DYNAMIC PROPERTIES OF CORTICAL EVOKED (10 HZ) OSCILLATIONS - THEORY AND EXPERIMENT

Experiments probed the dynamic properties of stimulus-evoked (almost-e qual-to 10 Hz) oscillations in somatosensory cortex of anesthetized ra ts. Experimental paradigms and statistical time series analysis were b ased on theoretical ideas from a dynamic approach to temporal patterns of neuronal activity. From the results of a double-stimulus paradigm we conclude that the neuronal response contains two components with di fferent dynamics and different coupling to the stimulus. Based on this result a quantitative dynamic model is derived, making use of normal form theory for bifurcating vector fields. The variables used are abst ract, but measurable, dynamic components. The model parameters capture the dynamic properties of neuronal response and are related to experi mental results. A structural interpretation of the model can be given in terms of the collective dynamics of neuronal groups, their mutual i nteraction, and their coupling to peripheral stimuli. The model predic ts the stimulus-dependent lifetime of the oscillations as observed in experiment. We show that this prediction relies on the basic concept o f dynamic bistability and does not depend on the modeling details.