Background: The perception of visual forms is crucial for effective interactions with our environment and for the recognition of visual objects. Thus, to determine the codes underlying this function is a fundamental theoretical objective in the study of the visual forms perception. The vast majority of research in the field is based on a hypothetico-deductive approach. Thus, we first begin by formulating a theory, then we make predictions and finally we conduct experimental tests. After decades of application of this approach, the field remains far from having a consensus as to the traits underlying the representation of visual form. Our goal is to determine, without theoretical a priori or any bias whatsoever, the information underlying the discrimination and recognition of 3D visual forms in normal human adults.
Methods: To this end, the adaptive bubble technique developed by Wang et al. [2011] is applied on six 3D synthetic objects under varying views from one test to another. This technique is based on the presentation of stimuli that are partially revealed through Gaussian windows, the location of which is random and the number of which is established in such a way as to maintain an established performance criterion. Gradually, the experimental program uses participants’ performance to determine the stimulus regions that participants use to recognize objects. The synthetic objects used in this study are unfamiliar and were generated from a program produced at C. Edward Connor’s lab, Johns Hopkins University School of Medicine.
Results: The results were integrated across participants to establish regions of presented stimuli that determine the observers’ ability to recognize them—i.e., diagnostic attributes. The results will be reported in graphical form with a Z scores mapping that will be superimposed on silhouettes of the objects presented during the experiment. This mapping makes it possible to quantify the importance of the different regions on the visible surface of an object for its recognition by the participants.
Conclusions: The diagnostic attributes that have been identified are the best described in terms of surface fragments. Some of these fragments are located on or near the outer edge of the stimulus while others are relatively distant. The overlap is minimal between the effective attributes for the different points of view of the same object. This suggests that the traits underlying the recognition of objects are specific to the point of view. In other words, they do not generalize through the points of view.
Background: The concept of stochastic facilitation suggests that the addition of precise amounts of white noise can improve the perceptibility of a stimulus of weak amplitude. We know from previous research that tactile and auditory noise can facilitate visual perception, respectively. Here we wanted to see if the effects of stochastic facilitation generalise to a reaction time paradigm, and if reaction times are correlated with tactile thresholds. We know that when multiple sensory systems are stimulated simultaneously, reaction times are faster than either stimulus alone, and also faster than the sum of reaction times (known as the race model).
Methods: Five participants were re-tested in five blocks each of which contained a different background noise levels, randomly ordered across sessions. At each noise level, they performed a tactile threshold detection task and a tactile reaction time task.
Results: Both tactile threshold and tactile reaction times were significantly affected by the background white noise. While the preferred amplitude for the white noise was different for every participant, the average lowest threshold was obtained with white noise presented binaurally at 70 db. The reaction times were analysed by fitting an ex-Gaussian, the sum of a Gaussian function and an exponential decay function. The white noise significantly affected the exponential parameter (tau) in a way that is compatible with the facilitation of thresholds.
Conclusions: We therefore conclude that multisensory reaction time facilitation can, at least in part, be explained by stochastic facilitation of the neural signals.
Abstract: Contrast is the differential luminance between one object and another. Contrast sensitivity (CS) quantifies the ability to detect this difference: estimating contrast threshold provides information about the quality of vision and helps diagnose and monitor eye diseases. High contrast visual acuity assessment is traditionally performed in the eye care practice, whereas the estimate of the discrimination of low contrast targets, an important complementary task for the perception of details, is far less employed. An example is driving when the contrast between vehicles, obstacles, pedestrians, and the background is reduced by fog. Many conditions can selectively degrade CS, while visual acuity remains intact. In addition to spatial CS, “temporal” CS is defined as the ability to discriminate luminance differences in the temporal domain, i.e., to discriminate information that reaches the visual cortex as a function of time. Likewise, temporal sensitivity of the visual system can be investigated in terms of critical fusion frequency (CFF), an indicator of the integrity of the magnocellular system that is responsible for the perception of transient stimulations. As a matter of fact, temporal resolution can be abnormal in neuro-ophthalmological clinical conditions. This paper aims at considering CS and its application to the clinical practice.
Abstract: The teaching of professionalism, a key aspect of medical competence that regulates physician’s behavior towards patients, colleagues, society, and self, should be included in the curriculum of every training program. Studies suggest a variety of formats to teach and evaluate professionalism in residents, being role modeling, reflection, case discussions, and 360-degree assessments the most commonly used. However, little is published about the need to train faculty for teaching and evaluating professionalism, or how to improve institutional culture, so that principles that are indicated to teach in theory are also fulfilled in practice.
Abstract: Training in residency programs is highly competitive, it requires the formation of competent physicians that achieve the performance standards that were declared for their technical skills, attitudes and interpersonal abilities. The use of simulation and technology on the medical education has increased considerably. Particularly in ophthalmology the simulators used are: live models from animal or cadavers, mannequins, wet laboratories, simulated patients, part-task moles, laser or surgical models, and more recently, virtual reality (VR). VR places a person in a simulated environment that has a specific sense of self-location, where the participant interacts with the objects within the setting. Teaching with VR refers to the use of the available resources in technology and visualization of structures to improve the educational experience of medical students, residents and physicians in professional continuous development programs. Several authors highlight the benefits of assessing trainees with the tools, they argue that the key contribution of this model is in the formative assessment. Rather than evaluating and putting a score on student’s grades, VR provides a powerful experience for the acquisition of skills. A conclusion is the need to develop studies to document the effects that it has on knowledge, skills and behaviors, and to patient related outcomes.
Abstract: Ophthalmology residency training programs need authentic methods of assessment to show that trainees have learned and can do what is expected upon graduation. Written and oral examinations are necessary to assess knowledge but other methods are needed to assess skill. Workplace-based assessments (WPBAs) should be utilized to observe resident skill in the clinic and during surgery. Several such assessment tools have been published and validated. These tools have the additional benefit of facilitating specific formative feedback and thus can be used for both teaching and assessing.
Abstract: The outcomes of modern ophthalmic surgery, especially cataract surgery, continue to improve and patients now realistically expect an excellent and speedy outcome with good vision and few complications. Social and regulatory demands for greater transparency and accountability in medicine have increased, highlighting a fundamental ethical tension in medical education—balancing the needs of trainees (who have not yet mastered the technique) to gain experience by performing surgery, with patient safety and the needs of the public to be protected from risk. Patient safety and well-being are the paramount considerations in any training program and must be the first consideration in program design. A variety of different educational strategies, each implemented with the aim of improving operative skills assessment and teaching, has recently been described in the literature. Effective use of these educational tools, combined with a structured approach to teaching and providing meaningful feedback, could improve outcomes, decrease complications and improve the quality and efficiency of surgical training in ophthalmology. Supervisors must assess their teaching style and communication, as being a good surgeon does not necessarily make a good trainer. Open disclosure must be given to patients about who will be performing the surgery, and communication during surgery between supervisors and trainees must be clear, respectful and appropriate.
