Is anorexia nervosa a neuropsychological disease?

Evidence for central nervous system, and more particularly cortical, etiology of anorexia nervosa is reviewed. Topics covered are neuropsychiatric comorbidity, inheritance patterns, the neurobiology of body-image disturbance and of the eating function, perinatal and alcoholic insult to the brain, neurochemical and neuroelectric disturbance, anatomic and metabolic brain imaging, and neuropsychological impairment. It is concluded that there is indeed an important neuropsychological etiological dimension to anorexia nervosa. The profile most frequently associated with anorexia nervosa is right posterior hypometabolism, followed by right anterior hypermetabolism, both associated with right-sided abnormal electroencephalogram spiking. It is also proposed that bulimia consists of a positive neurological subtype and that restricting anorexia represents a negative neurological subtype. Priorities for further research into anorexia nervosa are specified to include twin adoption studies, brain electrical topography studies, postmortem histological studies, and experimentally inspired neuropsychological studies.     

The Effects of Word Identity,Case, and SOA on Word Priming in a Subliminal Context

Journal of Psycholinguistic Research - It is widely assumed that subliminal word priming is case insensitive and that a short SOA (<?100 ms) is required to observe any...     

Evening and morning EEG differences between young men and women adults

Evening and morning waking EEG (eyes closed) was recorded in 16 women and 13 men aged 18-26 years old. Participants were fitted with a 13-electrode montage (Fp1, Fp2, FZ, F7, F8, C3, C4, T3, T4, P3, P4, O1, and O2) referred to linked ears. For each recording electrode, EEG total spectral amplitude power (microV/Hz, 0.75-19.75 Hz) was compared using 2 (Gender) x 2 (Moments) analyses of variance for repeated measures and LSD post-hoc tests. We found significant simple Gender effects, with women displaying higher EEG values for Central, Frontal, Parietal, and left Temporal leads. Simple Moment effects were also found, with lower morning values in Temporal and left Frontal recording sites. A Gender x Moment interaction was found at the right Frontal recording site. No significant effects were found for Prefrontal and Occipital recording sites, whatsoever. These results bring new understandings of gender and time of day effects in waking EEG and point to different sensitivity in different cortical areas. The present results could explain some of the observations related to gender differences in cognitive performance.     

Visual perception in domestic dogs: susceptibility to the Ebbinghaus–Titchener and Delboeuf illusions

Susceptibility to geometrical visual illusions has been tested in a number of non-human animal species, providing important information about how these species perceive their environment. Considering their active role in human lives, visual illusion susceptibility was tested in domestic dogs (Canis familiaris). Using a two-choice simultaneous discrimination paradigm, eight dogs were trained to indicate which of two presented circles appeared largest. These circles were then embedded in three different illusory displays; a classical display of the Ebbinghaus–Titchener illusion; an illusory contour version of the Ebbinghaus–Titchener illusion; and the classical display of the Delboeuf illusion. Significant results were observed in both the classical and illusory contour versions of the Ebbinghaus–Titchener illusion, but not the Delboeuf illusion. However, this susceptibility was reversed from what is typically seen in humans and most mammals. Dogs consistently indicated that the target circle typically appearing larger in humans appeared smaller to them, and that the target circle typically appearing smaller in humans, appeared larger to them. We speculate that these results are best explained by assimilation theory rather than other visual cognitive theories explaining susceptibility to this illusion in humans. In this context, we argue that our findings appear to reflect higher-order conceptual processing in dogs that cannot be explained by accounts restricted to low-level mechanisms of early visual processing.     

A review of abnormalities in the perception of visual illusions in schizophrenia

Specific abnormalities of vision in schizophrenia have been observed to affect high-level and some low-level integration mechanisms, suggesting that people with schizophrenia may experience anomalies across different stages in the visual system affecting either early or late processing or both. Here, we review the research into visual illusion perception in schizophrenia and the issues which previous research has faced. One general finding that emerged from the literature is that those with schizophrenia are mostly immune to the effects of high-level illusory displays, but this effect is not consistent across all low-level illusions. The present review suggests that this resistance is due to the weakening of top–down perceptual mechanisms and may be relevant to the understanding of symptoms of visual distortion rather than hallucinations as previously thought.     

Evidence for the Modulation of Sub-Lexical Processing in Go No-Go Naming: The Elimination of the Frequency �� Regularity Interaction

The Frequency (high vs. low) × Regularity (regular vs. exception) interaction found on naming response times is often taken as evidence for parallel processing of sub-lexical and lexical systems. Using a Go/No-go naming task, we investigated the effect of nonword versus pseudohomophone foils on sub-lexical processing and the subsequent Frequency × Regularity interaction. We ran two experiments: (1) a Go/No-go naming task with nonword foils (e.g., bint) and (2) a Go/No-go naming task with pseudohomophone foils (e.g., pynt). Experiment 1 replicated the Frequency × Regularity interaction on naming response times supporting the notion of parallel sub-lexical and lexical processing. Experiment 2 eliminated the Frequency × Regularity interaction providing evidence for the modulation of sub-lexical information. These results indicate that using pseudohomophones in the Go/No-go naming task minimized information provided from sub-lexical processing and maximized information provided from the lexical system.     

Early Huntington's disease affects movements in transformed sensorimotor mappings

This study examined the effect of transformed visual feedback on movement control in Huntington's disease (HD). Patients in the early stages of HD and controls performed aiming movements towards peripheral targets on a digitizing tablet and emphasizing precision. In a baseline condition, HD patients were slower but showed few precision problems in aiming. When visual feedback was inverted in both vertical and horizontal axes, patients showed problems in initial and terminal phases of movement where feedback is most critical. When visual feedback was inverted along a single axis as in a mirror-inversion, HD patients showed large deviations and over-corrections before adaptation. Adaptation was similar in both groups. These results suggest that HD impairs on-line error correction in novel movements.     

The influence of size in weight illusions is unique relative to other object features

Psychonomic Bulletin & Review - Research into weight illusions has provided valuable insight into the functioning of the human perceptual system. Associations between the weight of an object...     

What do dogs (<Emphasis Type="Italic">Canis familiaris</Emphasis>) see? A review of vision in dogs and implications for cognition research

Over the last 20 years, a large amount of research has been conducted in an attempt to uncover the cognitive abilities of the domestic dog. While substantial advancements have been made, progress has been impeded by the fact that little is known about how dogs visually perceive their external environment. It is imperative that future research determines more precisely canine visual processing capabilities, particularly considering the increasing number of studies assessing cognition via paradigms requiring vision. This review discusses current research on visual cognition and emphasizes the importance of understanding dog visual processing. We review several areas of vision research in domestic dogs, such as sensitivity to light, visual perspective, visual acuity, form perception, and color vision, with a focus on how these abilities may affect performance in cognition tasks. Additionally, we consider the immense diversity seen in dog morphology and explore ways in which these physical differences, particularly in facial morphology, may result in, or perhaps even be caused by, different visual processing capacities in dogs. Finally, we suggest future directions for research in dog vision and cognition.