Unique processing during a period of high excitation/inhibition balance in adult-born neurons

Science. 2012 Mar 9;335(6073):1238-42. doi: 10.1126/science.1214956. Epub 2012 Jan 26.

Abstract

The adult dentate gyrus generates new granule cells (GCs) that develop over several weeks and integrate into the preexisting network. Although adult hippocampal neurogenesis has been implicated in learning and memory, the specific role of new GCs remains unclear. We examined whether immature adult-born neurons contribute to information encoding. By combining calcium imaging and electrophysiology in acute slices, we found that weak afferent activity recruits few mature GCs while activating a substantial proportion of the immature neurons. These different activation thresholds are dictated by an enhanced excitation/inhibition balance transiently expressed in immature GCs. Immature GCs exhibit low input specificity that switches with time toward a highly specific responsiveness. Therefore, activity patterns entering the dentate gyrus can undergo differential decoding by a heterogeneous population of GCs originated at different times.

Publication types

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

MeSH terms

  • Animals
  • Dentate Gyrus / cytology*
  • Dentate Gyrus / physiology*
  • Electric Stimulation
  • Entorhinal Cortex / cytology
  • Entorhinal Cortex / physiology
  • Excitatory Postsynaptic Potentials
  • Female
  • GABAergic Neurons / physiology
  • Glutamic Acid / metabolism
  • Inhibitory Postsynaptic Potentials
  • Mice
  • Mice, Inbred C57BL
  • Neural Inhibition*
  • Neurogenesis*
  • Neuronal Plasticity
  • Neurons / cytology
  • Neurons / physiology*
  • Patch-Clamp Techniques
  • Perforant Pathway
  • Synapses / physiology
  • Synaptic Potentials*

Substances

  • Glutamic Acid