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Annual Review of Neuroscience Apr 2024Seeing in three dimensions is a major property of the visual system in mammals. The circuit underlying this property begins in the retina, from which retinal ganglion... (Review)
Review
Seeing in three dimensions is a major property of the visual system in mammals. The circuit underlying this property begins in the retina, from which retinal ganglion cells (RGCs) extend to the same or opposite side of the brain. RGC axons decussate to form the optic chiasm, then grow to targets in the thalamus and midbrain, where they synapse with neurons that project to the visual cortex. Here we review the cellular and molecular mechanisms of RGC axonal growth cone guidance across or away from the midline via receptors to cues in the midline environment. We present new views on the specification of ipsi- and contralateral RGC subpopulations and factors implementing their organization in the optic tract and termination in subregions of their targets. Lastly, we describe the functional and behavioral aspects of binocular vision, focusing on the mouse, and discuss recent discoveries on the evolution of the binocular circuit.
PubMed: 38635868
DOI: 10.1146/annurev-neuro-111020-093230 -
Scientific Reports Apr 2024We aimed to investigate the changes in cupping in chiasmal lesion optic neuropathy (chON) compared to baseline optic disc and glaucoma. We used a novel study design to...
We aimed to investigate the changes in cupping in chiasmal lesion optic neuropathy (chON) compared to baseline optic disc and glaucoma. We used a novel study design to enroll patients who had fundus photographs incidentally taken during routine health check-ups prior to the onset of optic neuropathy. In 31 eyes (21 patients) with chON and 33 eyes (30 patients) with glaucoma, we investigated the change in cup-to-disc (C/D) area from the baseline to overt cupping using flicker analysis. Compared to the baseline, 23 eyes (74.2%) had increased cup size and 3 (9.7%) had vascular configuration changes in the chONgroup; in contrast, all glaucoma eyes exhibited changes in cup size and vascular configuration. The increase in C/D area ratio was significantly smaller in chON (0.04 ± 0.04) compared to glaucoma (0.10 ± 0.04, P < 0.001); the minimum residual neuroretinal rim width showed a more pronounced difference (29.7 ± 8.2% vs 7.1 ± 3.9%, P < 0.001). The changes distributed predominantly towards the nasal direction in chON, contrasting the changes to the arcuate fibers in glaucoma. In conclusion, our results provide the first longitudinal evidence of true pathological cupping in chONcompared to photographically disease-free baseline. The marked difference in the residual minimum rim width reaffirms the importance of rim obliteration in the differential diagnosis between the two diseases.
Topics: Humans; Optic Disk; Glaucoma; Optic Nerve Diseases; Optic Chiasm; Fundus Oculi; Intraocular Pressure
PubMed: 38632299
DOI: 10.1038/s41598-024-59419-3 -
Surgical Neurology International 2024Giant internal carotid artery (ICA) aneurysms are usually treated through flow diversion, coiling, or a combination of both. However, certain cases that fail the...
BACKGROUND
Giant internal carotid artery (ICA) aneurysms are usually treated through flow diversion, coiling, or a combination of both. However, certain cases that fail the endovascular treatment pose a technical challenge.
CASE DESCRIPTION
A 68-year-old male presented with gradual visual changes affecting his right eye and was found to have a giant unruptured right paraophthalmic aneurysm. The aneurysm showed growth, and the patient's symptoms worsened despite coiling and flow diversion. Due to the location of this aneurysm and persistent compression of the optic chiasm by the coil mass, his right ICA was sacrificed, and an expanded endoscopic endonasal approach was successfully used to clip the residual aneurysm, remove the coil mass, and thus, decompress the optic chiasm. The patient's visual symptoms improved after that, and post clipping imaging demonstrated adequate occlusion of his right paraophthalmic aneurysm.
CONCLUSION
Recognizing the option of an endoscopic endonasal approach for clipping giant internal carotid aneurysms is of great importance. This approach can be safe and technically successful for the treatment of paraophthalmic aneurysms that fail the typical endovascular treatment.
PubMed: 38628543
DOI: 10.25259/SNI_939_2023 -
World Neurosurgery Apr 2024Suprasellar cysticercosis is a rare entity. Only a few cases are reported in the literature. Clinically, present with visual loss and endocrinopathy and radiologically...
