Modelling positive Granger Causality and negative phase lag between cortical areas

Click here to view linked References Different measures of directional influence have been employed to infer effective connectivity in the brain. When the connectivity be-tween two regions is such that one them (the sender) strongly influ-ences the other (the receiver), a positive phase lag is often expected. The assumption is that the time difference implicit in the relative phase reflects the transmission time of neuronal activity. However, Brovelli et al. (2004) observed that, in monkeys engaged in processing a cognitive task, a dominant directional influence from one area of sen-sorimotor cortex to another may be accompanied by either a negative or a positive time delay. Here we present a model of two brain regions, coupled with a well-defined directional influence, that displays similar features to those observed in the experimental data. This model is inspired by the theoretical framework of Anticipated Synchronizatio