The NS has an innate program to respond to danger by attack or escape (as do all vertebrate animal species). The SN is intended to return to regulated social functioning once the danger has been removed. Human beings, unlike other animal species (whose SN can return to the regulated state on its own) need, especially in children, external regulation to effect this return to the basic state.
This regulation, which involves interaction with another human whose SN is regulated, is called co-regulationIt is therefore through co-regulation that the deregulated SN of an individual exposed to a hazard returns to regulation. If the danger persists or if the individual does not find co-regulation, deregulation takes place over time at the cost of adaptations that involve brain regions devoted to emotions and social interactions: development of automatic patterns that condition behavior, based on belief systems, repressed (non-metabolized) emotions. This is fundamentally an adaptive mechanism based on dissociation.
This corresponds to a fundamental adaptation mechanism at the neurobiological level, which explains the development of personality sub-compartments that are independent (to varying degrees) of each other. These sub-compartments organize themselves to maintain an internal equilibrium and thus try to replace the lost equilibrium (the one that existed before the danger occurred) and which could not be restored. These new internal balances (but which remain fundamentally imbalances) most often manifest themselves in the form of psychic states experienced as polarizations or antagonisms.
There is only one alternative to dissociation, and that isassociationThe latter can be seen as one of the main functions of the SN: to integrate in a coherent and meaningful way the different components of an individual's experiences. This work involves the SN as a whole.
Co-regulation, because it brings into play, as a priority, the oldest structures of the NS (devoted to survival mechanisms), constitutes a key factor in mobilizing the possibilities of the NS to proceed with this association process.
From the perspective of the IR model, it is the peritraumatic dissociation mechanism that accounts for the development of the parts as described in IFS, and their organization in rigid interaction patterns. When it is deep and involved from the period of attachment, it accounts for dissociative personalities according to Ono Van der Hart's theory of structural dissociation (Nijenhuis and van der Hart 2011). From this point of view, the vision of the IR model differs from that of the IFS model in that the fundamental psychopathological mechanism is constituted by peritraumatic dissociation and not, as represented by the IFS vision, by the detour from the normal functioning of parts that the individual would be endowed with at birth. The IR model, like the IFS model, however, recognizes the modular functioning of the psyche (multiplicity of the psyche).
Dissociation appears to be more fundamental than traumatic memory (which also proceeds from dissociation through the fragmentation of memory elements). This element is primordial in the treatment of attachment disorders which do not give rise to episodic memories, but are immediately inscribed in the brain in the form of dissociative memory.