Differential contribution of anterior and posterior midline regions during mental simulation of counterfactual and perspective shifts in autobiographical memories

Integrated World Modeling Theory (IWMT) Implemented: Towards Reverse Engineering Consciousness with the Free Energy Principle and Active Inference

“…In this model, precision-weighting/gain-amplification takes place via "big loop recurrence" with the frontal lobes [64], with the more specific suggestion that selection/biasing of policies over forward models cause efference copies to be projected to posterior generative models. In line with recent proposals [106], the hippocampus can operate with either "predictive-suppressive" or "fictive prediction error" modes, which are here suggested to correspond to degree of coupling with respective posterior vs. frontal cortices, with the former corresponding to direct suppression of observations, and the latter facilitating the 'reinstatement' of memories, and novel imaginings for the sake of planning and causal reasoning [68,107]. This frontal coupling is hypothesized to be a source of "successor representations" (i.e., population vectors forming predictive anticipatory sweeps of where the organism is likely to go next) via integration of likely policies and action models (via dorsal prefrontal cortex) and evaluations of likely outcomes (via ventral prefrontal cortex).…”

“…Computationally speaking, this setup would correspond to a Kalman variational auto-encoder [66]. Experientially speaking, this integration of organismic spatiotemporal trajectories with auto-associative filling-in could provide not just a basis for forming episodic memories, but also the imagination of novel scenarios [67,68]. Importantly, memories and imaginings can be generated by cortex on its own-given a lifetime of experience with a functioning entorhinal/hippocampal system-but medial temporal lobe involvement appears to be required for these dynamics to be shaped in novel directions that break free of past experience [69][70][71][72].…”

“…Neuroimaging evidence suggests these grids may be dynamically coupled in various ways [68], with these aspects of higher-order cognition being understood as a kind of generalized navigation/search process [86,87]. A further GNN is speculatively adduced in parietal cortices as a mesh grid placed on top of a transformed representation of the primary sensorimotor homunculus (cf.…”

Integrated World Modeling Theory (IWMT) Implemented: Towards Reverse Engineering Consciousness with the Free Energy Principle and Active Inference

“…Computationally speaking, this setup would correspond to a Kalman variational auto-encoder [66]. Experientially speaking, this integration of organismic spatiotemporal trajectories with auto-associative filling-in could provide not just a basis for forming episodic memories, but also the imagination of novel scenarios [67,68]. Importantly, memories and imaginings can be generated by cortex on its own-given a lifetime of experience with a functioning entorhinal/hippocampal system-but medial temporal lobe involvement appears to be required for these dynamics to be shaped in novel directions that break free of past experience [69][70][71][72].…”

Integrated World Modeling Theory (IWMT) Revisited

“…That is, IWMT suggests that hippocampal representations are unlikely to themselves be directly introspectable, as deep spatiotemporal hierarchies and grounding within sensory modalities are likely required for coherent conscious experience. Precuneus-based maps may also be aligned with dynamics in the dorsomedial prefrontal cortex (another midline structure) (Hassabis et al, 2014;Li et al, 2018;Faul et al, 2020), the latter of which is here interpreted as sources of "attention schemas" (Graziano, 2019), upper levels of action hierarchies, and-perhaps most saliently with respect to conscious awareness-as an additional level of hierarchical control over the pre-supplementary eye fields. With precise sequencing shaped by striatal-thalamic-cerebellar loops (Gao et al, 2018), these frontal representations may provide a source of coherent vectors for directing the "mind's eye", so influencing what is likely to be 'projected' onto the precuneus as a kind of inner 'theater.'…”