Persistent spatial information in the FEF during object-based short-term memory does not contribute to task performance

J Cogn Neurosci. 2014 Jun;26(6):1292-9. doi: 10.1162/jocn_a_00599. Epub 2014 Mar 27.

Abstract

We previously reported the existence of a persistent spatial signal in the FEF during object-based STM. This persistent activity reflected the location at which the sample appeared, irrespective of the location of upcoming targets. We hypothesized that such a spatial signal could be used to maintain or enhance object-selective memory activity elsewhere in cortex, analogous to the role of a spatial signal during attention. Here, we inactivated a portion of the FEF with GABAa agonist muscimol to test whether the observed activity contributes to object memory performance. We found that, although RTs were slowed for saccades into the inactivated portion of retinotopic space, performance for samples appearing in that region was unimpaired. This contrasts with the devastating effects of the same FEF inactivation on purely spatial working memory, as assessed with the memory-guided saccade task. Thus, in a task in which a significant fraction of FEF neurons displayed persistent, sample location-based activity, disrupting this activity had no impact on task performance.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Attention / physiology
  • Frontal Lobe / drug effects
  • Frontal Lobe / physiology*
  • GABA-A Receptor Agonists / pharmacology
  • Macaca mulatta
  • Male
  • Memory, Short-Term / physiology*
  • Muscimol / pharmacology
  • Neurons / drug effects
  • Neurons / physiology*
  • Photic Stimulation
  • Prefrontal Cortex / drug effects
  • Prefrontal Cortex / physiology*
  • Psychological Tests
  • Psychomotor Performance / physiology
  • Saccades
  • Space Perception / physiology*
  • Task Performance and Analysis

Substances

  • GABA-A Receptor Agonists
  • Muscimol