Publicações científicas

Cortical gamma activity during auditory tone omission provides evidence for the involvement of oscillatory activity in top-down processing

Gurtubay IG, Alegre M [ES], Valencia M, Artieda J [ES].
Neurophysiology Section, Clínica Universitaria, University of Navarra, Apdo. 4209 31008 Pamplona, Spain.

Revisão:Experimental Brain Research

Data: 1/Nov/2006

Neurofisiologia [ES]

Perception is an active process in which our brains use top-down influences to modulate afferent information. To determine whether this modulation might be based on oscillatory activity, we asked seven subjects to detect a silence that appeared randomly in a rhythmic auditory sequence, counting the number of omissions ("count" task), or responding to each omission with a right index finger extension ("move" task).

Despite the absence of physical stimuli, these tasks induced a 'non-phase-locked' gamma oscillation in temporal-parietal areas, providing evidence of intrinsically generated oscillatory activity during top-down processing. This oscillation is probably related to the local neural activation that takes place during the process of stimulus detection, involving the functional comparison between the tones and the absence of stimuli as well as the auditory echoic memory processes. The amplitude of the gamma oscillations was reduced with the repetition of the tasks. Moreover, it correlated positively with the number of correctly detected omissions and negatively with the reaction time.

These findings indicate that these oscillations, like others described, may be modulated by attentional processes. In summary, our findings support the active and adaptive concept of brain function that has emerged over recent years, suggesting that the match of sensory information with memory contents generates gamma oscillations.

CITAÇÃO DO ARTIGO Exp Brain Res. 2006 Nov;175(3):463-70

talvezlhe interesse

QUE TECNOLOGIA UTILIZAMOS? 

A Clínica é o hospital privado com maiores recursos tecnológicos de Espanha, tudo num único centro.

Imagen de un PET, tecnología de vanguardia en la Clínica Universidad de Navarra

OS NOSSOS
PROFISSIONAIS

Os profissionais da Clínica realizam um trabalho contínuo de investigação e formação, sempre em benefício do paciente.

Imagen profesionales de la Clínica Universidad de Navarra

RAZÕES PARA VIR
À CLÍNICA

Conheça porque é que somos diferentes em relação a outros centros sanitários. Qualidade, rapidez, comodidade e resultados.

Imagen del edificio de la Clínica Universidad de Navarra