Social interaction and sex differences influence rat temperature circadian rhythm under LD cycles and constant light.

Circadian rhythms produce an efficient organization of animal behaviour over the 24h day. In some species, social cues have been found to have a role as synchronizers of these rhythms. Here, the influence of social interaction on rat circadian behaviour was investigated, addressing the question of whether cohabitation would produce a delay in the appearance of arrhythmicity under constant light conditions. To this end, the circadian rhythms of male and female rat body temperature were studied for 10days under light-dark conditions, followed by 33days under constant bright light. Half of the animals were maintained in individual cages, whilst the others were maintained in larger cages in groups of three rats of the same sex. Results showed that individual circadian rhythms under 24hour light-dark (LD) cycles were more stable and with higher amplitude in grouped than in isolated animals, and higher in males than in females. During the first days under constant light (LL), the stability of the rhythm was also higher in males than in females, but there were no differences according to the group. Moreover, we did not find significant differences in the time of circadian rhythm loss under LL, since high individual variability was found for this variable. On the other hand, female rats living in isolation showed a delayed acrophase in the circadian rhythm under LD conditions compared with those living in groups. These results suggest that cohabitation increases the internal coherence of circadian behaviour, and could be interpreted as indicating that living in isolation may induce a level of stress that disturbs manifestation of the circadian rhythm, especially in females, which are also more reactive than males to external signals.

[Dissociation of conceptual and linguistic information based on a case study]. / Disociación de la información conceptual y lingüística a partir de un estudio de caso.

INTRODUCTION: Grouping the stimuli that we perceive in abstract categories is basic to understand our surroundings. Research gathered in the last few years with neuroimage techniques and brain damaged patients shows the role of the left temporal area in the organization of the semantic categories. CASE REPORT: A young aphasic patient study is reported who, after a cerebral haemorrhagia in the left temporo-parieto-occipital area, shows significant semantic difficulties. The results of this woman in several linguistic and semantic tasks indicate that her difficulties are conceptual rather than linguistics, since she makes well any task that does not demand access to the meaning of the words, but she fails in those tasks which require to understand the concepts. CONCLUSIONS: The results of this patient show the key role that the left temporal area has in the organization of the semantic categories. As consequence of the injury in that zone, the patient shows an organization of the stimuli based more in associative criteria than taxonomic and guided by the experience and functional adaptation the daily routine.

Disociación de la información conceptual y lingüística a partir de un estudio de caso / Dissociation of conceptual and linguistic information based on a case study

Introduction. Grouping the stimuli that we perceive in abstract categories is basic to understand our surroundings. Research gathered in the last few years with neuroimage techniques and brain damaged patients shows the role of the left temporal area in the organization of the semantic categories. Case report. A young aphasic patient study is reported who, after a cerebral haemorrhagia in the left temporo-parieto-occipital area, shows significant semantic difficulties. The results of this woman in several linguistic and semantic tasks indicate that her difficulties are conceptual rather than linguistics, since she makes well any task that does not demand access to the meaning of the words, but she fails in those tasks which require to understand the concepts. Conclusions. The results of this patient show the key role that the left temporal area has in the organization of the semantic categories. As consequence of the injury in that zone, the patient shows an organization of the stimuli based more in associative criteria than taxonomic and guided by the experience and functional adaptation the daily routine (AU)

Introducción. Agrupar los estímulos que percibimos en categorías abstractas es fundamental para poder comprender nuestro entorno. Las investigaciones realizadas en los últimos años con técnicas de neuroimagen y pacientes lesionados cerebrales muestran el papel del área temporal izquierda en la organización de las categorías semánticas. Caso clínico. Se presenta el caso de una joven afásica que, tras una hemorragia cerebral, presenta una lesión en la región temporoparietooccipital izquierda que le ocasiona importantes dificultades semánticas. Los resultados de esta mujer en diferentes tareas lingüísticas y semánticas indican que sus trastornos son más de naturaleza conceptual que lingüística, ya que realiza bien todas aquellas tareas que no exigen conocer el significado de las palabras, mientras que falla en las que requieren entender los conceptos. Además, el trastorno alcanza a todas las categorías semánticas, tanto las pertenecientes al dominio de los seres vivos como al de los inanimados. Conclusiones. Los resultados de esta paciente muestran el papel clave que desempeña el área temporal izquierda en la organización de las categorías semánticas. A causa de la lesión en esa zona, esta paciente muestra una organización de los estímulos fundamentada más en criterios asociativos que taxonómicos, y guiada por la experiencia y la adaptación funcional al entorno cotidiano (AU)