Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 39
Filter
1.
Clin Neurophysiol ; 165: 117-124, 2024 Jun 29.
Article in English | MEDLINE | ID: mdl-39013355

ABSTRACT

OBJECTIVE: Video-based eye tracking was used to investigate saccade, pupil, and blink abnormalities among patients with Huntington's disease (HD) who watched sequences of short videos. HD, an autosomal dominant neurodegenerative disorder resulting from a CAG mutation on chromosome 4, produces motor and cognitive impairments including slow or irregular eye movements, which have been studied using structured tasks. METHODS: To explore how HD affects eye movements under instruction free conditions, we assessed 22 HD patients and their age matched controls in a 10-minute video-based free viewing task. RESULTS: Patients with HD experienced a significant reduction in saccade exploration rate following video clip transitions, an increase in pupil reactions to luminance changes after clip transitions, and a significant higher blink rate throughout the task compared to the control group. CONCLUSIONS: These results show that HD has a significant impact on how patients visually explore and respond to their environment under unconstrained and ecologically natural conditions. SIGNIFICANCE: Eye tracking in HD patients revealed saccadic, pupil, and blink abnormalities in early HD patients, suggestive of brain circuitry abnormalities that probably involve brain stem deficits. Further research should explore the impact of these changes on the quality of life of the patients affected by the disease.

2.
Vision (Basel) ; 8(1)2024 Mar 18.
Article in English | MEDLINE | ID: mdl-38535763

ABSTRACT

The tremendous increase in the use of video-based eye tracking has made it possible to collect eye tracking data from thousands of participants. The traditional procedures for the manual detection and classification of saccades and for trial categorization (e.g., correct vs. incorrect) are not viable for the large datasets being collected. Additionally, video-based eye trackers allow for the analysis of pupil responses and blink behaviors. Here, we present a detailed description of our pipeline for collecting, storing, and cleaning data, as well as for organizing participant codes, which are fairly lab-specific but nonetheless, are important precursory steps in establishing standardized pipelines. More importantly, we also include descriptions of the automated detection and classification of saccades, blinks, "blincades" (blinks occurring during saccades), and boomerang saccades (two nearly simultaneous saccades in opposite directions where speed-based algorithms fail to split them), This is almost entirely task-agnostic and can be used on a wide variety of data. We additionally describe novel findings regarding post-saccadic oscillations and provide a method to achieve more accurate estimates for saccade end points. Lastly, we describe the automated behavior classification for the interleaved pro/anti-saccade task (IPAST), a task that probes voluntary and inhibitory control. This pipeline was evaluated using data collected from 592 human participants between 5 and 93 years of age, making it robust enough to handle large clinical patient datasets. In summary, this pipeline has been optimized to consistently handle large datasets obtained from diverse study cohorts (i.e., developmental, aging, clinical) and collected across multiple laboratory sites.

3.
eNeuro ; 2024 Feb 08.
Article in English | MEDLINE | ID: mdl-38331578

ABSTRACT

Spontaneous eye blinking is gaining popularity as a proxy for higher cognitive functions, as it is readily modulated by both environmental demands and internal processes. Prior studies were impoverished in sample size, sex representation and age distribution, making it difficult to establish a complete picture of the behavior. Here we present eye-tracking data from a large cohort of normative participants (n=604, 393 F, aged 5-93 years) performing two tasks: one with structured, discrete trials (interleaved pro/anti-saccade task; IPAST) and one with a less structured, continuous organization in which participants watch movies (free-viewing; FV). Sex- and age-based analyses revealed that females had higher blink rates between the ages of 22 and 58 years in the IPAST, and 22 and 34 years in FV. We derived a continuous measure of blink probability to reveal behavioral changes driven by stimulus appearance in both paradigms. In the IPAST, blinks were suppressed near stimulus appearance, particularly on correct anti-saccade trials, which we attribute to the stronger inhibitory control required for anti-saccades compared to pro-saccades. In FV, blink suppression occurred immediately after scene changes, and the effect was sustained on scenes where gaze clustered among participants (indicating engagement of attention). Females were more likely than males to blink during appearance of novel stimuli in both tasks, but only within the age bin of 18-44 years. The consistency of blink patterns in each paradigm endorses blinking as a sensitive index for changes in visual processing and attention, while sex and age differences drive interindividual variability.Significance Statement Eye-tracking is becoming useful as a non-invasive tool for detecting preclinical markers of neurological and psychiatric disease. Blinks are understudied despite being an important supplement to saccade and pupil eye-tracking metrics. The present study is a crucial step in developing a healthy baseline for blink behavior to compare to clinical groups. While many prior blink studies suffered from small sample sizes with relatively low age- and sex-diversity (review by Jongkees & Colzato, 2016), our large cohort of healthy participants has permitted a more detailed analysis of sex and age effects in blink behavior. Furthermore, our analysis techniques are robust to temporal changes in blink probability, greatly clarifying the relationship between blinking, visual processing, and inhibitory control mechanisms on visual tasks.

