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Acta Ophthalmologica Mar 2018To evaluate the role of neural integrators (NI) in the oculomotor system. (Review)
Review
PURPOSE
To evaluate the role of neural integrators (NI) in the oculomotor system.
METHODS
A literature search was carried out using several electronic databases during the months of June 2014 to March 2015. The following keywords were used to generate focused results: 'neural integrators', 'gaze-holding', 'oculomotor integration', 'impaired gaze-holding', 'gaze evoked nystagmus' and 'gaze dysfunction'. Further materials were found through searching relevant articles within reference lists. Seventy-one articles were sourced for this review which analysed animal and human subjects and network models; 45 were studies of humans, 16 studies of primates, three studies of felines and one study from rats and network models. The remaining articles were literature reviews.
RESULTS
The horizontal and vertical, including torsional, NI are located logically in the brainstem, nearby their appropriate target extraocular motoneuron nuclei for stable eye position in eccentric position. The nucleus prepositus hypoglossi (NPH) and medial vestibular nuclei (MVN) are closely linked at the caudal pons and dorsal rostral medulla, integrating horizontal conjugate eye movement. The interstitial nucleus of Cajal (INC) integrates vertical and torsional eye movement at the upper midbrain. The integrator time constant is averaged to 25 seconds in human horizontal and animal vertical NI to perform its function. Case reports revealed that dysfunction of horizontal NI also resulted in vertical ocular deviations, indicating some overlap of horizontal and vertical gaze control. Furthermore, pharmacological inactivation of NI exposed a population of inhibitory neurotransmitters that permits its mechanism of action; allowing for smooth conjugate movement.
CONCLUSIONS
Neural integrators operate to integrate eye velocity and eye position information to provide signals to extraocular motoneurons to attain and maintain a new position. Therefore, NI allow image stabilization during horizontal and vertical eye movements at eccentric positions for comfortable single vision.
Topics: Animals; Eye Movements; Fixation, Ocular; Humans; Oculomotor Nerve; Sensory Receptor Cells; Visual Fields
PubMed: 27874249
DOI: 10.1111/aos.13307 -
Eye (London, England) Mar 2021The purpose of this study is to systematically review the reported data of normal optical coherence tomography (OCT) results in the paediatric population. A systematic... (Review)
Review
The purpose of this study is to systematically review the reported data of normal optical coherence tomography (OCT) results in the paediatric population. A systematic literature search was performed using the PubMed, Embase, and Web of Science databases, using the keywords "optical coherence tomography"; "normative data" or "healthy eyes"; "children" or "paediatric population". Studies with at least 50 participants were included, irrespective of the OCT equipment employed. We excluded the OCT angiography studies or the studies investigating the choroidal thickness. Seventy-four studies were included in the final analysis and information on study design, number of participants, demographic characteristics, type of OCT equipment, OCT parameters and results was collected. Due to the high variability of OCT instruments and parameters used, a meta-analysis was not feasible. We report the normative values for the peripapillary retinal nerve fibre layer thickness and the macular retinal thickness for each ETDRS quadrant, as provided by the studies included in the present analysis. We also report the influence of ethnicity, age, gender, eye laterality, ISNT rule, spherical equivalent, and axial length on OCT results.
