Thinking outside the synapse

Bridging the gap between the parallel, distributed processing of groups of neurons and the serial, integrated processing of higher cognitive functions is a difficult hallenge. One possible mechanism originates in the shared space of the extracellular compartment. The opening and closing of ion channels in this space produce mechanical waves, presumably in the ultrasonic range. If the combined activities of enough channels produce strong enough waves, then integrated ultrasonic signals could broadcast information throughout the brain. If the broadcast signals are selectively received by target neurons, then several cognitive abilities readily emerge, including learning, memory, pattern recognition, and problem solving.