scholarly journals IDENTIFYING TRENDS IN MICROSACCADE RATE ON OCULOMOTOR TRACKER IN EARLY VS LATE STAGE PEDIATRIC CASES WITH PERSISTENT POST-CONCUSSION SYMPTOMS (PPCS)

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0016
Author(s):  
Prem Kumar Thirunagari ◽  
Nancy Phu ◽  
David Tramutolo ◽  
Hector Rieiro ◽  
Tanya Polec ◽  
...  
Keyword(s):  
Eye Movements ◽  
Late Stage ◽  
Visual Processing ◽  
Pediatric Patients ◽  
Early Stage ◽  
Statistical Significance ◽  
Small Sample ◽  
T Test ◽  
Fixational Eye Movements

Background: Oculomotor and visual processing deficits occur commonly after brain injury in young athletes. A subset of these concussed athletes do experience prolonged recoveries or PPCS with ongoing oculomotor deficits and visual symptoms. There have been limited studies conducted to determine the significance of oculomotor tracking (OMT) testing in the pediatric population, and even less investigating the role of microsaccades. Hence, investigations on microsaccades(MS), physiological adjustive micro eye movements critical in visual processing and central/peripheral visual integration, may provide insight on the role of visual dysfunction in PPCS course, prognosis, and management. Purpose: The purpose of this study is to identify possible MS rate trends and differences between early and late stage PPCS pediatric patients. Methods: A retrospective cohort study of 41 pediatric patients with PPCS or symptoms greater than one month from injury. Data was collected from 7/1/2018 to 12/1/2019 and the age group ranged from 8 to 21 years. For each participant, using the OMT device we measured the number of saccades generated, the size and speed of the microsaccades, the area covered and the ratio of vertical-to-horizontal direction component of the fixational eye movements, using a 250 Hz video-eye tracker mounted inside a HTC Vive VR headset. Participants were instructed to fixate on a central dot for 140 seconds, in 20-second intervals. Patients were classified into early or late stages of PPCS (early stage: 1-6 months; late stage: >6 months) to compare MS rate between stages. Exclusion criteria included history of visual disorders, learning disorders, seizure disorder, or intracranial hemorrhage. Results: 27 patients were in the early stage while 14 patients were in the late stage. The early stage group had a mean MS rate of 125 beats/min while the late stage group had a mean MS rate of 116 beats/min. A two sample t-test assuming no difference between early and late stage patients resulted in a p value of 0.51. Conclusion: There is a potential trend in declining MS numbers with progressive PPCS stage. Although the t-test didn’t show statistical significance, this could be due to the small sample size of our study. Future studies are needed to validate this initial finding and to identify the significance of microsaccade patterns in concussion prognosis and management. [Figure: see text]

3-methyadenine inhibits lipopolysaccharides-induced pulmonary inflammation at the early stage of silicosis via blocking NF-κB signaling pathway

2021 ◽  
pp. 074823372110394
Author(s):  
Yujing Zhang ◽  
Shuai Huang ◽  
Shiyi Tan ◽  
Mingke Chen ◽  
Shang Yang ◽  
...  
Keyword(s):  
Lung Injury ◽  
Late Stage ◽  
Caspase 3 ◽  
Inflammatory Responses ◽  
Early Stage ◽  
Pulmonary Inflammation ◽  
Mechanism Study ◽  
Silica Dust ◽  
Tnf Α

Occupational exposure to silica dust is related to pulmonary inflammation and silicosis. Lipopolysaccharides (LPSs) could aggravate apoptosis in alveolar macrophages (AMs) of human silicosis through autophagy, yet how the reduction of autophagy attenuated LPS-induced lung injury and the related mechanisms need to be investigated. In the study, we aim to understand the role of 3-methyladenine (3-MA), an inhibitor of autophagy, in LPS-mediated inflammatory responses and fibrosis. We collected AMs from observers/silicosis patients. The results showed that LPS induced NF-κB-related pulmonary inflammation in observers and silicosis patients, as confirmed by an increase in the expression of IL-1β, IL-6, TNF-α, and p65, which could be inhibited by 3-MA treatment. In mice models, at the early stage (7d) of silicosis, but not the late (28d) stage, blocking autophagy reversed the increased levels of IL-1β, IL-6, TNF-α, and p65 caused by LPS. Mechanism study revealed that LPS triggered the expression of LC3 II, p62, and cleaved caspase-3 at the early stage exposed to silica, which could be restored by 3-MA, while there was no difference in the expression of LAMP1 either at the early or late stage of silicosis in different groups. Similarly, 3-MA treatment did not prevent fibrosis characterized by destroyed alveoli, collagen deposition, and increased expression of α-SMA and Col-1 induced by LPS at the late stage of silicosis. The results suggested that 3-MA has a role in the protection of lung injury at the early stage of silicosis and provided an experimental basis for preventive strategies of pulmonary inflammation and silicosis.

