Fig. 6: Proposed model of brain–body–brain feedback loop of emotional initiation and maintenance.

An emotive stimulus evokes responses in the amygdala and periaqueductal grey (PAG) which lead to changes in behaviour (freezing) and somatic physiology (breathing). The 4 Hz breathing entrains the OB which in turn organizes neural firing in the dmPFC which allows to maintain the ongoing behaviour, perhaps via its connections with the amygdala for example. The dotted line between the OB and dmPFC indicates that this connection is unlikely to be monosynaptic and has not been well described. Image credit: Allen Institute.