Laminar Organization of Encoding and Memory Reactivation in the Parietal Cortex

Neuron. 2017 Sep 13;95(6):1406-1419.e5. doi: 10.1016/j.neuron.2017.08.033.

Abstract

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 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 cortical delta waves and hippocampal sharp-wave ripples. Thus, PC neuron motion encoding is consistent across cortical laminae, and this consistency is maintained during memory reactivation.

Keywords: delta wave; high-frequency local field potential; hippocampus; memory reactivation; modular organization; movement decoding; multi-unit activity; parietal cortex; posterior parietal cortex; template matching.

MeSH terms

  • Animals
  • Hippocampus / physiology*
  • Locomotion / physiology*
  • Male
  • Memory / physiology*
  • Neurons / physiology
  • Parietal Lobe / cytology
  • Parietal Lobe / physiology*
  • Rats
  • Self Stimulation
  • Sleep / physiology