Topographical working memory: differences in pointing versus performing a pathway in 4-5 year old children

Recently, several studies have highlighted the importance of topographical working memory in navigation. This was also supported by clinical evidence showing the presence of specific topographical working memory deficits in different types of pathologies that disrupt navigational skills (i.e., individuals affected by developmental topographical disorientation; patients treated surgically for a drug-resistant temporal lobe epilepsy; stroke patients; patients affected by Alzheimer Dementia). In the present study, we take into account the contribution of motor action to spatial representation during navigation by comparing two tasks (WalCT: Piccardi et al., 2008; 2014 and Laser-WalCT: De Nigris et al., 2013) of topographical working memory, one in which the child has to perform by walking the path previously demonstrated by the examiner and another one, in which the child has to manually point the path previously observed. A total of 51 (19 females) typically developing children aged 4–5 years performed WalCT, Laser-WalCT and Corsi Block-Tapping Test (CBT; Corsi, 1972), the latter a well-known visuo-spatial memory test. Cognitive non-verbal test (Raven’s Coloured Progressive Matrices, CPM; Raven, 1986) was performed to assess cognitive development. WalCT, Laser-WalCT and CBT were performed in randomized order and analyzed according to the longest list of items that the children were be able to repeat. Our results showed no gender differences supporting previous findings, suggesting that sex differences on spatial tasks emerge in adolescence. We also found that a greater effort was needed to reproduce a sequence of steps in a large-scale context than to reproduce a sequence of reaching movements in a small-scale context. In general, working memory measured on large-scale context, with or without motor activity, develops later than working memory measured on small-scale context. Specifically, 4 years old children demonstrated more difficulty in performing Laser-WalCT than WalCT with respect to 5 years children. The difference between WalCT and Laser-WalCT in 4 years old children is an interesting finding, since older children as well as young adults and adults did not differ in their performance when they had to act on a pathway or to point it. This data suggests the presence of a specific time period in which motor action has to be integrated with navigational information.