Archive for March, 2011

Looking back over the design of this piece, I have noticed certain recurring themes in my work. The more and more I work with the visualisation of audio signals, the more I become interested in the notion of signal modulation and aesthetics. My work with Tip31c transistors is such an example of aesthetic signal modulation, as the audio data fed into the circuit via the transistor effectively modulates the signal in the current, affecting the brightness of the LED. Similarly, my Processing based audio visualisers work in a similar manner: a shape is drawn, using the audio variable to control size, translation and colour. This variable is effectively modulated by variations in the signal being fed to the FFT. The FFT (or fast Fourier transform), is also of interest as it also fits with this notion of signal aesthetics. Using the FFT, a signal is broken down into its component oscillations. What I find most interesting about this application of audio signals to visual media is the sense of synchronicity. As both the audio and the visual are run off the same signal, they have the same source data. The data is just plotted in a different manner.

This whole concept of brainwave entrainment and its potential for therapeutic use is somewhat reminiscent of the Penfield Mood Organ from Phillip K Dick’s Do Android’s Dream of Electric Sheep? The device, which sadly does not appear in Ridley Scott’s adaptation, is a home appliance for the regulation of emotion states. The appliance is seemingly based around the Penfield Wave Transmitter, a similar tool that can also be used for the projection of emotional states. This concept is really interesting, given the nature of my research. Wahbeh, Calabrese and Zwickey’s 2007 study on the psychological and physiological effects of binaural beats suggests that exposure to delta (0-4Hz) binaural beat frequencies can have positive psychological and physiological effects. If this is a result of brainwave entrainment, then it fits with the concept of the Penfield Wave Generator: through the use of specific frequency signals, one can affect neurological activity, and effectively emotional states.

I find this reference to Penfield of further interest due to some of the reading I have been doing over the last year. About a year ago, I read Oliver Sacks’ The Man Who Mistook  His Wife for a Hat. One chapter, entitled Reminiscence, refers to a number of cases where patients would hear music when there appeared to be none. In the chapter, Sacks refers to Wilder Penfield, the Canadian neurologist who invented the Montreal Procedure. This procedure, in which the patient is conscious under general anaesthetic, allowed Penfield to map the function of the various areas of the brain through stimulation and observation. A similar procedure was performed on banjo player Eddie Adcock during an operation to treat a tremor in his hand. Adcock played his banjo whilst surgeons continued with the deep brain stimulation, allowing them to test the effect of the neurological implant on Adcock’s motor skills and the effectiveness of the treatment.

During Penfield’s experiments, he was able to identify the source of the elaborate mental states felt by many epileptics during the onset of a seizure. Looking through Penfield’s notes, there are multiple cases where Penfield is able to elicit this hallucinatory state through the precise stimulation of areas of the temporal lobe. This stimulus, as Sacks puts it, “would instantly call forth intensely vivid hallucinations of tunes, people, scenes, which would be experienced, lived. as compellingly real, in spite of the prosaic atmosphere of the operating room, and could be described to those present in fascinating detail.” These hallucinations, on further inspection, would appear rooted in the experiences and memories of the patients. Many recall hearing songs they associated with their youth, often not recognising the tune but being able to sing along. Furthermore, when the stimulus was less precise, Penfield observed an apparent blending of memories. In one case, a young boy, during stimulus the patient would observe a bank robbery in his hallucination, without ever having witnessed such an event. Additionally, there was no sound in the hallucination: it was purely visual. After the stimulus was less precise, with the signal spreading to other areas of the lobe, the patient appeared to have a hallucination in which further elements of his own memories were merged with the bank robbery hallucination. It transpires that the boy was a comic book reader, who had read a comic which involved a bank robbery. This, it would appear, explained the absence of audio from his initial hallucination, as the boy would have no contextual understanding of the sounds associated with a bank robbery. This also seems to suggest that memory and perception are a series of sensory snap shots, which are stored in the brain and can be accessed via stimulation of certain areas. This is somewhat fitting with the analogy of the human computer, suggesting that memories are stored similar to files on a hard drive.

Penfield’s work is of further interest when exploring this analogy of the human machine. The Montreal Procedure, from what I am able to interpret with my very limited experience with neurosurgery, involves the probing of various neurological tissues and the observation of the patient’s response. Penfield appears to use this technique to identify areas of scarred and damaged tissue, removing those areas that would not have a negative effect on the patient. In the analogy, these areas of damaged tissue seem to correspond to the damaged connectors in a circuit. Just as a faulty connection might result in a short circuit or electrical discharge in the circuit, these damaged tissues can cause an electrical discharge within the brain or a seizure.

I’m interested in exploring these ideas further. I have been experimenting with photo editing, coming up with a few prints that relate to this idea. I am currently referring to this one as the electronic homunculus.

I’ve also been experimenting with the Processing Image Adjust library, using audio signals to manipulate the contrast and gamma of an image. For the images, I have been using medical photographs, such as x rays, MRI and retinal photography. These sketches seem to work really well with glitchy, downtempo audio with interesting dynamics, such as Squarepusher’s Conc 2 Symmetric from Do You Know Squarepusher? The ambience of the music also seems fitting the atmosphere of the images. I’ll post a link when I record a demo of the sketch.