4.
Arthroscopy ; 39(1): 41-50, 2023 01.
Article in English | MEDLINE | ID: mdl-35724802

ABSTRACT

PURPOSE: To validate an arthroscopic approach for performing significant acetabular rim correction and circumferential labral reconstruction required to treat severe pincer-type femoroacetabular impingement. METHODS: Using a minimum of 2-year follow-up, data from 48 hips, including 47 patients (11 male, 36 female; mean age of 42 years) having undergone significant arthroscopic acetabuloplasty for severe pincer impingement (center edge angle >45°) with concomitant circumferential allograft labral reconstruction were analyzed to determine improvements in patient-reported outcomes and degree of radiographic correction. RESULTS: Findings demonstrated a 98% success rate, including substantial improvements on all radiographic measurements and patient-reported outcomes. Minimal clinically important differences were met with extremely strong measures of effect. The mean center edge angle improved from 49° to 36° (MΔ = 13.96, P ≤ .001, standard deviation [SD] = 55.97, confidence interval [CI] 12.17- 15.62, d = 2.33) and the mean Tönnis angle improved from -6° to 0° (MΔ = 6.2, P ≤ .001, SD = 2.76 CI -7.1 to -5.39, d = 2.29). Modified Hip Harris Scores improved by a mean of 34.45 points (P ≤ .001, SD = 20.64, 95% CI 28.45-40.44, d = 1.66). Lower extremity functional scale scores improved by a mean of 27.35 points (P ≤ .001, SD = 18.37, 95% CI 22.02-32.69, d =1.48). No complications were reported. One case converted to a total hip arthroplasty (2%). CONCLUSIONS: Findings validated that the significant acetabular rim correction required to treat severe pincer morphology is safe and feasible via an arthroscopic approach. This, in addition to concomitant circumferential allograft labral reconstruction, resulted in improvement in patient-reported outcomes and radiographic measurements. LEVEL OF EVIDENCE: Level IV, therapeutic case-series.


Subject(s)
Femoracetabular Impingement , Humans , Male , Female , Adult , Hip Joint/surgery , Treatment Outcome , Arthroscopy/methods , Patient Reported Outcome Measures , Retrospective Studies , Follow-Up Studies
5.
J Neurol ; 269(9): 4920-4938, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35501501

