The retention in rats of an incompletely learned maze solution for short intervals of time.

Abstract

It is generally stated that the ability to reproduce previously learned material decreases with the passing of time and that the most rapid forgetting occurs immediately after learning. In most cases a negatively accelerated curve has been obtained when efficiency of retention is plotted against successive increments of time. Experimental studies, however, have yielded a significant number of deviating cases in which an initial rise in the curve of retention precedes a negatively accelerated section.Ebbinghaus (5), in 1885, made the first experimental attempt to plot the memorial history of an acquired material by taking retention tests at successive points in time and plotting the amount retained against the time unit. The curve of retention, as traced by Ebbinghaus, shows a descent which is initially rapid and which then becomes less and less rapid as time elapses. Ebbinghaus obtained his curve with the use of only one subject, with only one type of material, nonsense syllables, and with only the relearning method of measuring the amounts retained. The general trend of the curve, however, has received experimental substantiation by many investigators who have varied the conditions extensively. Radossawljewitsch ( 14), Finkenbinder (6), Luh (10), Bean (2), and Strong (17), varied the experimental conditions both in regard to the character of the material for which retention was tested and in the methods in terms of which retention was measured. They made use of nonsense syllables, poetry, consonants, abstract words and typewriting, and they measured retention by the methods of anticipation, recognition, 385

The relationship between transfer and the length of the interval separating the mastery of the two problems.

“…The curve of retention in rats of an incompletely learned mazehabit exhibits a marked initial rise (reminiscence) for fairly short intervals of time prior to the somewhat gradual decline (forgetting) (3). In a more recent study (9) such a curve was plotted for rats of three different ages, namely, young subjects (30 days of age), post-pubescent rats (150 days old), and adult subjects (300 days old) for fairly long as well as short intervals of time.…”

The Cholinergic Synapse and the Site of Memory

“…At this point we may ask why such an increase in synaptic conductivity does not manifest itself with the passage of time when no drugs are injected. Finally, Dr. J. L. McGaugh has pointed out that there are old animal studies which purport to find similar effects (Anderson, 1940;Bunch & Lang, 1939;Bunch & Magdsick, 1933). There are various possible answers.…”

CREB and neuronal selection for memory trace

“…Whether reactivation of an established fear memory trace causes reconsolidation or extinction-like changes remains an unanswered question. It has been thought that subpopulations of neurons that are active during behavior training may be reactivated later in the brain, and this activity replay may cause strengthening of a previously acquired memory (Bunch and Magdisck, 1933; Wilson and McNaughton, 1994). Thus, it will be interesting to determine whether repeated reactivation of neurons injected with CREB enhances the established fear memory.…”