A Treatise on the Physics and Psychology of Heavy Metal Music

Though the metal fan-base is largely young, white, male, and blue-collar, and that it has been often associated with "brutally aggressive music played mostly for minds clouded by drugs", I must confess that I am a devout heavy metal music fan and a typical headbanger. However, I seem to take as much interest in other genres of music as well, including classical Indian music, old Bengali songs as well.

But let me clear things a bit first. I am not a white, no longer in my youth, not a blue-collar and not a drug user. Yet the music just fills me with adrenaline rush, I feel energized and above all, the melodies just mesmerize me!

Perhaps you may argue that metal song lovers may have a 'low self esteem', as this study might suggest; but I have evidence to the contrary too! You certainly can't dismiss these young physicists doing their research in the 'high energy' domain of the giga-electron-volts at the LHC labs in CERN, Geneva, as mere dolts!  Here is a 'sonification' of some of their mathematical findings into music as they delve deep into the Heisenberg's Uncertainty of finding the 'God particle', the revered Higgs' Boson! They, kind of, selected their data from a chosen hexadecimal set and then converted them into the more familiar octave formats, compressed them and mixed them with some bass/drums to make the more metal friendly. The 4-lepton part of this song could even strike a chord between the pro-Christ and the anti-Christ theme of heavy metal in some dark corner of your psyche, as they reach toward a low entropy, in a very similar way matter and antimatter behave. [Sonification in the context of science isn't a new kid on the block. Proteins (amino acid sequences) have already been heard and listened].

Well, you guessed it right. I find a lot of physics and maths in it. Whereas most of you would disagree on the issue that hard rock had anything to do with any melody of any sort and would label it as high decibel noise, a very organized pattern of music can be discerned if one just judged it from a neutral and impartial standpoint. However, to be really be able to get into the heart of it, one ought to have a high musical processing power in 'real time', akin to having a faster CPU (Central Processing Unit) in computer jargon. What (musical tone) gets interpreted as a square wave to one's auditory cortex (or along the tonotopic pathway/basilar membrane), may actually turn out to be a composite of various other frequencies (their harmonics). This can be decoded in mathematical terms by the Fourier Transform. Thus what seems to you as a guitar belching out a harrowing 'noise' may actually be two or three guitars which differ slightly in phase, frequency or tune on careful scrutiny. It could be that I follow the music so well because I don't pay much attention to the lyrics or that English is not my first language that I can drift myself to the luxury and intricacy of the wafting melodies. Anyway, I must mention that some lyrics such as Iron Maiden's are so hard to overlook for they are so rich in Philosophy! Psychedelic drugs may enhance in understanding and following these artistic intricacies by inhibiting the dominant left hemisphere and thereby allowing the art-interpreting right half of the brain to be in charge.

Then the length tension relationship the guitar string has to follow a particular frequency (tune) is governed by physics as well. It's amazing how the performers manage to pluck the chords at exactly the same place and with the same displacement on the time scale so reproducibly well. Moreover, the two guitarists play the tune in unison ! Maybe the drummer gives some kind of 'global clock source' for synchronization or perhaps 'mirror neurons' might play a role. Well I don't care, who does?

Another aspect that baffles me is that how the 'disorganized' crowd synchronize themselves into the organized dancing movements at live concerts [see video:Lamb of God-Walk with me in hell; warning: explicit lyrics]. This might throw some light on herd behavior as well. This pattern of dancing is quite different from the "Mexican wave" that is observed especially in Football matches [see video]. In the latter case, the crowd performs the act consciously with inputs supposedly coming from the cerebral cortex, and the crowd is well organized. This behavior is also seen in honey bees as a means of communication, in their own language. And language of any kind is considered a higher function. In contrast, in the former case, the activity is more likely be originating from a lower CNS area, such as the locomotor pattern generator at the spinal cord level, (with assisted inputs from a higher region in the brain, perhaps) which appears more like a 'reflex' phenomenon than a well coordinated effort.

Then the faint and whispered insinuations seems to imprint a 'suggestion' in our psyche [see video, and watch out for the words "it's only getting worse": Lamb of God]. After all, music is about perception per se and not the mere analysis of mechanical vibrations. There are also cases of suicides arising out of the 'subliminal messages' contained within the lyrics, although they remain yet to be confirmed.

