Beyond spatial memory: the anterior thalamus and memory for the temporal order of a sequence of odor cues

J Neurosci. 2006 Mar 15;26(11):2907-13. doi: 10.1523/JNEUROSCI.5481-05.2006.


Influential recent proposals state that the anterior thalamic (AT) nuclei constitute key components of an "extended hippocampal system." This idea is, however, based on lesion studies that used spatial memory tasks and there has been no evidence that AT lesions cause deficits in any hippocampal-dependent nonspatial tasks. The present study investigated the role of the AT nuclei in nonspatial memory for a sequence of events based on the temporal order of a list of odors, because this task has recently been shown to depend on the integrity of the hippocampal formation. After preoperative training, rats with excitotoxic lesions of the AT nuclei showed a severe and selective postoperative impairment when required to remember the order of pseudorandom sequences of six odors. The rats with AT lesions were able instead to learn two new tasks that required recognition memory and the identification of the prior occurrence of events independent of their order. These results strongly matched those described after hippocampal lesions and provide the first unequivocal evidence of a detrimental effect of an AT lesion on a nonspatial hippocampal-dependent memory task.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anterior Thalamic Nuclei / drug effects
  • Anterior Thalamic Nuclei / physiology*
  • Anterior Thalamic Nuclei / physiopathology
  • Anterior Thalamic Nuclei / surgery
  • Anterior Thalamic Nuclei / ultrastructure
  • Cues*
  • Excitatory Amino Acid Agonists / toxicity
  • Female
  • Hippocampus / injuries
  • Hippocampus / physiology
  • Memory / physiology*
  • Memory Disorders / pathology
  • Memory Disorders / physiopathology
  • Mental Recall / physiology
  • Microinjections
  • N-Methylaspartate / toxicity
  • Odorants*
  • Random Allocation
  • Rats
  • Reversal Learning / physiology
  • Reward
  • Smell / physiology*
  • Time Perception / physiology*


  • Excitatory Amino Acid Agonists
  • N-Methylaspartate