Topics: Child; Choroid; Cross-Sectional Studies; Humans; Refraction, Ocular; Retina; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 32929184
DOI: 10.1038/s41433-020-01177-3 -
Brain Research Oct 2023Light is detected in the eye by three classes of photoreceptors (rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs)) that are each optimized... (Meta-Analysis)
Meta-Analysis Review
Light is detected in the eye by three classes of photoreceptors (rods, cones, and intrinsically photosensitive retinal ganglion cells (ipRGCs)) that are each optimized for a specific function and express a particular light-detecting photopigment. The significant role of short-wavelength light and ipRGCs in improving alertness has been well-established; however, few reviews have been undertaken to assess the other wavelengths' effects regarding timing and intensity. This study aims to evaluate the impact of different narrowband light wavelengths on subjective and objective alertness among the 36 studies included in this systematic review, 17 of which were meta-analyzed. Short-wavelength light (∼460-480 nm) significantly improves subjective alertness, cognitive function, and neurological brain activities at night, even for a sustained period (∼6h) (for λmax: 470/475 nm, 0.4 < |Hedges's g| < 0.6, p < 0.05), but except early morning, it almost does not show this effect during the day when melatonin level is lowest. Long-wavelength light (∼600-640 nm) has little effect at night, but significantly increases several measures of alertness at lower irradiance during the daytime (∼1h), particularly when there is homeostatic sleep drive (for λmax: ∼630 nm, 0.5 < |Hedges's g| < 0.8, p < 0.05). The results further suggest that melanopic illuminance may not always be sufficient to measure the alerting effect of light.
Topics: Circadian Rhythm; Sleep; Retinal Cone Photoreceptor Cells; Retinal Ganglion Cells; Retinal Rod Photoreceptor Cells
PubMed: 37364848
DOI: 10.1016/j.brainres.2023.148470 -
Neurological Sciences : Official... Mar 2021Migraine is one of the most common disabling diseases in the world. Its recurrent attacks may lead to abnormalities in the structure of the brain and retina. An... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Migraine is one of the most common disabling diseases in the world. Its recurrent attacks may lead to abnormalities in the structure of the brain and retina. An increasing number of studies have investigated retinal nerve fiber layer (RNFL) thickness alterations in migraine by the optical coherence tomography (OCT); however, no consensus has yet reached.
METHOD
We searched Pubmed, Embase, and Web of Science databases to identify studies that investigated RNFL thickness in migraine by OCT measurement and performed a meta-analysis of eligible studies.
RESULTS
Twenty-six studies were included in the meta-analysis, comprising 1530 migraine patients and 1105 healthy controls. The mean RNFL thickness was thinner in the migraine group compared to the control group (SMD =- 0.53). In the subgroup analyses, RNFL thickness were decreased most significantly in the superior (SMD = - 0.71) and inferior (SMD = - 0.63) quadrants among all quadrants. Migraine with aura (SMD = - 0.91) showed a greater effect size of RNFL thickness reduction than migraine without aura (SMD =- 0.47). Spectral-domain OCT (SMD = - 0.55) seems more sensitive to detect RNFL thickness reduction than time-domain OCT (SMD = - 0.44). In addition, age, sex, disease duration, attack frequency, and intraocular pressure were not significantly associated with RNFL thickness.
CONCLUSIONS
The findings from our comprehensive meta-analysis with large datasets strengthen the clinical evidence of the RNFL thickness reduction in migraine. RNFL thickness via spectral-domain OCT measurement demonstrates the potential role in differentiating patients with migraine, especially migraine with aura, from healthy controls.
Topics: Humans; Migraine Disorders; Nerve Fibers; Retina; Retinal Ganglion Cells; Tomography, Optical Coherence
PubMed: 33439389
DOI: 10.1007/s10072-020-04992-4 -
NeuroImage Oct 2016Transcranial alternating current stimulation (tACS) applies exogenous oscillatory electric field potentials to entrain neural rhythms and is used to investigate... (Review)
Review
Transcranial alternating current stimulation (tACS) applies exogenous oscillatory electric field potentials to entrain neural rhythms and is used to investigate brain-function relationships and its potential to enhance perceptual and cognitive performance. However, due to current spread tACS can cause cutaneous activation of the retina and phosphenes. Several lines of evidence suggest that retinal phosphenes are capable of inducing neural entrainment, making the contributions of central and peripheral stimulation to the effects in the brain difficult to disentangle. In this literature review, the importance of this issue is further illustrated by the fact that photic stimulation can have a direct impact on perceptual and cognitive performance. This leaves open the possibility that peripheral photic stimulation can at least in part explain the central effects that are attributed to tACS. The extent to which phosphene perception contributes to the effects of exogenous oscillatory electric fields in the brain and influence perception and cognitive performance needs to be examined to understand the working mechanisms of tACS in neurophysiology and behaviour.
