, 2023 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-37365512

RESUMEN

PURPOSE: To compare the degree of myopia between the dominant and non-dominant eyes in teenagers with intermittent exotropia (IXT) in China. METHODS: A total of 199 IXT patients with myopia were included in this retrospective study and were divided into two groups according to the difference between near and distance exodeviation: basic IXT and convergence insufficiency (CI) IXT. Refractive errors were analyzed by spherical equivalent (SE) values. Patients were further stratified into anisometropia group and non-anisometropia group based on binocular SE values difference greater than 1.0D or not. RESULTS: There were 127 patients in the CI IXT group, with a near deviation of 46.94 ± 20.53 prism diopters (PD) and a distance deviation of 28.36 ± 14.34 PD, and there were 72 (36.2%) patients in the basic IXT group, with a near deviation of 37.68 ± 22.21 PD and a distance deviation angle of 33.21 ± 23.96 PD. The near exodeviation was significantly larger in the CI group than in the basic IXT group(P < 0.001). In the CI IXT group, the mean SE was - 2.09 ± 1.45 diopters (D) in the dominant eye and - 2.53 ± 1.44D in the non-dominant eye, while in the basic IXT group, the mean SE was - 2.46 ± 1.56D in the dominant eye and - 2.89 ± 1.37D in the non-dominant eye. The anisometropia group included 43 patients, while non-anisometropia group included 156 patients. The near and distance exodeviation in the anisometropia group were 45.26 ± 24.41 PD and 33.53 ± 23.31 PD, respectively, and those in the non-anisometropia group were 43.42 ± 20.69 PD and 29.07 ± 16.84 PD, respectively. There were no significant differences in near and distance deviation (P = 0.78 and P = 0.73 respectively) between the two groups. The SE of the dominant eye was less myopic than of the non-dominant eyes in both the CI and anisometropia groups (P = 0.002 and P < 0.001, respectively). CONCLUSIONS: Our study revealed that convergence insufficiency IXT is more common than the basic type in pediatric myopic population and is characterized by higher inter-eye differences of myopia. The dominant eye was found to be less myopic in IXT patients, particularly in those with convergence insufficiency and anisometropia.


Asunto(s)
Anisometropía , Exotropía , Miopía , Trastornos de la Motilidad Ocular , Adolescente , Niño , Humanos , China/epidemiología , Enfermedad Crónica , Estudios Retrospectivos
17.
Proc Natl Acad Sci U S A ; 117(25): 14453-14463, 2020 06 23.
Artículo en Inglés | MEDLINE | ID: mdl-32513717

RESUMEN

Deep regions of the brain are not easily accessible to investigation at the mesoscale level in awake animals or humans. We have recently developed a functional ultrasound (fUS) technique that enables imaging hemodynamic responses to visual tasks. Using fUS imaging on two awake nonhuman primates performing a passive fixation task, we constructed retinotopic maps at depth in the visual cortex (V1, V2, and V3) in the calcarine and lunate sulci. The maps could be acquired in a single-hour session with relatively few presentations of the stimuli. The spatial resolution of the technology is illustrated by mapping patterns similar to ocular dominance (OD) columns within superficial and deep layers of the primary visual cortex. These acquisitions using fUS suggested that OD selectivity is mostly present in layer IV but with extensions into layers II/III and V. This imaging technology provides a new mesoscale approach to the mapping of brain activity at high spatiotemporal resolution in awake subjects within the whole depth of the cortex.


Asunto(s)
Mapeo Encefálico/métodos , Corteza Visual/fisiología , Vigilia/fisiología , Animales , Predominio Ocular/fisiología , Femenino , Macaca mulatta , Masculino , Estimulación Luminosa , Reproducibilidad de los Resultados , Análisis Espacio-Temporal , Ultrasonografía/métodos , Corteza Visual/diagnóstico por imagen
18.
Int J Mol Sci ; 24(5)2023 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-36902131

RESUMEN

Assessing the molecular mechanism of synaptic plasticity in the cortex is vital for identifying potential targets in conditions marked by defective plasticity. In plasticity research, the visual cortex represents a target model for intense investigation, partly due to the availability of different in vivo plasticity-induction protocols. Here, we review two major protocols: ocular-dominance (OD) and cross-modal (CM) plasticity in rodents, highlighting the molecular signaling pathways involved. Each plasticity paradigm has also revealed the contribution of different populations of inhibitory and excitatory neurons at different time points. Since defective synaptic plasticity is common to various neurodevelopmental disorders, the potentially disrupted molecular and circuit alterations are discussed. Finally, new plasticity paradigms are presented, based on recent evidence. Stimulus-selective response potentiation (SRP) is one of the paradigms addressed. These options may provide answers to unsolved neurodevelopmental questions and offer tools to repair plasticity defects.


