THE EFFECTS OF ANXIETY ON MOTORIC EXPRESSION OF THE STARTLE RESPONSE

The present study was designed to investigate the effects of anxiety on a motor output system through the use of the startle response paradigm. Most of the research dealing with anxiety to date has examined the effects of anxiety on the higher central nervous system, while little attention has been given to the possible detrimental effects of anxiety on motor output systems. Startle stimuli, 85 and 60 dB SPL noise bursts, were presented with and without a 50 dB SPL prepulse to college students who were low or high in state or trait anxiety. Integrated periorbital electromyographic activity (EMG) was used to assess the latency, amplitude and probability of startle eyeblink responding. An analysis of response latency revealed that Ss low in state anxiety responded more quickly to the 85 than to the 60 dB stimulus, whereas Ss high in state anxiety responded with equal latency to both levels of stimulus intensity. Given that response latency is the most sensitive indicator of the efferent (motor) component of the startle response, these results indicate that a high state of anxiety may result in indiscriminate motoneuronal firing to stimuli of different intensities. The results are discussed in terms of the effects of motoneural insensitivity on behavior, and in terms of the relevance of the findings to past and future research in the area of anxiety. © 1991.