Related Experiment Videos
Memory decays at the same rate in macaques with and without brain lesions when expressed in d' or arcsine terms
1Department of Physiology, University of Rochester Medical Center, NY 14642.
Abstract:
Data from the literature on the effect of lesions upon recognition memory in the monkey have been examined. On the basis of percentage scores the published data can be interpreted as showing that the ability to recognize a previously seen object decays faster in macaques with brain lesions than it does in normal animals. A reanalysis of the extensive data in terms of d' of Signal Detection Theory or by arcsine transform suggests, on the contrary, that the rate of decay from 0 to 600 s, is essentially the same in normal animals and in those with lesions (particularly temporal lobe lesions). Indeed, in d' or arcsine terms, the effect of the lesions is fully developed at the shortest times used, and shows no increase as a function of the delay between initial presentation and test. Thus, very different conclusions stem from the choice of scale.
Insights
Brain lesions do not affect recognition memory decay in monkeys. Reanalyzing data using Signal Detection Theory shows lesion effects are immediate and do not worsen over time.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Animal Behavior
Background:
- Recognition memory is crucial for daily functioning.
- Previous studies suggested brain lesions impair recognition memory.
- The impact of lesions on memory decay rates requires further investigation.
Purpose of the Study:
- To re-evaluate the effect of brain lesions on recognition memory decay in monkeys.
- To determine if lesion effects on memory decay are scale-dependent.
Main Methods:
- Literature review and reanalysis of existing monkey lesion data.
- Application of Signal Detection Theory (d') and arcsine transformation for data analysis.
- Comparison of memory decay rates in lesioned versus normal monkeys.
Main Results:
- Percentage score analysis suggested faster memory decay in lesioned monkeys.
- Signal Detection Theory (d') and arcsine analysis revealed no difference in memory decay rates between lesioned and normal monkeys.
- Lesion effects were immediate and did not increase with longer delays.
Conclusions:
- The choice of analytical scale significantly impacts conclusions regarding lesion effects on recognition memory.
- Signal Detection Theory provides a more robust measure for assessing memory function after brain lesions.
- Temporal lobe lesions, specifically, do not alter the rate of recognition memory decay.