Valentina Vengeliene, Hamid R Noori, Rainer Spanagel
Numerous studies in the preclinical alcohol research field show that pharmacological interventions and many other manipulations can influence alcohol consumption in a free choice paradigm in rats. These studies provide a measure of the total amount of alcohol consumed per day, but do not offer information on the drinking patterns within this period of measurement. Here we used a novel drinkometer system and methods used to analyse multiscale statistical dynamics of complex systems in order to characterize transitions between baseline and relapse-like drinking phases and to study treatment effects on relapse-like behaviour. Our data show that development of drinking behaviour undergoes critical phase transitions. Under baseline conditions, voluntary alcohol consumption in rats can be expressed as characteristic oscillations that follow diurnal activity and differ in their amplitude and frequency, depending on the ethanol concentration. This diurnal drinking rhythmicity is altered during a relapse condition, measured as an increased ethanol drinking frequency demonstrating that the deprivation phase may be a crucial component in the development of addictive behaviour. Pharmacological and other manipulations during this period interfere with either drinking frequency or the amount of ethanol consumed during a drinking approach. Intensive longitudinal datasets that derive from our drinkometer system and new multiscale statistical analysis methods provide a much deeper insight into experimental manipulation of drinking behaviour and enables us to observe progression of drinking behaviour in a stage-by-stage fashion.