ABSTRACT

OBJECTIVES: This study (1) describes and compares saccade and pupil abnormalities in patients with manifest alpha-synucleinopathies (αSYN: Parkinson's disease (PD), Multiple System Atrophy (MSA)) and a tauopathy (progressive supranuclear palsy (PSP)); (2) determines whether patients with rapid-eye-movement sleep behaviour disorder (RBD), a prodromal stage of αSYN, already have abnormal responses that may indicate a risk for developing PD or MSA. METHODS: Ninety (46 RBD, 27 PD, 17 MSA) patients with an αSYN, 10 PSP patients, and 132 healthy age-matched controls (CTRL) were examined with a 10-min video-based eye-tracking task (Free Viewing). Participants were free to look anywhere on the screen while saccade and pupil behaviours were measured. RESULTS: PD, MSA, and PSP spent more time fixating the centre of the screen than CTRL. All patient groups made fewer macro-saccades (> 2◦ amplitude) with smaller amplitude than CTRL. Saccade frequency was greater in RBD than in other patients. Following clip change, saccades were temporarily suppressed, then rebounded at a slower pace than CTRL in all patient groups. RBD had distinct, although discrete saccade abnormalities that were more marked in PD, MSA, and even more in PSP. The vertical saccade rate was reduced in all patients and decreased most in PSP. Clip changes produced large increases or decreases in screen luminance requiring pupil constriction or dilation, respectively. PSP elicited smaller pupil constriction/dilation responses than CTRL, while MSA elicited the opposite. CONCLUSION: RBD patients already have discrete but less pronounced saccade abnormalities than PD and MSA patients. Vertical gaze palsy and altered pupil control differentiate PSP from αSYN.


Subject(s)
Multiple System Atrophy , Parkinson Disease , Supranuclear Palsy, Progressive , Synucleinopathies , Biomarkers , Eye-Tracking Technology , Humans , Multiple System Atrophy/diagnosis , Parkinson Disease/complications , Parkinson Disease/diagnosis , Supranuclear Palsy, Progressive/diagnosis
6.
Exp Brain Res ; 240(6): 1873-1885, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35445861

ABSTRACT

The pupil responds to a salient stimulus appearing in the environment, in addition to its modulation by global luminance. These pupillary responses can be evoked by visual or auditory stimuli, scaled with stimulus salience, and enhanced by multisensory presentation. In addition, pupil size is modulated by various visual stimulus attributes, such as color, area, and motion. However, research that concurrently examines the influence of different factors on pupillary responses is limited. To explore how presentation of multiple visual stimuli influences human pupillary responses, we presented arrays of visual stimuli and systematically varied their luminance, color, and set size. Saliency level, computed by the saliency model, systematically changed with set size across all conditions, with higher saliency levels in larger set sizes. Pupillary constriction responses were evoked by the appearance of visual stimuli, with larger pupillary responses observed in larger set size. These effects were pronounced even though the global luminance level was unchanged using isoluminant chromatic stimuli. Furthermore, larger pupillary constriction responses were obtained in the blue, compared to other color conditions. Together, we argue that both cortical and subcortical areas contribute to the observed pupillary constriction modulated by set size and color.


Subject(s)
Light , Pupil , Humans , Photic Stimulation , Pupil/physiology
7.
Curr Rev Musculoskelet Med ; 15(2): 27-37, 2022 Apr.
Article in English | MEDLINE | ID: mdl-35141846

ABSTRACT

PURPOSE OF REVIEW: The current review investigates outcomes and failure rates associated with arthroscopic circumferential allograft labral reconstruction of the hip, both as a revision and primary procedure in treating femoroacetabular hip impingement and labral-related pathology. RECENT FINDINGS: Numerous studies within the last decade have demonstrated excellent patient-reported outcomes, high rates of return-to-play in athletes, and low failure rates in patients having undergone arthroscopic circumferential allograft labral reconstruction of the hip. Removal of chronically diseased and injured labral tissue can eliminate a significant pain-generator from the hip joint. Additionally, circumferential reconstruction of the labrum restores the hoop fiber strength and fluid seal akin to what would be seen with native, healthy labral tissue. Recent research has shown that arthroscopic circumferential allograft labral reconstruction may be used not only in the revision setting, but as a primary procedure. Circumferential labral reconstruction should be considered when a surgeon feels that the labrum is irreparable or has failed previous repair. Arthroscopic circumferential allograft labral reconstruction of the hip can be utilized as treatment option not only in revision settings, but also in primary treatment for femoroacetabular impingement and labral pathology.