Topics: Animals; Brain Mapping; Brain Waves; Evidence-Based Medicine; Evoked Potentials, Visual; Humans; Phosphenes; Photic Stimulation; Retinal Ganglion Cells; Transcranial Direct Current Stimulation; Visual Cortex; Visual Pathways; Visual Perception
PubMed: 26453929
DOI: 10.1016/j.neuroimage.2015.09.067 -
Ophthalmic Research 2024Anterior ischemic optic neuropathy (AION) can mimic glaucoma and consequently cause difficulties in differential diagnosis. The purpose of this paper was to summarize... (Review)
Review
INTRODUCTION
Anterior ischemic optic neuropathy (AION) can mimic glaucoma and consequently cause difficulties in differential diagnosis. The purpose of this paper was to summarize differences in diagnostic tests that can help perform a correct diagnosis.
METHODS
The search strategy was performed according to the PRISMA 2009 guidelines, and four databases were used: MEDLINE, Embase, Web of Science, and Cochrane. Totally, 772 references were eligible; 39 were included after screening with respect to inclusion criteria that included English language and published in the 20 years before search date.
RESULTS
Ninety percent (n = 35) of included studies used optical coherence tomography (OCT). Glaucomatous eyes had a significantly greater cup area, volume and depth, cup-to-disk ratio, a lower rim volume and area, and a thinner Bruch's membrane opening-minimum rim width. Retinal nerve fiber layer (RNFL) thinning in glaucomatous eyes occurred primarily at the superotemporal, inferotemporal, and inferonasal sectors, while AION eyes demonstrated mostly superonasal thinning. Glaucoma eyes showed greater macular ganglion cell layer thickness, except at the inferotemporal sector. OCT angiography measurements demonstrated a significant decrease in superficial and deep macular vessel density (VD) in glaucoma compared to AION with similar degree of visual field damage; the parapapillary choroidal VD was spared in AION eyes compared to glaucomatous eyes.
CONCLUSION
By use of OCT imaging, optic nerve head parameters seem most informative to distinguish between glaucoma and AION. Although both diseases affect the RNFL thickness, it seems to do so in different sectors. Differences in structure and vascularity of the macula can also help in making the differential diagnosis.
Topics: Humans; Optic Neuropathy, Ischemic; Diagnosis, Differential; Tomography, Optical Coherence; Nerve Fibers; Retinal Ganglion Cells; Optic Disk; Glaucoma; Visual Fields; Intraocular Pressure
PubMed: 38262372
DOI: 10.1159/000535568 -
American Journal of Hypertension Feb 2023The rates of uncontrolled hypertension, along with downstream cardiovascular outcomes, has been worsening in this country. Despite the plethora of antihypertensive...
BACKGROUND
The rates of uncontrolled hypertension, along with downstream cardiovascular outcomes, has been worsening in this country. Despite the plethora of antihypertensive medications on the market, the prevalence of resistant hypertension (RH) is estimated to be 13.7%. Therefore in addition to increased clinical education and focus on lifestyle management of hypertension and medication compliance, new therapies are needed to address this rise in hypertension.
METHODS
A systematic review of the available medical literature was performed to identify emerging treatment options for RH.
RESULTS
Six different pharmacologic classes and 2 procedural interventions were identified as being appropriate for review in this paper. The pharmacologic classes to be explored are non-steroidal mineralocorticoid receptor antagonists, aminopeptidase A inhibitors, dual endothelin antagonists, aldosterone synthetase inhibitors, atrial natriuretic peptide inhibitors, and attenuators of hepatic angiotensinogen. Discussion of procedural interventions to lower blood pressure will focus on renal denervation and devices that increase carotid baroreceptor activity.
CONCLUSIONS
Promising medication and procedural interventions are being developed and studied to expand our treatment arsenal for patients with uncontrolled essential hypertension and RH.
