Ilusão da máscara côncava durante a síndrome de abstinência leve do álcool / Hollow-face illusion during during mild alcohol withdrawal syndrome

A ilusão da máscara côncava caracteriza-se pela inversão visual da profundidade durante a observação do reverso de uma máscara da face humana, que é percebido como convexo. O objetivo deste trabalho foi investigar a percepção monocular da profundidade ou relevo de uma máscara côncava, sob quatro condições de iluminação distintas, em 8 indivíduos com a Síndrome de Abstinência do Álcool (SAA) leve comparativamente a 8 participantes saudáveis. As contribuições nesta área de investigação são escassas e os resultados encontrados são controversos. Além disso, resta investigar a condição monocular de observação do estímulo. A máscara côncava foi posicionada no interior deuma caixa e observada através de um visor. Não foram observadas diferenças significativas entre os indivíduos com a SAA leve e os observadores saudáveis. A maioria dos observadores realizou a inversão visual da profundidade da máscara côncava, percebendo a face ilusória convexa. Ressalta-se a supremacia dos processos cognitivos, de alta ordem (top-down), sobre os processos sensoriais, de baixa ordem (bottom-up), na ilusão da máscara côncava. A observação monocular facilitou a ilusão e não foi adequada para investigar os prejuízos no processamento cognitivo de informações visuais causados pela SAA leve

The hollow-face illusion is the visual depth inversion that happens when a hollow mask of a human face is perceived as convex. The aim of thiswork was to investigate the monocular perception of depth or relief of a hollow mask, under four distinct illumination conditions, in 8 individuals with mild alcohol withdrawal, comparing to 8healthy participants. Scientific contributions in this research area are scarce and the results are controversial. Furthermore, it remains to investigate the status of monocular observationof the stimulus. The hollow mask was placed inside of a box and observed through a viewfinder. There was not significant differences between the individuals with mild alcohol withdrawal and the healthy observers. The significant majority of the observers made the visual depth inversion,perceiving the convex illusory face. It is important to notice the dominance of the high order, cognitive process (top-down) over low ordersensorial process (bottom-up) in the hollow-face illusion. The monocular observation facilitated illusion and it was not suitable to investigate the impairments in the cognitive processing of visual information caused by mild SAA

Neuroimaging differences in spatial cognition between men and male-to-female transsexuals before and during hormone therapy.

INTRODUCTION: Neuropsychological abnormalities in transsexual patients have been reported in comparison with subjects without gender identity disorder (GID), suggesting differences in underlying neurobiological processes. However, these results have not consistently been confirmed. Furthermore, studies on cognitive effects of cross-sex hormone therapy also yield heterogeneous results. AIM: We hypothesized that untreated transsexual patients differ from men without GID in activation pattern associated with a mental rotation task and that these differences may further increase after commencing of hormonal treatment. METHOD: The present study investigated 11 male-to-female transsexual (MFTS) patients prior to cross-sex hormone therapy and 11 MFTS patients during hormone therapy in comparison with healthy men without GID. Using functional magnetic resonance imaging at 3-Tesla, a mental rotation paradigm with proven sexual dimorphism was applied to all subjects. Data were analyzed with SPM5. MAIN OUTCOME MEASURES: Patterns of brain activation associated with a mental rotation task. RESULTS: The classical mental rotation network was activated in all three groups, but significant differences within this network were observed. Men without GID exhibited significantly greater activation of the left parietal cortex (BA 40), a key region for mental rotation processes. Both transsexual groups revealed stronger activation of temporo-occipital regions in comparison with men without GID. CONCLUSIONS: Our results confirmed previously reported deviances of brain activation patterns in transsexual men from men without GID and also corroborated these findings in a group of transsexual patients receiving cross-sex hormone therapy. The present study indicates that there are a priori differences between men and transsexual patients caused by different neurobiological processes or task-solving strategies and that these differences remain stable over the course of hormonal treatment.

Incidence of stereopsis after treatment of infantile esotropia with botulinum toxin A.

