Evolutionary antecedents of emotion in an invertebrate species

The study of animal emotion (affect) is of growing interest in disciplines including neuroscience, psychopharmacology and animal welfare science. Although we cannot measure the conscious component of animal emotion, we can use operational definitions of emotion to allow us to identify and measure behavioural and physiological indicators of such states. To date, nearly all research on animal emotion has been on vertebrates. However, there has been a recent surge of interest in the idea that studying emotion-like processes in invertebrates can provide us with new insights into the evolutionary basis of these states, their underlying neurophysiological mechanisms, and functions that may be conserved across species. So far, invertebrate studies have tended to focus on short-term emotion-like behaviours (e.g. avoidance in crayfish: Fossat et al. 2014. Science 344, 1293-1297; jumping and freezing in flies: Gibson et al. 2015. Curr. Biol. 25, 1401-1415). However, emotional states also include longer-term ‘moods’ which may act to integrate cumulative experience of short-term emotions and thus adaptively inform decisions about positive or negative outcomes in current (especially ambiguous) situations (e.g. Harding et al. 2004. Nature 427, 312; Mendl et al. 2010. Proc Roy Soc. B. 277, 2895-2904). There is now some evidence for such states in insects (Bateson et al. 2011. Curr Biol. 21, 1070-1073; Perry et al. 2016. Science 353, 1529-1531; see Mendl et al. Curr. Biol. 21, R463-R465 and Mendl & Paul, Science 353, 1499-1500), and this project will further investigate this possibility in the fruit fly, Drosophila melanogaster.

The aim of the PhD is to test the hypothesis that cumulative experience of reward and punishment generates a neural state (an evolutionary precursor of mood) that biases decisions in favour of positively or negatively valenced outcomes. Additional aims include investigating how such cumulative effects can be modelled statistically (e.g. as a Bayesian inference process), and how manipulations of targeted neural circuitry alter the function of this mood-like state. To this end, the student will receive training in animal learning and behaviour (including behavioural decision-making assays), neuroscience of decision-making (including genetic, opto/thermo-genetic and electrophysiological techniques for altering the function of targeted neural circuits), and statistical modelling methods, from a supervisory team with expertise in all areas.
Supervisors’ websites: http://www.bristol.ac.uk/vetscience/people/michael-t-mendl/ and https://mail.google.com/mail/u/0/#advanced-search/from=James.Hodge%40bristol.ac.uk&subset=all&within=1d&sizeoperator=s_sl&sizeunit=s_smb/15801215ac4b98c3?projector=1