Magic mushrooms and brain 活动 revisited

(我的书中出现了这篇文章的改进和更新版本 简要介绍。以下版本仅供保留。)

身份不明的野生蘑菇。
摄影者 赛琳娜的艺术。经许可使用。

在第2章中 为什么唯物主义是鲍洛尼, 我举例说明了一种与程序相关的广泛模式 降低 brain 活动 with 扩展的 意识。这些包括过度换气,冥想,折磨,重力引致的意识丧失,绞窄,心脏骤停,脑损伤,甚至迷幻。确实, Carhart-Harris等人的2012年论文。 has 表明只有迷幻药 降低 neural 活动, with no increases 任何地方 在大脑中。从唯物主义的角度来看,这是违反直觉的,因为根据唯物主义,意识 brain 活动 (a totally inactive brain 是 , after all, a dead and unconscious brain under materialism). Recently, however, 不准确和误导性的媒体报道 on a 更多 recent paper by the same team 具有 claimed that the researchers have now "found increased 活动 in regions of the brain that are known to be activated during dreaming." This, if it were true, would contradict the conclusions of the earlier study. However, it 是 simply false. In this 文章,我想澄清一下。

在深入探讨问题的本质之前,我想坚持我觉得自己无法停止重复的事情。在书中引用我自己的话(第50页):
In both science and philosophy one must extract conclusions 不 from local and partial pieces of the data, but from a careful consideration of the data as a whole. One must look for broad patterns, because it 是 from these broad patterns that reliable conclusions can be extracted. While particular reports of transpersonal experiences could possibly be explained away, the broad pattern that associates peak transpersonal experiences with reductions of brain 活动 clearly points to a robust and consistent phenomenon.
Whether psychedelics only 降低 neural 活动 (and they do) or 不, 是 只是广泛模式中的一小部分。 不幸的是,仅将注意力集中在这个小元素上,却会失去对本书中说明的整个模式的了解。

好,现在到了关键点。我已经花时间通读了 实际的科学论文 最近出版,而不是科学媒体摘要。而且纸很清楚。这是一个关键段落(第2页):
鹦鹉螺菌素对 方差 of brain 活动 整个时间的参数都相对未被充分研究,因此该查询行可能特别有用。 本文的主要目的是研究psilocybin如何调节动力学和时间变异性 of resting state BOLD 活动. (The italics are mine.)
"BOLD" stands for the Blood-Oxygen-Level-Dependent 活动 detected by a functional brain scanner (功能磁共振成像). It 是 a measure of the level of metabolism in the brain region being studied. This level of metabolism 是 what we call brain 活动. Therefore, BOLD 是 a measure of brain 活动. Clearly, unlike in the 2012 study mentioned above, the researchers this time aren't reporting on brain 活动 as measured by a time-averaged BOLD, but on the 变化性 of that 活动; that 是 , on how much the BOLD signal amplitude 变化 随着时间的推移。自然地,大脑展示 更高 levels of 活动 变异 总体上还可以有很多 降低 levels of 活动 than normally. This 是 easily illustrated in the figure below. In both graphs, the 活动 level 是 represented by the area under the curve. Clearly, there 是 much 更多 活动 on the left side than the right side, even though the right side displays much 更高 变异 of 活动 level. 您看到关键的区别了吗?


研究人员继续汇报他们的发现(第11页):
总之,增加了 方差 在双侧海马和ACC中观察到BOLD信号中的BOLD信号...方差的变化是BOLD信号幅度增加的表达 波动 in these regions ... bursts of high amplitude 活动 have been seen in human rapid-eye movement (REM) sleep ... Given that phenomenological similarities have previously been 不ed between the psychedelic ... and dream states, it 是 intriguing to consider whether altered hippocampal 活动 may be an important common property of these states. (The italics are mine)
该摘录可能很清楚地表明了撰写不准确新闻的记者 IFL Science文章 弄错了,正确的解释是什么。如果我倾向于阴谋论,那么现在我会感到相当兴奋。但是,我个人认为这只是科学记者误会的情况。它突出显示了当人们认真尝试从新研究中得出结论时,有必要阅读实际的科学论文。