PURPOSE: The incidence of stereoscopic vision following surgery for infantile esotropia has been reported, but not from patients treated with simultaneous bimedial injection of botulinum toxin A. We previously reported other findings from 41 patients treated with botulinum toxin A before the age of 12 months. The purpose of this study was to report the incidence of stereopsis in these patients after long-term follow-up. PATIENTS AND METHODS: Data were acquired by recording the response to subjective stereoscopic testing during the postinjection follow-up period when reliable subjective responses could be obtained. At least 5 years had passed following injection, and the mean age of the patients was 8 years. RESULTS: Of the 41 patients, 11 were lost to follow-up, 10 had no stereopsis, 9 had gross stereopsis (according to Titmus fly tests), 1 had 800 seconds of stereoscopic vision, 2 had 400 seconds, 2 had 200 seconds, 1 had 60 seconds, and 5 had 40 seconds. CONCLUSIONS: In this study, two-thirds of the patients acquired stereopsis following simultaneous bimedial injection of botulinum toxin A for infantile esotropia. Stereopsis acquisition following injection of botulinum toxin A had a success rate comparable with that reported for surgically corrected infantile esotropia. Bimedial injection of botulinum toxin A accompanied by alternate patching prior to injection and diligent attention at ages ranging from 4 to 12 months is a simple and efficacious method for the management of infantile esotropia.

Retinal toxicity associated with cisplatin and etoposide in pediatric patients.

Cisplatin is an effective chemotherapeutic agent used in the treatment of many pediatric solid tumors. Retinal toxicity is a side effect of the drug reported in adults, but is not well described in pediatric patients. We present the cases of two children treated with cisplatin and etoposide who experienced retinal toxicity documented by visual evoked response (VER) and electroretinogram (ERG). significantly, both patients had abnormal renal function. The mechanism of visual toxicity induced by cisplatin is unknown but may result from central nervous system (CNS) accumulation of drug after repeated doses, especially with high-dose platinum (HDP) containing regimens. Because clearance of platinum is related to adequate renal-function, patients with any decrease in glomerular filtration rate (GFR) may have delayed platinum excretion. We propose that the patients at greatest risk of cisplatin-induced toxicity are those pretreated with nephrotoxic therapy or those with impairment of renal function from other causes. These patients should have prospective ophthalmologic evaluation especially when treated with HDP containing regimens.

Sudden onset of subjective dimensionality: a case study.

For 45 years, Bob had no subjective sense of depth; the world appeared two-dimensional to him. Then, when he was viewing mountain vistas while using marijuana, he suddenly was able to see three dimensions. This case, apparently unique in the literature, suggests that subjective dimensionality may be functionally separate from use of distance cues.

Botulinum alignment for congenital esotropia.

BACKGROUND: Botulinum toxin injection into the medial rectus has been recommended by several investigators as an alternative to incisional surgery for treatment of patients with congenital (essential infantile) esotropia. Currently, there are no published studies demonstrating both the motor and sensory results of congenital esotropic patients aligned by botulinum toxin. METHODS: The author traveled to two medical centers to personally and objectively examine, with standardized testing methods, 12 patients with congenital esotropia who had been aligned for a minimum of 6 months by the age of 2 years by other investigators. The selected patients had been followed for a minimum of 3 years and were of sufficient maturity to reliably respond to sensory testing. A comparison was made between the author's conclusions about the binocularity results of these patients and the assessment of the treating ophthalmologists. RESULTS: Only 6 of the 12 patients demonstrated optimum motor alignment to within 10 prism diopters (PD) of orthophoria at the time of the study. A minimum of 1-month (average, 5 months) post-botulinum injection was found to be necessary to establish this alignment. Only three of these six aligned patients could both fuse and demonstrate gross stereopsis without the assistance of compensatory prisms. These results can be contrasted to a previously reported group of surgically aligned cases in which 66 of 90 patients aligned by 2 years of age could both fuse and demonstrate stereopsis, without any use of compensatory prisms. CONCLUSION: These results must be considered preliminary. However, alignment by botulinum appears to be less effective in establishing evidence for binocularity than incisional surgery in the treatment of congenital esotropia (P < 0.001).

Reduced binocular depth inversion as an indicator of cannabis-induced censorship impairment.

Measurements of binocular depth inversion using a stereoscopic slide projection with polarized light were performed in healthy volunteers before and after cannabis intake. Since binocular depth inversion represents an illusion occurring in the perception of semantically meaningful objects projected in a 3-D inverted fashion, the hypothesis can be tested that cannabis-induced "psychedelic states" represent a condition in which the human CNS is unable to correct implausible perceptual hypotheses. The data demonstrate a strong cannabis-induced impairment of binocular depth inversion.