Is visual information integrated across saccades?

After subjects established fixation on a target cross, 12 dots were presented parafoveally. When the dots were presented, the subjects made an eye movement to the location of the dots, and during the saccade the 12 initially presented dots were replaced by 12 other dots. The 24 dots were part of a 5 × 5 matrix, and the task of the subject was to report which dot was missing. The data were consistent with other recent studies: subjects could successfully report the location of the missing dot far above chance (54%), whereas performance in a control condition (in which the two sets of dots were presented to different spatial and retinal locations) was almost at chance level (10%). However, a number of control conditions demonstrated that the effect was due primarily to persistence from the phosphor of the cathode ray tube used for stimulus presentation and that little of the visual information integrated was across two fixations. Implications of the results for a theory of integration across saccades are discussed.     

Presurgical Coping, Depression, and Quality of Life in Persons with Parkinson's Disease

This study describes utilization of coping strategies and evaluates the interaction between coping strategies, depression, and quality of life (QOL) in patients with Parkinson's disease (PD) who are being considered for neurosurgical intervention. Eighty patients (mean age 61.7 years) with PD being evaluated for possible deep brain stimulation completed self-report instruments of coping strategies (Coping Responses Inventory), depression (Beck Depression Inventory), and disease-specific QOL (Parkinson's Disease Questionnaire-39). Analyses showed that patients with PD cope with the acute stressor of approaching neurosurgery through a variety of strategies, but particularly avoidant and behavioral strategies. When the correlated but apparently opposing effects of cognitive and behavioral strategies were teased apart, greater use of cognitive strategies was associated with more severe depressive symptomatology (and poorer QOL), while greater use of behavioral strategies appeared to be associated with less depression. Depressive symptomatology, in turn, was associated with poorer QOL. However, coping had minimal direct association with QOL. From this it was concluded that patients with advanced PD generate a variety of coping responses to an acute stressor such as surgery, and the use of behavioral strategies, in particular seeking of alternative enjoyable activities, may be associated with better mood if salutary effects are not overwhelmed by less helpful cognitive coping techniques. The minimization of depressive symptomatology, in turn, is associated with better QOL.     

Localized disruption of Narp in medial prefrontal cortex blocks reinforcer devaluation performance

Neuronal activity regulated pentraxin (Narp) is a secreted protein that regulates α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors (AMPAR) aggregation and synaptogenesis. Mapping of Narp-positive neurons in brain has revealed it is prominently expressed in several limbic system projection pathways. Consistent with this localization pattern, Narp knockout mice show deficits in using the current value of a reinforcer to guide behavior, a critical function of the limbic system. To help assess whether this behavioral deficit is due to impairment of synaptogenesis during development or in modulating synaptic signaling in the mature brain, we have used a dominant negative Narp viral construct which blocks trafficking of endogenous Narp to axons. Focal injection of this viral construct into the medial prefrontal cortex (mPFC) of adult mice, a region containing Narp-positive projection neurons, blocked reinforcer devaluation. Thus, these results indicate that Narp released from mPFC neurons plays a key role in mediating synaptic changes underlying instrumental reinforcer devaluation.     

Semantic Fluency Performance of Patients with Cortical and Subcortical Neurodegenerative Diseases

Previous studies using the Animals Fluency Test have shown that dementia patients with Alzheimer's disease (AD), Huntington's disease (HD), or Parkinson's disease (PD) produce fewer correct words and have smaller semantic cluster sizes than controls or PD patients without dementia (PDND). Although the number of correct words generated by the patients with AD was positively correlated with mental status, cluster size, surprisingly, was not. To increase word output and increase the reliability of estimates of cluster size, semantic fluency was reexamined using the Supermarket Fluency Task. Overall, patients with HD or PD with dementia (PDD) exhibited reduced cluster sizes compared to older controls or PDND patients, but cluster sizes were only marginally reduced for patients with AD. These effects were evident only for female participants, because the cluster sizes for elderly control men were substantially smaller than those of elderly women. For the female patients with AD, cluster size was correlated with mental status, but the relationship was nonlinear. Cluster size was normal for mildly demented patients with AD, but much reduced for moderately or severely demented participants. In contrast to a previous report, in the present study the proportion of category labels generated was increased for patients with HD with dementia but not for patients with AD. This finding questions one line of evidence that semantic memory stores undergo “bottom-up” degradation in AD. Together with previous results, these findings indicate that semantic cluster size reflects efficiency of access to semantic knowledge which is similarly compromised in subcortical and cortical diseases.     

