Low dose scopolamine affects discriminability but not rate of forgetting in delayed conditional discrimination
Tóm tắt
The effect of scopolamine on remembering was examined in a delayed conditional discrimination procedure with rats. Remembering was quantified by a negative exponential function fitted to estimates of discriminability derived from a signal detection type of analysis. This function had two parameters: a measure of initial discriminability of the sample stimuli in the absence of a memory requirement (at zero delay) and a measure of rate of forgetting. Eight rats were trained on an auditory delayed conditional discrimination task until they were showing stable performance. Each rat then received doses of 0, 0.005, 0.014, 0.042, 0.125 and 0.375 mg/kg scopolamine IP in a saline vehicle. There was a highly significant, largely linear, decrease in initial discriminability. This was obvious even at the lowest dose of scopolamine. Poorer memory, as demonstrated by an increase in b, was only apparent at the highest dose. Significant changes in per cent of correct responses were also only obtained at higher doses. These results show that initial discriminability and rate of forgetting are pharmacologically as well as theoretically independent. They suggest that the measure of initial discriminability used here is a particularly sensitive measure of at least some types of cholinergic dysfunction; and they also suggest that effects of scopolamine in other working memory tasks could be more a result of changed stimulus processing than of impairment of memorial processes.
Tài liệu tham khảo
Aigner TG, Mishkin M (1986) The effects of physostigmine and scopolamine on recognition memory in monkeys. Behav Neural Biol 45:81–87
Bartus RT, Johnson HR (1976) Short-term memory in the rhesus monkey: disruption from the the anti-cholinergic scopolamine. Pharmacol Biochem Behav 5:39–46
Baum WM (1974) On two types of derivation from the matching law: bias and undermatching. J Exp Anal Behav 22:231–242
Beatty WW, Bierley RA (1986) Scopolamine impairs encoding and retrieval of spatial working memory in rats. Physiol Psychol 14:82–86
Berryman R, Cumming WW, Nevin JA (1963) Acquisition of delayed matching in the pigeon. J Exp Anal Behav 6:101–107
Caine ED, Weingartner H, Ludlow CL, Cudahy EA, Wehry S (1981) Qualitative analysis of scopolamine-induced amnesia. Psychopharmacology 74:74–80
Davison MC, Tustin RD (1978) The relation between the generalised matching law and signal detection theory. J Exp Anal Behav 29:331–336
Dunnett SB (1985) Comparative effects of cholinergic drugs and lesions of nucleus basalis or fimbria-fornix on delayed matching in rats. Psychopharmacology 87:357–363
Edhouse WV, White KG (1988) Sources of proactive interference in animal memory. J Exp Psychol [Anim Behav] 14:56–70
Grant DS (1981) Short-term memory in the pigeon. In: Spear NE, Miller RR (eds) Information processing in animals: memory mechanisms. Erlbaum Hillsdale, NJ, pp 227–256
Heise GA, Milar KS (1984) Drugs and stimulus control. In: Iversen LL, Iversen SD, Snyder SH (eds) Handbook of psychopharmacology, vol 18. Plenum Press, New York, pp 129–190
Honig WK, Thompson RKR (1982) Retrospective and prospective processing in animal working memory. In: Bower GH (ed) The psychology of learning and motivation, vol 16. Academic Press, New York, pp 239–283
McCarthy D, White KG (1987) Behavioural models of delayed detection and their application to the study of memory. In: Commons ML, Nevin JA, Rachlin HC (eds) Quantitative analysis of behaviour, vol 5. The effect of intervening events on reinforcement value. Ballinger, Cambridge, MA, pp 29–54
Milar KS (1981) Cholinergic drug effects on visual discriminations: a signal detection analysis. Psychopharmacology 74:383–388
Miyamoto M, Kato J, Narumi S, Nagaoka A (1987) Characteristics of memory impairment following lesioning of the basal forebrain and medial septal nucleus in rats. Brain Res 419:19–31
Pontecorvo MJ, Evans HL (1985) Effects of aniracetam on delayed matching to sample performance by pigeons and monkeys. Pharmacol Biochem Behav 22:745–752
Snedecor GW, Cochran WG (1967) Statistical methods, 6th edn. Iowa State University Press, Ames
Spencer DGJ, Pontecorvo MJ, Heise GA (1985) Central cholinergic involvement in working memory: effects of scopolamine on continuous nonmatching and discrimination performance in the rat. Behav Neurosci 99:1049–1065
Warburton DM, Brown K (1971) Attenuation of stimulus sensitivity induced by scopolamine. Nature 230:126–127
White KG (1985) Characteristics of forgetting functions in delayed matching to sample. J Exp Anal Behav 44:15–34
White KG (1987) Psychophysics of remembering. Harvard Symposium on Quantitative Analyses of Behavior: signal Detection. Harvard University, Boston
White KG, McKenzie J (1982) Delayed stimulus control: recall for single and relational stimuli. J Exp Anal Behav 38:305–312
Zar JH (1974) Biostatistical analysis. Prentice-Hall, New Jersey