Σε συνέχεια του μαθήματος για τη μνήμη (Ε4) …
Η περίπτωση της μεθόδου PET, αλλά και άλλες προσεγγίσεις:
With PET scans, the time available for the person to perform each test task is relatively short (less than a minute), because the radiation source decays so rapidly. After each task, the person must wait several minutes for the level of radioactivity emitted to become negligible before another dose can be administered for the next task.
METHOD: Regional cerebral blood flow was measured with positron emission tomography in eight men with stabilized schizophrenia and eight healthy men while they were performing a graded random number generation task. Twelve scans were made for each subject. Covariations between randomness of responses and regional activation were analyzed.
METHOD: Thirteen medication-free patients and 13 matched healthy comparison subjects performed a working memory (n-back) task and sensorimotor baseline task during positron emission tomography. «Functional connectivity» patterns, reflecting distributed correlated activity that differed most between groups, were extracted by a canonical variates analysis.
Peigneux, Philippe; Laureys, Steven; Delbeuck, Xavier; Maquet, Pierre
In rats, the firing sequences observed in hippocampal ensembles during spatial learning are replayed during subsequent sleep, suggesting a role for posttraining sleep periods in the offline processing of spatial memories. Here, using regional cerebral blood flow measurements, we show that, in humans, hippocampal areas that are activated during route learning in a virtual town are likewise activated during subsequent slow wave sleep. Most importantly, we found that the amount of hippocampal activity expressed during slow wave sleep positively correlates with the improvement of performance in route retrieval on the next day. These findings suggest that learning-dependent modulation in hippocampal activity during human sleep reflects the offline processing of recent episodic and spatial memory traces, which eventually leads to the plastic changes underlying the subsequent improvement in performance.
Τελικά το ψαχτήρι μου έδωσε μόνον 4.160.000 σελίδες (!!!) για τα λήμματα:
pet brain recherche memory