Clinical Neurophysiology and Neuroimaging Unit, Division of Neuropsychiatry, Department of Psychiatry, Geneva University Hospitals, University of Geneva, 2 chemin du Petit-Bel-Air, Chêne-Bourg, 1225 Geneva, Switzerland.
J Neural Transm (Vienna). 2010 Apr;117(4):489-98. doi: 10.1007/s00702-010-0384-9. Epub 2010 Mar 9.
Recent studies have indicated that gamma band oscillations participate in the temporal binding needed for the synchronization of cortical networks involved in short-term memory and attentional processes. To date, no study has explored the temporal dynamics of gamma band in the early stages of dementia. At baseline, gamma band analysis was performed in 29 cases with mild cognitive impairment (MCI) during the n-back task. Based on phase diagrams, multiple linear regression models were built to explore the relationship between the cognitive status and gamma oscillation changes over time. Individual measures of phase diagram complexity were made using fractal dimension values. After 1 year, all cases were assessed neuropsychologically using the same battery. A total of 16 MCI patients showed progressive cognitive decline (PMCI) and 13 remained stable (SMCI). When adjusted for gamma values at lag -2, and -3 ms, PMCI cases displayed significantly lower average changes in gamma values than SMCI cases both in detection and 2-back tasks. Gamma fractal dimension of PMCI cases displayed significantly higher gamma fractal dimension values compared to SMCI cases. This variable explained 11.8% of the cognitive variability in this series. Our data indicate that the progression of cognitive decline in MCI is associated with early deficits in temporal binding that occur during the activation of selective attention processes.
最近的研究表明，γ 波段振荡参与了短期记忆和注意力过程中皮质网络同步所需的时间绑定。迄今为止，尚无研究探讨痴呆早期 γ 波段的时间动态。在基线时，在 n 回任务期间对 29 例轻度认知障碍（MCI）患者进行了γ 波段分析。基于相图，建立了多元线性回归模型，以探索认知状态与随时间变化的γ 振荡之间的关系。使用分形维数值对相图复杂性的个体度量进行了测量。一年后，所有病例均使用相同的电池进行神经心理学评估。共有 16 名 MCI 患者表现出进行性认知下降（PMCI），13 名患者保持稳定（SMCI）。当调整滞后 2 毫秒和 3 毫秒的γ 值时，PMCI 病例在检测和 2 回任务中的γ 值平均变化明显低于 SMCI 病例。PMCI 病例的γ 分形维数明显高于 SMCI 病例。该变量解释了该系列中 11.8％的认知变异性。我们的数据表明，MCI 中认知能力下降的进展与选择性注意过程激活过程中发生的时间绑定早期缺陷有关。
