Dependence between the latency of sensorimotor reactions and parameters of the somatosensory evoked potentials related to this reaction: A study in humans

In 18 27- to 56-year-old tested subjects, we measured the latency of sensorimotor reactions (SMRL) and parameters of the somatosensory evoked potentials (SSEP), related to these reactions, observed in two experimental paradigms. In test 1, every third stimulus in a train of identical stimuli was considered the “necessary” signal, while in test 2, the subject had to select such a signal from three different versions of the stimuli presented in a randomized manner. For each subject, we selectively averaged the SSEP related to different (short and long) SMRL. We demonstrated the existence of different types of the dependences between the SSEP parameters and the values of SMRL; the pattern of these dependences could be different in tests 1 and 2. For test 1, a negative dependence between the variations of SMRL and amplitude of the P100 SSEP component was observed, while test 2 results were characterized by a clearly expressed negative correlation between the SMRL, and N150 amplitude (P<0.05). Negative correlation between the SMRL and integral amplitude of the P100-N150-P250 complex (P<0.05) was a common manifestation of the dependence between the SMR and SSEP parameters observed under conditions of both tests. We suppose that the dependences between the variations of SSEP parameters and SMRL values reflect changes in the level of mobilization of attention and in the structure of the latter in the course of performance of a sensorimotor task.