![]() Nolte's The Human Brain : An Introduction to Its Functional Anatomy. Von Economo neurons, also known as spindle neurons, found in a few select parts of the cerebral cortex of apes and some other intelligent animals, possess a single axon and dendrite and as such have been described as bipolar. In some cases where two fibers are apparently connected with a cell, one of the fibers is really derived from an adjoining nerve cell and is passing to end in a ramification around the ganglion cell, or, again, it may be coiled helically around the nerve process which is issuing from the cell. Sometimes the extensions, also called processes, come off from opposite poles of the cell, and the cell then assumes a spindle shape. In the spinal ganglia īipolar cells are also found in the spinal ganglia, when the cells are in an embryonic condition. The majority of the bipolar neurons belonging to the vestibular nerve exist within the vestibular ganglion with axons extending into the maculae of utricle and saccule as well as into the ampullae of the semicircular canals. In the vestibular nerve īipolar neurons exist within the vestibular nerve as it is responsible for special sensory sensations including hearing, equilibrium and motion detection. On-center bipolar cells have inhibitory synapses with the photoreceptors and therefore are excited by light and suppressed in the dark. The excitatory synapses thus convey a suppressive signal to the off-center bipolar cells. The off-center bipolar cells have excitatory synaptic connections with the photoreceptors, which fire continuously in the dark and are hyperpolarized (suppressed) by light. Bipolar cells come in two varieties, having either an on-center or an off-center receptive field, each with a surround of the opposite sign. Rather, they pass the information by graded signal changes. Bipolar cells in the retina are also unusual in that they do not fire impulses like the other cells found within the nervous system. ![]() The specific location of the bipolar cells allow them to facilitate the passage of signals from where they start in the receptors to where they arrive at the amacrine and ganglion cells. ![]() Often found in the retina, bipolar cells are crucial as they serve as both direct and indirect cell pathways. ![]()
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