The effect of lens-induced anisometropia on sterolocalization

Little research has been done to study the effect of anisometropia on the ability of subjects to localize an object in space using binocular depth cues. Rendering a patient artificially anisometropic is similar to prescribing an unbalanced refraction or inducing anisometropia in a monovision contact lens fit. We investigated the effect of induced anisometropia on stereolocalization. Spectacle lenses were used to create the anisometropic conditions and all subjects were pretested for isometropia while wearing their best distance refractive corrections. Thirty-eight subjects judged the distance of a floating vectographic Quoit\u27s Ring target under varying amounts of anisometropia in a featureless field. The amounts of anisometropia induced ranged between 0.50 D and 1.75 D. The results indicate that there is no statistically significant difference in the ability to stereolocalize with up to 1.00 D of anisometropia, however, beyond this limit a statistically significant decrease in performance clearly exists

Relationship between central and peripheral visual tendencies and center of balance responses to yoked prism

Peripheral vision has been shown to help stabilize subjects on a balance task more than central vision. Lenses and prisms have been shown to affect a person\u27s center of balance. A study by Jeske demonstrated significant shifts in center of balance upon the application of yoked prism. The question posed by this study is, do subjects who tend to pay more attention to peripheral visual information respond differently to 12 prism diopters of vertically yoked prism than do those subjects who pay more attention to central visual information? Replication of the results found by Jeske was also attempted. Subjects were 25 non-optometry students. The subject\u27s tendency to pay attention to peripheral or central visual information was measured using a combination of the scores on a distance maddox rod phoria, peripheral visual response speed as measured by the Wayne Peripheral Awareness Tester and Trainer, and score on the rod and frame apparatus. The subject\u27s center of balance response to vertically yoked prism was measured using the BALANCE SYSTEM: from the Chattecx corporation. It consists of a computerized balance platform from which footplates take rapid samples of percent of body weight shift based on an X-Y coordinate system. The X values quantified leftward or rightward center of balance position (X COB). The Y values quantified the forward or rearward center of balance positions (YCOB). Postural sway, dispersion, was also measured (PS). No significant differences were found between the prism conditions in the XCOB or PS analysis. Significant differences were seen in the YCOB variable when the base-down yoked prism condition was compared to the base\u27 UP prism condition. The central or peripheral processing characteristics did not show a significant relationship to YCOB response to yoked prism. Effects of refractive error and habitual standing posture on YCOB response to yoked prism was also measured. The myopes and the emmetropes responded significantly (p\u3c 0.05) more to the base-up prism than did the hyperopes, and the hyperopes and emmetropes responded signiticantly (p\u3c 0.05) more to the base-down yoked prism. Signiticant differences (p\u3c0.05) between subjects with a forward habitual posture and those with a rearward habitual posture were found for the base-down and baseup conditions, as well as the post base-up condition. Jeske\u27s study was only partially replicated. The center versus peripheral processing characteristics are not predictors of an individual\u27s response to yoked prism. Better predictors of center of balance response to yoked prism are refractive error and habitual standing posture

The role of the frontal cortex in memory: an investigation of the Von Restorff effect

Evidence from neuropsychology and neuroimaging indicate that the pre-frontal cortex (PFC) plays an important role in human memory. Although frontal patients are able to form new memories, these memories appear qualitatively different from those of controls by lacking distinctiveness. Neuroimaging studies of memory indicate activation in the PFC under deep encoding conditions, and under conditions of semantic elaboration. Based on these results, we hypothesize that the PFC enhances memory by extracting differences and commonalities in the studied material. To test this hypothesis, we carried out an experimental investigation to test the relationship between the PFC-dependent factors and semantic factors associated with common and specific features of words. These experiments were performed using Free-Recall of word lists with healthy adults, exploiting the correlation between PFC function and fluid intelligence. As predicted, a correlation was found between fluid intelligence and the Von-Restorff effect (better memory for semantic isolates, e.g., isolate “cat” within category members of “fruit”). Moreover, memory for the semantic isolate was found to depend on the isolate's serial position. The isolate item tends to be recalled first, in comparison to non-isolates, suggesting that the process interacts with short term memory. These results are captured within a computational model of free recall, which includes a PFC mechanism that is sensitive to both commonality and distinctiveness, sustaining a trade-off between the two

S4S8-RPA phosphorylation as an indicator of cancer progression in oral squamous cell carcinomas.

