Physiological Mechanisms Underlying Motion-Induced Blindness

Visual disappearance illusions - such as motion-induced blindness (MIB) - are commonly used to study the neural underpinnings of visual perception. In such illusions a salient visual target becomes perceptually invisible. Previous studies are inconsistent regarding the role of primary visual cortex (V1) in these illusions. Here we provide physiological and psychophysical evidence supporting a role for V1 in generating MIB

Crossing the ‘Uncanny Valley’: Adaptation to Cartoon Faces Can Influence Perception of Human Faces

In this study we assessed whether there is a single face space common to both human and cartoon faces by testing whether adaptation to cartoon faces can affect perception of human faces. Participants were shown Japanese animation cartoon videos containing faces with abnormally large eyes. The use of animated videos eliminated the possibility of position-dependent retinotopic adaptation (because the faces appear at many different locations) and more closely simulated naturalistic exposure. Adaptation to cartoon faces with large eyes significantly shifted preferences for human faces toward larger eyes, consistent with a common, non-retinotopic representation for both cartoon and human faces. This supports the possibility that there are representations that are specific to faces yet common to all kinds of faces

A Cortical Region Consisting Entirely of Face-Selective Cells

Face perception is a skill crucial to primates. In both humans and macaque monkeys, functional magnetic resonance imaging (fMRI) reveals a system of cortical regions that show increased blood flow when the subject views images of faces, compared with images of objects. However, the stimulus selectivity of single neurons within these fMRI-identified regions has not been studied. We used fMRI to identify and target the largest face-selective region in two macaques for single-unit recording. Almost all (97%) of the visually responsive neurons in this region were strongly face selective, indicating that a dedicated cortical area exists to support face processing in the macaque

Multivariate Patterns in Object-Selective Cortex Dissociate Perceptual and Physical Shape Similarity

Prior research has identified the lateral occipital complex (LOC) as a critical cortical region for the representation of object shape in humans. However, little is known about the nature of the representations contained in the LOC and their relationship to the perceptual experience of shape. We used human functional MRI to measure the physical, behavioral, and neural similarity between pairs of novel shapes to ask whether the representations of shape contained in subregions of the LOC more closely reflect the physical stimuli themselves, or the perceptual experience of those stimuli. Perceptual similarity measures for each pair of shapes were obtained from a psychophysical same-different task; physical similarity measures were based on stimulus parameters; and neural similarity measures were obtained from multivoxel pattern analysis methods applied to anterior LOC (pFs) and posterior LOC (LO). We found that the pattern of pairwise shape similarities in LO most closely matched physical shape similarities, whereas shape similarities in pFs most closely matched perceptual shape similarities. Further, shape representations were similar across participants in LO but highly variable across participants in pFs. Together, these findings indicate that activation patterns in subregions of object-selective cortex encode objects according to a hierarchy, with stimulus-based representations in posterior regions and subjective and observer-specific representations in anterior regions

The neurons that mistook a hat for a face

Despite evidence that context promotes the visual recognition of objects, decades of research have led to the pervasive notion that the object processing pathway in primate cortex consists of multiple areas that each process the intrinsic features of a few particular categories (e.g. faces, bodies, hands, objects, and scenes). Here we report that such category-selective neurons do not in fact code individual categories in isolation but are also sensitive to object relationships that reflect statistical regularities of the experienced environment. We show by direct neuronal recording that face-selective neurons respond not just to an image of a face, but also to parts of an image where contextual cues-for example a body-indicate a face ought to be, even if what is there is not a face

Patients’ bowel symptom experiences and self-care strategies following sphincter-saving surgery for rectal cancer

Aims and objectives: To investigate patients’ bowel symptom experiences and self-care strategies following sphincter-saving surgery for rectal cancer and the relationship between bowel symptom experiences and the self-care strategies used. Background: Earlier diagnosis of rectal cancer allows for less invasive surgical treatments such as sphincter-saving procedures to be performed. Although a permanent stoma is generally not required, patients experience changes in bowel function following this surgery. However, limited research exists on patients’ bowel symptom experiences and the self-care strategies used to manage symptoms following sphincter-saving surgery of rectal cancer. Design: Quantitative descriptive correlational. Methods: A convenience sample of 143 patients aged 30 to over 70 years was used. Data were collected (April 2010–December 2010) using the Illness Perception Questionnaires, the Difficulties of Life Scale and a researcher developed Self-care Strategy Measure. The research was underpinned by the Symptom Management Theory. Findings: Relating to the four most effective self-care strategies used respondents reporting more bowel symptom were more likely to use the self-care strategy proximity/knowing the location of a toilet at all times. Females, respondents with high timeline cyclical scores and respondents with high physiological responses scores were more likely to use protective clothing. Respondents reporting more bowel symptom and with high social responses scores were more likely to use bowel medication. Females were more likely to wear incontinence pads. Conclusion: This research provides insights into the daily bowel symptom experiences of patients following sphincter-saving surgery for rectal cancer. It demonstrates the range of self-care strategies that individuals use to manage their bowel symptoms and the self-care-strategies that were most effective for them. Relevance to clinical practice: Patients should be encouraged to report on-going bowel problems following sphincter-saving surgery for rectal cancer. Supportive care for patients should be comprehensive and tailored to meet individual needs

A face feature space in the macaque temporal lobe

The ability of primates to effortlessly recognize faces has been attributed to the existence of specialized face areas. One such area, the macaque middle face patch, consists almost entirely of cells that are selective for faces, but the principles by which these cells analyze faces are unknown. We found that middle face patch neurons detect and differentiate faces using a strategy that is both part based and holistic. Cells detected distinct constellations of face parts. Furthermore, cells were tuned to the geometry of facial features. Tuning was most often ramp-shaped, with a one-to-one mapping of feature magnitude to firing rate. Tuning amplitude depended on the presence of a whole, upright face and features were interpreted according to their position in a whole, upright face. Thus, cells in the middle face patch encode axes of a face space specialized for whole, upright faces