                                     Lamb of God 512 on Jimmy Kimmel live & Moshers                                                                                

Now, in a recent development, two doctoral students from Cornell University [don't miss the videos and the simulations in this website!] have found some deep similarities between crowd movement in mosh pits, which to them looked so fundamentally similar to randomly moving gas molecules bumping into each other. The moshers run, bash and bump into each other in a chaotic way. Schools of fish and flocks of birds show this type of behavior too. Needless to say, I am in full agreement with their research. Bear in mind, moshpits can be deadly and you might end up with a black eye!

Some interesting questions keep popping up. Why is the representation from black people into this genre of music so poor, despite many of them staying in the US or UK for generations? I hope you won't marginalize me alongside James Watson or Shockely, if I were to suggest that a genetic cause was more likely than an epigenetic one, because I feel that the latter would wear out with passage of time. A notable exception to this is the great vocalist Howard Jones of Killswitch Engage, who is black. Some women are also in the metal arena as well, including Lena of "Infected rain" and Leaves' Eyes' Liv Kristine, encroaching on this so called "masculine" bastion.

Some noteworthy words that convey their meaning in the way/effect they are pronounced, need mentioning. Judas Priest's "But there's always someone trying to put it down" gives you the 'Doppler'y feeling of 'down', Similarly, Dio's "You can be invisible" hammers deep inside your psychology to emphasize this invisiblity, Some music videos like this one by Metallica, which portrays a wonderfully inspired sci-fi theme is well worth watching too [Video:Metallica All Nightmare Long]. Heavy metal would be nowhere without the advancement in electronics technology and the guitar riffs.

That metal mania has carved its niche in the general populace can be exemplified by the ghastly terrorist attack in the Bataclan concert hall in Paris.

We can only pray "Heal the world, make it a better place, for you and for me and the entire human race." as Michael Jackson said.

Jesse L. Silverberg, Matthew Bierbaum, James P. Sethna, & Itai Cohen (2013). Collective Motion of Moshers at Heavy Metal Concerts 10.1103/PhysRevLett.110.228701 arXiv: 1302.1886v1



Last modified: June 30, 2018
Reference: hyper-links, unless specifically mentioned

Metallica Goes The Stem Cell Way

I had previously written a little about stem cells. While researchers still don’t yet know exactly how the four factors transform the fully differentiated fibroblast cells back into pluripotency, possible explanations are pouring in.

Pluripotency (by which the stem cell may become any tissue; muscle or nerve, for example) and “self renewal” (cells should not only differentiate, some ready stock of stem cells must be there for future need) are important determinants for stem cells.

According to Shinya Yamanaka, the steps could be somewhat like this: c-Myc first confers the open chromatin state and immortality to the skin fibroblasts. But it also induces apoptosis by acting on the p53, “the guardian of the genome”. Apoptosis or cellular senescence causes the cells to die. Klf4 inhibits p53 induced apoptosis. Again, if we added only Klf4 and c-Myc we would get tumor cells (both being oncogenes). Oct4 here acts and makes ES like cells (ES= Embryonic Stem) out of what was destined to be tumor cells. Sox2 confers pluripotency and you’ve got what you wanted.

Now, we just have to hand pick the right cells from the petridish. Scientists can do it either by looking for Fbx15 expression or the expression of nanog in the treated sample. Both Fbx15 and Nanog are targets of Oct3/4 and Sox2; but Nanog is found to be more closely associated with pluripotency, as is evidenced by adult chimera formation (chimera is a monstrous fire breathing creature like dragon of ancient mythology).

There have been some important modifications. Researchers have shown that one could still get human induced pluripotent stem cells (iPSC) without the need of the c-myc oncogene. The mode of delivery of these four factors could also be undertaken by plasmids, rather than the traditional retroviral vector approach. Retroviruses (like c-Myc) could potentially induce cancer. You may like to hear this Nature Podcast where both Yamanaka and Rudolph Jaenisch give a very good summary. As a bonus, you may also appreciate another way of creating iPSC. Replace the genome in “early embryonic cells” or zygotes (fertilized eggs) during cell division. During cell division, the nuclear membrane disappears and the factors are no longer in the nucleus. They are in the cytoplasm. Dieter Egli explains that if you replaced the genome of this zygote with another (genome) while the cell was still dividing, the new genome would adapt to the new cytosolic environment and get instructions from the factors in the cytosol. It will go ‘back in time’ and become a stem cell.

