chronaxie, chronaxy Phys.
(ˈkrəʊnəksɪ)
Also chronaxia.
[a. F. chronaxie (L. Lapicque 1909, in Comptes Rendus de la Soc. de Biol. LXVII. 283), f. Gr. χρόν-ος time + ἀξία value.]
The minimum time required by a constant electric current of twice the threshold intensity to excite a muscle or nerve fibre, used as an index of excitability. Also attrib.
| 1917 Sci. Amer. Suppl. LXXXIII. 389/2 To this constant representing a period of time Lapicque gives the name of chronaxia. For a given kind of muscle the chronaxia has an invariable value, about one-tenth that of the useful time. 1922 Nature 5 Jan. 30/2 Chronaxy of the sensitive rachidian nerves of the upper limb in man. 1924 Ibid. CXIII. 427/1 The need for a review of the work on chronaxie. 1944 Electronic Engin. XVII. 27 Chronaxie is defined as that period of time for which a current, having twice the rheobasic value, must flow in order to produce the same minimal contraction. 1950 Ibid. XXII. 88 The response to electrical stimulation of muscle and nerve (chronaxie measurement). |