scholarly journals The role of action intentionality and effector in the subjective expansion of temporal duration after saccadic eye movements

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David Melcher ◽  
Devpriya Kumar ◽  
Narayanan Srinivasan
Keyword(s):  
Eye Movements ◽  
Visual Processing ◽  
Saccadic Eye Movements ◽  
Intentional Binding ◽  
Opposite Pattern ◽  
Motor Action ◽  
Saccade Onset ◽  
Backward Shift ◽  
The Moment

Abstract Visual perception is based on periods of stable fixation separated by saccadic eye movements. Although naive perception seems stable (in space) and continuous (in time), laboratory studies have demonstrated that events presented around the time of saccades are misperceived spatially and temporally. Saccadic chronostasis, the “stopped clock illusion”, represents one such temporal distortion in which the movement of the clock hand after the saccade is perceived as lasting longer than usual. Multiple explanations for chronostasis have been proposed including action-backdating, temporal binding of the action towards the moment of its effect (“intentional binding”) and post-saccadic temporal dilation. The current study aimed to resolve this debate by using different types of action (keypress vs saccade) and varying the intentionality of the action. We measured both perceived onset of the motor action and perceived onset of an auditory tone presented at different delays after the keypress/saccade. The results showed intentional binding for the keypress action, with perceived motor onset shifted forwards in time and the time of the tone shifted backwards. Saccades resulted in the opposite pattern, showing temporal expansion rather than compression, especially with cued saccades. The temporal illusion was modulated by intentionality of the movement. Our findings suggest that saccadic chronostasis is not solely dependent on a backward shift in perceived saccade onset, but instead reflects a temporal dilation. This percept of an effectively “longer” period at the beginning of a new fixation may reflect the pattern of suppressed, and then enhanced, visual processing around the time of saccades.

Gamma Knife surgery for cerebral arteriovenous malformations in children: a 13-year experience

2008 ◽  
Vol 1 (4) ◽  
pp. 296-304 ◽  
Author(s):  
David Hung-Chi Pan ◽  
Yu-Hung Kuo ◽  
Wan-Yuo Guo ◽  
Wen-Yuh Chung ◽  
Hsiu-Mei Wu ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Pediatric Patients ◽  
Pediatric Population ◽  
Statistical Significance ◽  
Adult Population ◽  
Gamma Knife Surgery ◽  
Morbidity Rate ◽  
Obliteration Rate

Object Studies on the efficacy of arteriovenous malformation (AVM) radiosurgery have largely been conducted in the adult population. Clinically, the results may not always be applicable to pediatric patients. Moreover, studies involving the pediatric population have largely comprised small- (< 3 cm3) and medium-sized (3–10 cm3) AVMs. For large (> 10 cm3) AVMs in children, sparse radiosurgical results are available. The current study was conducted to further clarify the role of radiosurgery in the treatment of pediatric AVMs. Methods A retrospective analysis was performed of data obtained in 105 pediatric patients (< 18 years of age) with cerebral AVMs treated by Gamma Knife surgery (GKS) between 1993 and 2006. For statistical comparison the authors studied data acquired in 458 adult patients with AVMs treated during the same period. The patients underwent follow-up magnetic resonance imaging at 6-month intervals. Cerebral angiography was used to confirm the obliteration of the AVM. Results In pediatric patients, the AVM obliteration rate at 48 months after a primary GKS was 65%. Repeated GKS in those in whom primary treatments failed further ablated some AVMs, for an overall obliteration rate of 81%. The efficacy of GKS correlated with the size of the AVM: 91% for small, 86% for medium, and 64% for large AVMs. The treatments were associated with an 8% morbidity rate and < 1% mortality rate. Posttreatment hemorrhage occurred in 4 (4%) of 105 patients. Obliteration rates at 48 months of small and extremely large (> 20 cm3) AVMs were similar in the pediatric and adult groups, whereas AVMs between 3 and 10 cm3 responded less efficaciously in children (p = 0.042). The AVMs with volumes ranging from 10 to 20 cm3 were also associated with a lower obliteration rate in children at 48 months, but statistical significance was not reached (p = 0.279). Conclusions Gamma Knife surgery is an effective and safe treatment alternative for pediatric AVMs. The medium (3–10-cm3) and large (10–20-cm3) AVMs tend to respond less efficaciously than those of comparable size in adults.

