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International Journal of Molecular... Jul 2019Retinal ganglion cells (RGCs) extend axons out of the retina to transmit visual information to the brain. These connections are established during development through... (Review)
Review
Retinal ganglion cells (RGCs) extend axons out of the retina to transmit visual information to the brain. These connections are established during development through the navigation of RGC axons along a relatively long, stereotypical pathway. RGC axons exit the eye at the optic disc and extend along the optic nerves to the ventral midline of the brain, where the two nerves meet to form the optic chiasm. In animals with binocular vision, the axons face a choice at the optic chiasm-to cross the midline and project to targets on the contralateral side of the brain, or avoid crossing the midline and project to ipsilateral brain targets. Ipsilaterally and contralaterally projecting RGCs originate in disparate regions of the retina that relate to the extent of binocular overlap in the visual field. In humans virtually all RGC axons originating in temporal retina project ipsilaterally, whereas in mice, ipsilaterally projecting RGCs are confined to the peripheral ventrotemporal retina. This review will discuss recent advances in our understanding of the mechanisms regulating specification of ipsilateral versus contralateral RGCs, and the differential guidance of their axons at the optic chiasm. Recent insights into the establishment of congruent topographic maps in both brain hemispheres also will be discussed.
Topics: Animals; Axons; Brain; Cell Lineage; Humans; Retinal Ganglion Cells; Vision, Binocular; Visual Pathways
PubMed: 31277365
DOI: 10.3390/ijms20133282 -
American Journal of Ophthalmology Oct 2022We evaluated patients with hypertropia compatible with a diagnosis of superior oblique (SO) palsy to ascertain whether the 3-step test (3ST) can distinguish SO atrophy...
PURPOSE
We evaluated patients with hypertropia compatible with a diagnosis of superior oblique (SO) palsy to ascertain whether the 3-step test (3ST) can distinguish SO atrophy characteristic of trochlear nerve pathology from masquerading conditions.
DESIGN
Prospective cross-sectional study.
METHODS
In an academic practice, we performed quasi-coronal plane, surface coil magnetic resonance imaging in 83 patients clinically diagnosed with SO palsy. We evaluated alignment, SO cross-sectional area, SO contractility, and rectus muscle pulley positions.
RESULTS
A total of 57 patients with mean age 39 years (SD = 21 years) had unilateral SO palsy manifested by SO atrophy (22 congenital and 35 acquired). There was normal SO size in 26 patients with an average age of 39 years (SD =16 years) considered masquerades (8 congenital and 18 acquired). Maximum palsied SO cross-section averaged 9.5 ± 3.8 mm, less than 18.4 ± 3.9 mm contralaterally (P < 10). In masquerades, maximum hypertropic SO cross-section was 20.7 ± 3.1 mm, which was not different from the hypotropic SO or the contralesional muscle in SO palsy. Head tilt testing in masquerades was indistinguishable from SO palsy. In SO palsy, central hypertropia averaged 13.2 ± 9.4Δ, increasing to 21.1 ± 14.0Δ in ipsilateral tilt, and decreasing to 4.3 ± 5.3Δ in contralateral tilt. In masquerades, central hypertropia averaged 13.1 ± 8.7Δ, and was 17.7 ± 11.1Δ in ipsilateral and decreasing to 4.9 ± 5.1Δ in contralateral tilt. Upright hypertropia was larger at 17.7 ± 9.9Δ in congenital than 12.0 ± 8.4Δ in acquired SO palsy (P = 0025) but was indistinguishable from congenital masquerades. Contractile change in SO cross-section was bilaterally similar in masquerades. Relevant coordinates of rectus pulleys were similar bilaterally in masquerades.
CONCLUSIONS
The 3ST pattern characteristic of unilateral SO palsy may be mimicked in all respects by masquerades.
Topics: Adult; Atrophy; Cross-Sectional Studies; Humans; Oculomotor Muscles; Paralysis; Prospective Studies; Strabismus; Trochlear Nerve Diseases
PubMed: 35618024
DOI: 10.1016/j.ajo.2022.05.017 -
Current Reviews in Musculoskeletal... Aug 2020The purpose of this review is to discuss relevant anatomy and pathoanatomy in the knee following anterior cruciate ligament reconstruction, risk factors for... (Review)
Review
PURPOSE OF REVIEW
The purpose of this review is to discuss relevant anatomy and pathoanatomy in the knee following anterior cruciate ligament reconstruction, risk factors for contralateral ACL tear, and mechanisms of contralateral injuries in the pediatric population.
