Single-Neuron Representation of Memory Strength and Recognition Confidence in Left Human Posterior Parietal Cortex

Ueli Rutishauser, Tyson Aflalo, Emily R. Rosario, Nader Pouratian, Richard A. Andersen

Research output: Contribution to journalArticlepeer-review

51 Scopus citations


The human posterior parietal cortex (PPC) is thought to contribute to memory retrieval, but little is known about its specific role. We recorded single PPC neurons of two human tetraplegic subjects implanted with microelectrode arrays, who performed a recognition memory task. We found two groups of neurons that signaled memory-based choices. Memory-selective neurons preferred either novel or familiar stimuli, scaled their response as a function of confidence, and signaled subjective choices regardless of truth. Confidence-selective neurons signaled confidence regardless of stimulus familiarity. Memory-selective signals appeared 553 ms after stimulus onset, but before action onset. Neurons also encoded spoken numbers, but these number-tuned neurons did not carry recognition signals. Together, this functional separation reveals action-independent coding of declarative memory-based familiarity and confidence of choices in human PPC. These data suggest that, in addition to sensory-motor integration, a function of human PPC is to utilize memory signals to make choices. Rutishauser, Aflalo, et al. studied the role of human posterior parietal cortex in declarative memory retrieval. They found neurons that encode memory-based familiarity and confidence for decisions in an action-independent manner, thereby revealing a role for the posterior parietal cortex in translating memories into choices.

Original languageEnglish (US)
Pages (from-to)209-220.e3
Issue number1
StatePublished - Jan 3 2018
Externally publishedYes


  • confidence
  • episodic memory
  • human
  • memory retrieval
  • posterior parietal cortex
  • recognition memory
  • single neuron

ASJC Scopus subject areas

  • Neuroscience(all)


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