Suprasellar cysticercosis is a rare entity. Only a few cases are reported in the literature. Clinically, present with visual loss and endocrinopathy and radiologically mimic craniopharyngioma, cystic pituitary adenoma, and Rathke cleft cyst. We present the case of a 34-year-old woman with a history of diminution of vision for 2 months. On examination, her visual acuity was 6/9 bilaterally, per the Snellen chart. The visual field showed incomplete temporal hemianopia in the right eye and a severely depressed field in the left eye. She was evaluated with magnetic resonance imaging (MRI) of the brain, which showed multiple well-defined enhancing cystic lesions in the suprasellar cistern splaying the optic chiasm. Enzyme-linked immunoelectrotransfer blot testing was not done due to the lack of availability at our center. She underwent left pterional craniotomy and excision of the cysts. Multiple cysts were noted during surgery, and all were dissected from the surrounding structures. However, there was a spillage of cystic contents during excision, and they are not associated with any adverse reactions, unlike hydatid cysts. She recovered well. Histopathology suggestive of cysticercal cyst, no scolexes. As per Infectious Diseases Society of America, non-operated subarachnoid neurocysticercosis requires prolonged antiparasitic agents along with steroids. She received 6 weeks of albendazole 15 mg/kg/day and steroids tapered over 3 weeks. At 2 years of follow-up, her visual acuity improved to 6/6 with a normal visual field. Follow-up MRI showed complete removal of all cysts with no relapse. Early surgery is safe and effective. Visual outcome depends on the timing of the diagnosis and prompt intervention.
PubMed: 38616022
DOI: 10.1016/j.wneu.2024.04.036 -
Acta Radiologica (Stockholm, Sweden :... Apr 2024Differential diagnosis of hypothalamic-optic chiasmatic gliomas (HOCGs) and craniopharyngiomas on magnetic resonance imaging (MRI) can be quite challenging.
BACKGROUND
Differential diagnosis of hypothalamic-optic chiasmatic gliomas (HOCGs) and craniopharyngiomas on magnetic resonance imaging (MRI) can be quite challenging.
PURPOSE
To compare the MRI features of HOCGs and cranipharyngiomas.
MATERIAL AND METHODS
Patients diagnosed with HOCG or craniopharyngioma in histopathological evaluation between 2012 and 2022 and who underwent preoperative contrast-enhanced brain MRI were included. Various MRI features were retrospectively evaluated for each lesion: T2-weighted imaging and fluid attenuation inversion recovery hyperintensity, calcification, cystic change, T1-weighted (T1W) imaging hyperintensity of the cystic component, hemorrhage, involvement of sellar, suprasellar or other adjacent structures, lobulated appearance, presence of hydrocephalus, and contrast enhancement pattern. Apparent diffusion coefficient (ADC) values were also evaluated and compared.
RESULTS
Among 38 patients included, 13 (34%) had HOCG and 25 (66%) had craniopharyngioma. Craniopharyngiomas had a significantly higher rate of cystic changes, calcification, and T1W imaging hyperintensity of the cystic component than HOCGs ( <0.05). Of HOCGs, 92% had chiasm involvement, 23% had optic nerve involvement, and 31% had brain stem involvement. On the other hand, chiasm involvement was observed in 8% of craniopharyngiomas, but none had optic nerve and/or brain stem involvement ( <0.05). While 62% (8/13) of HOCGs had diffuse homogeneous enhancement, 80% (20/25) of craniopharyngiomas had a diffuse heterogeneous enhancement pattern. Mean ADC values were significantly higher in craniopharyngiomas compared to HOCGs (2.1 vs. 1.6 ×10mm/s, <0.05).
CONCLUSION
Although some neuroimaging findings may overlap, features such as presence of cyst and calcification, brain stem and optic pathway involvement, different enhancement patterns, and ADC values may be helpful in the differential diagnosis of HOCGs and craniopharyngiomas.
PubMed: 38613353
DOI: 10.1177/02841851241241527 -
Journal of Neurosurgery Apr 2024Preservation of visual function is important in surgery for suprasellar tumors. Visual evoked potentials (VEPs) are expected to play an important role in monitoring...
