Severe scene learning impairment, but intact recognition memory, after cholinergic depletion of inferotemporal cortex followed by fornix transection

Cereb Cortex. 2010 Feb;20(2):282-93. doi: 10.1093/cercor/bhp097. Epub 2009 May 15.


To examine the generality of cholinergic involvement in visual memory in primates, we trained macaque monkeys either on an object-in-place scene learning task or in delayed nonmatching-to-sample (DNMS). Each monkey received either selective cholinergic depletion of inferotemporal cortex (including the entorhinal cortex and perirhinal cortex) with injections of the immunotoxin ME20.4-saporin or saline injections as a control and was postoperatively retested. Cholinergic depletion of inferotemporal cortex was without effect on either task. Each monkey then received fornix transection because previous studies have shown that multiple disconnections of temporal cortex can produce synergistic impairments in memory. Fornix transection mildly impaired scene learning in monkeys that had received saline injections but severely impaired scene learning in monkeys that had received cholinergic lesions of inferotemporal cortex. This synergistic effect was not seen in monkeys performing DNMS. These findings confirm a synergistic interaction in a macaque monkey model of episodic memory between connections carried by the fornix and cholinergic input to the inferotemporal cortex. They support the notion that the mnemonic functions tapped by scene learning and DNMS have dissociable neural substrates. Finally, cholinergic depletion of inferotemporal cortex, in this study, appears insufficient to impair memory functions dependent on an intact inferotemporal cortex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / physiology
  • Afferent Pathways / anatomy & histology
  • Afferent Pathways / physiology
  • Animals
  • Axotomy
  • Basal Nucleus of Meynert / cytology
  • Basal Nucleus of Meynert / physiology
  • Cholinergic Fibers / physiology*
  • Denervation
  • Fornix, Brain / anatomy & histology
  • Fornix, Brain / physiology
  • Fornix, Brain / surgery
  • Hippocampus / anatomy & histology
  • Hippocampus / physiology*
  • Learning / physiology*
  • Learning Disabilities / etiology
  • Learning Disabilities / pathology
  • Learning Disabilities / physiopathology
  • Macaca fascicularis
  • Macaca mulatta
  • Male
  • Neuropsychological Tests
  • Neurosurgical Procedures
  • Neurotoxins
  • Recognition, Psychology / physiology*
  • Teaching
  • Temporal Lobe / anatomy & histology
  • Temporal Lobe / physiology*
  • Visual Perception / physiology*


  • Neurotoxins
  • Acetylcholine