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Background/Objectives: Dopamine dysfunction (DA) is a hallmark of many neurological disorders. In this case, the mechanism of changes in dopamine transmission on behavior remains unclear. This study is a look into the intricate link between disrupted DA signaling, neuronal activity patterns, and behavioral abnormalities in a hyperdopaminergic animal model. Methods: To study the relationship between altered DA levels, neuronal activity, and behavioral deficits, local field potentials (LFPs) were recorded during four different behaviors in dopamine transporter knockout rats (DAT-KO). At the same time, local field potentials were recorded in the striatum and prefrontal cortex. Correlates of LFP and accompanying behavioral patterns in genetically modified (DAT-KO) and control animals were studied. Results: DAT-KO rats exhibited desynchronization between LFPs of the striatum and prefrontal cortex, particularly during exploratory behavior. A suppressive effect of high dopamine levels on the striatum was also observed. Wild-type rats showed greater variability in LFP patterns across certain behaviors, while DAT-KO rats showed more uniform patterns. Conclusions: The decisive role of the synchrony of STR and PFC neurons in the organization of motor acts has been revealed. The greater variability of control animals in certain forms of behavior probably suggests greater adaptability. More uniform patterns in DAT-KO rats, indicating a loss of striatal flexibility when adapting to specific motor tasks. It is likely that hyperdopaminergy in the DAT-KO rat reduces the efficiency of information processing due to less synchronized activity during active behavior.

Introduction. Changes in the expression of the dopamine transporter (DAT) have been identified in patients with a number of neuropsychiatric disorders, but their significance for pathogenesis remains unclear. DAT knockout rats are a promising model of frontostriatal dysfunctions involved in adapting learning processes to current organism's needs, motivation, and experience.The objective was to evaluate the effect of DAT disruption on the interaction of classical and instrumental conditioning processes (associative learning).Methods and materials. Rats from a local colony were used: knockouts (n=31), heterozygotes (n=32), and wild type rats (n=24). DAT knockout (Slc6a3) was detected by PCR followed by restriction analysis. The rats were kept individually with limited access to food and unlimited access to water. In the operant chambers equipped with a MED-PC interface (MED Associates, USA), 3 experiments were performed: 1) classical conditioning; 2) autoshaping of operant responding; 3) reward learning based on secondary reinforcement. Statistical analysis was performed using SigmaPlot 12.5 (Systat Software Inc., USA) and SPSS Statistics 21 (IBM, USA).Results. We revealed that DAT disruption in rats did not affect the formation of conditioned reflex connections in classical conditioning (1) but was accompanied by impairments in the autoshaping of the operant response (2) and learning based on secondary reinforcement (3).Conclusion. The observed impairments of associative learning might be associated with a decreased incentive value of stimuli in hyperdopaminergic state.