Role of Eye Movements in the Retinal Code for a Size Discrimination Task

2007 ◽  
Vol 98 (3) ◽  
pp. 1380-1391 ◽  
Author(s):  
Ronen Segev ◽  
Elad Schneidman ◽  
Joe Goodhouse ◽  
Michael J. Berry
Keyword(s):  
Eye Movements ◽  
Visual Information ◽  
Ganglion Cells ◽  
Multielectrode Array ◽  
Retinal Ganglion ◽  
Size Discrimination ◽  
Fixational Eye Movements ◽  
Stationary Objects ◽  
A Minor

The concerted action of saccades and fixational eye movements are crucial for seeing stationary objects in the visual world. We studied how these eye movements contribute to retinal coding of visual information using the archer fish as a model system. We quantified the animal's ability to distinguish among objects of different sizes and measured its eye movements. We recorded from populations of retinal ganglion cells with a multielectrode array, while presenting visual stimuli matched to the behavioral task. We found that the beginning of fixation, namely the time immediately after the saccade, provided the most visual information about object size, with fixational eye movements, which consist of tremor and drift in the archer fish, yielding only a minor contribution. A simple decoder that combined information from ≤15 ganglion cells could account for the behavior. Our results support the view that saccades impose not just difficulties for the visual system, but also an opportunity for the retina to encode high quality “snapshots” of the environment.

scholarly journals Modeling the role of fixational eye movements in real-world scenes

2015 ◽  
Vol 151 ◽  
pp. 78-84 ◽  
Author(s):  
Andrés Olmedo-Payá ◽  
Antonio Martínez-Álvarez ◽  
Sergio Cuenca-Asensi ◽  
J.M. Ferrández ◽  
E. Fernández
Keyword(s):  
Eye Movements ◽  
Real World ◽  
Fixational Eye Movements

Central CO2 chemoreception in developing bullfrogs: anomalous response to acetazolamide

2003 ◽  
Vol 94 (3) ◽  
pp. 1204-1212 ◽  
Author(s):  
Barbara E. Taylor ◽  
Michael B. Harris ◽  
E. Lee Coates ◽  
Matthew J. Gdovin ◽  
J. C. Leiter
Keyword(s):  
Carbonic Anhydrase ◽  
Late Stage ◽  
Rana Catesbeiana ◽  
Early Stage ◽  
Lung Ventilation ◽  
Carbonic Anhydrase Activity ◽  
Spinal Nerve ◽  
Before And After ◽  
Hypercapnic Response

Central CO2 chemoreception and the role of carbonic anhydrase were assessed in brain stems from Rana catesbeiana tadpoles and frogs. Buccal and lung rhythms were recorded from cranial nerve VII and spinal nerve II during normocapnia and hypercapnia before and after treatment with 25 μM acetazolamide. The lung response to acetazolamide mimicked the hypercapnic response in early-stage and midstage metamorphic tadpoles and frogs. In late-stage tadpoles, acetazolamide actually inhibited hypercapnic responses. Acetazolamide and hypercapnia decreased the buccal frequency but had no effect on the buccal duty cycle. Carbonic anhydrase activity was present in the brain stem in every developmental stage. Thus more frequent lung ventilation and concomitantly less frequent buccal ventilation comprised the hypercapnic response, but the response to acetazolamide was not consistent during metamorphosis. Therefore, acetazolamide is not a useful tool for central CO2 chemoreceptor studies in this species. The reversal of the effect of acetazolamide in late-stage metamorphosis may reflect reorganization of central chemosensory processes during the final transition from aquatic to aerial respiration.

scholarly journals Prevalence of multiple subtypes of binocularly-modulated visual neurons in the mouse superior colliculus

2020 ◽  
Author(s):  
Ashley Lynn Russell ◽  
Jason W Triplett
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Visual Processing ◽  
Spatial Summation ◽  
Stimulus Presentation ◽  
Visual Neurons ◽  
Evoked Activity ◽  
Multiple Species ◽  
Binocular Perception

A central role of the visual system is to integrate inputs from both eyes to form one coherent visual perception. The superior colliculus (SC) plays a central role in visual processing, gaze orientation and vergence eye movements necessary for binocular vision. Indeed, the SC receives direct inputs from both the contralateral and ipsilateral eye and binocularly-modulated neurons have been identified in the SC of multiple species. However, evidence for binocular processing in rodents, particularly mice, has not been functionally confirmed. In this study we recorded visually-evoked activity in the mouse SC while presenting visual stimuli to each eye individually or both together and reveal a surprising diversity of binocularly-modulated responses. Strikingly, we found that ~2/3 of all identified neurons in the anteromedial SC were binocularly-modulated. Furthermore, we identified four binocular subtypes based on their differential responses under varying ocularities of stimulus presentation. Interestingly, we found both orientation- and direction- selective (OS and DS, respectively) neurons in all four binocular subtypes. And, tuning properties of binocular neurons were distinct from neighboring monocular neurons, exhibiting more linear spatial summation. Together, these data suggest that binocular neurons are prevalent in the anteromedial SC of the mouse. Additionally, the distinct tuning properties of binocular neurons suggest a previously unappreciated complexity of visual processing in the SC, which may contribute to binocular perception.

