lickcalc: Easy Analysis of Lick Microstructure in Experiments of Rodent Ingestive Behaviour

Lick microstructure is a term used in behavioural neuroscience to describe the information that can be obtained from a detailed examination of rodent drinking behaviour. Rather than simply recording total intake (volume consumed), lick microstructure examines how licks are grouped and the spacing of these groups of licks. This type of analysis can provide important insights into why an animal is drinking, for example, whether it is influenced by taste or affected by the consequences of consumption (e.g., feeling 'full'). Here, we present a software package, lickcalc, that allows detailed microstructural analysis of licking patterns. The software is browser based and is hosted at https://lickcalc.uit.no, or the repository can be downloaded and installed locally. Lick timestamps can be loaded from a variety of formats, and different analysis and plotting options allow quality control of data and the determination of critical parameters for microstructural analysis, including the number and size of lick bursts. Data can be divided into epochs for detailed examination of changes across the session. Batch processing and custom configurations are supported. In this manuscript, we demonstrate the use of the functions exposed by lickcalc by analysing data comparing lick patterns between mice on a protein-restricted and a control (non-restricted) diet. We show that lickcalc allows quality control of the data and the uncovering of subtle differences in lick behaviour that are not apparent when just considering the total number of licks. This software makes microstructural analysis accessible to any researcher who wishes to employ it while providing sophisticated analyses with high scientific value.