Reflex receptive fields for human withdrawal reflexes elicited by non-painful and painful electrical stimulation of the foot sole.

摘要: Abstract Objectives : Human withdrawal reflex receptive fields (RRFs) were assessed for 4 different electrical stimulus intensities, ranging from below the pain threshold (PTh) to up two times PTh intensity (0.8×, 1.2×, 1.6×, and 2.0×PTh). Methods Thirteen subjects participated, reflexes recorded in a sitting position. The stimuli delivered random order 12 positions distributed over foot sole. Tibialis anterior (TA), gastrocnemius medialis (GM), vastus lateralis (VL), biceps femoris (BF) recorded. Further, knee ankle joint angle changes Results strongest seen TA compared with other 3 muscles. Dorsi-flexion dominated distal talocrural corresponding field area. An expansion of RRF GM was when increasing 0.8×PTh 1.2×PTh 1.6×PTh, indicating gradually towards border, where contraction is inappropriate reaction. For BF VL, borders areas not detected. By integrating size within (i.e. volume), all muscles tested, most clearly GM. subjective correlated volume TA, GM, BF. Conclusions In conclusion, highest sensitivity centre RRF, while needed eliciting increased border. Within stronger evoked intensity. limit supports modular organisation.