Dopamine-dependent pathology and trace processes

Abstract

So-called analogs of evoked potentials can be regarded as a reliable criterion for assessing the transformation of trace processes in outpacing excitation. Dogs were injected with the dopamine antagonist haloperidol at the stage of stabilization of a motor conditioned reflex. The configuration of the evoked potential analogs in the motor cortex and basal ganglia became of the same type, without visible pathological symptoms. Evoked potential analogs with simple and complex (M) configuration were recorded after administration of L-DOPA. Specific distortions of trace processes were observed at subclinical stages of dopamine pathology. Key Words: analogues of evoked potentials; dopamine-related d&ordeG" trace processesIt has been generally accepted that prediction is based on the memorizing of biologically significant situations. Experiments have shown that probabilistic prediction is based on the formation of trace processes which gradually transform into outpacing excitation [2,4]. So-called analogs of evoked potentials (EP) or the dynamics of the reproduction of EP configuration during the intersignal period are an objective criterion for the assessment of trace processes [1,4].Stabilization of EP parameters and configuration during training suggests that the ratio of afferentations to a given brain structure is not random and l-effects the functional role of this structure. The emergence of EP analogs indicates that the reproduction of the traces of the given afferentation complex is necessary for the solution of adaptive task. In fact, typical EP analogs exist for each structure at each level of training [4,5].During training the dynamics of EP analogs first lags behind than outpaces the EP dynamics. Institute of Brain Research, Ru,ssian Academy of Medical Sciences, MoscowConsequently, EP analogs react earlier than EP to changes in afferentations. This is particularly important for situations when the afferentation complexes are pathologically distorted; this occurs, for example, in modeled DOPA-dependent sylnptoms. The restriction of motor afferent complexes was observed in neuroleptical parkinsonism; psychomotor excitation caused by L-DOPA was accompanied by afferent overload [5]. The dynamics of trace processes that outpace excitation remains unclear under conditions of dopamine-related disorders. The dynamics of EP analogs allows one to monitor these processes in various brain divisions, including the analyzing and extrapyramidal structures. This is particularly important for the early, symptom-free stages of dopamine-related disorders since it is reasonable to expect that it will be reflected by the dynamics of EP analogs.Our objective was to find out how tmcc processes are related to contralateral changes in dopamine lnetabolism. Bearing in mind the postulate tliat brain functions are associated with preseJvation of the traces of previous processes in brain structures, the identification of the early inanifestations of