REACTION-TIME RESPONDING IN RATS

The use of reaction time has a great tradition in the field of human i nformation processing research. In animal research the use of reaction time test paradigms is mainly limited to two research fields: the rol e of the striatum in movement initiation; and aging. It was discussed that reaction time responding can be regarded as ''single behavior'', this term was used to indicate that only one behavioral category is me asured, allowing a better analysis of brain-behavior relationships. Re action time studies investigating the role of the striatum in motor fu nctions revealed that the initiation of a behavioral response is depen dent on the interaction of different neurotransmitters (viz. dopamine, glutamate, GABA). Studies in which lesions were made in different bra in structures suggested that motor initiation is dependent on defined brain structures (e.g. medialldorsal striatum, prefrontal cortex). It was concluded that the use of reaction time measures can indeed be a p owerful tool in studying brain-behavior relationships. However, there are some methodological constraints with respect to the assessment of reaction time in rats, as was tried to exemplify by the experiments de scribed in the present paper. On the one hand one should try to contro l for behavioral characteristics of rats that may affect the validity of the parameter reaction time. On the other hand, the mean value of r eaction time should be in the range of what has been reported in man. Although these criteria were not always met in several studies, it was concluded that reaction time can be validly assessed in rats. Finally , it was discussed that the use of reaction time may go beyond studies that investigate the role of the basal ganglia in motor output. Since response latency is a direct measure of information processing this p arameter may provide insight into basic elements of cognition. Based o n the significance of reaction times in human studies the use of this dependent variable in rats may provide a fruitful approach in studying brain-behavior relationships in cognitive functions. (C) 1998 Elsevie r Science Ltd. All rights reserved.