The Experts below are selected from a list of 2274 Experts worldwide ranked by ideXlab platform
Russell G Foster - One of the best experts on this subject based on the ideXlab platform.
-
melanopsin and rod cone photoreceptive systems account for all major accessory visual functions in mice
Nature, 2003Co-Authors: Samer Hattar, Mark W Hankins, Robert J Lucas, R H Douglas, Martin Biel, Nicholas Mrosovsky, S. Thompson, Franz Hofmann, Russell G FosterAbstract:In the mammalian retina, besides the conventional rod–cone system, a melanopsin-associated photoreceptive system exists that conveys photic information for accessory visual functions such as Pupillary light Reflex and circadian photo-entrainment1,2,3,4,5,6,7. On ablation of the melanopsin gene, retinal ganglion cells that normally express melanopsin are no longer intrinsically photosensitive8. Furthermore, Pupil Reflex8, light-induced phase delays of the circadian clock9,10 and period lengthening of the circadian rhythm in constant light9,10 are all partially impaired. Here, we investigated whether additional photoreceptive systems participate in these responses. Using mice lacking rods and cones, we measured the action spectrum for phase-shifting the circadian rhythm of locomotor behaviour. This spectrum matches that for the Pupillary light Reflex in mice of the same genotype11, and that for the intrinsic photosensitivity of the melanopsin-expressing retinal ganglion cells7. We have also generated mice lacking melanopsin coupled with disabled rod and cone phototransduction mechanisms. These animals have an intact retina but fail to show any significant Pupil Reflex, to entrain to light/dark cycles, and to show any masking response to light. Thus, the rod–cone and melanopsin systems together seem to provide all of the photic input for these accessory visual functions.
Mark Vandam - One of the best experts on this subject based on the ideXlab platform.
-
Pupillary response and phenotype in asd latency to constriction discriminates asd from typically developing adolescents
Autism Research, 2018Co-Authors: Georgina Lynch, Stephen M James, Mark VandamAbstract:Brain imaging data describe differences in the ASD brain, including amygdala overgrowth, neural interconnectivity, and a three-phase model of neuroanatomical changes from early post-natal development through late adolescence. The Pupil Reflex test (PRT), a noninvasive measure of brain function, may help improve early diagnosis and elucidate underlying physiology in expression of ASD endophenotype. Commonly observed characteristics of ASD include normal visual acuity but difficulty with eye gaze and photosensitivity, suggesting deficient neuromodulation of cranial nerves. Aims of this study were to confirm sensitivity of the PRT for identifying adolescents with ASD, determine if a phenotype for a subtype of ASD marked by Pupil response is present in adolescence, and determine whether differences could be observed on a neurologic exam testing cranial nerves II and III (CNII; CNIII). Using Pupillometry, constriction latency was measured serving as a proxy for recording neuromodulation of cranial nerves underlying the Pupillary Reflex. The swinging flashlight method, used to perform the PRT for measuring constriction latency and return to baseline, discriminated ASD participants from typically developing adolescents on 72.2% of trials. Results further confirmed this measure's sensitivity within a subtype of ASD in later stages of development, serving as a correlate of neural activity within the locus–coeruleus norepinephrine (LC–NE) system. A brainstem model of atypical PRT in ASD is examined in relation to modulation of cranial nerves and atypical arousal levels subserving the atypical Pupillary Reflex. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary Milder forms of autism spectrum disorder (ASD) can be difficult to diagnose based on behavioral testing alone. This study used eye-tracking equipment and a hand-held penlight to measure the Pupil Reflex in adolescents with “high functioning” ASD and in adolescents without ASD. The ASD group showed a delay in Pupil response. This is the first eye-tracking study to conduct this test as typically performed by a clinical provider, demonstrating differences in older individuals with a subtype of ASD.
Samer Hattar - One of the best experts on this subject based on the ideXlab platform.
-
melanopsin and rod cone photoreceptive systems account for all major accessory visual functions in mice
Nature, 2003Co-Authors: Samer Hattar, Mark W Hankins, Robert J Lucas, R H Douglas, Martin Biel, Nicholas Mrosovsky, S. Thompson, Franz Hofmann, Russell G FosterAbstract:In the mammalian retina, besides the conventional rod–cone system, a melanopsin-associated photoreceptive system exists that conveys photic information for accessory visual functions such as Pupillary light Reflex and circadian photo-entrainment1,2,3,4,5,6,7. On ablation of the melanopsin gene, retinal ganglion cells that normally express melanopsin are no longer intrinsically photosensitive8. Furthermore, Pupil Reflex8, light-induced phase delays of the circadian clock9,10 and period lengthening of the circadian rhythm in constant light9,10 are all partially impaired. Here, we investigated whether additional photoreceptive systems participate in these responses. Using mice lacking rods and cones, we measured the action spectrum for phase-shifting the circadian rhythm of locomotor behaviour. This spectrum matches that for the Pupillary light Reflex in mice of the same genotype11, and that for the intrinsic photosensitivity of the melanopsin-expressing retinal ganglion cells7. We have also generated mice lacking melanopsin coupled with disabled rod and cone phototransduction mechanisms. These animals have an intact retina but fail to show any significant Pupil Reflex, to entrain to light/dark cycles, and to show any masking response to light. Thus, the rod–cone and melanopsin systems together seem to provide all of the photic input for these accessory visual functions.