8.
Arthroscopy ; 36(10): 2611-2613, 2020 10.
Article in English | MEDLINE | ID: mdl-33039036

ABSTRACT

In the past 5 years, arthroscopic labral reconstruction of the hip has rapidly evolved from a salvage procedure used primarily in the setting of multiple failed prior hip surgical procedures to an alternative, and even preferable, primary treatment option for labral pathology and femoroacetabular impingement. As opposed to labral repair, labral reconstruction allows for complete removal of all damaged, pain-generating tissue; optimal correction of underlying bony impingement; and consistent creation of a graft that appropriately restores the fluid hip seal, improves pressurization and stabilization, and decreases contact pressure. Allograft tissue, in particular, allows for accurate and reliable graft length creation and does not rely on native tissue quality. Hips that undergo labral reconstruction have been shown to have positive outcomes at minimum 2-year follow-up, despite the fact that in many cases, these hips have more damage and a poorer preoperative prognosis. Patients report decreased pain, increased function, and greater quality of life after labral reconstruction, and this new evidence suggests that they can resume high-level physical activity as well. Circumferential labral reconstruction is no longer a salvage procedure and is an important tool for the hip arthroscopist; however, it requires high proficiency in hip arthroscopy to perform.


Subject(s)
Cartilage, Articular , Femoracetabular Impingement , Allografts , Arthroscopy , Athletes , Cartilage, Articular/surgery , Femoracetabular Impingement/surgery , Hip Joint , Humans , Quality of Life , Return to Sport , Treatment Outcome
9.
Arthroscopy ; 36(8): 2137-2144, 2020 08.
Article in English | MEDLINE | ID: mdl-32360267

ABSTRACT

PURPOSE: To assess the outcomes of complete, primary, arthroscopic hip labral reconstruction among patients aged 40 years and older compared with those who underwent primary labral repair and compared with patients aged 30 to 39 years who underwent complete, primary labral reconstruction. METHODS: We recruited all patients who underwent arthroscopic labral reconstruction between March 2010 and June 2015 and were aged 30 to 65 years or who underwent arthroscopic labral repair between June 2009 and June 2015 and were aged 40 to 65 years. The modified Harris Hip Score (mHHS), Lower Extremity Function Score, and visual analog scale score for average pain were collected preoperatively and at minimum 2-year follow-up. Failure was defined as the need for revision ipsilateral hip surgery. The rate of conversion to total hip arthroplasty (a subset of failure) was assessed separately. RESULTS: A total of 363 hips in 343 patients met the inclusion criteria. Follow-up was available for 312 hips (86.0%), and the average time to follow-up was 4.2 years (range, 2.0-8.5 years). After adjustment for differences in follow-up time between groups, failure was 3.29 times more likely for hips in the repair group aged 40 years and older than for hips in the reconstruction group aged 40 years and older (relative rate, 3.29; 95% confidence interval, 1.25-8.69; P = .02), and there was no difference in the failure rate for hips in the reconstruction group aged 40 years and older compared with hips in the reconstruction group aged 30 to 39 years (relative rate, 0.58; 95% confidence interval, 0.18-1.89; P = .37). The rate of conversion to total hip arthroplasty was not meaningfully different between the 3 groups. Among hips for which treatment did not fail, average improvement in the mHHS measured 35 points and both labral reconstruction groups saw a greater mHHS improvement than the labral repair group of patients aged 40 years and older (P = .01 and P < .01). CONCLUSIONS: Labral reconstruction led to a lower failure rate, greater average improvement in the mHHS, and equivalent postoperative patient-reported outcome scores compared with labral repair among patients aged 40 years and older in this study population, and the outcomes of labral reconstruction were similar between patients aged 40 years and older and those aged 30 to 39 years. Complete labral reconstruction may be particularly advantageous in patients aged 40 years and older. LEVEL OF EVIDENCE: Level III, retrospective comparative study.


