Fecha: Viernes 11 de junio de 2010
Abstract: «The process of perception begins when the limbic system predicts a goal, directs the sensory systems to acquire necessary information, encode it in microscopic action potentials, and send it to the sensory cortices. Within milliseconds the information triggers a burst of gamma oscillation in every sensory cortex. The bursts are seen in the mesoscopic electrocorticogram (ECoG). Close examination at high spectral, temporal and spatial resolution reveals complex structured patterns. When expressed as multivariate feature vectors, the patterns relate not to the microscopic information. Instead they relate to the history, context, and significance of the information for the subjects. About 300 milliseconds later a burst of beta oscillation emerges over all the sensory cortices and the limbic system. The phase-locked beta oscillation carries a macroscopic spatial pattern. Its feature vector also relates to the meaning, not the information. Similar feature vectors have now been extracted and classified from scalp EEGs. It appears that beta bursts are carriers of percepts. To aid further exploration I will define and describe the basic spatiotemporal morphologies revealed by high-definition ECoG and EEG: the dipole field; the closed field; the Rayleigh burst; the amplitude modulation (AM) pattern; the phase modulation (phase cone) pattern; the null spike; and the vortex.»
Professor Freeman is also interested in the history of the contributions to science and particularly neuroscience by the Arabic scholars living in Al-Andalus during Cordoba Caliphate and later periods. Any people insterested to discuss with professor Freeman about this interesting topic, please let me know to the email below in order to arrange a meeting with him.
jtorres@onsager.ugr.es
Instituto «Carlos I» de Física Teórica y Computacional
Grupo de neurofísica y neurociencia computacional.
Universidad de Granada.
http://ergodic.ugr.es/neurofisica/neurofisica.html