AN EXPERIMENTAL TEST OF THE "INHIBITION" AND "CONSOLIDATION" THEORIES OF REMINISCENCE

A Rapid Form of Offline Consolidation in Skill Learning

The brain strengthens memories through consolidation, defined as resistance to interference (stabilization) or performance improvements between the end of a practice session and the beginning of the next (offline gains) [1]. Typically, consolidation has been measured hours or days after the completion of training [2], but the same concept may apply to periods of rest that occur interspersed in a series of practice bouts within the same session. Here, we took an unprecedented close look at the within-seconds time course of early human procedural learning over alternating short periods of practice and rest that constitute a typical online training session. We found that performance did not markedly change over short periods of practice. On the other hand, performance improvements in between practice periods, when subjects were at rest, were significant and accounted for early procedural learning. These offline improvements were more prominent in early training trials when the learning curve was steep and no performance decrements during preceding practice periods were present. At the neural level, simultaneous magnetoencephalographic recordings showed an anatomically defined signature of this phenomenon. Beta-band brain oscillatory activity in a predominantly contralateral frontoparietal network predicted rest-period performance improvements. Consistent with its role in sensorimotor engagement [3], modulation of beta activity may reflect replay of task processes during rest periods. We report a rapid form of offline consolidation that substantially contributes to early skill learning and may extend the concept of consolidation to a time scale in the order of seconds, rather than the hours or days traditionally accepted.

Reliability and specificity of individual differences in reminiscence

In investigating Eysenck's (1965) suggestion of the specificity of reminiscence, 50 high school boys were tested on 2 gross motorcoordination tasks-one involving tracking and the other balance. In the practice schedule, which was identical for both tasks, all Ss were given 20 50-sec. trials with a 10-sec. intertrial rest. A 5-min. interpolated rest was given after every fourth trial. The reliability of individual differences in reminiscence for both tasks was found to be extremely low. While Eysenck's hypothesis was not necessarily weakened, doubt was cast upon the specificity of reminiscence in the usual context of the word.

Some physiological concomitants of pursuit rotor performance and reminiscence

A frustration theory of pursuit rotor performance and reminiscence has previously been presented (Costello, 1967; Costello & Discipio, 1967). The theory was reformulated in terms of arousal theory and the following hypotheses were tested: (1) an inverted "U" relationship exists between level of arousal and performance level; (2) reminiscence results when S during the rest period moves closer to his optimum level of arousal; (3) massed practice produces a higher level of arousal than spaced practice; (4) experimental conditions producing a high drive state will also increase his arousal level. Findings in line with these hypotheses were found for EMG measures but not for GSR and pulse rate. In view of what appears to be the task-specific nature of the physiological results it was concluded that there was no particular advantage in reformulating the frustration theory in terms of arousal theory.

A new theory of post-rest upswing or "warm-up" in motor learning

Post-rest upswing in motor learning is traditionally explained in psychological terms, i.e., either as a regaining of “set” or as extinction of SIR. It is suggested that physiological evidence points to an alternative, namely a true “warming-up” of the muscles involved in the work under consideration. The hypothesis is shown to explain certain otherwise puzzling features of “warm-up” in pursuit rotor performance.