Introduction

sports psychologists consider mental skills as an important factor in the progress and success of athletes [1]. Acquisition of new motor skills are very important issues in life from childhood to old age. Memory is one of the most important great abilities of the brain in all humans, which is known as a person's ability to remember and recall. One type of memory is working memory, which is known for comparing short term information with information stored in long term memory [3]. Research has shown that people who have a higher working memory capacity have better cognitive performance than people whose working memory capacity is lower [4]. With increasing age, during the physiological processes of old age, the function of some parts of the brain deteriorate, and old age is associated with a decrease in cognitive function as well as working memory [8]. A component that can be related to working memory is motor imagery. Motor imagery is the mental representation of an action without engaging in its actual execution. Lower-intensity motor imagery activates neural networks that control the preparation of the actual movement and the execution of the corresponding action. Since imagery is a completely internal process and is considered based on cognitive processes, or more clearly a top-down process [16], it is possible that there is a connection between motor imagery and working memory. This is while it has been shown that imaging ability decreases with aging [17]. Neurophysiological techniques have shown that the cortical and subcortical regions of the brain, which play the role of planning and controlling movement, start their activity during mental training. Therefore, in this research, we investigated the relationship between motor imagery and working memory capacity of young people and the elderly.

Method: The research method of the current research was correlational. The variables measured in this research were working memory ability (number of correct answers, percentage of correct answers, standard deviation of response time and average response time) and imaging ability (motor imagery and visual imagery) in young and elderly people. The research sample consisted of 40 people (20 elderly people with an average age of 68.59±5.78 years and 20 young people with an average age of 27.53±3.58 years). N-back test was used to measure the working memory of young people and the elderly. Also, in order to check the motor imagery ability of young people and the elderly, the Motor imagery questionnaire was used. In the statistical analysis of the research, before testing the hypotheses, the normality of the data in young people was examined through the Shapiro-Wilk test, and the results of this test showed that the imaging information and working memory information do not have a normal distribution (P<0.05). For this reason, Spearman's test was used to investigate the relationship between visualization variables and working memory. Also, for the data of elderly people, the results of the Shapiro-Wilk test showed that only the information related to the average response time did not have a normal distribution (P<0.05), and the rest of the information had a normal distribution (P<0.05). Non-parametric Spearman correlation was used to measure the correlation of imaging information with average response time index, but Pearson correlation was used in other cases. In addition, the non-parametric equivalent of the independent t-test (Mann-Whitney U) was used to compare the data of young and elderly people.

    It should be noted that in all tests, a significance level of 0.05 was considered and statistical analysis was performed using SPSS version 25 software.

Results: The results showed that in the youth group, movement imagery had a significant and inverse correlation with components of average response time (ρ=-0.50, P=0.029, N=19) and standard deviation of response time (ρ=-0.48, 0.038 (P=19, N=19). But there was no significant correlation with the components of the number of correct answers (ρ=-0.25, P=0.3, N=19) and percentage of correct answers (ρ=-0.26, P=0.27, N=19) (P<0.05). The results also showed that, in this group, visual imagery ability has no significant correlation with: number of correct answers (ρ=0.11, P=0.065, N=19), percentage of correct answers (ρ=0.12, P=0.60, N=19), average response time (ρ=0.32, P=0.18, N=19) and standard deviation of response time (ρ=0.43, P=0.066, N=19). (P<0.05). But the results showed that in the elderly group, motor imagery ability had a positive and significant correlation with the components: number of correct answers (r=0.53, P=0.026, N=17), percentage of correct answers (r=0.66, P=0.004, N=17) and average response time (ρ=0.525, P=0.03, N=17), and there was no significant correlation with the component of standard deviation of response time (r=0.12, P=0.63, N=17). In visual imaging ability, this group only has a positive and significant correlation with the percentage of correct answers (r=0.62, P=0.008, N=17), and there is no significant correlation with the other components, all (P<0.05). Also, the results of comparing young and elderly people showed that the scores of visual imageries, motor imagery, the number of correct answers, the percentage of correct answers, the average response time, and the standard deviation of the response time of young people are higher than the elderly people.

Conclusion: The findings of this research showed that young people have significant differences in all components of working memory compared to elderly people. It is possible that the decrease in cognitive function has a neural basis, which is strengthened in old age by the increase in neuronal death. Therefore, it is possible that with the reduction of the brain capacity of the elderly, they will experience a decrease in cognitive abilities, which can affect the working memory abilities of the elderly. Research has shown that this decline in cognitive abilities is partly due to lack of motor activity in old age. If the person increases his activity, it is possible that the decrease in cognitive abilities will be compensated to some extent [27,28]. This shows that working memory is related to movement ability. Also, in this research, it was shown that elderly people have less visual and motor imagery ability compared to young people. This result is in line with previous findings that show a decrease in motor and visual imagery capabilities in the elderly [17]. The remarkable finding in this research was that there was a significant and inverse correlation between the motor imagery ability of young people who used their kinesthetic sense and the components: average response time and standard deviation of response time. Also, in the young participants, an inverse correlation has been observed between the motor imagery ability and the time components of working memory. This issue clearly shows that young people put the most emphasis on providing the answer in the shortest time while performing a task. Also, in this group, it was observed that visual imagery ability has little relationship with working memory ability. This emphasizes that young people use their kinesthetic sense more to create moving images in the mind, because it provides more confidence to people and it has also been shown that it can better learn skills through motor imagery [16]. On the contrary of young people, it was observed among the elderly that there was a direct and significant correlation between the ability to imagine movement and the following components: the number of correct answers, the percentage of correct answers, and the average response time. That is, with the increase in the scores of motor imagery, these cases increased. In addition, it was shown that the ability to visual imagery in the elderly has a positive and significant correlation with the percentage of correct answers. All these findings show that elderly people emphasize accuracy in solving problems related to working memory.

Keywords: Motor imagery, working memory, elderly, young, imagery.

Ethical Considerations

Compliance with ethical guidelines

The ethical principles observed in the article, such as the informed consent of the participants, the confidentiality of information, the permission of the participants to cancel their participation in the research. Ethical approval was obtained from the Research Ethics Committee of the University of Shiraz.

Funding

This study was extracted from the MSc thesis of Alireza Abdoli Masinan at Department of Motor Behavior of Shiraz University.

Authors' contribution

All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.

Conflict of interest

The authors declared no conflict of interest.

Acknowledgements

The authors would like to thank all participants of the present study.