The neurochemical (neuropeptide) correction of disturbed automatic functions is a topical problem of modern neurophysiology and medicine. Most of the experimental studies on vegetative and motor reactions and the possibilities to compensate for their disturbance have been performed on partially immobilized animals [4, 5, 7, 8]. Only a few complex studies on vegetative and motor reactions under the conditions of free behavior have been conducted. We did not find publications on such studies on insectivores. Thyroliberin (thyrotropin-releasing hormone) is interesting because of its pronounced cardiovascular effect [1, 2]. This hormone attracts special attention as a specific regulator of respiration. Currently, thyroliberin is used in clinical practice to relieve hypoxia and normalize respiration and blood circulation in newborns [1, 2, 11‐13]. Therefore, we studied the role of thyroliberin in the regulation of conditioned motor and vegetative reactions in hedgehogs. The experiments were carried out on 13 hedgehogs Erinaceus europaeus. We used the model of eating behavior with simultaneous recording of the motor, respiratory, and cardiac components of higher nervous activity (HNA) in free-moving animals. An advantage of this method is that it allows the researcher to monitor the ratio between the three components of HNA at different stages of the formation of conditioned reflexes and to study the effects of neuropeptides on these components in animals belonging to lower stages of mammalian evolution. The electrocardiogram (ECG) was recorded with the use of silver cuff-shaped electrodes attached to three limbs (the two fore and the left hind). The respiratory component was recorded with the use of a nipple tube filled with graphite powder and set in a special cuff, which was attached to the hedgehog’s abdomen. To avoid noise when recording the vegetative activity in free-moving animals, we (together with V.P. Ivanov, an engineer at our laboratory) developed and built an operational amplifier with a high input resistance in the cardiograph. The noise caused by the effect of the supply-line frequency on the ECG record was eliminated with the use of special filters and shielded wires. Taking into account that hedgehogs would curl up into a ball, we used the following experimental procedure. Hedgehogs deprived of food (for one or two days) with the cuffs attached to them were taught to receive food reinforcement from the feeder (five to seven days). After this, conditioned reflexes were formed in the animals. A 50-dB, 200-Hz sound above the human hearing threshold served as a conditioned stimulus, and a 50-Hz sound, as a differentiation stimulus. Vegetative parameters were recorded on an N338-6P six-channel automatic recorder. In addition to positive conditioned responses, an internal inhibition of the extinction and differentiation types was formed in hedgehogs. We used an acute extinction, with an absence of motor responses to three consecutive nonreinforcements serving as a criterion for extinction. We measured the background heart rate (HR) and respiration rate (RR), their changes in response to the conditioned stimulus at different stages of the formation of the conditioned reflex, latent periods (LPs) of the motor and vegetative components, intersignal activity, and changes of these parameters after thyroliberin administration. The thyroliberin was prepared at the Department of the Chemistry of Natural Compounds, Faculty of Chemistry, St. Petersburg State University. The preparation was administered subcutaneously at a dose of 35‐40 μ g/kg 10 min before the experiment. We found that conditioned motor food-procuring responses were the first to be formed and reinforced: this took 60‐65 simultaneous applications of the conditioned and unconditioned stimuli. At the stage of reinforced conditioned responses, their latent period was relatively constant; its duration was 2.5 ∠ 0.53 s. Conditioned respiratory responses were formed later, after 75‐80 applications of the stimuli. At the initial stages, there were no constant patterns of conditioned respiratory responses. At the stage of reinforcement, the conditioned-response frequency tended to decrease. It took considerably more time for the cardiac component to PHYSIOLOGY