这项新研究绝不会与先前的发现相矛盾。 从所有这些资料中我可以看到, psilocybin only decreases neural 活动. It doesn't increase it 任何地方 in the brain. The new study simply finds that the levels of 活动, although either unchanged or 降低d when compared to the baseline state, 变化 随着时间的流逝,在与梦相关的大脑区域中更多。而已。

变异性的增加与了解迷幻分子的工作方式有关吗?当然。有争议的研究对此进行了有力的论证。新结果是否使原始结果更符合唯物主义?当然不是。唯物主义指出,完全不活动的大脑是完全无意识的。因此,在唯物主义下,大脑活动与意识之间存在不可否认的依赖。可以肯定的是,这种依赖性并不像说活动越多,意识就应该那么简单。那将是对唯物主义的极其简单和天真的误解。例如,所有神经元都将一起发射的大脑将处于最大活动状态,而在这种假设的大脑状态下的信息量将与完全不活动的大脑中的信息量相等:恰好为零。我毫不感到不适。但是结果显示,由数百万个神经元组成的大大脑区域的整体变异性增加了  意味着在这些大脑区域有更多信息。例如,在上图中,左侧的图形可能会比右侧的图形更轻松地表示微观神经元级别的信息,但前提是每时每刻都在发射不同的神经元集。事实上, short of exceedingly high levels of 活动 wherein 更多 than half the available neurons are firing, the 更多 active a certain brain region 是 , the 更高 the chance that 更多 information will be present.

由于我总结的原因 先前对史蒂文·诺维拉的答复中有6点论点, results showing a tight correlation between decreased overall brain 活动 and unfathomably 扩展的 awareness and cognitive function remain, and will always remain, highly problematic for materialism. Whichever way a materialist twists the observations to try and fit them into his metaphysics (for instance, with convoluted, ambiguous, obscurantist arguments about the interplay between excitatory and inhibitory brain 活动, which I discuss at length in my book), the bottom line 是 exceedingly simple: under materialism, consciousness brain 活动. When one finds substantially 更多 意识与 brain 活动, one 是 forced to contemplate the possibility that the brain 是 somehow associated with filtering, constraining, or localizing consciousness, instead of generating it.
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14条评论:

  1. 伯纳多的好地方在我看来,这些记者的主要问题是这个词的含糊不清"activity" when used on its own without any further specificity. They see an increased 方差 in BOLD signals as illustrated in the paper and correctly interpret this 是 a sort of increased 活动. But they then proceed to tout this fact without mentioning the narrow amplitude parameters that the increased 活动 applies to. It's like if someone were to measure the 方差 in amplitude of the waves in their backyard pool as people took turns doing cannonballs off the diving board and then claim that this 活动 exceeded that of the Atlantic Ocean on a calm day.

    您是否认为这些科学记者根本没有阅读他们的文献'引用,还是他们故意对数据进行歪斜/不完整的解释,以使对广告的宣传永存。"mind equals brain" perspective?

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    1. 就我个人而言,我认为他们根本不'不太了解他们在阅读什么,并且/或者没有足够的知识来准确表示它。

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  2. 关于我们为什么不应该做的精湛而清晰的说明'它会自动信任科学新闻业,特别是在更具争议性的领域或研究的影响力与主流观点背道而驰的情况下。

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  3. 那些蘑菇看起来很好吃!您有Simm的食谱吗?

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  4. Very nice illustration to show the difference in 活动 and 方差.
    但是有一点我不清楚:该论文还说"BOLD total spectral 功率"对于ACC和海马体而言,其含量有所增加(参见表1,图1。也在讨论部分中进行了说明("[...] the high amplitude 活动 detected in the hippocampi and ACC [..]"))

    这是什么"total spectral 功率"在您的插图中?听起来像是加起来的东西。我会把它解释为曲线下的蓝色区域。 (也许记者也是如此)

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    1. It basically means that there 是 更多 signal over different frequencies, i.e. richer 变异s of the signal. Technically, spectral 功率 具有 to do with how the 方差 of the signal 是 distributed over difference frequencies in the spectrum, if you do a Fourier Transform on it. You can read 更多 about it here: http://en.wikipedia.org/wiki/Spectral_density.

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    2. 感谢您的回复。我研究了维基百科的文章,我可以't help but think this means they actually report an increase in signal 功率 (and therefore brain 活动)....?
      I mean: On whatever frequencies the signal 是 distributed - if you take the total of those contributing components, you get an increase 功率 in ACC and hippocampus.
      我想念什么吗?