Asunto(s)
Roedores , Corteza Visual , Animales , Plasticidad Neuronal/fisiología , Corteza Visual/fisiología , Neuronas , Predominio Ocular
19.
Int J Mol Sci ; 24(6)2023 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-36982823

RESUMEN

Both hemispheres connect with each other by excitatory callosal projections, and whether inhibitory interneurons, usually believed to have local innervation, engage in transcallosal activity modulation is unknown. Here, we used optogenetics in combination with cell-type-specific channelrhodopsin-2 expression to activate different inhibitory neuron subpopulations in the visual cortex and recorded the response of the entire visual cortex using intrinsic signal optical imaging. We found that optogenetic stimulation of inhibitory neurons reduced spontaneous activity (increase in the reflection of illumination) in the binocular area of the contralateral hemisphere, although these stimulations had different local effects ipsilaterally. The activation of contralateral interneurons differentially affected both eye responses to visual stimuli and, thus, changed ocular dominance. Optogenetic silencing of excitatory neurons affects the ipsilateral eye response and ocular dominance in the contralateral cortex to a lesser extent. Our results revealed a transcallosal effect of interneuron activation in the mouse visual cortex.


Asunto(s)
Predominio Ocular , Corteza Visual , Animales , Ratones , Corteza Visual/fisiología , Neuronas/fisiología , Interneuronas/fisiología
20.
J Neurosci ; 41(7): 1470-1488, 2021 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-33376158

RESUMEN

The mammalian visual cortex contains multiple retinotopically defined areas that process distinct features of the visual scene. Little is known about what guides the functional differentiation of visual cortical areas during development. Recent studies in mice have revealed that visual input from the two eyes provides spatiotemporally distinct signals to primary visual cortex (V1), such that contralateral eye-dominated V1 neurons respond to higher spatial frequencies than ipsilateral eye-dominated neurons. To test whether binocular visual input drives the differentiation of visual cortical areas, we used two-photon calcium imaging to characterize the effects of juvenile monocular deprivation (MD) on the responses of neurons in V1 and two higher visual areas, LM (lateromedial) and PM (posteromedial). In adult mice of either sex, we find that MD prevents the emergence of distinct spatiotemporal tuning in V1, LM, and PM. We also find that, within each of these areas, MD reorganizes the distinct spatiotemporal tuning properties driven by the two eyes. Moreover, we find a relationship between speed tuning and ocular dominance in all three areas that MD preferentially disrupts in V1, but not in LM or PM. Together, these results reveal that balanced binocular vision during development is essential for driving the functional differentiation of visual cortical areas. The higher visual areas of mouse visual cortex may provide a useful platform for investigating the experience-dependent mechanisms that set up the specialized processing within neocortical areas during postnatal development.SIGNIFICANCE STATEMENT Little is known about the factors guiding the emergence of functionally distinct areas in the brain. Using in vivo Ca2+ imaging, we recorded visually evoked activity from cells in V1 and higher visual areas LM (lateromedial) and PM (posteromedial) of mice. Neurons in these areas normally display distinct spatiotemporal tuning properties. We found that depriving one eye of normal input during development prevents the functional differentiation of visual areas. Deprivation did not disrupt the degree of speed tuning, a property thought to emerge in higher visual areas. Thus, some properties of visual cortical neurons are shaped by binocular experience, while others are resistant. Our study uncovers the fundamental role of binocular experience in the formation of distinct areas in visual cortex.


Asunto(s)
Diferenciación Celular/fisiología , Visión Binocular/fisiología , Corteza Visual/crecimiento & desarrollo , Corteza Visual/fisiología , Algoritmos , Animales , Mapeo Encefálico , Predominio Ocular/fisiología , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Neocórtex/crecimiento & desarrollo , Neocórtex/fisiología , Plasticidad Neuronal , Estimulación Luminosa , Privación Sensorial , Percepción Espacial/fisiología , Visión Monocular/fisiología , Campos Visuales
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