Increased coherence among striatal regions in the theta range during attentive wakefulness

The striatum, the largest component of the basal ganglia, is usually subdivided into associative, motor and limbic components. However, the electrophysiological interactions between these three subsystems during behavior remain largely unknown. We hypothesized that the striatum might be particularly active during exploratory behavior, which is presumably associated with increased attention. We investigated the modulation of local field potentials (LFPs) in the striatum during attentive wakefulness in freely moving rats. To this end, we implanted microelectrodes into different parts of the striatum of Wistar rats, as well as into the motor, associative and limbic cortices. We then used electromyograms to identify motor activity and analyzed the instantaneous frequency, power spectra and partial directed coherence during exploratory behavior. We observed fine modulation in the theta frequency range of striatal LFPs in 92.5 ± 2.5% of all epochs of exploratory behavior. Concomitantly, the theta power spectrum increased in all striatal channels (P < 0.001), and coherence analysis revealed strong connectivity (coefficients >0.7) between the primary motor cortex and the rostral part of the caudatoputamen nucleus, as well as among all striatal channels (P < 0.001). Conclusively, we observed a pattern of strong theta band activation in the entire striatum during attentive wakefulness, as well as a strong coherence between the motor cortex and the entire striatum. We suggest that this activation reflects the integration of motor, cognitive and limbic systems during attentive wakefulness.

Diagnóstico serológico (elisa) de borreliosis de lyme en un grupo humano de riesgo, Piura-Perú / Serological diagnosis (elisa) of lyme disease in a risk human group, Piura-Peru

Se realizó un estudio en 35 sueros de agricultores (mayor ó igual a 13 años), residentes en el distrito de Sapillica, provincia de Ayabaca, departamento de Piura, a fin de determinar anticuerpos IgM e IgG a Borrelia burgdorferi utilizando la prueba de ELISA (kig Sigma Diagnostic, MO-USA). 3 (8.57 por ciento) de los 35 sueros fueron positivos con valores de indice de 1.34, 1.78 y 1.08. El descarte de reacción cruzada con otras pruebas: Venereal Disease Research Laboratory, anticuerpos treponémicos fluorescentes (FTA), factor reumatoideo (RF), reacción de aglutinación microscópica (RAM) para leptospira interrogans y biflexa y anticuerpo antinucleares (ANA), fueron negativos en todos los sueros positivos a Borrelia burgdorferi, con excepción de una muestra que fue reactiva a FTA. Los agricultores investigados han sido considerados como grupo de riesgo para Borreliosis de Lyme, por el tipo de actividad laboral que realizan y por la presencia de Haemaphysalis leporispalustris e Ixodes en Piura. Los resultados obtenidos demostraron la presencia IgM e IgG a títulos mayores del valor positivo de corte e índice, que sugieren infección producida por Borrelia burgdorferi