Acomputer program has been developed to analyze the neuronal signals in thecerebello-thalamo<ortical pathway. The mathematical constants in an equation capable of approximating cortical responses were systematically altered by the program in the calculation of theoretical cortical values. Using the correlation coefficient between the computergenerated and the experimentally produced cortical responses to the same thalamic signal, as evoked by a cerebellar stimulation, the effects of varying these constants can be determined. As these constants bear physiological meanings, the connections between the cerebellum, thalamus, and motor cortex, believed to play an important role in voluntary movements, can be studied in simulated, normal, and abnormal situations by introducing different values of these parameters into the program.
Based on anatomical and electrophysiological studies, Asanuma et al. (I) have reported the existence of projections from the thalamic nucleus of ventralis lateralis to wide areas of the motor cortex. Asanuma and Hunsperger (2) further ascertained physiologically inputs to the same thalamic nucleus from deep cerebellar nuclei. They suggested that this cerebella-thalamo-cortical circuitry is concerned with the outgoing impulses from the cerebellum causing movements, a view in concert with the current concept of central control of movements (3).
Recently, we have developed a mathematical description of the above-mentioned circuitry, one which is capable of predicting the cortical responses, within a distance from a focal point and at a depth down to 500 itrn from the cortical surface, to a thalamic signal generated by, e.g., a cerebellar stimulation (4). The behavior of certain mathematical constants which represent important physiological parameters within this cerebella-thalamo-cortical pathway, however, requires further analysis. This article presents a computer program designed for this purpose, using the degree of correlation between theoretical and experimental cortical signals as an index.
THE MATHEMATICAL APPROXIMATION
The cortical response, CORTEX(t, + L, R,x), at a distance R (R 2 0) from a cerebral focal point, at a depth x (0 < x < 500 ~0 from the cortical surface and Copyright