scholarly journals Feasibility of Conducting a Music Therapy Study With Hospice Patients with Dementia & Agitation

2011 ◽  
Vol 11 (2) ◽  
Author(s):  
Barbara Reuer ◽  
Julie Guy ◽  
Ann Sturley ◽  
Matt Soskins ◽  
Charles R. Lewis
Keyword(s):  
Music Therapy ◽  
Late Stage ◽  
Small Sample Size ◽  
Statistical Significance ◽  
Small Sample ◽  
Music Intervention ◽  
Post Intervention ◽  
Music Therapist ◽  
Therapy Assessment ◽  
Hospice Patients

This study's purpose was to explore non-pharmacological means for decreasing agitation in hospice patients with late stage dementia administered by caregivers.  Subjects in the study were patients on service with San Diego Hospice and the Institute for Palliative Medicine, diagnosed with late stage dementia, as determined by a FAST (Functional Assessment Staging) score of 7, and who were known to become agitated while performing certain tasks (e.g., bathing or eating). A music therapist assessed the subjects using an adaptation of the Music Therapy Assessment (Krout, 2000). The Short Portable Mental Status Questionnaire (SPMSQ) and Blessed Dementia Scale were administered pre- and post- intervention to assess cognitive functioning severity of dementia, respectively. Caregivers were trained to administer the Agitated Behavior Scale (ABS) after performing the stressful task without music (baseline). The music therapist created a CD for each subject based on the following: a) music background/preferences of subject (preferred styles of music, favorite selections or artists), obtained from family/caregiver, and b) subject responses observed during the assessment. Caregivers were instructed to complete the agitated task during the music intervention and immediately following the task completed an ABS evaluation. Out of the 51 patients referred for the study, 11 met inclusion criteria and were consented. Eight subjects completed the study. According to demographic information the majority of subjects were female, had previous music experience, and lived in a skilled nursing facility. The most frequent agitated task was bathing, which caused agitation in 75% of subjects. SPMSQ results indicated all patients had severe cognitive impairment and pre-/post-scores were the same. Pre-music intervention ABS scores were a mean of 23.46 (SD=5.8), and a mean of 20.69 (SD=7.1) for post-music intervention. This indicated that subjects became slightly less agitated overall though the effects were not statistically significant (t (7) = 1.41, p=0.2). Further analysis was unwarranted due to the lack of statistical significance and the small sample size. Two subjects demonstrated decreased agitation levels. Study limitations, implications for further research, and feasibility of research with late stage dementia patients receiving hospice care are discussed by the researchers.

scholarly journals Beyond Fixation: detailed characterization of neural selectivity in free-viewing primates

2021 ◽  
Author(s):  
Jacob L Yates ◽  
Shanna H Coop ◽  
Gabriel H Sarch ◽  
Ruei-Jr Wu ◽  
Daniel A Butts ◽  
...  
Keyword(s):  
Eye Movements ◽  
Receptive Fields ◽  
Natural Behavior ◽  
Visual Neurons ◽  
Trained Subjects ◽  
V1 Neurons ◽  
Fixational Eye Movements ◽  
Neural Selectivity

Virtually all vision studies use a fixation point to stabilize gaze, rendering stimuli on video screens fixed to retinal coordinates. This approach requires trained subjects, is limited by the accuracy of fixational eye movements, and ignores the role of eye movements in shaping visual input. To overcome these limitations, we developed a suite of hardware and software tools to study vision during natural behavior in untrained subjects. We show this approach recovers receptive fields and tuning properties of visual neurons from multiple cortical areas of marmoset monkeys. Combined with high-precision eye-tracking, it achieves sufficient resolution to recover the receptive fields of foveal V1 neurons. These findings demonstrate the power of this approach for characterizing neural response while simultaneously studying the dynamics of natural behavior.

Geminography — The science of twinning applied to the early-stage derivation of non-merohedric twin laws

2003 ◽  
Vol 218 (3) ◽  
Author(s):  
Massimo Nespolo ◽  
G. Ferraris
Keyword(s):  
Structural Study ◽  
Late Stage ◽  
Early Stage ◽  
Black Box ◽  
Software Packages ◽  
Structure Solution

AbstractThe recognition of twinning and the determination of the twin laws are nowadays often entrusted to "black-box" software packages. This approach may be both risky and uneconomical. It is risky because never a procedure should be blindly applied. It is uneconomical if procrastinates the analysis of twinning at the very late stage of structure solution and refinement, whereas in many cases this analysis can and should be applied much earlier. In this paper we present a brief survey of the working strategies to be applied to the structural study of twinned crystals, emphasizing the role of the crystallographer, rather than that of the machine.

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