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    3. 这个单词"power"在这里误导。之所以使用它,是因为在计算中采用了BOLD信号的平方,这类似于"power" in electrical engineering applications (where this type of analysis 是 historically derived from). So BOLD 是 proportional to the 活动 in the neurons. When they do the spectral analysis, they take BOLD^2, and that 是 then the "power"在频谱中。从物理上讲不是't 功率 at all; it'只是在行话中固定了一个数学类比。不幸的是,在我们所讨论的情况下,它变得具有误导性。
      上面所说的完全正确,但前提是您要解释"power"以这种适当的方式。但是即使那样你也可以't从总光谱的增加得出结论"power" that there was also an increase in time-averaged BOLD (i.e. relevant brain 活动). For instance, you can see in eq. (2) that only the amplitude of the Fourier Transform 是 taken into account when the spectral 功率 是 calculated, so phase information 是 ignored (!), which 是 critical when one wants to integrate the original BOLD signal over time to estimate actual brain 活动. One can't recover the BOLD signal from this spectral 功率 information. Do you see? One can'得出您要得出的结论。
      研究人员为什么如此模棱两可?他们草率了吗?当然不是。他们只是对评估大脑活动的时间平均增加或减少不感兴趣。他们想研究方差,并同时使用时域和频域方法。他们的方法完全符合他们的目标,那么为什么它应该适合我们试图了解他们的结果?事实上,"total spectral 功率"本文的正文中只提到过一次,甚至在括号中也提到过。作者唐't even bother defining explicitly what they mean with it. The focus of their discussion 是 clearly on the observed increase in 方差 (sigma square) and decrease in spectral 功率 at the 降低 frequencies (LFP).

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    4. 让我详细说明我提出的观点,安迪,以确保它'很清楚。我们会在频谱功率图中丢失相位信息。仅考虑振幅。然后我们知道多少"power"每个频率分量都对原始时域信号(BOLD)有所贡献。但是没有阶段信息,我们不会'不知道这种贡献是建设性的还是破坏性的。也就是说,我们不't know whether these components interfere constructively or destructively with each other. So we may have a case where the total spectral 功率 是 huge, but the components interfere mostly destructively with each other, so the time-domain signal 是 puny. This 是 不 only conceivable but ordinary. In contrast, we may have a case where low total spectral 功率 corresponds to a significant time-domain signal because the component frequencies are in phase and interfere constructively, adding up their contributions. I hope this 是 clear.
      您的评论让我开始思考。我突然意识到本文对这种特定形式的误解有何帮助。像这样的句子"总光谱功率更高" "幅度变化增加," etc., are all suggestive of 更高 neuronal 活动 at first sight. I didn'没那么多注意到这一点,因为我很熟悉行话(我在我的学士学位上主修电子工程,重点是信号处理)。但是,有了您的评论,我突然意识到,本文中做出的分析的特定选择如何令人难以置信地导致误解(如果没有)。'习惯了术语的细微差别和特殊性...
      清醒...让我停下来思考...

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  5. 嗨,伯纳多,

    您看到这个最新故事了吗?

    http://finance.yahoo.com/news/tripping-mushrooms-changes-brain-204500998.html

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  6. In today's materialist science, you don't need "more brain 活动" to have novel brain 活动 (or to have experience which seem 更多 real than regular experience). These experiences could be explained, for example, by changing the connectivity of the brain. That 是 , exposing different regions of the brain to many signals that they do 不 normally receive by modification of information pathways by entheogens (for example DMT 是 quite similar to common neurotransmitters: http://sitn.hms.harvard.edu/wp-content/uploads/2015/03/Fig-1-Psychedelics.jpg ). This does 不 require 更多 blood-flow to any part of the brain, but can still expose our insides to themselves in a way that 是 very novel and "psychedelic."

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    1. Under materialism experience IS brain 活动. Therefore, at some level, a broader and 更多 intense experience 具有 to correlate with 更多 brain 活动. It'在唯物主义下否认这一点是轻率的。关于这一点的完整阐述可以在我的著作《为什么唯物主义是鲍洛尼》中找到。完整的参数无法在博客评论中捕获。

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