ABSTRACT
The inner ear contains sensory organs which signal changes in head movement. The vestibular sacs, in particular, are sensitive to linear accelerations. Electron microscopic images have revealed the structure of tiny sensory hair bundles, whose mechanical deformation results in the initiation of neuronal activity and the transmission of electrical signals to the brain. The structure of the hair bundles is shown in this paper to be that of the most efficient two-dimensional phased-array signal processors.
Subject(s)
Cilia/ultrastructure , Hair Cells, Vestibular/physiology , Hair Cells, Vestibular/ultrastructure , Models, Biological , Saccule and Utricle/physiology , Signal Transduction/physiology , Acceleration , Acoustic Maculae/anatomy & histology , Acoustic Maculae/physiology , Animals , Cilia/physiology , Cochlea/physiology , Microscopy, Electron , Otolithic Membrane/anatomy & histology , Otolithic Membrane/physiology , Saccule and Utricle/anatomy & histologyABSTRACT
Mammalian macular endorgans are linear bioaccelerometers located in the vestibular membranous labyrinth of the inner ear. In this paper, the organization of the endorgan is interpreted on physical and engineering principles. This is a necessary prerequisite to mathematical and symbolic modeling of information processing by the macular neural network. Mathematical notations that describe the functioning system were used to produce a novel, symbolic model. The model is six-tiered and is constructed to mimic the neural system. Initial simulations show that the network functions best when some of the detecting elements (type I hair cells) are excitatory and others (type II hair cells) are weakly inhibitory. The simulations also illustrate the importance of disinhibition of receptors located in the third tier in shaping nerve discharge patterns at the sixth tier in the model system.