RECENT FINDINGS
Contralateral ACL rupture rates following ACL reconstruction (ACLR) range from 4% to 42%. Pediatric patients show increased risk compared with adults, likely due to inherent anatomical differences along with biomechanical and neuromuscular changes that occur in both the operative and contralateral knees following index ACLR. Pediatric athletes who return to sport more quickly have been found to be at increased risk for contralateral tears, as have athletes who participate in cutting and pivoting sports. Contralateral tears tend to occur via non-contact mechanisms. Pediatric patients are at increased risk of contralateral ACL injury following index ACL reconstruction compared with adults. Further study is warranted to determine appropriate biologic, functional, and rehabilitative parameters gauged toward preventing contralateral ACL tear while minimizing time lost from sport.
PubMed: 32474896
DOI: 10.1007/s12178-020-09652-w -
The Journal of Comparative Neurology Jun 2016The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions... (Review)
Review
The present Review deals with the motor control of facial expressions in humans. Facial expressions are a central part of human communication. Emotional face expressions have a crucial role in human nonverbal behavior, allowing a rapid transfer of information between individuals. Facial expressions can be either voluntarily or emotionally controlled. Recent studies in nonhuman primates and humans have revealed that the motor control of facial expressions has a distributed neural representation. At least five cortical regions on the medial and lateral aspects of each hemisphere are involved: the primary motor cortex, the ventral lateral premotor cortex, the supplementary motor area on the medial wall, and the rostral and caudal cingulate cortex. The results of studies in humans and nonhuman primates suggest that the innervation of the face is bilaterally controlled for the upper part and mainly contralaterally controlled for the lower part. Furthermore, the primary motor cortex, the ventral lateral premotor cortex, and the supplementary motor area are essential for the voluntary control of facial expressions. In contrast, the cingulate cortical areas are important for emotional expression, because they receive input from different structures of the limbic system.
Topics: Animals; Cerebral Cortex; Face; Facial Expression; Humans; Neural Pathways
PubMed: 26418049
DOI: 10.1002/cne.23908 -
Ear, Nose, & Throat Journal Sep 2022To explore the degree to which patients undergoing unilateral endoscopic sinus surgery (ESS) experience post-operative contralateral sinonasal symptoms and determine...
OBJECTIVES
To explore the degree to which patients undergoing unilateral endoscopic sinus surgery (ESS) experience post-operative contralateral sinonasal symptoms and determine risk factors for contralateral symptomatology following unilateral ESS.
METHODS
Patients who underwent unilateral surgery for chronic rhinosinusitis (CRS) were contacted and asked if they felt symptomatic on the contralateral side at that point in time. Nasal Obstruction Symptom Evaluation (NOSE) scores were obtained based on contralateral symptomatology they recalled at the following time points: pre-ESS, 1 month post-ESS, and 3 months post-ESS. Demographics, contralateral symptomatology, and NOSE scores were compared between those with 2 or fewer sinusotomies versus 3 or more sinusotomies.
RESULTS
Of the 97 patients included in this study, 24% of patients reported contralateral congestion, a median of 24 months post-ESS, and more than 10% of patients reported other contralateral symptoms including swelling, rhinorrhea, difficulty breathing, and hyposmia post-ESS. Those with 2 or fewer sinusotomies were more likely to feel that they had developed worsened sensation of contralateral sinus swelling ( = .008). The median amount of time from the participants' index surgery until the time they were interviewed was 24 months. There were no differences in long-term contralateral symptomatology between those who did and did not have septoplasty (27%).
CONCLUSION
Patients who have unilateral ESS for CRS may experience long-term contralateral symptoms. Having a septoplasty did not affect contralateral symptoms.
PubMed: 36084932
DOI: 10.1177/01455613221125932 -
The Journal of Neuroscience : the... Aug 2021The striatum plays critical roles in visually-guided decision-making and receives dense axonal projections from midbrain dopamine neurons. However, the roles of striatal...
The striatum plays critical roles in visually-guided decision-making and receives dense axonal projections from midbrain dopamine neurons. However, the roles of striatal dopamine in visual decision-making are poorly understood. We trained male and female mice to perform a visual decision task with asymmetric reward payoff, and we recorded the activity of dopamine axons innervating striatum. Dopamine axons in the dorsomedial striatum (DMS) responded to contralateral visual stimuli and contralateral rewarded actions. Neural responses to contralateral stimuli could not be explained by orienting behavior such as eye movements. Moreover, these contralateral stimulus responses persisted in sessions where the animals were instructed to not move to obtain reward, further indicating that these signals are stimulus-related. Lastly, we show that DMS dopamine signals were qualitatively different from dopamine signals in the ventral striatum (VS), which responded to both ipsilateral and contralateral stimuli, conforming to canonical prediction error signaling under sensory uncertainty. Thus, during visual decisions, DMS dopamine encodes visual stimuli and rewarded actions in a lateralized fashion, and could facilitate associations between specific visual stimuli and actions. While the striatum is central to goal-directed behavior, the precise roles of its rich dopaminergic innervation in perceptual decision-making are poorly understood. We found that in a visual decision task, dopamine axons in the dorsomedial striatum (DMS) signaled stimuli presented contralaterally to the recorded hemisphere, as well as the onset of rewarded actions. Stimulus-evoked signals persisted in a no-movement task variant. We distinguish the patterns of these signals from those in the ventral striatum (VS). Our results contribute to the characterization of region-specific dopaminergic signaling in the striatum and highlight a role in stimulus-action association learning.
