Effect of initial joint position on nerve-cuff recordings of muscle afferents in rabbits

Abstract

The objective was to characterize nerve-cuff recordings of muscle afferents to joint rotation over a large part of the physiological joint range. This information is needed to develop control strategies for functional electrical stimulation (FES) systems using muscle afferent signals for sensory feedback. Five acute rabbit experiments were performed. Tripolar cuff electrodes were implanted around the tibial and peroneal divisions of the sciatic nerve in the rabbit's left leg. The electroneurograms (ENG) were recorded during passive ankle rotation, using a ramp-and-hold profile starting at seven different joint positions (excursion = 5 degrees, velocity = 10 degrees/s, initial positions 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100%, 110 , and 120 ). The amplitude of the afferent activity was dependent on the initial joint position. The steady-state sensitivity of both nerve responses increased with increasing joint flexion, whereas the dynamic sensitivity increased initially but then decreased. The results indicate that recordings of the muscle afferents may provide reliable information over only a part of the physiological joint range. Despite this limitation, muscle afferent activity may be useful for motion feedback if the movement to be controlled is within a narrow joint range such as postural sway.

Model-based ankle joint angle tracing by cuff electrode recordings of peroneal and tibial nerves

“…ENG recorded from peroneal and tibial nerves were dominated by the kinematics of ankle joint and the sensitivity of afferent signals were not constant [13]. ENG signals were influenced by three fundamental factors, namely, the initial position, the range of movement, and the stretch velocity.…”

“…It was shown that higher ankle stretch velocities resulted in a higher dynamic muscle spindle response, but had only marginal effect on the steady-state response provided that the ankle motion was terminated at the same position. Jensen et al [13] defined the steady-state and dynamic sensitivities of nerve responses under a small ramp-and-hold motion and investigated the influence of initial joint position on the muscle afferent signals. The results showed that the steady-state and dynamic sensitivities were largely dependent on the initial position.…”

State-space decoding of primary afferent neuron firing rates

“…However, attempts at providing graded measurements of limb-state (e.g. ground reaction force or joint position) with nerve cuff recordings have had limited success (Jensen et al 2001). In general, research towards the use of nerve cuff recordings for continuous joint-angle estimation has been limited to a single isolated joint, typically the ankle, and tested only in anesthetized animals (Cavallaro et al 2003, Jensen et al 2001, Jensen et al 2002, Micera et al 2001).…”

“…ground reaction force or joint position) with nerve cuff recordings have had limited success (Jensen et al 2001). In general, research towards the use of nerve cuff recordings for continuous joint-angle estimation has been limited to a single isolated joint, typically the ankle, and tested only in anesthetized animals (Cavallaro et al 2003, Jensen et al 2001, Jensen et al 2002, Micera et al 2001). Cavallaro et al (Cavallaro et al 2003) sought to improve continuous state estimation from nerve cuff recordings and tested several advanced signal processing methods, but reported difficulty in achieving generalization, especially for movements with large joint angular excursions.…”

Selectivity of Peripheral Neural Interfaces

“…Today sensory information has been extracted from peripheral nerves containing afferent fi bers from the skin ( Haugland et al, 1999 ;Inmann et al, 2001 ;Sinkjaer et al, 2003 ) or muscles ( Jensen et al, 2002( Jensen et al, , 2001( Jensen et al, , 2000 or bladder ( Jezernik et al, 2001( Jezernik et al, , 2000. In the fi rst two cases the recorded afferent activity was used to detect distinct events during movement.…”