Mental simulation of drawing actions enhances delayed recall of a complex figure

The role of mental imagery in pantomimes of actions towards and away from the body

This study aimed to explore the relationship between action execution and mental rotation modalities. To this end, pantomime gesture (i.e. the mime of the use of an object) was used as its execution relies on imagery processes. Specifically, we tried to clarify the role of visuo-spatial or motor and body-related mental imagery processes in pantomime gestures performed away (AB, e.g. drawing on a sheet) and towards the body (TB, e.g. brushing the teeth). We included an "actual use" condition in which participants were asked to use a toothbrush and make 3, 6, or 9 circular movements close to their mouth (as if they were brushing their teeth) or to use a pencil and make 3, 6, or 9 circular movements on a desk (as if they were drawing circles). Afterwards, participants were asked to pantomime the actual use of the same objects ("pantomime" condition). Finally, they were asked to mentally rotate three different stimuli: hands, faces, and abstract lines. Results showed that participants were faster in AB than TB pantomimes. Moreover, the more accurate and faster the mental rotation of body-related stimuli was, the more similar the temporal duration between both kinds of pantomimes and the actual use of the objects appeared. Instead, the temporal similarity between AB pantomimes and pencil actual use, as well as, the duration of AB pantomime and actual use, were associated with the ability to mentally rotate abstract lines. This was not true for TB movements. These results suggest that the execution of AB and TB pantomimes may involve different mental imagery modalities. Specifically, AB pantomimes would not only require to mentally manipulate images of body-parts in movement but also represent the spatial relations of the object with the external world.

Enactment effect in patients with Alzheimer's disease

Introduction: Subjects can improve their performance on memory for action phrases if, during the encoding condition, they self-perform actions associated with verbs (subject-performed condition), or if they perceive the actions carried out by experimenter (experimenter-performed condition), with respect to a verbal task condition in which they only read or listen to the stimuli. This facilitation is labeled "Enactment effect" (EE), and is thought to be associated with episodic integration processes binding actions and nouns together in a coherent representation. Only recently, studies addressed EE in AD individuals reporting significant improvements on memory tasks in the subject-performed encoding condition. However, no studies tried to explore the cognitive mechanisms supporting EE in AD individuals. Method: Performance on recognition and cued recall tasks for action phrases were assessed in a sample of 32 mild-to-moderate AD individuals and 30 healthy adults, in verbal, subject-performed and experimenter-performed encoding conditions. Moreover, a cognitive assessment was completed to explore the possible correlates of EE in our participants. Results: Results showed that both subject-performed and experimenter-performed encoding conditions produced similar advantages over the verbal condition, in both memory tasks in both groups. Moreover, these memory advantages were strongly associated to executive processes, in both AD and healthy adults. Conclusions: The present study confirmed that EE is spared in mild to moderate AD. Our findings supported the role of episodic integration processes and suggested a contribution of executive processes in EE.

Visuospatial Organization and Recall in Cerebellar Ataxia

Poor visuospatial skills can disrupt activities of daily living. The cerebellum has been implicated in visuospatial processing, and patients with cerebellar injury often exhibit poor visuospatial skills, as measured by impaired memory for the figure within the Rey-Osterrieth complex figure task (ROCF). Visuospatial skills are an inherent aspect of the ROCF; however, figure organization (i.e., the order in which the figure is reconstructed by the participant) can influence recall ability. The objective of this study was to examine and compare visuospatial and organization skills in people with cerebellar ataxia. We administered the ROCF to patients diagnosed with cerebellar ataxia and healthy controls. The cerebellar ataxia group included patients that carried a diagnosis of spinocerebellar ataxia (any subtype), autosomal dominant cerebellar ataxia, or cerebellar ataxia with unknown etiology. Primary outcome measures were organization and recall performance on the ROCF, with supplemental information derived from cognitive tests of visuospatial perception, working memory, processing speed, and motor function. Cerebellar ataxia patients revealed impaired figure organization relative to that of controls. Figure copy was impaired in the patients, but their subsequent recall performance was normal, suggesting compensation from initial organization and copying strategies. In controls, figure organization predicted recall performance, but this relationship was not observed in the patients. Instead, processing speed predicted patients' recall accuracy. Supplemental tasks indicated that visual perception was intact in the cerebellar ataxia group and that performance deficits were more closely tied to organization strategies than with visuospatial skills.