Why is “blindsight” blind? A new perspective on primary visual cortex,recurrent activity and visual awareness

The neuropsychological phenomenon of blindsight has been taken to suggest that the primary visual cortex (V1) plays a unique role in visual awareness, and that extrastriate activation needs to be fed back to V1 in order for the content of that activation to be consciously perceived. The aim of this review is to evaluate this theoretical framework and to revisit its key tenets. Firstly, is blindsight truly a dissociation of awareness and visual detection? Secondly, is there sufficient evidence to rule out the possibility that the loss of awareness resulting from a V1 lesion simply reflects reduced extrastriate responsiveness, rather than a unique role of V1 in conscious experience? Evaluation of these arguments and the empirical evidence leads to the conclusion that the loss of phenomenal awareness in blindsight may not be due to feedback activity in V1 being the hallmark awareness. On the basis of existing literature, an alternative explanation of blindsight is proposed. In this view, visual awareness is a “global” cognitive function as its hallmark is the availability of information to a large number of perceptual and cognitive systems; this requires inter-areal long-range synchronous oscillatory activity. For these oscillations to arise, a specific temporal profile of neuronal activity is required, which is established through recurrent feedback activity involving V1 and the extrastriate cortex. When V1 is lesioned, the loss of recurrent activity prevents inter-areal networks on the basis of oscillatory activity. However, as limited amount of input can reach extrastriate cortex and some extrastriate neuronal selectivity is preserved, computations involving comparison of neural firing rates within a cortical area remain possible. This enables “local” read-out from specific brain regions, allowing for the detection and discrimination of basic visual attributes. Thus blindsight is blind due to lack of “global” long-range synchrony, and it functions via “local” neural readout from extrastriate areas.     

中西部农村中小学生所受抚养方式与心理健康水平的分析

通过对中西部地区农村中小学心理健康状况的调查,从中随机选取1600份问卷进行抽样分析,分析结果为接受不同抚养方式的中小学生,在孤独倾向、身体症状、冲动倾向及总体心理健康水平方面上具有显著差异。     

The effects of patient's frequency of attendance and etiology of symptoms,on the General Practitioners wellbeing

IntroductionThe presence of Medically Unexplained Symptoms and a high Frequency of Attendance negatively affects the General Practitioners’ (GP) wellbeing. Although, overlapping between both phenomena is partial, with a number of frequent attenders reporting medically unexplained symptoms during consultation, there is no evidence on how GP's well-being it is affected by the specific main effects of these factors and their interaction. Evidence is also scant on the psychological processes explaining the negative impact of attendance and the etiology of symptoms on GP's wellbeing.ObjectiveDrawing on the Job Demand-Control and the Conservation of Resource stress models, this paper tests the moderating effects of the GP’ perception of patient's attendance and etiology of symptoms on the relationship between patient's demands and feedback on the GP's wellbeing.MethodA total of 105 volunteer GPs self-reported on the study variables through an experience sampling methodology after 898 patients’ consultation. Patients attendance and etiology of symptoms were categorized according to the physician self-perception and an external criterion (organizational records).ResultsPerception of Patients Frequent Attendance and Medically Unexplained Symptoms were positively related to physician's Emotional Exhaustion. Contrary to expected the test of the moderation effects of patients characteristics on the relation between patient's demands and feedback and the GP's emotional exhaustion were stronger for normal attenders compared with frequent attenders. An ad hoc study shows this unexplained result is related to the GP's expectations on Frequent vs. normal attenders’ behaviors. No significant results were found when the external criterion of classification was used.ConclusionCombined analysis of Frequency of Attendance and Etiology of Symptoms lead to a better understanding of the GP's decreased wellbeing. Also, the perception of the strain level (demands/positive feedback levels) associated to the consultation with different types of patients contribute to explain the consequences for the GP's wellbeing, especially when GP's expectations on patient's behaviors are violated.