Oral cancers are easily accessible compared to many other cancers. Nevertheless, oral cancer is often diagnosed late, resulting in a poor prognosis. Most oral cancers are squamous cell carcinomas that predominantly develop from cell hyperplasias and dysplasias. DNA damage is induced in these tissues directly or indirectly in response to oncogene-induced deregulation of cellular proliferation. Consequently, a DNA Damage response (DDR) and a cell cycle checkpoint is activated. As dysplasia transitions to cancer, proteins involved in DNA damage and checkpoint signaling are mutated or silenced decreasing cell death while increasing genomic instability and allowing continued tumor progression. Hyperphosphorylation of Replication Protein A (RPA), including phosphorylation of Ser4 and Ser8 of RPA2, is a well-known indicator of DNA damage and checkpoint activation. In this study, we utilize S4S8-RPA phosphorylation as a marker for cancer development and progression in oral squamous cell carcinomas (OSCC). S4S8-RPA phosphorylation was observed to be low in normal cells, high in dysplasias, moderate in early grade tumors, and low in late stage tumors, essentially supporting the model of the DDR as an early barrier to tumorigenesis in certain types of cancers. In contrast, overall RPA expression was not correlative to DDR activation or tumor progression. Utilizing S4S8-RPA phosphorylation to indicate competent DDR activation in the future may have clinical significance in OSCC treatment decisions, by predicting the susceptibility of cancer cells to first-line platinum-based therapies for locally advanced, metastatic and recurrent OSCC

Output order and variability in free recall are linked to cognitive ability and hippocampal volume in elderly individuals.

Adapted from the work of Kahana and colleagues (e.g., Kahana, 1996), we present two measures of order of recall in neuropsychological free recall tests. These are the position on the study list of the first recalled item, and the degree of variability in the order in which items are reported at test (i.e., the temporal distance across the first four recalled items). We tested two hypotheses in separate experiments: (1) whether these measures predicted generalized cognitive ability, and (2) whether they predicted gray matter hippocampal volume. To test hypothesis 1, we conducted ordinal regression analyses on data from a group of 452 participants, aged 60 or above. Memory performance was measured with Rey's AVLT and generalized cognitive ability was measured with the MMSE test. To test hypothesis 2, we conducted a linear regression analysis on data from a sample of 79 cognitively intact individuals aged 60 or over. Memory was measured with the BSRT and hippocampal volume was extracted from MRI images. Results of Experiment 1 showed that the position of the first item recalled and the degree of output order variability correlated with MMSE scores only in the delayed test, but not in the immediate test. In Experiment 2, the degree of variability in the recall sequence of the delayed trial correlated (negatively) with hippocampal size. These findings confirm the importance of delayed primacy as a marker of cognitive ability, and are consistent with the idea that the hippocampus is involved in coding the temporal context of learned episodes

A study on the specificity of the association between hippocampal volume and delayed primacy performance in cognitively intact elderly individuals.

Delayed recall at the primacy position (first few items on a list) has been shown to predict cognitive decline in cognitively intact elderly participants, with poorer delayed primacy performance associated with more pronounced generalized cognitive decline during follow-up. We have previously suggested that this association is due to delayed primacy performance indexing memory consolidation, which in turn is thought to depend upon hippocampal function. Here, we test the hypothesis that hippocampal size is associated with delayed primacy performance in cognitively intact elderly individuals. Data were analyzed from a group (N=81) of cognitively intact participants, aged 60 or above. Serial position performance was measured with the Buschke selective reminding test (BSRT). Hippocampal size was automatically measured via MRI, and unbiased voxel-based analyses were also conducted to explore further regional specificity of memory performance. We conducted regression analyses of hippocampus volumes on serial position performance; other predictors included age, family history of Alzheimer's disease (AD), APOE ε4 status, education, and total intracranial volume. Our results collectively suggest that there is a preferential association between hippocampal volume and delayed primacy performance. These findings are consistent with the hypothesis that delayed primacy consolidation is associated with hippocampal size, and shed light on the relationship between delayed primacy performance and generalized cognitive decline in cognitively intact individuals, suggesting that delayed primacy consolidation may serve as a sensitive marker of hippocampal health in these individuals

Data quality up to the third observing run of Advanced LIGO: Gravity Spy glitch classifications

Understanding the noise in gravitational-wave detectors is central to detecting and interpreting gravitational-wave signals. Glitches are transient, non-Gaussian noise features that can have a range of environmental and instrumental origins. The Gravity Spy project uses a machine-learning algorithm to classify glitches based upon their time–frequency morphology. The resulting set of classified glitches can be used as input to detector-characterisation investigations of how to mitigate glitches, or data-analysis studies of how to ameliorate the impact of glitches. Here we present the results of the Gravity Spy analysis of data up to the end of the third observing run of Advanced LIGO. We classify 233981 glitches from LIGO Hanford and 379805 glitches from LIGO Livingston into morphological classes. We find that the distribution of glitches differs between the two LIGO sites. This highlights the potential need for studies of data quality to be individually tailored to each gravitational-wave observatory