Enhancing effects of lithium on memory are not by-products of learning or attentional deficits.
We recently reported that chronic lithium (LiCl), at therapeutic plasma levels, enhanced spatial working memory and retention of an aversive contingency. Here we examine the possibility that these effects be secondary to LiCl effects on the ability to ignore irrelevant stimuli or on fear conditioning. In Experiment 1, rats subjected to >30 daily intraperitoneal injections of LiCl (2mmol/kg) or saline underwent conditioned emotional response training (CER: 2 CS pairings with 1-s, 1-mA shock) after 40 pre-exposures either to the CS (latent inhibition-LiCl/latent inhibition-saline, n=8) or to another stimulus (control-LiCl/control-saline, n=8). In Experiment 2, eight LiCl and eight saline animals were trained in on-the-baseline (VI-60s) CER (1-s, 0.15-mA shock in CS-signalled periods) in the Skinner box. In Experiment 1, LiCl animals showed normal latent inhibition. In both experiments, their fear conditioning was unimpaired. Therefore, the previously reported memory improvement under chronic lithium cannot be attributed to changes in the ability to ignore irrelevant stimuli or in fear conditioning.
Tsaltas
Eleftheria
E
Experimental Psychology Laboratory, Department of Psychiatry, Athens University Medical School, Eginition Hospital, 74, Vas. Sofias Ave., 11528 Athens, Greece. tsaltasl@med.uoa.gr
Kyriazi
Theodora
T
Poulopoulou
Cornelia
C
Kontis
Dimitrios
D
Maillis
Antonios
A
D000818:Animals; D018692:Antimanic Agents / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology; D003216:Conditioning, Operant / Q000187:drug effects; D004644:Emotions / Q000187:drug effects; D007266:Inhibition, Psychological; D018021:Lithium Chloride / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology
D018692:Antimanic Agents; D018021:Lithium Chloride