Burgess Adrian P, Ali Lia
Division of Neuroscience and Psychological Medicine, Imperial College School of Science, Technology and Medicine, St Dunstan's Road, W6 8RP, London, UK.
Int J Psychophysiol. 2002 Nov;46(2):91-100. doi: 10.1016/s0167-8760(02)00108-3.
We examined two subjectively distinct memory states that are elicited during recognition memory in humans and compared them in terms of the gamma oscillations (20-60 Hz) in the electroencepahalogram (EEG) that they induced. These subjective states, 'recollection' and 'familiarity' both entail correct recognition but one involves a clear and conscious recollection of the event including memory for contextual detail whilst the other involves a sense of familiarity without clear recollection. Here we show that during a verbal recognition memory test, the subjective experience of 'recollection' induced higher amplitude gamma oscillations than the subjective experience of 'familiarity' in the time period 300-500 ms after stimulus presentation. Recollection, but not familiarity, was also associated with greater functional connectivity in the gamma frequency range between frontal and parietal sites. Furthermore, the magnitude of the gamma functional connectivity varied over time and was modulated at 3 Hz. Previous studies in animals have shown local theta frequency modulation (3-7 Hz) of gamma-oscillations but this is the first time that a similar effect has been reported in the human EEG.
我们研究了人类在识别记忆过程中引发的两种主观上不同的记忆状态，并根据它们所诱发的脑电图（EEG）中的伽马振荡（20 - 60赫兹）对其进行了比较。这些主观状态，即“回忆”和“熟悉感”，都涉及正确的识别，但其中一种涉及对事件的清晰且有意识的回忆，包括对情境细节的记忆，而另一种则涉及没有清晰回忆的熟悉感。在此我们表明，在言语识别记忆测试期间，在刺激呈现后300 - 500毫秒的时间段内，“回忆”的主观体验比“熟悉感”的主观体验诱发了更高幅度的伽马振荡。回忆（而非熟悉感）还与额叶和顶叶部位之间伽马频率范围内更强的功能连接有关。此外，伽马功能连接的强度随时间变化，并以3赫兹进行调制。先前在动物身上的研究表明伽马振荡存在局部theta频率调制（3 - 7赫兹），但这是首次在人类脑电图中报告类似的效应。