Subject(s)
Acetabulum/surgery , Arthroplasty, Replacement, Hip/statistics & numerical data , Arthroscopy/methods , Pain Measurement , Adult , Age Factors , Aged , Female , Hip/surgery , Hip Injuries/surgery , Hip Joint/surgery , Humans , Male , Middle Aged , Pain/surgery , Patient Reported Outcome Measures , Patient Satisfaction , Postoperative Period , Registries , Reoperation , Retrospective Studies , Treatment Outcome , Visual Analog Scale
10.
Eur J Neurosci ; 2019 May 11.
Article in English | MEDLINE | ID: mdl-31077473

ABSTRACT

The saliency map has played a long-standing role in models and theories of visual attention, and it is now supported by neurobiological evidence from several cortical and subcortical brain areas. While visual saliency is computed during moments of active fixation, it is not known whether the same is true while engaged in smooth pursuit of a moving stimulus, which is very common in real-world vision. Here, we examined extrafoveal saliency coding in the superior colliculus, a midbrain area associated with attention and gaze, during smooth pursuit eye movements. We found that SC neurons from the superficial visual layers showed a robust representation of peripheral saliency evoked by a conspicuous stimulus embedded in a wide-field array of goal-irrelevant stimuli. In contrast, visuomotor neurons from the intermediate saccade-related layers showed a poor saliency representation, even though most of these neurons were visually responsive during smooth pursuit. These results confirm and extend previous findings that place the SCs in a unique role as a saliency map that monitors peripheral vision during foveation of stationary and now moving objects.

11.
J Hip Preserv Surg ; 5(2): 166-173, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29876134

ABSTRACT

This study aims to present the surgical technique for reconstructing both the acetabular labrum and the ligamentum teres and to describe the early outcomes of this procedure in a 15-year-old male with recurrent hip instability. A 15-year-old patient with recurrent left hip dislocation, hip joint instability and failed non-operative intervention presented following two left hip dislocations. A labral reconstruction was performed utilizing an iliotibial band allograft tissue with a concomitant ligamentum teres reconstruction using a tibialis anterior allograft. The patient was assessed pre- and postoperatively using modified Harris Hip Score, Lower Extremity Functional Scale and Visual Analogue Scale for pain and satisfaction. The patient reported improvement on all measures, including hip stability 14 months following surgery. The patient has not reported any episodes or subjective feelings of instability, has not required further surgical procedures in the hip and has returned to full sports participation. This case report demonstrates a technique for and early outcomes of simultaneous arthroscopic ligamentum teres and acetabular labrum reconstruction in a patient with recurrent hip instability. Short-term outcomes suggest improved hip stability, reduced pain, high patient satisfaction and return to pre-injury activities at 14 months postoperative in this single case report.

13.
Front Hum Neurosci ; 12: 58, 2018.
Article in English | MEDLINE | ID: mdl-29487519

ABSTRACT

Emotional and economic incentives often conflict in decision environments. To make economically desirable decisions then, deliberative neural processes must be engaged to regulate automatic emotional reactions. In this functional magnetic resonance imaging (fMRI) study, we evaluated how fixed wage (FW) incentives and performance-based (PB) financial incentives, in which pay is proportional to outcome, differentially regulate positive and negative emotional reactions to hypothetical colleagues that conflicted with the economics of available alternatives. Neural activity from FW to PB incentive contexts decreased for positive emotional stimuli but increased for negative stimuli in middle temporal, insula, and medial prefrontal regions. In addition, PB incentives further induced greater responses to negative than positive emotional decisions in the frontal and anterior cingulate regions involved in emotion regulation. Greater response to positive than negative emotional features in these regions also correlated with lower frequencies of economically desirable choices. Our findings suggest that whereas positive emotion regulation involves a reduction of responses in valence representation regions, negative emotion regulation additionally engages brain regions for deliberative processing and signaling of incongruous events.

