Reconsidering the Border between the Visual and Posterior Parietal Cortex of Mice

Abstract

The posterior parietal cortex (PPC) contributes to multisensory and sensory-motor integration, as well as spatial navigation. Based on primate studies, the PPC is composed of several subdivisions with differing connection patterns, including areas that exhibit retinotopy. In mice the composition of the PPC is still under debate. We propose a revised anatomical delineation in which we classify the higher order visual areas rostrolateral area (RL), anteromedial area (AM), and Medio-Medial-Anterior cortex (MMA) as subregions of the mouse PPC. Retrograde and anterograde tracing revealed connectivity, characteristic for primate PPC, with sensory, retrosplenial, orbitofrontal, cingulate and motor cortex, as well as with several thalamic nuclei and the superior colliculus in the mouse. Regarding cortical input, RL receives major input from the somatosensory barrel field, while AM receives more input from the trunk, whereas MMA receives strong inputs from retrosplenial, cingulate, and orbitofrontal cortices. These input differences suggest that each posterior PPC subregion may have a distinct function. Summarized, we put forward a refined cortical map, including a mouse PPC that contains at least 6 subregions, RL, AM, MMA and PtP, MPta, LPta/A. These anatomical results set the stage for a more detailed understanding about the role that the PPC and its subdivisions play in multisensory integration-based behavior in mice.

Adaptive integration of self-motion and goals in posterior parietal cortex

“…We recorded in medial PPC (mPPC/V2m), where there is less innervation from primary visual cortex or thalamic visual areas (Reep et al, 1994;Nitz, 2009;Wilber et al, 2015;Olsen and Witter, 2016;Olsen et al, 2017). However, it is important to note that analogous anatomical regions in mice are considered part of the higher visual cortex (Glickfeld and Olsen, 2017;Hovde et al, 2019;Gilissen et al, 2021) and that mPPC receives dense afferents from dysgranular RSC (dRSC) where visually evoked responsivity has been reported (Fischer et al, 2020;Mao et al, 2020;Powell et al, 2020;Zhuang et al, 2017). Unsurprisingly, we find that a subset of PPC neurons were sensitive to the egocentric position of the visual target.…”

“…In rodents, pursuit requires the dorsal striatum, superior colliculus (SC), and zona incerta (Schiller and Stryker, 1972;Cooper et al, 1998;Hoy et al, 2016Hoy et al, , 2019Shang et al, 2019;Zhao et al, 2019;Kim et al, 2019). Sensory cues relevant to predatory behavior (e.g., the sight, sound, or smell of prey) are potentially combined in areas such as posterior parietal cortex (PPC), which possesses reciprocal connectivity to sensorimotor cortical regions and projects to the SC and dorsal striatum (Reep et al, 1994;Wilber et al, 2015;Hovde et al, 2019;Gilissen et al, 2021). Lateralized PPC damage produces hemispatial neglect, impairing detection and orientation to stimuli present in contralateral space (Bisiach and Luzzatti, 1978;Behrmann et al, 1997).…”

Cortical and Subcortical Circuits for Cross-Modal Plasticity Induced by Loss of Vision

“…Recent studies demonstrated that PPC is involved in resolving sensory conflict during auditory-visual discrimination tasks (Song et al, 2017 ) and is involved in transferring sensory-specific signals to higher order association areas (Gallero-Salas et al, 2021 ). RL and AM, two HVAs, are considered part of the PPC because they display connectivity patterns similar to other components of the PPC (Gilissen et al, 2021 ).…”

Adaptive integration of self-motion and goals in posterior parietal cortex

“…Our neuronal recordings were conducted in medial PPC (mPPC/V2m) where there is less direct innervation from primary visual cortex or thalamic visual areas (Reep et al, 1994;Nitz, 2009;Wilber et al, 2015;Olsen and Witter, 2016;Olsen et al, 2017). However, it is important to note that analogous anatomical regions in mice are considered part of the higher visual cortex (Glickfeld and Olsen, 2017;Hovde et al, 2019;Gilissen et al, 2020) and that mPPC receives dense afferents from dysgranular RSC (dRSC) where visually-evoked responsivity has been reported (Fischer et al, 2020;Mao et al, 2020;Powell et al, 2020;Zhuang et al, 2017). Taken together, it seemed highly probable that PPC activity would be influenced by visual information and consistent with this hypothesis, we report that a subset of PPC neurons were sensitive to the egocentric position of the visual target (Figure 6).…”

“…Multisensory cues that define the context of predatory behavior (e.g. the sight, sound, or smell of prey) are potentially combined in association cortices such as posterior parietal cortex (PPC) which possesses reciprocal connectivity to sensorimotor cortical regions and projects to the SC and dorsal striatum (Reep et al, 1994;Wilber et al, 2015;Hovde et al, 2019;Gilissen et al, 2020). PPC damage produces hemispatial neglect, which manifests as an inability to detect or orient to stimuli present in space contralateral to the site of lesion (Bisiach and Luzzatti, 1978;Behrmann et al, 1997).…”