Brainstem circuits supporting adaptive instinctive behaviours

Instinctive behaviours that achieve defence, feeding, aggression and parental care have evolved across animal phyla to ensure survival without the need for learning.

Contrary to common belief, instinctive behaviours are not ‘hard-wired’ reflexes, but can be flexible in both action selection and execution.

They are modulated by internal states, such as stress, hunger or oestrous cycle, and may undergo short- and long-lasting adaptations in order to accommodate environmental changes and individual needs.

The aim of this proposal is to gain a mechanistic understanding of adaptive instinctive behaviour output within a quantitative neuroethological framework and by combining molecular, cellular and circuit-level approaches.

I will focus on the vertebrate periaqueductal gray (PAG), an evolutionarily conserved brainstem region that plays a crucial role in the initiation and execution of virtually all instinctive behaviours.

Despite this, a comprehensive analysis of the cellular and network properties of the PAG, and their behavioural correlates, is lacking.

In addition to generating the first dataset of PAG network topology using high resolution in vitro anatomical and electrophysiological approaches, we will study its neural computations across multiple instinctive behaviours and during motivational conflict using neural activity recordings in freely behaving mice.

Building on these results, we will test the role of neuromodulation in imparting flexibility to this circuit (and the selection of appropriate behaviours), focussing on naturally-occurring neuromodulatory changes during the oestrous cycle.

By establishing how the PAG – a critical circuit that closely precedes motor neuron recruitment – controls and imparts flexibility to instinctive behaviours, this proposal will expand our knowledge on the neural and molecular basis of adaptive behavioural output that is fundamental for the survival of all animals, with an emphasis on the female brain.