Basal forebrain lesions in monkeys disrupt attention but not learning and memory

Mary Lou Voytko, David S. Olton, Russell T. Richardson, Linda K. Gorman, Joseph R. Tobin, Donald L. Price

Research output: Contribution to journalArticlepeer-review

409 Scopus citations


Cognitive impairments in humans and animals have been linked to dysfunction of neurons in the basal forebrain cholinergic system (BFCS). Degeneration of these cells may be, in part, responsible for some of the cognitive deficits observed in Alzheimer's disease (AD). Although memory deficits are associated with lesions of the BFCS in rats, impairments in memory have been more subtle following similar lesions in monkeys. To evaluate the effects of BFCS lesions on cognitive processes in monkeys, we have systematically investigated the behavioral effects of ibotenic acid injections in the medial septum, nucleus of the diagonal band of Broca, and nucleus basalis of Meynert in cynomolgus monkeys, using a large series of cognitive tasks that examined different mnemonic and attentional abilities. These lesions did not impair accuracy in delayed nonmatching-to-sample, delayed response, simple or concurrent visual discriminations, spatial discriminations, or discrimination reversals. However, these lesions disrupted attentional focusing. Similar impairments in attention have been noted in patients with AD. BFCS lesions increased sensitivity to injections of the cholinergic antagonist scopolamine in a delayed nonmatching-to-sample task, indicating that the central cholinergic system was compromised in these monkeys. In concert, the results of this study suggest that the primate basal forebrain may be more involved in attentional than mnemonic processes, and that degeneration of neurons in the BFCS in cases of AD may contribute to the attention deficits observed in these individuals.

Original languageEnglish (US)
Pages (from-to)167-186
Number of pages20
JournalJournal of Neuroscience
Issue number1
StatePublished - Jan 1994


  • attention
  • basal forebrain
  • cholinergic system
  • ibotenic acid
  • learning
  • medial septum
  • memory
  • monkeys
  • nucleus basalis of Meynert
  • nucleus of the diagonal band of Broca

ASJC Scopus subject areas

  • General Neuroscience


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