In recent decades, there has been a notable increase in research activity focused on the aversive and reward circuits of the brain. The evidence indicates that the parabrachial nucleus (PBn) is a crucial element in the generation of aversion responses in mice. Following successful stimulation of the PBn, mice display increased aversive and stress-related ehaviours. The study employs Fos TRAP2-ChR2 mice, opioids such as oxycodone, and a range of imaging technologies to monitor and manipulate neural pathways. Behavioral tests and optogenetic manipulation are used to assess real-time behavioral responses in mice, with the aim of uncovering the neural pathways and mechanisms involved in PBn-mediated aversion. Nevertheless, the underlying mechanisms of these behaviours remain unclear. The objective of this study is to investigate the connectomics of the parabrachial nucleus (PBn) in order to determine its association with regions involved in motivation, such as the nucleus ambiguus or the amygdala. It is hypothesised that this association may lead to aversion by affecting these regions. An alternative hypothesis is that if the parabrachial nucleus is connected to areas that are not directly related to it, it may be considered a motivational area in its own right. The identification of these connections will elucidate the underlying mechanisms of aversion mediated by PBn, thereby providing a deeper understanding of the neural basis of aversive behaviour and its regulation.