Now, a bit of refreshment. Watch this awe inspiring Metallica video called 'All nightmare long'. It portrays the Tunguska event, A-bomb, Soviet Revolution, American supremacy (?) and ‘revival of organisms’. Some key phrases are:

• “like a split worm, a part of the organism can reconstitute the whole”. Check about Planarians (flat worms, picture on the left), they not only reconstitute but also become separate individuals!
• “Instead of offspring, they become skin cells, nerves and muscle”- just as we described! Seems Metallica is well informed! Do see this wonderful video in YouTube (Metallica All Nightmare Long (Official Music Video))

Reference: hyper-links and

Okita, K., Ichisaka, T., & Yamanaka, S. (2007). Generation of germline-competent induced pluripotent stem cells Nature, 448 (7151), 313-317 DOI: 10.1038/nature05934

Developmental reprogramming after chromosome transfer into mitotic mouse zygotes, doi:10.1038/nature05879

Brains of Guitarists in Unison Harmonize Too

During the 80's, I listened to heavy metal bands like Iron Maiden and Metallica, although I couldn't follow their lyrics always. What used to captivate me in awe was how the guitarists synchronized themselves together so well. It apparently seemed as if only one guitar was playing in the background, which on closer scrutiny revealed the actual truth: it was really a duet. It is only now that scientists are beginning to find the secret behind this 'time and phase synchrony'.

Scientists at the Max Planck Institute for Human Development in Berlin, have shown that musicians playing the same tune have their brains 'coupled' together. They started off experimenting with 8 such musician pairs. They first recorded the brain activity of each
'duetter' by taking their electroencephalographic recordings (EEG). The musicians kept the EEG set-up atop their heads throughout the experiment.

After taking the baseline EEG recordings, the researchers then made the guitarists to listen to metronome beats. Metronome beats are beats of sound that occur periodically and are used to keep track of time. They found that the EEG activities of the players were synchronized to that of the metronome beats. Next, the lead guitarist of the pair had to tap his guitar in a gesture to signal his partner as to when and at what speed they would begin. At this point, the researchers looked at the brainwaves of the guitarists again and found that the EEG of both the guitarists were in synchrony to each other (and no longer to the metronome beats). Curiously, this happened even before the actual performance began. This oscillatory synchronization was found to be especially stronger at the frontal and central electrode sites (of the EEG leads). This may indicate simultaneous firing of the motor and somatosensory neurons.

This experiment also throws light as to how empathy and the 'mirror neuron network' might be working. These inter-personally coordinated behaviors will only result if they happen fast and both the sensory and the motor actions are coordinated. Certainly, there has to be some kind of a feedback between the pair for effective harmonization to occur.

It has been previously seen that in addition to the EEG coupling; magnetoencephalography (MEG; measures the magnetic field around the skull) and electromyography (EMG: measures the muscle activity) related well between neuronal activity of a person to the voluntary activity of the same person. The new finding may help us probe the basis of social interaction but it also poses a question: how do the performers synchronize and through which media? You can find videos of duetting guitarists and the corresponding EEG recordings at Biomedcentral.

P.S. Finally, let me allow to propose 2 mechanisms which may be responsible for this apparent 'phase lock'. Firstly, the performers have a very clear idea about the piece they were about to perform, since they are well rehearsed. Naturally, the guitarists are in tune with the next intermezzo and if they were to strum chord C major, their corresponding motor planning areas would become active. It is known that the motor planning areas become electrically active even before the execution of actual action (1). Secondly, we can also assume that they, being emphatically coupled to the music, get connected across by mirror neurons. The mirror neuron system then does the rest: driving the players in a rapturous synchrony.


