Functional characteristics of mechanoreceptors in sinus hair follicles of the cat

Abstract

1. The discharge of impulses in afferent fibres dissected from the infraorbital and ulnar nerves of anaesthetized cats was recorded during controlled movements of the maxillary and carpal sinus hairs.2. Four main types of afferent units were identified. Two had slowly adapting responses characteristic of the epidermal type I, and dermal type II mechanoreceptors of the hairy skin. Two rapidly adapting responses to movement of the sinus hairs were found, one with a high velocity threshold and another with a low velocity threshold.3. The slowly adapting units showed a power relationship between the degree of displacement of the hair and the mean interspike interval of the response. Slowly adapting units also exhibited a power relationship between the velocity of displacement of a hair and the mean interspike interval of the response.4. The conduction velocities of all types of afferent units were measured and fell in the range of the Aalpha, fast myelinated fibres.5. Movements of the carpal sinus hairs yielded both types of slowly adapting response recorded in fibres of the ulnar nerve directly innervating the carpal sinus hair follicles, and rapidly adapting responses from Pacinian corpuscles, found in close association with, but external to, these follicles.6. On the basis of the findings in this study and the results of anatomical investigations of the receptor structures in the sinus hair follicle a correlation between the distinguishable afferent responses and the morphologically identifiable nerve endings has been proposed.

Discharge patterns of the slowly adapting mechanoreceptor afferent units innervating the non-warty skin of the frog.

“…was very large. These characteristics of Ft I and Ft II units are comparable to those of sinus type I and sinus type II SA units of cats (GoTTSCHALDT et al, 1973).…”

“…The time-courses of the discharges were obtained on the post-stimulus time (PST) histograms made over 50 trials, and analyzed in terms of time-constants by means of the standard "peeling off" procedure (PERL, 1960;GOTTSCHALDT et al, 1973;. A microcomputer (MZ-80K, Sharp) was used to measure the ISIs with a time resolution of 1 msec and to construct a PST histogram.…”

Bat wing sensors support flight control

“…Their small size suggests that they may be specialized vellus hairs (15). Merkel cells detect the direction, amplitude, and duration of deflection of the hair (16). Interestingly, the tactile wing hairs of the bat are found on both surfaces of the dactylopatagium, the membrane between the fingers, indicating that the bat's ventral hand surface is not glabrous, e.g., hairless, in contrast to other nonhoofed mammals such as primates or rodents.…”

Empirically inspired simulated electro-mechanical model of the rat mystacial follicle-sinus complex

“…Regarding the mechanoreceptors, both irregularly and regularly firing SA responses have been observed in the biology (named, respectively, SAI and SAII responses (Gottschaldt et al 1973)), whereas the simple mechanoreceptor model used here leads only to the regular firing illustrated in figure 4. The phenomenon of 'phase-locking' (synchronizing of response spikes to phase of vibratory stimuli) has been reported in several works, but we do not attempt to reproduce it here.…”