OBJECTIVE
Preservation of visual function is important in surgery for suprasellar tumors. Visual evoked potentials (VEPs) are expected to play an important role in monitoring visual function during surgery. Given the lack of information in this field, the authors aimed to investigate the effects of optic nerve compression caused by suprasellar tumors to understand the possible usefulness of VEP monitoring using off-response (OFR) VEP.
METHODS
Eleven healthy volunteers who underwent surgery for standard record confirmation and 32 patients with optic chiasm lesions who underwent surgery were examined. Preoperative, postoperative, and intraoperative VEPs were recorded. Propofol anesthesia was administered during intraoperative VEP monitoring. Patients who underwent surgery were monitored using the same stimulation method during surgery. Light stimulation was given from a luminant pad on the eyelids, and low-intensity stimulation with continuous 500-msec emission and 500 msec off was performed. The luminescence intensity of the stimulation was at a maximum of 8000 lx with three attenuation steps, each of which was recorded repeatedly.
RESULTS
The OFR potentials and delay latencies decreased as stimulus intensity decreased. In the patient with temporal hemianopia, monocular stimulation produced the highest OFR in the contralateral occipital lobe of the stimulated eye. The authors recorded preoperative, intraoperative, and postoperative VEP in 32 patients and observed intraoperative changes in 23 patients. In the cases where VEP declined during intraoperative recording, it recovered when surgery was discontinued. Furthermore, 3 patients eventually achieved a higher VEP than that achieved at the beginning of the surgery, and rapid recovery was confirmed with visual field examination immediately after surgery. Of the 5 patients in whom VEP did not recover during surgery, 3 showed decreased visual field and acuity after surgery. In 15 cases, potential dropped temporarily but returned to the original potential, and their visual field recovered after surgery.
CONCLUSIONS
OFR has a diagnostic element in the visual field, in which the maximal potential was recorded on the opposite side of the stimulus with monocular stimulation. Unambiguous determination required stimulation of different intensities in both eyes or 1 eye and multiple recording electrodes placed in the occiput. Monitoring the OFR provides real-time alerts, making it a valuable tool for visual function evaluation in suprasellar surgery.
PubMed: 38608298
DOI: 10.3171/2024.1.JNS232118 -
Neurosurgical Focus Apr 2024The authors aim to describe the advantages, utility, and disadvantages of the transpalpebral mini-orbitozygomatic (MOZ) approach for tumors of the lateral and superior...
OBJECTIVE
The authors aim to describe the advantages, utility, and disadvantages of the transpalpebral mini-orbitozygomatic (MOZ) approach for tumors of the lateral and superior orbit, orbital apex, anterior clinoid, anterior cranial fossa, middle cranial fossa, and parasellar region.
METHODS
The surgical approach from skin incision to closure is described while highlighting key technical and anatomical considerations, and cadaveric dissection demonstrates the surgical steps and focuses on important anatomy. Intraoperative images were included to supplement the cadaveric dissection. A retrospective review of adults who had undergone the MOZ approach for nonvascular pathology performed by a single neurosurgeon from 2017 to 2023 was included in this institutional review board-approved study. Descriptive statistics was used to summarize the data. Four representative cases were included to demonstrate the utility of the MOZ approach.
RESULTS
The study included 65 patients (46 female, 19 male), average age 54.84 years, who had undergone transpalpebral MOZ surgery. Presenting symptoms included visual changes (53.8% of cases), vision loss (23.1%), diplopia (21.8%), and proptosis (13.8%). The optic nerve and optic chiasm were involved in 32.3% and 10.8% of cases, respectively. The most common pathology was meningioma (81.5% of cases), and gross-total resection was achieved in 50% of all cases. Major complications included an infection and a carotid injury. Improvement of preoperative symptoms was reported in 92.2% of cases. Visual acuity improved in 12 patients. The mean follow-up was 8.57 ± 8.45 months.
CONCLUSIONS
The MOZ approach is safe and durable. The transpalpebral incision provides better cosmesis and functional outcomes than those of standard anterolateral approaches to the skull base. Careful consideration of the limits of the approach is paramount to appropriate application on a case-by-case basis. Further quantitative anatomical studies can help to define and compare the utility of the approach to open cranio-orbital and endoscopic transorbital approaches.
