De Rosa E, Hasselmo ME, Baxter MG (2000) Contribution of the cholinergic basal forebrain to proactive interference between stored odor memories during associative learning in rats: 192 IgG-saporin immunotoxic lesions. Neuroscience 2000 Abstracts 563.8. Society for Neuroscience, New Orleans, LA.
Summary: Previous electrophysiological studies and a computational model suggest that cholinergic neuromodulation may reduce olfactory associative interference during learning (Hasselmo & Bower, 1993; Hasselmo et al., 1992). Using a simultaneous discrimination task where rats were required to learn a baseline odor pair (A+B-) and then two novel odor pairs: A-C+ (with an overlapping component A) and D+E- (with no overlapping component), De Rosa & Hasselmo (2000) demonstrated that a 0.25 mg/kg systemic dose of scopolamine (SCOP) selectively increased proactive interference. Under the influence of SCOP, the rats were impaired on acquiring the odor pair AC and not the odor pair DE relative to their normal saline performance. To localize this effect male Sprague-Dawley rats, with bilateral selective cholinergic lesions of the horizontal limb of the diagonal band of Broca (HDB group) or of all of the cholinergic nuclei of the basal forebrain (BF group), were tested on our task. Neither lesion impaired normal acquisition of either odor pair relative to the sham-operated control rats. However, the BF group, but not the HDB and control groups, were sensitive to a lower dose of SCOP (0.125 mg/kg) than in the previous study: this dose selectively impaired the BF group on acquiring the odor pair AC and not the odor pair DE relative to their normal saline performance, suggesting that weaker cholinergic modulation after removing the majority of cholinergic neurons in the basal forebrain makes the system more sensitive to proactive interference during blockade of remaining cholinergic effects.
Related Products: 192-IgG-SAP (Cat. #IT-01)