Lindenberger, U., Li, S., Gruber, W., & Müller, V. (2009). Brains swinging in concert: cortical phase synchronization while playing guitar BMC Neuroscience, 10 (1) DOI: 10.1186/1471-2202-10-22 Last modified: Jan 19, 2010
Reference:(1) William F. Ganong, Control of Posture & Movement, 22nd Ed, Review of Medical Physiology, Page: 202

An Anatomy of Noise And Its Implications

Noise is something we dislike, because by definition, noise means unwanted sound. But this definition is subjective, for what is music to my ears (say the heavy metal band Metallica) is noise to most people. In fact Iraqi prisoners were forced to listen to Metallica songs as a means of torture (culture shock and noise) by the American soldiers. Perhaps a better definition is, wrong sound at the wrong place at the wrong time.

Apart from acoustic noise; there is visual noise as found in television as ‘snow’, electronic noise (e.g. thermal noise or Johnson noise), cosmic noise and so on. Speaking of acoustic noise, one can’t help but think about the dreaded ‘noise pollution’ that seems to envelop us all. In addition to the nuisance it poses, it also causes anxiety, insomnia, increased blood pressure (hypertension), deafness and a hell lot of other bad things. So, it seems that noise is all bad. It’s not always so!

There is a disease called otosclerosis. In this disease, the footplate of stapes (a small bone in the middle ear) gets fixed to the oval window of the internal ear, producing conductive deafness. The patient can not hear normally as the ossicular (bony) conducting chain is at fault. But surprisingly, such persons hear well in noisy places (market, railway station). This phenomenon called Paracusis Willisii is said to occur due to the fact that one has to speak out real loud (over and above the background noise) in such places; thus making this loud voice cross the patients’ threshold of hearing. However, it may also be possible that the amplitude of the voice (in decibel) might ‘ride’ (summate) on the background noise amplitude, and this combined sound amplitude is heard by the ears. The brain then does some kind of fuzzy logic (or acts as a differential amplifier); and the ‘information’ is decoded. So, it seems that noise isn’t all that bad.

In ‘information theory’ even noise is said to contain information in it. One fine example that illustrates how visual noise might contain information is random dot stereography (and autostereogram). So, noise could be meaningful.

In diabetes mellitus, a very common disease across the globe, the blood glucose level rises. This and other metabolic products causes a condition called diabetic neuropathy, among other things. The person’s sense of touch is diminished and this results in inattention to sustained pressure(causes decreased circulation) or trauma to the affected area. This, along with the increased blood glucose and infection may then cause gangrene of the limb which might require an amputation of that limb. Cloutier et al have resorted to noise in an attempt to address the issue.

They applied mechanical noise directly over sensory neurons and have found that both vibration and tactile perception in these patients improved. This mechanical noise was christened as ‘stochastic resonance’ (stochastic means random or probabilistic; this particular term is coined since the frequencies are not tuned to match any particular frequency), and was applied at an imperceptible level. They applied this noise to the great toe of some of the affected individuals, while the controls received none (i.e. no SR). The effect was studied by measuring the vibration perception threshold (VPT). VPT was significantly lower in patients receiving SR compared to the controls (no SR). As the threshold was low, the patients’ sensitivity to detect vibration and tactile sensation improved. They hoped that a continually vibrating shoe insert could improve nerve function in these cases.

In another instance, Toshio Mori and Shoichi Kai of the University of Kyushu, Japan, showed that noise might improve brain function. They shone periodic signals (of 5 Hz flicker) onto the right eyelids and noisy signals onto the left eyelids of the subjects when they were at rest, and measured the intensity of their brain waves. Brain waves are electrical signals that occur in the brain due to the firing of neurons and are detected by electroencephalography (EEG). They found a sharp peak at 5 Hz, the frequency of the periodic varying signal. As they increased the strength of the noise signal relative to the periodic signal, a ‘harmonic’ peak emerged in the alpha wave band at 10 Hz. As the noise signal gained strength, this peak first increased and then diminished. The researchers believe that this harmonic peak is indicative of stochastic resonance in the cerebral visual cortex. Stochastic because of the non-linear way the brainwave behaves in response to the external stimulus. They argue that naturally occurring background electrical noise in the brain (from electron transport chains, neuronal activities) may play important roles in cognition and behavior.

