Laminar organization of encoding and memory reactivation in the parietal cortex

Egocentric neural coding has been observed in parietal cortex (PC), but its topographical and laminar organization is not well characterized. We used multi-site recording to look for evidence of local clustering and laminar consistency of linear and angular velocity encoding in multi-neuronal spiking activity (MUA) and in the high-frequency (300-900 Hz) component of the local field potential (HF-LFP), believed to reflect local spiking activity. Rats were trained to run many trials on a large circular platform, either to LED-cued goal locations or as a spatial sequence from memory. Tuning to specific self-motion states was observed consistently, and exhibited distinct cortical depth-invariant coding properties. These patterns of collective local and laminar activation during behavior were reactivated in compressed form during post-experience sleep, and temporally coupled to hippocampal sharp wave ripples. Thus, PC neuron motion encoding is consistent across cortical laminae, and this consistency is maintained during memory reactivation.\n\nHighlights O_LIParietal cortex MUA encodes specific movements coherently across laminae.\nC_LIO_LIThis organizational scheme is maintained during subsequent memory reactivation\nC_LIO_LIMUA and HF-LFP showed similar self-motion tuning and memory reactivation dynamics\nC_LIO_LIThis establishes the utility of MUA and HF-LFP for human memory reactivation studies\nC_LI