A model of path integration and representation of spatial context in the retrosplenial cortex

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Delineating the unique functional contribution of the retrosplenial cortex in the hippocampal-diencephalic-cingulate network

The research described in this thesis investigates the unique anatomy of the retrosplenial cortex and its functional contributions to spatial working memory in the rat. The retrosplenial cortex, which is composed of Brodmann’s areas 29 and 30, has attracted attention due its apparent variable size across species and its strategic anatomical position. Reflecting its anatomical connectivity, the area has been associated with a range of cognitive functions including but not limited to episodic memory, visual processing, and navigation, but yet its exact functions have been hard to define. In humans, damage to the retrosplenial cortex can result in both anterograde and retrograde amnesia (Valenstein et al., 1987; Maguire, 2001) and can cause an interesting type of topographical disorientation where patients can recognise landmarks but are unable to utilise them to orient themselves and navigate an environment (Maguire, 2001; Vann et al., 2009). Additionally, the retrosplenial cortex is one of the first regions to exhibit pathological changes in Alzheimer’s disease and its deterioration can predict mild cognitive impairment (Pangas et al., 2010). Most recently, the area has also been associated with schizophrenia (Bluhm et al., 2009) and states of dissociation (Vesna et al., 2020). Due to its deep anatomical position in the human brain, the majority of intervention research concerning the functions of the retrosplenial cortex comes from animal studies using rodents. Although there is no consensus to its precise function, rodent studies point to multiple roles in spatial cognition including landmark coding, consolidation of spatial knowledge, and particularly, the integration between spatial reference frames