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Resumen Introduccion La diabetes mellitus tipo 2 (DMT2) es una enfermedad cronica que continua produciendo complicaciones neurologicas a pesar de las mejorias en las estrategias terapeuticas. Ademas de la clasica neuropatia diabetica periferica (NDP), el deterioro cognitivo (DC), podria considerarse una mas de estas complicaciones. Objetivo Analisis del Alzheimer disease assessment scale–cognitive (ADAS-COG), en una poblacion de sujetos con DMT2 y determinar su posible asociacion con la presencia de NDP. Materiales y metodos Se estudiaron 54 pacientes con DMT2, media de edad: 71,1 ± 5,6; varones: 22, mujeres: 32. Grupo control: n = 32, media de edad: 70,5 ± 7,2, varones 15, mujeres 17. El grupo con DMT2, se dividio en dos subgrupos: uno con NDP (n = 37) y otro sin NDP (n = 17). El test de Wilcoxon, para muestras apareadas, se empleo para la comparacion de los puntajes del ADAS-COG entre los diferentes subgrupos. Resultados La comparacion de los puntajes del ADAS-COG entre los diferentes grupos mostraron: a) diferencias significativas (p Conclusiones Nuestros resultados proveen evidencia de la existencia de un DC en algunos pacientes con DMt2. Este deterioro se hallaria asociado a la presencia de NDP. Estas observaciones permitirian plantear la presencia de un DC asociado a la DMt2 y considerar al mismo como una complicacion tardia mas de la enfermedad.

Most languages have a basic or “canonical” word order, which determines the relative positions of the subject (S), the verb (V), and the object (O) in a typical declarative sentence. The frequency of occurrence of the six possible word orders among world languages is not distributed uniformly. While SVO and SOV represent around 85% of world languages, orders like VSO (9%) or OSV (0.5%) are much less frequent or extremely rare. One possible explanation for this asymmetry is that biological and cognitive constraints for structured sequence processing make some word orders easier to be processed than others. Therefore, the high frequency of these word orders would be related to their higher learnability. The aim of the present study was to compare the learnability of different word orders between groups of adult subjects. Four artificial languages with different word orders were trained: two frequent (SVO, SOV) and two infrequent (VSO, OSV). In a test stage, subjects were asked to discriminate between new correct sentences and syntax or semantic violations. Higher performance rates and faster responses were observed for more frequent word orders. The results support the hypothesis that more frequent word orders are more easily learned.

El objetivo del presente trabajo es exponer una breve revisión del estudio del razonamiento analógico desde la Teoría de los Marcos Relacionales (TMR), considerando los modelos formulados hasta la actualidad y la exploración experimental. A su vez, se abordará el estudio del desarrollo del azonamiento analógico en la infancia, surgido en el marco de las controversias generadas por los distintos enfoques de la psicología. Se expondrán los hallazgos obtenidos utilizando métodos de imágenes cerebrales desde las ciencias cognitivas. Finalmente se comentarán las posibles aplicaciones de este paradigma. Los estudios revisados acerca del razonamiento analógico desde la TMR proveen relevante evidencia empírica, principalmente en el ámbito de la evaluación y sugieren ventajas de este paradigma en comparación con proximaciones cognitivistas. A su vez, se propone su implementación como instrumento de entrenamiento cognitivo. En conclusión, la TMR propone un modelo útil al estudio del razonamiento analógico desde la perspectiva del análisis del comportamiento.

A wide range of studies have found late positive ERP components in response to anomalies during processing of structured sequences. In language studies, this component is named Syntactic Positive Shift (SPS) or P600. It is characterized by an increase in potential peaking around 600 ms after the appearance of the syntactic anomaly and has a centroparietal topography. Similar late positive components were found more recently in non-linguistic contexts. These results have led to the hypothesis that these components index the detection of anomalies in rule-governed sequences, or the access to abstract rule representations, regardless of the nature of the stimuli. Additionally, there is evidence showing that the SPS/P600 is sensitive to probability manipulations, which affect the subjects’ expectancy of the stimuli. Our aim in the present work was to address the hypothesis that the late positive component is modulated by the subject's expectancy of the stimuli. To do so, we employed an artificial grammar learning task, and controlled the frequency of presentation to different kind of sequences during training. Results showed that certain sequence types elicited a late positive component which was modulated by different factors in two distinct time windows. In an earlier window, the component was higher for sequences which had a low or null probability of occurrence during training, while in a later window, the component was higher for incorrect than correct sequences. Furthermore, this late window effect was absent in those subjects whose performance was not significantly above chance. Two possible explanations for this effect are suggested.

Event-related potentials (ERPs) correlates of two test criteria of an abstract category task were dissociated. In a stimulus equivalence task, 10 subjects observed pairs of figures presented serially in three conditions: reflexivity (generalized identity), equivalence (arbitrary derived relations from a previous training), and unrelated pairs. They were instructed to decide whether the second item in a pair matched or mismatched the first one. Participants’ performance in reflexivity matching tests was faster and more accurate than in equivalence matching or mismatching responses. In the three conditions, an occipital P2, a frontal N2 and a parietal P3 ERP component were elicited. The earlier components P2 and N2 exhibited reflexivity matching effects, while the later component (P3) exhibited the only equivalence matching effect. In addition, the subtracted ERP components from unrelated minus identity and unrelated minus equivalence trials were computed within two time windows: 150–250 ms (dN300) and 350–450 ms (dN400). While both dN300 waves were not significantly different, the comparison of both dN400 waves showed statistical differences. Correlates of partially perceptual (but contextually abstract) concepts are elicited earlier than those of pure abstract concepts. These ERPs correlates of stimulus equivalence relation tests of semantic categories are in concordance with the behavioral data.

Semantic priming has been widely observed at both behavioral and electrophysiological levels as reductions in response times and N400 magnitudes respectively. However, the possibility that stimulus relations derived from associative learning elicit N400 priming effects comparable to those found in language has not been properly addressed yet. Equivalence relations emerge after establishing a set of arbitrary and intra-experimentally defined relations through associative learning, thus allowing the study of derived stimulus relations in the absence of semantic content. The present study aimed to compare ERP correlates of priming in semantically related words and pseudowords related through equivalence. We found similar behavioral and N400 effects when comparing unrelated vs related prime-target pairs in language and stimulus equivalence tasks, suggesting that priming engages at least partially overlapping neural mechanisms in both contexts. In addition, we found a posteriorly distributed late positivity in the semantic priming task only, which may be reflecting language-specific processing. Fil: Tabullo, Angel Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Yorio, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Zanutto, Bonifacio Silvano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina Fil: Wainselboim, Alejandro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentina

• Brain-stem auditory evoked potentials were recorded in 35 human immunodeficiency virus (HIV)—seropositive subjects from the Centers for Disease Control groups III and IV, 24 HIV-negative drug abusers, and 62 normal healthy controls. None of the patients had evidence of neurological complications. History of alcohol consumption was an exclusion criterion. The values of central conduction times I-V and III-V showed significant differences between the HIV-seropositive subjects and normal healthy controls, as well as between the HIV-seropositive subjects and HIV-negative drug abusers. Central conduction times I-III showed no differences between groups, except in the left ear of Centers for Disease Control group IV compared with controls. No statistical differences were found in the central conduction times between HIV-negative drug abusers and normal healthy controls. The results suggest a subclinical involvement of the upper brain stem in HIV infection. It could be produced by direct action of the virus on central nervous system structures.