AUTONOMIC NERVOUS-SYSTEM RESPONSES CORRELATE WITH MENTAL REHEARSAL INVOLLEYBALL TRAINING

The aim of this study was to assess objectively the processes of menta l rehearsing (imagery) by measuring variations of the autonomic nervou s system (or ANS responses) during an open-ended complex motor skill i n two actual experiments (volleyball) and during mental rehearsing tak ing place between them. Comparison between pre- and post-test (volleyb all) scores related to imagining and non-imagining performances reveal ed significant improvement in the former (chi(2) = 20.9, P < 0.00001) while in the latter chi(2) = 27, P < 0.9, NS. The ANS parameters (skin potential and resistance, skin temperature and heat clearance, instan taneous heart rate and respiratory frequency) were quantified by origi nal techniques and indices. Results from a principal component analysi s showed a strong correlation between the responses in actual tasks (p re- and post-test volleyball) and during mental imagery, since the sam e preferential variables appeared on the main axis in 87% of cases. Th us the same autonomic channels seemed to be used during the actual act ivity and during the mental imagery of this activity. So far as phasic results were concerned, the main finding was a differing development of skill between imagining and non-imagining volleyball players. No cl ear difference was seen between pre- and posttests in non-imaginers, e xcept an increase in the median of the duration of the response observ ed in heat clearance, mi and mt respectively [m(1) = 5.8 (SD 4.1) s, m (2) = 7.6 (SD 3.9) s, P < 0.001]. Conversely, for other ANS parameters , a significant decrease was seen in the post-test responses compared to pre-test responses in the imagining group [for instance, the median of the duration of the resistance responses decreased from m(1) = 12. 6 (SD 4.3)s, and m(2) = 7.8(SD 4.5)s, P < 0.0001 in imaginers, while n o change was observed in non-imaginers: 9.6 (SD 6.0) s vs 9.5 (SD 6.1) s, NS] except in the duration of the heat clearance response where an increase was seen [ml = 7.3 (SD 5.0) s vs mt = 7.6 (SD 3.1) s, NS]. C ompared to the non-imagining group, the latter result may also have be en associated with a response decrease in the imagining group. Thus me ntal rehearsing induced a specific pattern of autonomic response: decr eased amplitude, shorter duration and negative skin potentials compare d to the control group. As this pattern was associated with better per formance in the tests it can be suggested that in the case of open-end ed motor activity, mental rehearsing may help in the construction of s chema which can be reproduced, without thinking, in actual practice. T hus a neural information process might develop in the central nervous system changing from a parallel into a serial treatment.