A stimulus line of a particular orientation will thus evoke a particular profile of activity across the channels. The organization of the auditory nerve, cochlear nucleus and higher auditory structures is such that neighbouring cells can be activated stimulation of neighbouring points on the basilar membrane. Concentric simply means having the same centre. So this refers to the dart-board like organization of the receptive field structure of retinal ganglion cells. The cupula is a cup-like structure that stretches across each semicircular canal and is moved by fluid movement within the canal.
Fluid movement occurs as a result of angular acceleration.
Hair cells are imbedded in the cupula so when it moves their hairs are bent. The hair cells of the auditory system are essentially the same as the hair cells of the vestibular system. If you wear special glasses with prisms arranged to invert the optical image, it initially looks as though the world is upside down. When you take the glasses off, things again appear inverted and you need to adapt again. One of the people involved in these early studies was Kohler working in Innsbruck in Switzerland.