Topics: Adult; Humans; Male; Female; Middle Aged; Neurosurgeons; Skull Base; Cranial Fossa, Anterior; Meningeal Neoplasms; Cadaver
PubMed: 38560929
DOI: 10.3171/2024.1.FOCUS23875 -
Developmental Dynamics : An Official... Mar 2024Neuronal lamination is a hallmark of the mammalian central nervous system (CNS) and underlies connectivity and function. Initial formation of this tissue architecture...
BACKGROUND
Neuronal lamination is a hallmark of the mammalian central nervous system (CNS) and underlies connectivity and function. Initial formation of this tissue architecture involves the integration of various signaling pathways that regulate the differentiation and migration of neural progenitor cells.
RESULTS
Here, we demonstrate that mTORC1 mediates critical roles during neuronal lamination using the mouse retina as a model system. Down-regulation of mTORC1-signaling in retinal progenitor cells by conditional deletion of Rptor led to decreases in proliferation and increased apoptosis during embryogenesis. These developmental deficits preceded aberrant lamination in adult animals which was best exemplified by the fusion of the outer and inner nuclear layer and the absence of an outer plexiform layer. Moreover, ganglion cell axons originating from each Rptor-ablated retina appeared to segregate to an equal degree at the optic chiasm with both contralateral and ipsilateral projections displaying overlapping termination topographies within several retinorecipient nuclei. In combination, these visual pathway defects led to visually mediated behavioral deficits.
CONCLUSIONS
This study establishes a critical role for mTORC1-signaling during retinal lamination and demonstrates that this pathway regulates diverse developmental mechanisms involved in driving the stratified arrangement of neurons during CNS development.
PubMed: 38546215
DOI: 10.1002/dvdy.707 -
Journal of Clinical Neuroscience :... May 2024
Topics: Female; Humans; Arachnoiditis; Magnetic Resonance Imaging; Optic Chiasm; Adolescent
PubMed: 38537578
DOI: 10.1016/j.jocn.2024.03.022 -
World Neurosurgery Jun 2024Traditional microsurgical approaches for addressing intraventricular craniopharyngioma provide limited access to the retrochiasmatic area and tumors with significant...
Fully Endoscopic Minimally Invasive Trans-Eyebrow Supraorbital Translaminar Approach to Third Ventricle Craniopharyngiomas: Technical Nuances and Stepwise Illustrative Description.
BACKGROUND
Traditional microsurgical approaches for addressing intraventricular craniopharyngioma provide limited access to the retrochiasmatic area and tumors with significant lateral or rostrocaudal extensions. Extended endoscopic endonasal approaches can effectively overcome many of limitations, yet they require a favorable working angle between the optic chiasm and pituitary gland, as well as the involvement of the third ventricle floor by the tumor.
METHODS
Herein, the authors describe the surgical nuances of a keyhole technique for resecting third ventricle craniopharyngiomas via a fully endoscopic minimally invasive trans-eyebrow supraorbital translaminar approach (ESOTLA). A case description detailing the key surgical steps and application of the approach is provided, along with a series of cadaveric photographs to highlight the relevant anatomy and step-by-step dissection process.
RESULTS
The patient is a 44-year-old man who presented with polyuria, low urine specific gravity, and panhypopituitarism. Brain magnetic resonance imaging revealed a solid-cystic heterogeneous-enhanced retrochiasmatic mass within the third ventricle, consistent with craniopharyngioma. A 1-stage ESOTLA was indicated based on the narrow pituitary-chiasm angle and the high functional status of the patient. Near-total resection was achieved, and no new postoperative neurologic or endocrine change was observed. Targeted therapy was implemented based on the histologic result, and the most recent surveillance magnetic resonance imaging showed no evidence of the residual tumor.
CONCLUSIONS
By combining a keyhole approach with variable-angle endoscopic visualization through a smaller bony and soft tissue exposure, ESOTLA can provide enhanced illumination within the third ventricle, potentially addressing cosmetic concerns and limited exposure area/angle of freedom associated with its conventional microsurgical counterpart.
Topics: Humans; Craniopharyngioma; Male; Third Ventricle; Pituitary Neoplasms; Neuroendoscopy; Adult; Cerebral Ventricle Neoplasms; Eyebrows; Minimally Invasive Surgical Procedures; Neurosurgical Procedures; Magnetic Resonance Imaging
PubMed: 38522791
DOI: 10.1016/j.wneu.2024.03.095