Topics: Humans; Hypertension; Antihypertensive Agents; Blood Pressure; Kidney; Pressoreceptors
PubMed: 36201204
DOI: 10.1093/ajh/hpac111 -
Cells Mar 2022Galanin is a neuropeptide expressed in a small percentage of sensory neurons of the dorsal root ganglia and the superficial lamina of the dorsal horn of the spinal cord.... (Review)
Review
Galanin is a neuropeptide expressed in a small percentage of sensory neurons of the dorsal root ganglia and the superficial lamina of the dorsal horn of the spinal cord. In this work, we systematically reviewed the literature regarding the role of galanin and its receptors in nociception at the spinal and supraspinal levels, as well as in chronic pain conditions. The literature search was performed in PubMed, Web of Science, Scopus, ScienceDirect, OVID, TRIP, and EMBASE using "Galanin" AND "pain" as keywords. Of the 1379 papers that were retrieved in the initial search, we included a total of 141 papers in this review. Using the ARRIVE guidelines, we verified that 89.1% of the works were of good or moderate quality. Galanin shows a differential role in pain, depending on the pain state, site of action, and concentration. Under normal settings, galanin can modulate nociceptive processing through both a pro- and anti-nociceptive action, in a dose-dependent manner. This peptide also plays a key role in chronic pain conditions and its antinociceptive action at both a spinal and supraspinal level is enhanced, reducing animals' hypersensitivity to both mechanical and thermal stimulation. Our results highlight galanin and its receptors as potential therapeutic targets in pain conditions.
Topics: Animals; Chronic Pain; Galanin; Ganglia, Spinal; Sensory Receptor Cells; Spinal Cord
PubMed: 35269462
DOI: 10.3390/cells11050839 -
Lin Chuang Er Bi Yan Hou Tou Jing Wai... Jun 2021As one of the neurotrophic factors and insulin family, insulin like growth factor-1(IGF-1) can promote cell synthesis and metabolism in tissues and organs, activate... (Review)
Review
As one of the neurotrophic factors and insulin family, insulin like growth factor-1(IGF-1) can promote cell synthesis and metabolism in tissues and organs, activate cell growth, proliferation and differentiation, and inhibit cell apoptosis. Sensorineural hearing loss is the most common manifestation of the inner ear disease, which is mainly caused by the damage of cochlear hair cells. The lack of IGF-1 directly affects the growth, development and differentiation of cochlear hair cells, thus IGF-1 participates in the maintenance of cell survival and repair during inner ear cell injury. This article systematically reviews the recent research progress on the protective mechanism of IGF-1 on the inner ear.
Topics: Ear, Inner; Hair Cells, Auditory; Hearing Loss, Sensorineural; Humans; Insulin-Like Growth Factor I; Nerve Growth Factors; Spiral Ganglion
PubMed: 34304523
DOI: 10.13201/j.issn.2096-7993.2021.06.020 -
Journal of Neuroimmunology Dec 2018This meta-analysis aimed to systematically review current literature measuring the thickness of retinal nerve fiber layer (RNFL) in patients with myelin oligodendrocyte... (Meta-Analysis)
Meta-Analysis Review
This meta-analysis aimed to systematically review current literature measuring the thickness of retinal nerve fiber layer (RNFL) in patients with myelin oligodendrocyte glycoprotein antibodies (MOG-ab) associated optic neuritis. Ten studies were enrolled and the results showed that the degree of RNFL loss in MOG-ab-positive optic neuritis patients may not differ from that of AQP4-ab patients. However, patients who were positive for MOG-ab showed more severe RNFL loss than those who were seronegative.
Topics: Animals; Autoantibodies; Humans; Myelin-Oligodendrocyte Glycoprotein; Nerve Fibers; Observational Studies as Topic; Optic Neuritis; Retina; Retinal Neurons
PubMed: 30290966
DOI: 10.1016/j.jneuroim.2018.09.011