Clinical Neuroscience

[The role of sleep in the implicit learning processes]

CSÁBI Eszter, NÉMETH Dezsõ

JANUARY 30, 2014

Clinical Neuroscience - 2014;67(01-02)

[The role of sleep in different memory processes is debated. Probably it plays an active role in the memory consolidation or possibly it prevents forgetting by protecting against interference or it makes the memory performance more efficient by facilitating the forgetting. The beneficial effect of sleep in explicit memory is well demonstrated, while the role of sleep in implicit mechanisms has not been comprehensively characterized so far. There are several factors which affect the appearance of sleep effect, such as the structure, the length and the complexity of sequence being used, the awareness of the sequence, the length of the learning blocks and the offline period. Besides the classical sleep deprivation methods with healthy participants, examining patients with sleep disorders could be a new method of the investigation of the sleep effect which enables us to enrich our knowledge not only about the sleep-dependent memory consolidation but also the cognitive dysfunction related to sleep pathologies. This new line of research can help the development of more effective rehabilitation programs.]

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[Background and purpose - Neglect related to the body has many symptoms. We suggest that the various symptoms might be associated with the injuries of different cognitive functions referring to the body, which are caused by lesions of different brain areas. Therefore we investigated the injuries of two functions in a group of patients with neglect (N=10) contrary to patients without neglect (N=10) and healthy controls (N=10). These functions are: perception of body location in external space and the perception of body shape. Methods - We applied a novel method (Body Portraying Method), which is suitable for measuring subjective perception of both body location and body shape. Results - 1. Patients with left neglect perceived their bodies with a significant right shift compared to their real body position. In contrast to this, patients without neglect and healthy controls tended to shift the subjective location of their body to the left. 2. Patients with neglect perceived the shape of their bodies significantly more distorted than both patients without neglect and healthy controls. 3. In case of eight patients with neglect, the symptom of shifted body location to the right and the symptom of body shape distortion appeared together. However, injuries of these two functions dissociated in case of two neglect patients. Conclusions - Both the perception of body location in external space and the perception of body shape might become distorted in neglect. Furthermore, the dissociation of these symptoms supports our suggestion, that they might be associated with the injuries of different functions referring to the body. This result has practical issues as well. At the end of the study we discuss the necessity of appropriate tailored physiotherapy (fitted to the injured function) in the rehabilitation of patients with neglect.]

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