Differences found in signals generated by the nervous system in response to somatosensory stimuli among the studied groups are thought to be developmental in origin, as the most remarkable deviations were seen in younger monkeys.

ARTÍCULO ORIGINAL Potenciales evocados auditivos del tallo cerebral en monos rhesus (Macaca mulatta) en diferentes etapas fisiológicas en condiciones de cautiverio SUMMARYIn the phylogenetic scale, audition plays a very important role in the development of elaborated behaviors. The aim of this study was to evaluate the auditive response in the Macaca mulatta species at different physiologic stages, through brainstem's auditory evoked potentials (BAEP). 30 non-human primates Macaca mulatta were allotted into two groups of 15 males and 15 females distributed in five age-dependant groups of 2 males and 2 females as follows: Group 1 (0,1-3,1 year old); Group 2 (3,2-6,1 year old); Group 3 (6,2-9,1 year old); Group 4 (9,2-12,1 year old) and Group 5 (12,2-27,1 years and older). The BAEP were obtained by the stimulation of the ear with rarefaction "clicks" of 50 dB of intensity. The cerebral electric activity was picked up by gold disc electrodes, placed in the Cz (+), A1, A2 (-) and Fz derivations as land, according to the 10/20 international system. Four waves were detected in the five evaluated groups. Since no significant differences were found in the ANOVAs by separated afferences, an ANOVA of united afferences was done. It was observed that groups 1 and 5 provided significant differences in all evaluated waves, showing the extended latencies in relation to other groups. It was concluded that BAEP made it possible to identify changes that are generated from the development, maturation and aging in rhesus monkeys.Palabras clave: generadores neurales auditivos, latencias, potenciales evocados auditivos de tallo cerebral.

Evoked potentials allowed identifying changes generated during aging in rhesus monkeys and normative data for this species were obtained.

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In spinal cord injury (SCI) there is damage to the nervous tissue, due to the initial damage and pathophysiological processes that are triggered subsequently. There is no effective therapeutic strategy for motor functional recovery derived from the injury. Several studies have demonstrated neurons growth in cell cultures on polymers synthesized by plasma derived from pyrrole, and the increased recovery of motor function in rats by implanting the polymer in acute states of the SCI in contusion and transection models. In the process of transferring these advances towards humans it is recommended to test in mayor species, such as nonhuman primates, prioritizing the use of non-invasive techniques to evaluate the injury progression with the applied treatments. This work shows the ability of diffusion tensor imaging (DTI) to evaluate the evolution of the SCI in nonhuman primates through the fraction of anisotropy (FA) analysis and the diffusion tensor tractography (DTT) calculus. The injury progression was analysed up to 3 months after the injury day by FA and DTT. The FA recovery and the DTT re-stabilization were observed in the experimental implanted subject with the polymer, in contrast with the non-implanted subject. The parameters derived from DTI are concordant with the histology and the motor functional behaviour.