14.
Arthroscopy ; 34(2): 433-440, 2018 02.
Article in English | MEDLINE | ID: mdl-29100774

ABSTRACT

PURPOSE: Directly compare primary acetabular labral repair versus primary acetabular labral reconstruction using a self-controlled cohort study design. METHODS: Patients who underwent primary labral repair in one hip and primary labral reconstruction using iliotibial band allograft in the other hip by a single surgeon between August 2009 and November 2014 were identified. One patient with inflammatory arthritis was excluded. Patient-reported outcome data included change in Modified Harris Hip Score (MHHS), Lower Extremity Functional Scale (LEFS), average pain using a 10-point visual analog scale (VAS), and patient satisfaction (1: very dissatisfied, 10: very satisfied). Failure was defined as subsequent intra-articular hip surgery. Data were analyzed using McNemar's and Wilcoxon Signed Rank tests. RESULTS: Overall, 29 patients (58 hips) were included in the analysis. There were 23 females and 6 males. The average age at time of surgery was 32.6 years (range: 14.9-51.6 years). Follow-up was obtained from all 29 patients (100%) at a mean of 56 months (range = 27-85 months) postoperative for repaired hips and 40 months (range = 22-61 months) postoperative for reconstructed hips. No labral reconstruction hips failed, and 9 (31%) labral repair hips failed (P < .01). Among those that did not fail treatment, there was no difference in MHHS change (32.2 ± 15.4 vs 29.6 ± 15.4; P = .63), LEFS change (26.6 ± 16.5 vs 23.9 ± 17.8; P = .61), VAS pain change (-3.2 ± 2.4 vs -3.6 ± 2.1; P = .47), or satisfaction (8.6 ± 2.0 vs 8.7 ± 2.4; P = .59) between the repair and reconstruction groups, respectively. CONCLUSIONS: In this cohort of patients, hips that underwent primary labral repair were more likely to fail treatment than hips that underwent labral reconstruction (31% vs 0%, respectively). Among hips that did not fail treatment, patient-reported outcome scores were similar between groups. Excellent clinical results can be obtained with both forms of labral-preserving treatment but were more predictably observed with primary labral reconstruction in this cohort. LEVEL OF EVIDENCE: Level III, retrospective comparative study.


Subject(s)
Acetabulum/surgery , Arthroscopy/methods , Hip Injuries/surgery , Hip Joint/surgery , Adolescent , Adult , Cartilage, Articular/surgery , Cohort Studies , Fascia Lata/transplantation , Female , Humans , Male , Middle Aged , Pain Measurement/methods , Patient Reported Outcome Measures , Patient Satisfaction , Retrospective Studies , Treatment Outcome , Visual Analog Scale , Young Adult
15.
Proc Natl Acad Sci U S A ; 114(35): 9451-9456, 2017 08 29.
Article in English | MEDLINE | ID: mdl-28808026

ABSTRACT

Models of visual attention postulate the existence of a bottom-up saliency map that is formed early in the visual processing stream. Although studies have reported evidence of a saliency map in various cortical brain areas, determining the contribution of phylogenetically older pathways is crucial to understanding its origin. Here, we compared saliency coding from neurons in two early gateways into the visual system: the primary visual cortex (V1) and the evolutionarily older superior colliculus (SC). We found that, while the response latency to visual stimulus onset was earlier for V1 neurons than superior colliculus superficial visual-layer neurons (SCs), the saliency representation emerged earlier in SCs than in V1. Because the dominant input to the SCs arises from V1, these relative timings are consistent with the hypothesis that SCs neurons pool the inputs from multiple V1 neurons to form a feature-agnostic saliency map, which may then be relayed to other brain areas.


Subject(s)
Visual Cortex/physiology , Animals , Attention/physiology , Macaca mulatta , Male , Neurons/physiology , Photic Stimulation , Psychophysics , Reaction Time , Superior Colliculi , Visual Pathways/physiology
16.
J Hip Preserv Surg ; 4(1): 106-112, 2017 Jan.
Article in English | MEDLINE | ID: mdl-28630729

