Representational geometry of perceptual decisions in the monkey parietal cortex

Gouki Okazawa, Christina E. Hatch, Allan Mancoo, Christian K. Machens, Roozbeh Kiani

Research output: Contribution to journalArticlepeer-review


Lateral intraparietal (LIP) neurons represent formation of perceptual decisions involving eye movements. In circuit models for these decisions, neural ensembles that encode actions compete to form decisions. Consequently, representation and readout of the decision variables (DVs) are implemented similarly for decisions with identical competing actions, irrespective of input and task context differences. Further, DVs are encoded as partially potentiated action plans through balance of activity of action-selective ensembles. Here, we test those core principles. We show that in a novel face-discrimination task, LIP firing rates decrease with supporting evidence, contrary to conventional motion-discrimination tasks. These opposite response patterns arise from similar mechanisms in which decisions form along curved population-response manifolds misaligned with action representations. These manifolds rotate in state space based on context, indicating distinct optimal readouts for different tasks. We show similar manifolds in lateral and medial prefrontal cortices, suggesting similar representational geometry across decision-making circuits.

Original languageEnglish (US)
Pages (from-to)3748-3761.e18
Issue number14
StatePublished - Jul 8 2021


  • circuit model
  • decision making
  • face perception
  • frontal cortex
  • macaque monkey
  • motion perception
  • neural response manifold
  • parietal cortex
  • representational geometry
  • task difficulty

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology


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