Rhythms of Consciousness: Binocular Rivalry Reveals Large-Scale Oscillatory Network Dynamics Mediating Visual Perception

Consciousness has been proposed to emerge from functionally integrated large-scale ensembles of gamma-synchronous neural populations that form and dissolve at a frequency in the theta band. We propose that discrete moments of perceptual experience are implemented by transient gamma-band synchronization of relevant cortical regions, and that disintegration and reintegration of these assemblies is time-locked to ongoing theta oscillations. In support of this hypothesis we provide evidence that (1) perceptual switching during binocular rivalry is time-locked to gamma-band synchronizations which recur at a theta rate, indicating that the onset of new conscious percepts coincides with the emergence of a new gamma-synchronous assembly that is locked to an ongoing theta rhythm; (2) localization of the generators of these gamma rhythms reveals recurrent prefrontal and parietal sources; (3) theta modulation of gamma-band synchronization is observed between and within the activated brain regions. These results suggest that ongoing theta-modulated-gamma mechanisms periodically reintegrate a large-scale prefrontal-parietal network critical for perceptual experience. Moreover, activation and network inclusion of inferior temporal cortex and motor cortex uniquely occurs on the cycle immediately preceding responses signaling perceptual switching. This suggests that the essential prefrontal-parietal oscillatory network is expanded to include additional cortical regions relevant to tasks and perceptions furnishing consciousness at that moment, in this case image processing and response initiation, and that these activations occur within a time frame consistent with the notion that conscious processes directly affect behaviour.     

Screening HIV-infected patients for non-AIDS-defining malignancies

The use of antiretroviral therapy has reduced mortality and shifted the spectrum of malignancies affecting people living with HIV/AIDS (PLWH). We review guidelines and evidence for screening PLWH for non-AIDS-defining malignancies as compared with the general population. Cervical cancer screening clearly differs for HIV-seropositive women, with two Pap tests 6 months apart in the first year and then annually if normal. The role of cervical human papillomavirus screening has not yet been defined in HIV-seropositive women. Anal cancer screening consists of an annual digital rectal examination, and some (but not all) guidelines also recommend annual anal Pap tests. Screening for breast and colorectal cancer should follow standard, age-appropriate screening recommendations that apply to the general population. Screening HIV-infected men for prostate cancer, as with the general population, lacks a clear benefit. Despite increasing rates of hepatocellular carcinoma and lung cancers among PLWH, there is insufficient evidence to support routine screening.     

Skin immune surveillance by T cells—A new order?

Although studies of the skin have provided fundamental models for innate and adaptive immune surveillance of body surfaces, there remains relatively little understanding of the role that epithelial cells play in sensing infection and/or organ dysfunction, and the pathways available to them to communicate with local and systemic immune cells. In particular, evidence is emerging for a novel stress response initiated by local lymphocytes, rather than dendritic cells, and based on their recognition of epithelial stress-induced antigens. Its consequences are to sustain tissue integrity by providing immunoprotection and novel modes of immunoregulation, whereas its dysregulation may promote body surface immunopathologies.     

A comparison of physiological variables in aged and young women during and following submaximal exercise

Previously, we have examined how aging affects the physiological responses of men to endurance exercise. In the present investigation, we aimed to extend our assessment of the influence of aging on exercise‐induced responses by focusing on women. Ten young (20.3 ± 0.3 years; mean ± SE) and 10 aged (75.5 ± 1.2 years) women performed 30 min of cycling at 60–65% of their predetermined peak oxygen uptake. Data for respiratory exchange ratio (RER), heart rate, blood pressure, rectal temperature, and plasma metabolites were collected before exercise, at the 15th and 30th min of exercise, and at 5 and 15 min postexercise. A two‐way, repeated measures ANOVA with main effects of age and time was conducted on each variable. Our findings showed that age affected exercise‐induced responses of each variable quantified. Although RER, heart rate, temperature, and lactate were significantly (P < 0.05) higher among young women, blood pressure and glucose values were greater among aged women. Moreover, unlike previous results noted among men where age‐related differences primarily occurred during postexercise recovery, in women the effect of aging was detected during exercise itself. The data presented here indicate that aging impacts physiological responses of women to prolonged endurance exercise even when relative intensity (% of peak oxygen uptake) is held constant. Combined with our earlier study on men, these findings suggest that gender interacts with aging to determine whether age‐related differences are manifested during exercise itself, or during postexercise recovery. Am. J. Hum. Biol., 2009. © 2009 Wiley‐Liss, Inc.     

Relational Aggression and Adverse Psychosocial and Physical Health Symptoms Among Urban Adolescents

ABSTRACT Objectives: The purpose of this study was to examine relational aggression and its relationship with adverse psychosocial and physical health symptoms among urban, African American youth.
Design and Sample: Quantitative, cross-sectional survey design.
The sample consisted of 185 predominantly African American (95.1%) seventh-grade students (mean age: 13.0; female: 58%) attending 4 urban middle schools.
Measures: The Children's Social Behavior Scale and Social Experience Questionnaire were used to measure relational aggression and relational victimization. The Pediatric Symptom Checklist was used to assess psychosocial difficulties, including internalizing behaviors, externalizing behaviors, and attention problems. Physical health symptoms were measured with questions about colds/flu, headaches, and stomach aches.
Results: 2-way multivariate analysis of variance revealed significant differences in externalizing behavior, with perpetrators reporting higher levels than nonperpetrators. Victims reported more internalizing behavior than nonvictims; however, this was only significant for males. For females, significant negative effects on health outcomes were found, resulting from the interaction of perpetration and victimization.
Conclusions: Findings suggest that relational aggression is a common occurrence among urban, minority adolescents and may result in adverse health outcomes. These results provide several avenues for future research and implications for healthcare practice. Intervention strategies are needed to prevent relational aggression and continual or subsequent adverse health symptoms.     

Infrared spectroscopic examination of aqueous humor.

OBJECTIVE: The aim of this study was to report on a new technique for examining aqueous humor. PARTICIPANTS: Aqueous humor samples obtained from 198 patients (cataract: n=66 eyes; age-related macular degeneration [AMD]: n=66; diabetic macular edema: n=66) were in vitro examined by mid infrared spectroscopy. After training and validating the technique, 66 samples were taken for the final independent prediction. RESULTS: In computerized analysis of the spectrometric data, 22 (100%) cataract eyes were diagnosed as the cataract group, 17 (77%) diabetic macular edema eyes were diagnosed as the diabetic macular edema group, and 14 (64%) eyes with AMD were diagnosed as the AMD group. Mid infrared spectrometry could statistically significantly (P=0.004) differentiate between the 3 study groups. CONCLUSIONS: Mid infrared spectroscopic examination of aqueous humor may be able to differentiate eyes with cataract, AMD, or diabetic macular edema.