Topics: Animals; Association Learning; Axons; Choice Behavior; Corpus Striatum; Dominance, Cerebral; Dopamine; Dopaminergic Neurons; Eye Movements; Female; Male; Mice; Mice, Inbred C57BL; Nerve Fibers; Photic Stimulation; Reward
PubMed: 34253628
DOI: 10.1523/JNEUROSCI.0490-21.2021 -
Clinical Oncology (Royal College of... May 2021To analyse outcomes and patterns of failure in patients with oropharyngeal carcinoma (OPC) treated with definitive volumetric modulated arc therapy with omission of...
Radiotherapy for Oropharyngeal Carcinoma With an Uninvolved Contralateral Neck: The Safety of Omission of Contralateral High Level II and Retropharyngeal Lymph Nodes From Elective Target Volumes.
AIMS
To analyse outcomes and patterns of failure in patients with oropharyngeal carcinoma (OPC) treated with definitive volumetric modulated arc therapy with omission of contralateral high level II lymph nodes (HLII) and retropharyngeal lymph nodes (RPLN) in the contralateral uninvolved neck.
MATERIALS AND METHODS
Patients with OPC treated between January 2016 and July 2019 were retrospectively identified. In the absence of contralateral neck disease, institutional protocols allowed omission of contralateral HLII and contralateral RPLN in the additional absence of ipsilateral RPLN, soft palate/posterior pharyngeal wall primary.
RESULTS
In total, 238 patients with OPC and an uninvolved contralateral neck received definitive (chemo)radiotherapy with bilateral neck treatment. The median follow-up was 30.6 months. Two-year local control, regional control and overall survival were 91.0, 91.6 and 86.5%, respectively. Contralateral HLII were omitted in 159/238 (66.8%) patients; this included 106 patients in whom the primary tumour was at/crossed the midline. The contralateral RPLN region was omitted from elective target volumes for 175/238 (73.5%); this included 114 patients with a primary tumour at/crossed the midline. The mean contralateral parotid dose when contralateral HLII and RPLN were both omitted was 24.4 Gy, compared with 28.3 Gy without HLII/RPLN omission (P < 0.001). Regional progression occurred in 18/238 (7.6%) patients, all involving the ipsilateral neck with one bilateral. There were no recurrences in the contralateral HLII or RPLN regions.
CONCLUSION
In patients with OPC and an uninvolved contralateral neck receiving bilateral (chemo)radiotherapy, the omission of contralateral RPLN and HLII from elective target volumes was safe and could lead to reduced contralateral parotid doses.
Topics: Carcinoma; Humans; Lymph Nodes; Neoplasm Staging; Oropharyngeal Neoplasms; Retrospective Studies
PubMed: 33358282
DOI: 10.1016/j.clon.2020.12.007 -
Acta Otorhinolaryngologica Italica :... Oct 2015The aim of this study was to investigate the amount of binaural squelch effect (BSE) and head shadow effect (HSE) in children who use unilateral cochlear implants (CI)... (Review)
Review
The aim of this study was to investigate the amount of binaural squelch effect (BSE) and head shadow effect (HSE) in children who use unilateral cochlear implants (CI) and contralateral hearing aids (HA). The study group consisted of 19 CI recipient children who consistently wore a contralateral HA. Speech sounds were used to evaluate speech perception performance in noise. Testing was performed in three listening conditions: (1) bimodal listening with noise source on HA side; (2) CI only with noise source contralaterally (HA off); (3) CI only with noise source on the CI side. Statistical analysis revealed a significant difference between the three listening conditions and post hoc tests indicated significant differences for all pairwise comparisons (p < 0.001). The average BSE and HSE were 11.8% and 17.1% respectively. The majority of bimodal CI users showed BSE and HSE with significant speech perception improvement in the presence of noise.
Topics: Child; Cochlear Implantation; Cochlear Implants; Hearing Aids; Humans; Speech Perception; Treatment Outcome
PubMed: 26824917
DOI: 10.14639/0392-100X-497