However, not everything about noise is healthy as researchers from the University of California at San Francisco, USA suggest. They exposed healthy young rats to ‘white noise’, (random audio frequencies covering the full spectrum with randomly assigned amplitudes) and found that the development of their auditory cortex was delayed. They used electrophysiology tools to explore this. They also suspected that everyday environmental noise, also a type of white noise, could harm children by interfering with language acquisition and speech.

The story doesn't end here. Researchers have shown that noise has an important role in eukaryotic gene expression. When messenger RNAs (mRNA) are transcribed in the nucleus of a cell, they do so in a 'quantal' way; meaning that mRNAs are produced in spurt, in a stochastic (random) manner. The transcription process needs energy; as the promoter sequence have to be activated and for other biochemical reactions. This transcriptional noise may have implications in phenotypte diversity and cell differentiation process. Alternatively, bacterial pathogenicity may be increased by this 'noise' in gene expression.

The question is: should we scold our children when they continue with those awful noises? I am confused. But one more thing; it was this noise (in the microwave spectrum) that gave scientists the experimental proof that the Universe was expanding.

Last modified: never
Reference: Prolonged Mechanical Noise Restores Tactile Sense in Diabetic Neuropathic Patients.
Cloutier R, Horr S, Niemi JB, D' Andrea S, Lima C, Harry JD, Veves A.
Int J Low Extrem Wounds. 2009 Jan 6.

Noise in eukaryotic gene expression, doi:10.1038/nature01546

Noisy signals strengthen human brainwaves
T Mori and S Kai 2002 Phys. Rev. Lett. 88 218101

White Noise Delays Auditory Organization in the Brain

Noise, Wikipedia

Mori, T., & Kai, S. (2002). Noise-Induced Entrainment and Stochastic Resonance in Human Brain Waves Physical Review Letters, 88 (21) DOI: 10.1103/PhysRevLett.88.218101

Master Of Puppets Im Pulling Your Strings

How big is the universe or what is a universe after all? Well, a web search on the definition did not say much about these. One site described it as all matter and energy in space. Then we must ask ourselves which method we should adopt to detect these ALL matter and energy/energies. For example, a bat can not see. To this creature, the universe would appear as its tactile senses and the ultrasound echoes (bats use echolocation) would allow it to perceive. It thus appears that our observation is not only limited to the gadgets we build, but also the degrees of freedom (dimensions) in which we are accustomed to. We can't visualize 7 or say 14 dimensions, can we? What if the universe consisted of many sub-universes containing as many or as few of these dimensions? We may try to conjecture the infiniteness of the universe in our own familiar dimensions in the form of the 'recursive' Klein bottle (picture on the left), or the Moebius strip.

Take the case of those working at the Chandra observatory. They can see through X-ray vision and see the universe at a completely different perspective. The picture of one x-ray galaxy is given here, for your reference. Thus you have infra-red, ultra-violet, radio-wave astronomy and many more. If you are bit observing, you'd note that all those modalities cited above used the electromagnetic spectrum; perhaps because light's (and all other electromagnetic waves) speed were the highest and possibly also because that we can not imagine any other type of constructs of the universe(s), since we are slave to our senses and the dimensions they restrict ourselves in. We have seen how quantum theory can wreck havoc with our classical thinking, by its killer 'superposition'; its time we greet the new kid on the block: String Theory. If you thought quantum theory was too much, then this one is for you. Watch this fabulous video. Do read the text and ponder over them. It suggests that we are floating in a three dimensional space, surrounded by membranes. Even if there is 'another universe' nearby, we could not reach out of our 'braneworld' and see or touch them. So check out this video. Enjoy the possible proximity with another universe (may be God's own) with in your own reach but don't try to reach out; for they can't see you!

By the way, I think, gravity waves are a good contender in this regard. They are supposed to travel at the speed of thought. Secondly, they pass through all matter unchanged, beating even light in this regard. When we develop better SQUID devices, we may be better able to explore the cosmos.

BTW, the title of this post has been taken from the Master of Puppets song by Metallica. Here 'Master of Puppets' refers to God, and Strings to String theory. Nothing serious!

Last modified: April 1, 2009
Reference: hyper-links, unless specifically mentioned