Some Evidence is False

According to some philosophers who accept a propositional conception of evidence, someone's evidence includes a proposition only if it is true. I argue against this thesis by appealing to the possibility of knowledge from falsehood.     

An 18-month follow-up investigation of motor coordination and working memory in primary school children

The aim of the current study was to examine the relationship between motor coordination and visual working memory in children aged 5–11 years. Participants were 18 children with movement difficulty and 41 control children, assessed at baseline and following an 18-month time period. The McCarron Assessment of Neuromuscular Development provided a measure of motor skills and the CogState One-Back task was used to assess visual working memory. Multi-level mixed effects linear regressions were used to assess the relationship between fine motor skills, gross motor skills, and visual working memory. The results revealed that for children with movement difficulty, better fine motor skills at baseline significantly predicted greater One-Back accuracy and greater (i.e., faster) speed at 18-month follow-up. Conversely, fine motor skills at baseline did not predict One-Back accuracy and speed for control children. However, for both groups, greater One-Back accuracy at baseline predicted better fine and gross motor skills at follow-up. These findings have important implications for the assessment and treatment of children referred for motor difficulties and/or working memory difficulties.     

Advancing the trait EI content domain: Further evidence for the distinctiveness of interpersonal facets

This investigation sought to assess the congruence of the trait emotional intelligence (EI) sampling domain, reflected in the short form of the Trait Emotional Intelligence Questionnaire (TEIQue; Petrides & Furnham, 2006), with the theoretical content of trait EI—namely, the range of personality traits implicated in emotions. First, associations of the TEIQue factors with Emotion-Oriented Coping (EOC) and Social Coping (SC) were compared. Three of the four TEIQue factors were stronger predictors of EOC than SC; only the Emotionality factor was a stronger predictor of SC. Also, Emotionality did not add to the prediction of EOC in a simultaneous regression with the other factors. Secondly, by means of Structural Equation Modelling, the 30-item composite and a theoretically altered 16-item composite were compared as mediators between the Big Five and the emotion-laden dimension of mental health. Even though all interpersonal items (i.e., those pertaining to Sociability and Emotionality) were omitted for the altered composite, it outperformed the original composite in predicting a latent mental health composite of Stress, Anxiety, and EOC. The results highlight the distinct nature of Emotionality and Sociability facets and have implications for the refinement of the trait EI content domain.     

Lightness constancy and illumination discounting

Contrary to the implication of the term "lightness constancy", asymmetric lightness matching has never been found to be perfect unless the scene is highly articulated (i.e., contains a number of different reflectances). Also, lightness constancy has been found to vary for different observers, and an effect of instruction (lightness vs. brightness) has been reported. The elusiveness of lightness constancy presents a great challenge to visual science; we revisit these issues in the following experiment, which involved 44 observers in total. The stimuli consisted of a large sheet of black paper with a rectangular spotlight projected onto the lower half and 40 squares of various shades of grey printed on the upper half. The luminance ratio at the edge of the spotlight was 25, while that of the squares varied from 2 to 16. Three different instructions were given to observers: They were asked to find a square in the upper half that (i) looked as if it was made of the same paper as that on which the spotlight fell (lightness match), (ii) had the same luminance contrast as the spotlight edge (contrast match), or (iii) had the same brightness as the spotlight (brightness match). Observers made 10 matches of each of the three types. Great interindividual variability was found for all three types of matches. In particular, the individual Brunswik ratios were found to vary over a broad range (from .47 to .85). That is, lightness matches were found to be far from veridical. Contrast matches were also found to be inaccurate, being on average, underestimated by a factor of 3.4. Articulation was found to essentially affect not only lightness, but contrast and brightness matches as well. No difference was found between the lightness and luminance contrast matches. While the brightness matches significantly differed from the other matches, the difference was small. Furthermore, the brightness matches were found to be subject to the same interindividual variability and the same effect of articulation. This leads to the conclusion that inexperienced observers are unable to estimate both the brightness and the luminance contrast of the light reflected from real objects lit by real lights. None of our observers perceived illumination edges purely as illumination edges: A partial Gelb effect ("partial illumination discounting") always took place. The lightness inconstancy in our experiment resulted from this partial illumination discounting. We propose an account of our results based on the two-dimensionality of achromatic colour. We argue that large interindividual variations and the effect of articulation are caused by the large ambiguity of luminance ratios in the stimulus displays used in laboratory conditions.