ABSTRACT

The purpose of this article is to determine normative values for the length of the acetabular rim and detect differences between gender, age, ethnicity, height and leg length. Six measurements were taken on the acetabular rim of 143 cadaveric skeleton specimens (286 acetabula) using a coordinate-measuring device: circumferential (excluding acetabular notch), anterior inferior iliac spine (AIIS)-anterior, AIIS-posterior, 12-3 o'clock, 12-9 o'clock and 11-5 o'clock. Museum specimen height data and leg length data from a previous study were recorded for 109 of 143 specimens. Intraclass correlation coefficients were calculated. Student t-tests compared mean values. Multiple regression analysis was used to determine the relationship between acetabular rim length and gender, age, ethnicity, height and leg length. The average acetabular rim length in males for circumferential, AIIS-anterior, AIIS-posterior, 12-3, 12-9 and 11-5 o'clock were 15.8, 4.2, 11.7, 4.9, 4.7 and 9.5 cm, respectively; and for females: 13.7, 3.7, 10.0, 4.3, 4.1 and 8.3 cm, respectively. Intraclass correlation coefficients were 0.953, 0.930, 0.958, 0.857, 0.913 and 0.951, respectively, for each measurement. All six measurements were significantly larger for males (P < 0.001). Multiple regression analysis demonstrated a significant relationship between gender and rim length for all six measurements (P < 0.001) and between height and leg length and acetabular rim length for five of the six measurements exclusive of AIIS-anterior (P < 0.001). No significant trends between age or ethnicity and rim length were found. Average acetabular rim lengths were established. The acetabular rim is significantly longer in males and correlates with height and leg length. Age and ethnicity do not appear to be significant predictors of acetabular rim length. Normative values for acetabular rim lengths may assist in hip preservation surgery.

17.
Nat Commun ; 8: 14263, 2017 01 24.
Article in English | MEDLINE | ID: mdl-28117340

ABSTRACT

Models of visual attention postulate the existence of a saliency map whose function is to guide attention and gaze to the most conspicuous regions in a visual scene. Although cortical representations of saliency have been reported, there is mounting evidence for a subcortical saliency mechanism, which pre-dates the evolution of neocortex. Here, we conduct a strong test of the saliency hypothesis by comparing the output of a well-established computational saliency model with the activation of neurons in the primate superior colliculus (SC), a midbrain structure associated with attention and gaze, while monkeys watched video of natural scenes. We find that the activity of SC superficial visual-layer neurons (SCs), specifically, is well-predicted by the model. This saliency representation is unlikely to be inherited from fronto-parietal cortices, which do not project to SCs, but may be computed in SCs and relayed to other areas via tectothalamic pathways.


Subject(s)
Attention/physiology , Models, Neurological , Neurons/physiology , Superior Colliculi/physiology , Visual Perception/physiology , Animals , Computer Simulation , Macaca mulatta , Male , Models, Animal , Neural Pathways , Photic Stimulation/methods , Saccades , Software , Superior Colliculi/cytology , Thalamus/physiology
18.
Arthroscopy ; 32(12): 2513-2520, 2016 12.
Article in English | MEDLINE | ID: mdl-27720304

ABSTRACT

PURPOSE: To compare the outcome of labral repair versus labral reconstruction in patients presenting to a single surgeon for revision hip arthroscopy following previous labral treatment. METHODS: Patients who underwent revision labral repair or labral reconstruction using iliotibial band allograft, after previous labral debridement or repair, between 2009 and 2013 were identified. Hips that underwent revision labral reconstruction were further stratified into 2 graft groups (freeze-dried vs frozen allograft). Exclusion criteria were age <16 years, previous open hip surgery, or previous labral reconstruction. Failure was defined by subsequent intra-articular hip surgery. RESULTS: 113 hips (15 repair, 98 reconstruction) met the inclusion criteria. Patients who underwent revision labral repair were younger than patients who underwent revision labral reconstruction (27.8 years vs 34.6 years; P = .02). Follow-up was obtained from 14 (93%) labral repairs at an average of 4.7 years postoperation (range: 2.0-6.0 years) and 90 (92%) labral reconstructions at an average of 2.4 years postoperation (range: 2.0-4.0 years). Seven of 14 (50%) labral repair hips failed compared with 11/90 (12%) labral reconstruction hips (P < .01). Six of 61 (10%) frozen allografts failed compared with 5/29 (17%) freeze-dried allografts (P = .32). Patients who underwent revision labral repair were 4.1 (95% confidence interval 1.9, 8.8) times more likely to fail than patients who underwent revision labral reconstruction. CONCLUSIONS: Patients who underwent revision labral repair following previous repair or debridement were 2.6 times more likely to fail than patients who underwent revision labral reconstruction, controlling for calendar time. In addition, revision labral reconstruction with frozen allograft had lower propensity of failure than freeze-dried allograft. However, there was no statistically significant difference in patient-reported outcome scores between the 2 groups. Based on these results, complete labral reconstruction with longer, nonsegmental graft led to a lower failure rate in this study population and can be considered for treatment of patients presenting for revision labral treatment. LEVEL OF EVIDENCE: Level III, retrospective comparative study.


