Bilateral field advantage in visual crowding

Thirty randomly oriented T’s were presented in a circle around fixation at an eccentricity of 11° such that each T was crowded by its neighbors. Two locations within the same hemifield (unilateral condition) or one location in each hemifield (bilateral condition) were precued for subsequent probing. Observers were then asked to report the orientation of a target T at one of these locations. A bilateral field advantage was found: target identification was better when the two precued targets were in different hemifields than when they were within the same hemifield. This bilateral advantage was absent when only targets were presented, without any distracters. Further controls showed that this advantage could not be attributed to differences between horizontal and vertical target alignments or to visual field anisotropies. A similar bilateral advantage has been reported for multiple object tracking (Alvarez, G. A., & Cavanagh, P. (2005). Independent resources for attentional tracking in the left and right visual fields. Psychological Science 16(8), 637-643) and other attentional tasks. Our results suggest that crowding also demonstrates separate attentional resources in the left and right hemifields. There was a cost to attending to two targets presented unilaterally over attending to a single target. However, this cost was reduced when the two crowded targets were in separate hemifields.     

Mutational screening of the RB1 gene in Indian patients with retinoblastoma reveals eight novel and several recurrent mutations

Retinoblastoma is the most common primary intraocular malignancy in children, caused by inactivation of the RB1 gene on chromosome 13. We carried out a mutational screen of the exons and promoter of the RB1 gene in Indian patients with retinoblastoma in order to determine the range of mutations giving rise to disease. Forty-seven patients were screened for mutations in all exons and promoter of the RB1 gene by single strand conformation polymorphism followed by sequencing. Tumors were available from 27 patients (12 bilateral and 15 unilateral retinoblastoma) while only peripheral blood was available from 20 patients, all with bilateral disease. Mutations were found in 22 patients, 9 from the analysis of tumors and 13 from peripheral blood. Eight novel mutations were identified, including 4 single base changes, 2 small deletions and 1 duplication. These are g.64365T>G (Tyr325Ter), g.78131G>A (Trp515Ter), g.150061G>T (Glu587Ter), g.170383C>G (S834X), g.41924A>C (IVS3-2A>C), g.150064ins4, g.160792del22, and g.76940del14 (IVS15 del +20-33). Almost all mutations produced nonsense codons or frameshifts. Recurrent mutations, especially at CpG sites were seen predominantly. Detectable mutations in exons were found in 46% of patients tested. Large deletions, epigenetic changes as well as mutations in non-coding regions may be the cause of disease in the remainder of patients. Knowledge of the full range of mutations can aid in the design of screening tests for individuals at risk.     

Conscious updating is a rhythmic process

As the visual world changes, its representation in our consciousness must be constantly updated. Given that the external changes are continuous, it appears plausible that conscious updating is continuous as well. Alternatively, this updating could be periodic, if, for example, its implementation at the neural level relies on oscillatory activity. The flash-lag illusion, where a briefly presented flash in the vicinity of a moving object is misperceived to lag behind the moving object, is a useful tool for studying the dynamics of conscious updating. Here, we show that the trial-by-trial variability in updating, measured by the flash-lag effect (FLE), is highly correlated with the phase of spontaneous EEG oscillations in occipital (5-10 Hz) and frontocentral (12-20 Hz) cortices just around the reference event (flash onset). Further, the periodicity in each region independently influences the updating process, suggesting a two-stage periodic mechanism. We conclude that conscious updating is not continuous; rather, it follows a rhythmic pattern.     

Oral myiasis in a maxillofacial trauma patient

Oral Myiasis is a rare disease that is mostly reported in developing countries. It is primarily caused by the invasion of the human body by fly larvae. The phenomenon is well-documented in the skin, especially among animals. This case report describes the presentation of Oral Myiasis caused by Musca Nebulo (common house fly), in a 28-year-old patient, with recent maxillofacial trauma. The patient was treated by manual removal of the larvae, after topical application of turpentine oil, followed by surgical debridement and oral therapy with Ivermectin.     

Recurrent strokes caused by a malpositioned pacemaker lead

This case report illustrates the case of a patient who developed recurrent strokes after a pace maker lead was inserted into his left ventricle. It was removed successfully by the cardiothoracic surgeons but he remained very dependent functionally. This case highlights the importance of always reviewing the electrocardiogram and chest radiograph after the insertion of a pacemaker as late diagnosis of this complication can leave the patient with significant morbidity.     

Short-term exposure to an enriched environment enhances dendritic branching but not brain-derived neurotrophic factor expression in the hippocampus of rats with ventral subicular lesions

Environmental enrichment promotes structural and behavioral plasticity in the adult brain. We have evaluated the efficacy of enriched environment on the dendritic morphology and brain-derived neurotrophic factor (BDNF) expression in the hippocampus of ventral subicular-lesioned rats. Bilateral ventral subicular lesion has significantly reduced the dendritic architecture and spine density of hippocampal pyramidal neurons. The lesioned rats exposed to enriched housing for 10 days showed a significant degree of morphological plasticity in terms of enhanced dendritic branching and spine density. However, the BDNF expression in the hippocampus remained unchanged following subicular lesion and following environmental enrichment. We suggest the participation of other neurotrophic factors in mediating the synaptic plasticity events following exposure to environmental enrichment in ventral subicular-lesioned rats.     

Short photoperiod restores ventral subicular lesion-induced deficits in affective and socio-cognitive behavior in male Wistar rats

Photoperiod (day-length) has enduring effects on an organism's physiological functions like metabolism and behavioral phenotypes including cognition and affect. Circadian rhythm manipulations are potentially effective non-pharmacological strategies in the management of central nervous system insults. In our previous study, we demonstrated the efficacy of short photoperiod regime (SPR; 06/18 hr light-dark cycle) in establishing functional recovery in ventral subicular lesion (VSL) rats. The present study further demonstrates the efficacy of SPR in mitigating anxiety and depression as well as facilitating socio-cognitive behavior in VSL rats. VSL elevated the basal plasma corticosterone levels, increased anxiety, anhedonia, and behavioral despair with decreased self-care. The VSL rats also exhibited a considerable degree of impaired social cognition, in terms of altered social preference and social novelty. Exposure to SPR for 21 days mitigated the anxiety- and depressive-like phenotypes as well as improved social cognition significantly. Thus, the study demonstrated the effectiveness of SPR strategy in reversing most of the behavioral deficits caused by VSL. SPR, perhaps, would have regulated the hypothalamo-pituitary-adrenal axis responsiveness as we observed a decrease in plasma corticosterone levels following SPR in VSL rats. The study implies the need for developing a task-dependent SPR strategy to achieve complete behavioral recovery as the functional demands of each behavior is distinct. In summary, the study highlights the efficacy of photoperiod manipulation as a novel, non-pharmacological approach in mitigating the affective and cognitive deficits associated with neuropsychiatric disorders such as bipolar disorder and Alzheimer's disease wherein circadian rhythm alterations are implicated.     

Effect of rifampin and itraconazole on the pharmacokinetics of zanubrutinib (a Bruton's tyrosine kinase inhibitor) in Asian and non-Asian healthy subjects

Cancer Chemotherapy and Pharmacology - Zanubrutinib (BGB-3111) is a potent Bruton’s tyrosine kinase inhibitor with promising clinical activity in B-cell malignancies. Zanubrutinib was shown...