Some aspects of phonological impairment in aphasia

The relationships between expressive and receptive phonemic disorders and between disturbances of phoneme processing and general disorders of auditory comprehension were studied in 69 aphasic patients, by means of a phoneme discrimination test and of a standard aphasia battery. A significant but incomplete correlation between disorders of phonemic output and of phoneme analysis was found. The view is put forth that in some patients only phoneme encoding or decoding is disturbed, whereas in others a central level of phoneme processing is impaired. A significant but partial correlation was also found between disorders of phonological analysis and general disorders of auditory comprehension. This supports the view that, besides sequential phonological analysis, other processes operate in auditory comprehension.     

Quetiapine augmentation of selective serotonin reuptake inhibitors in treatment-resistant obsessive-compulsive disorder: a six-month follow-up case series

Obsessive-compulsive disorder (OCD) is a relatively common, often chronic and disabling disorder with high rates of partial and/or absent response to standard, recommended treatments, such as selective serotonin reuptake inhibitors (SSRIs) and psychotherapy. This article presents the cases of four patients suffering from OCD and comorbid mood or anxiety disorders, who were treated with SSRIs at adequate doses for at least 12 weeks, showing a partial response. Quetiapine treatment was added to SSRIs at a dose of 25 mg/day and titrated up to 200 mg/day. Patients were followed up for 6 months. After 12 weeks, all the patients were classified as "much improved" on the Clinical Global Impression-Improvement scale and showed a Yale-Brown Obsessive-Compulsive Scale score reduction > or =35%. After 6 months of follow-up, all the patients maintained the same level of improvement. Although quetiapine augmentation to SSRIs has shown mixed results in published controlled trials in the acute treatment (12 weeks) of patients with treatment-resistant OCD, this case series indicates that patients who benefit from this pharmacologic regimen in the acute phase tend to maintain such an improvement. Larger follow-up studies are warranted to confirm our findings.     

Finger-digit compatibility in Arabic numeral processing

Finger-digit response compatibility was tested by asking participants to identify Arabic digits by pressing 1 of 10 keys with all 10 fingers. The direction of the finger-digit mapping was varied by manipulating the global direction of the hand-digit mapping as well as the direction of the finger-digit mapping within each hand (in each case, from small to large digits, or the reverse). The hypothesis of a left-to-right mental number line predicted that a complete left-to-right mapping should be easier whereas the hypothesis of a representation based on finger counting predicted that a counting-congruent mapping should be easier. The results show that when all 10 fingers are used to answer, a mapping congruent with the prototypical finger-counting strategy reported by the participants leads to better performance than does a mapping congruent with a left-to-right oriented mental number line, both in palm-down and palm-up postures of the hands, and they demonstrate that finger-counting strategies influence the way that numerical information is mentally represented and processed.     

Horizontal and vertical Simon effect: different underlying mechanisms?

Reaction times are usually faster when stimulus and response occur at the same location than when they do not, even if stimulus location is irrelevant to the task (Simon effect). This effect was found with both horizontal and vertical stimulus-response arrangements. The same mechanisms have been proposed to be involved in either case. Here, we compared a horizontal and a vertical Simon task by means of a RT time-course analysis of the Simon effect. Also, we analysed the lateralised readiness potential (LRP), an index of covert response-preparation processes. In the horizontal task, the Simon effect decays over time and pre-activation occurs above the motor cortex ipsilateral to the stimulus. In contrast, the Simon effect does not decay over time and no early incorrect LRP deflection is observed in the vertical task. These findings suggest that typical activation accounts can fit only the horizontal Simon effect, while a translation explanation is more suitable for the vertical Simon effect.     

Crossmodal object-based attention: auditory objects affect visual processing

According to the object-based view, visual attention can be deployed to "objects" or perceptual units, regardless of spatial locations. Recently, however, the notion of object has also been extended to the auditory domain, with some authors suggesting possible interactions between visual and auditory objects. Here we show that task-irrelevant auditory objects may affect the deployment of visual attention, providing evidence that crossmodal links can also occur at an object-based level. Hence, in addition to the well documented control of visual objects over what we hear, our findings demonstrate that, in some cases, auditory objects can affect visual processing.     

Foreground–background segmentation and attention: A change blindness study

One of the most debated questions in visual attention research is what factors affect the deployment of attention in the visual scene? Segmentation processes are influential factors, providing candidate objects for further attentional selection, and the relevant literature has concentrated on how figure–ground segmentation mechanisms influence visual attention. However, another crucial process, namely foreground–background segmentation, seems to have been neglected. By using a change blindness paradigm, we explored whether attention is preferentially allocated to the foreground elements or to the background ones. The results indicated that unless attention was voluntarily deployed to the background, large changes in the color of its elements remained unnoticed. In contrast, minor changes in the foreground elements were promptly reported. Differences in change blindness between the two regions of the display indicate that attention is, by default, biased toward the foreground elements. This also supports the phenomenal observations made by Gestaltists, who demonstrated the greater salience of the foreground than the background.     

Are the inhibitory and faciliatory effects during retrieval of semantically related items present in amnestic mild cognitive impairment?

Prefrontal functions subserve inhibition control for retrieval of semantically related items inducing forgetting 19 a-MCI patients and 29 controls underwent neuropsychological evaluation and retrieval-practice paradigm (RPP) to estimate baseline remember (BR), retrieval-induced facilitation (FAC) and retrieval-induced forgetting (RIF). A-MCI patients underwent also 3 T-MRI to assess relationship between regional grey matter (rGM) volumes and RPP indexes Behaviourally, RIF and FAC were both observed controls, while RIF only was observed in a-MCI patients. In patients but not in controls, RIF was associated with cognitive efficiency and FAC with memory performance. Patients showed also associations between BR and rGM volumes in the precuneus, no association was found between rGM volumes and RIF and FAC. A-MCI patients did not benefit from repeated practice during retrieval of studied items, which is likely due to their memory disorder. In contrast, patient cognitive efficiency would drive retrieval suppression of interfering stimuli.     

A computational model of the Simon effect

Even though stimulus location is task irrelevant, reaction times are faster when the location of the stimulus corresponds with the location of the response than when it does not. This phenomenon is called the Simon effect. Most accounts of the Simon effect are based on the assumption that it arises from a conflict between the spatial code of the stimulus and that of the response. In this paper a computational model of this hypothesis is presented. It provides a computationally explicit mechanism of the Simon effect. Consistent with human performance, the model provides reaction times that indicate both an advantage for the ipsilateral, corresponding response (i.e., facilitation) and a disadvantage of the contralateral, noncorresponding response (i.e., inhibition). In addition, the model accounts for the fact that the size for the effect depends on task difficulty.