Subject(s)
Arthroscopy , Cartilage, Articular/surgery , Fascia/transplantation , Hip Injuries/surgery , Adolescent , Adult , Allografts , Cartilage, Articular/injuries , Cohort Studies , Debridement , Female , Humans , Male , Middle Aged , Reoperation , Retrospective Studies , Young Adult
19.
Orthopedics ; 39(6): e1080-e1084, 2016 Nov 01.
Article in English | MEDLINE | ID: mdl-27458896

ABSTRACT

The source of continued hip pain following fixation of traumatic femoral shaft fracture is not always clear. Intra-articular hip pathology is often overlooked when evaluating the etiology of residual pain. The purpose of this study was to describe cases of intra-articular hip pathology following traumatic femoral shaft fracture. This was a retrospective case series of patients presenting to a private practice orthopedic clinic from 2012 to 2015. Three patients presented with symptomatic intra-articular hip pathology following traumatic ipsilateral femoral shaft fracture. Patients who underwent hip arthroscopy with allograft labral reconstruction were identified retrospectively. Validated, subjective outcome scores administered included the Modified Harris Hip Score (MHHS), Lower Extremity Functional Scale (LEFS), visual analog scale (VAS) for pain, and VAS scale for patient satisfaction. Three patients were identified with residual, disabling groin pain after femoral shaft fracture fixation following a traumatic motor vehicle accident. All 3 patients were found to have a symptomatic ipsilateral labral tear. In 2 of the patients, an indentation on the lateral femoral head was appreciated, which was hypothesized to be caused by a subluxation event. All 3 patients were treated with arthroscopic hip surgery. At final follow-up, all 3 patients showed significant improvement in MHHS, VAS pain scores, level of satisfaction, and LEFS. Residual pain following ipsilateral femoral shaft fracture is not always related to implant. Intra-articular hip pathology should be considered in patients with lingering hip pain. [Orthopedics. 2016; 39(6):e1080-e1084.].


Subject(s)
Femoral Fractures/surgery , Hip Injuries/complications , Joint Dislocations/complications , Multiple Trauma/complications , Pain, Postoperative/etiology , Accidents, Traffic , Adult , Arthroscopy , Diaphyses/injuries , Diaphyses/surgery , Female , Femoral Fractures/complications , Follow-Up Studies , Fracture Fixation, Internal/adverse effects , Groin , Hip Injuries/surgery , Humans , Internal Fixators/adverse effects , Joint Dislocations/surgery , Male , Retrospective Studies , Rupture/complications , Rupture/surgery , Young Adult
20.
Arthrosc Tech ; 5(1): e89-97, 2016 Feb.
Article in English | MEDLINE | ID: mdl-27073784

ABSTRACT

Labral repair has been shown to be an effective treatment option with excellent early outcomes; however, in cases of severe labral damage or when the labral tissue is too large or diminutive, labral repair may be less effective. The purpose of this article is to present a modified technique for hip labral reconstruction using iliotibial band allograft tissue and a front-to-back fixation technique. The described technique is modified from the original report of a technique for arthroscopic labral reconstruction. The front-to-back technique allows the surgeon to make a graft that is longer than necessary and cut excess graft after front-to-back fixation, resulting in the correct graft size and a reproducible procedure. Allograft tissue offers several advantages, including the ability to control graft thickness and length, as well as the ability to eliminate donor-site morbidity. This procedure adds to the available techniques for treatment of labral pathology by providing a labral reconstruction technique using allograft tissue.

SELECTION OF CITATIONS
SEARCH DETAIL
...