Performance and reaction times in monaural localization of first names in the horizontal plane

Many studies have been conducted to measure monaural azimuthal sound localization performance with different sounds varying in frequency and complexity, but few have used linguistic stimuli. The present experimental design used subjects' first names in a monaural azimuthal localization task. Analysis of response accuracy showed that subjects are not more accurate in localizing their own first name than in localizing other first names and that there was no significant advantage of one ear over another. Reaction times were shorter when the subjects localized their own first name than when they localized any other first names and there was no significant ear advantage, but localizing other first names took more time with the right than with the left ear. All stimuli were better and more quickly localized on the side of the open ear, and there was no difference in acuity or velocity of localization with the two different speaker voices used. These results suggest that first names are processed through the controlateral auditory pathway and can be analyzed in the right hemisphere.     

Dissociation between priming and recognition in the expression of sequential knowledge

Exposure to a repeating sequence of target stimuli in a speeded localization task can support both priming of sequence-consistent responses and recognition of sequence components. Here, a task is introduced in which measures of priming and recognition are obtained concurrently, and it is demonstrated that priming of sequence-consistent responses occurs even when test stimuli are not recognized. The results show that sequence knowledge can be expressed in the absence of conscious recognition. However, we also show that this result is consistent with a simple model in which priming and recognition depend on exactly the same underlying memory strength variable.     

Toward optimal treatments for major depression

The treatment of major depression remains problematic for several reasons. In particular, the therapeutic response to medications usually does not manifest itself until a week after administration has begun, and more than half the patients will not experience a full recovery with the first antidepressant drug administration. There are, however, some pharmacologic strategies that can accelerate antidepressant response. When facing a treatment-resistant depression, combination therapy offers a more time-efficient approach to achieve remission than drug substitution. These interventions have been devised on a better understanding of the basis for the therapeutic response obtained with the first- and second-generation antidepressants, and evidence derived from controlled clinical trials of their superior effectiveness is growing. The rationale for such approaches will be described in this article, as well as their advantages and potential inconveniences. Ongoing research in this field continues to fuel the development of novel, better-tolerated, and more effective pharmacotherapies for depression.     

All-or-none bottleneck versus capacity sharing accounts of the psychological refractory period phenomenon

The goal of the present experiment was to test the predictions of Central Bottleneck and Central Capacity Sharing models. According to the Central Bottleneck model, dual task interference, as observed in the PRP paradigm, is caused by an all-or-none bottleneck in information processing. The Central Capacity Sharing model postulates that dual task interference is caused by a capacity limited process that can allocate capacity in a graded fashion. The Central Bottleneck model predicts no change in RT1 with decreasing SOA, whereas the Central Capacity Sharing model predicts that RT1 will increase with decreasing SOA and that the slope of the RT1 SOA effect will depend upon the difficulty of task 2. Subjects were required to perform a tone pitch judgement and shape-matching task in rapid succession. Task order was randomized and the SOA between the first and second stimulus varied from 50 to 1250 ms. Results from this experiment favour the Central Capacity Sharing model. The results were then run through simulations of both the Central Bottleneck and Central Capacity Sharing models. Results from the simulations also favoured the Central Capacity Sharing model. As the difficulty of the second task increased, more capacity was allocated to it, confirming the prediction that as task 2 difficulty increases, the RT1 SOA slope increases. The proportion of capacity allocated to the first task varied from.78 to.91 indicating that capacity can be allocated in a graded fashion.     

Delay-dependent working memory impairment in young-adult and aged 5-HT1BKO mice as assessed in a radial-arm water maze

Serotonin (5-HT) plays a modulatory role in mnemonic functions, especially by interacting with the cholinergic system. The 5-HT1B receptor is a key target of this interaction. The 5-HT1B receptor knockout mice were found previously to exhibit a facilitation in hippocampal-dependent spatial reference memory learning. In the present study, we submitted mice to a delayed spatial working memory task, allowing the introduction of various delays between an exposure trial and a test trial. The 5-HT1BKO and wild-type mice learned the task in a radial-arm water maze (returning to the most recent presented arm containing the escape platform), and exhibited a high level of performance at delays of 0 and 5 min. However, at the delay of 60 min, only 5-HT1BKO mice exhibited an impairment. At a delay of 90 min, all mice were impaired. Treatment by scopolamine (0.8 mg/kg) induced the same pattern of performance in wild type as did the mutation for short (5 min, no impairment) and long (60 min, impairment) delays. The 22-month-old wild-type and knockout mice exhibited an impairment at short delays (5 and 15 min). The effect of the mutation affected both young-adult and aged mice at delays of 15, 30, and 60 min. Neurobiological data show that stimulation of the 5-HT1B receptor inhibits the release of acetylcholine in the hippocampus, but stimulates this in the frontal cortex. This dual function might, at least in part, explain the opposite effect of the mutation on reference memory (facilitation) and delay-dependent working memory (impairment). These results support the idea that cholinergic-serotonergic interactions play an important role in memory processes.     

Neural substrates of impaired categorical perception of phonemes in adult dyslexics: an fMRI study

Phonological developmental dyslexics remain impaired in phonetic categorical perception (CP) even in adulthood. We studied the brain correlates of CP in dyslexics and controls using a block design fMRI protocol and stimuli from an phonetic continuum between natural /Pa/ and /Ta/ syllables. Subjects performed a pseudo-passive listening task which does not imply voluntary categorical judgment. In the control group, categorical deviant stimuli elicited specific activations in the left angular gyrus, the right inferior frontal gyrus and the right superior cingulate cortex. These regions were not activated in the dyslexic group in which activation was observed for acoustic but not phonetic changes in stimuli. Failures to activate key regions for language perception and auditory attention in dyslexic might account for persistent deficits in phonological awareness and reading tasks.     

Process Ontology: Conversations and Argumentations,Controversies in Mathematics and Mathematics as Socialisation

To better conceive the socializing and pragmatic aspects of mathematics, it can be useful to use a process ontology, which allows, starting from an analysis of the processes of conversations, to compare their recourse, from degree to degree, to supposedly common “virtualities”, in particular in argumentative conversations, with the construction of more complex mathematical entities that allow new symmetries, but also with controversies between mathematicians on the use of these entities.

     

LA PERCEPTION DES RELATIONS SPATIALES DANS LE DESSIN ET LE DEVELOPPEMENT DES OPERATIONS CONCRETES*

Pictorial perception entails complex cognitive skills. Piaget and Inhelder (1948) have shown that the understanding of spatial relations follows a path that leads from topological to Euclidean concepts. We hypothesize that there is a strong correlation between the performance on Piagetian spatial tasks and pictorial perception. The three-dimensional reconstruction of drawings is a good measure of pictorial perception. The study shows that pictorial perception is correlated significantly (p < 1%) with the performance on Piagetian spatial tasks, and also, to a lesser degree, on tasks of elementary logic. The spontaneous understanding of the meaning of the pictures (in this case sanitary messages) is related to the understanding of spatial relations, while the relationship is less strong with the recall of the messages.