Georgina Lynch - One of the best experts on this subject based on the ideXlab platform.
-
Pupillary response and phenotype in asd latency to constriction discriminates asd from typically developing adolescents
Autism Research, 2018Co-Authors: Georgina Lynch, Stephen M James, Mark VandamAbstract:Brain imaging data describe differences in the ASD brain, including amygdala overgrowth, neural interconnectivity, and a three-phase model of neuroanatomical changes from early post-natal development through late adolescence. The Pupil Reflex test (PRT), a noninvasive measure of brain function, may help improve early diagnosis and elucidate underlying physiology in expression of ASD endophenotype. Commonly observed characteristics of ASD include normal visual acuity but difficulty with eye gaze and photosensitivity, suggesting deficient neuromodulation of cranial nerves. Aims of this study were to confirm sensitivity of the PRT for identifying adolescents with ASD, determine if a phenotype for a subtype of ASD marked by Pupil response is present in adolescence, and determine whether differences could be observed on a neurologic exam testing cranial nerves II and III (CNII; CNIII). Using Pupillometry, constriction latency was measured serving as a proxy for recording neuromodulation of cranial nerves underlying the Pupillary Reflex. The swinging flashlight method, used to perform the PRT for measuring constriction latency and return to baseline, discriminated ASD participants from typically developing adolescents on 72.2% of trials. Results further confirmed this measure's sensitivity within a subtype of ASD in later stages of development, serving as a correlate of neural activity within the locus–coeruleus norepinephrine (LC–NE) system. A brainstem model of atypical PRT in ASD is examined in relation to modulation of cranial nerves and atypical arousal levels subserving the atypical Pupillary Reflex. Autism Res 2017. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Lay Summary Milder forms of autism spectrum disorder (ASD) can be difficult to diagnose based on behavioral testing alone. This study used eye-tracking equipment and a hand-held penlight to measure the Pupil Reflex in adolescents with “high functioning” ASD and in adolescents without ASD. The ASD group showed a delay in Pupil response. This is the first eye-tracking study to conduct this test as typically performed by a clinical provider, demonstrating differences in older individuals with a subtype of ASD.
Chien Cheng Huang - One of the best experts on this subject based on the ideXlab platform.
-
lack of Pupil Reflex and loss of consciousness predict 30 day neurological sequelae in patients with carbon monoxide poisoning
PLOS ONE, 2015Co-Authors: Jian Fang Zou, Hung Jung Lin, How-ran Guo, Qiming Guo, Hua Shao, Maofeng Liu, Fengling Liu, Lixin Dai, Chien Cheng HuangAbstract:Background Predicting the neurological sequelae of carbon monoxide poisoning (COP) has not been well studied. We investigated the independent predictors of neurological sequelae in patients with COP and combined these predictors to predict the prognosis. Methods This study was conducted at four hospitals in Shandong Province, China. Data were retrospectively collected from 258 patients with COP between November 1990 and October 2011. Thirty-day neurological sequelae were the primary endpoints. Results A lack of Pupil Reflex and a loss of consciousness appear to be independent predictors for neurological sequelae in patients with COP. The presence of either one had a sensitivity of 77.0% (95% confidence interval [CI]: 69.3–83.2), a specificity of 47.1% (95% CI: 38.3–56.0), positive predictive value (PPV) of 62.9% (95% CI: 55.2–70.1), and a negative predictive value (NPV) of 63.6% (95% CI: 52.6–73.4). With both predictors present, the sensitivity was 11.5% (95% CI: 6.9 to 18.3), the specificity was 99.2 (95% CI: 94.7–100.0), the PPV was 94.1% (95% CI: 69.2–99.7), and the NPV was 49.0% (95% CI: 42.5–55.5). Conclusions The risk for neurological sequelae apparently increased with the number of independent predictors. In patients with both predictors, the risk for neurological sequelae was 94.1%. Almost all (99.2%) patients with neither predictor had no neurological sequelae. This finding may help physicians make decisions about and dispositions for patients with COP. For patients with a higher risk, earlier treatment and more appropriate utilization of health care services, including hyperbaric oxygen, should be considered.
