Monday, October 23, 2006
Thursday, November 17, 2005
When I stated - too bluntly, I'm afraid - that the MPT will be proven correct by technologists before scientists, I certainly had no intention of implying there's a race on. I wished only to draw attention to the fact itself, that technologists are in this case apparently taking the lead in proposing and proving a scientific theory. It seems significant to me. Could it be symptomatic of the accelerating change phenomenon currently consuming our species, a harbinger of the coming technological singularity?
My goal with this blog is to reach out to the scientific community on behalf of a point of view consisting of Hawkins' ideas about the brain mixed with a few of my own. Christof Koch was kind enough to tell me that my hypothesis can't be validated with modern scientific tools. I wish only to express appreciation for that, and wonder how science might participate in the proving of my theory. It's rumored that Dale Antanitus, whose work I reference, is close to publishing a new book. Perhaps the answer is there.
Thursday, October 27, 2005
Proving the MPT theory
If, in fact, changing coalitions of larger neuron groups are the neuronal correlates of consciousness, our state-of-the-art research techniques are inadequate to follow this process. Our methods either cover large regions of the brain at a crude temporal resolution (such as fMRI, which tracks sluggish power consumption at time-scales of seconds), or we register precisely (within one thousandth of a second) the firing rate of one or a handful of neurons out of billions (microelectrode recording). We need fine-grained instruments that cover all of the brain to get a picture of how widely scattered groups of thousands of neurons work together.
Koch has provided here a critical piece of information for me. Science is not going to be able to prove my theory, even with its most state-of-the-art research techniques. Now I understand why so few in the scientific community are embracing Hawkins. If there's no way for them to prove a theory it's not very interesting. But if science can't prove a theory correct, isn't it destined for the speculation scrap heap? Not in this case.
What's going to prove the MPT theory correct is a working model, a functional AI. Hawkins and his team at Numenta are even now working feverishly on such a model, as undoubtedly are other labs and individuals. The first proof is going to stun the world. It will be followed by additional proofs. In this way will the frames-in-a-film theory of consciousness be proven. Not by scientists, but by technologists.
Wednesday, October 26, 2005
The Movie in Your Head
Whether or not such inspiration took place, it's significant that a scientist of Koch's caliber is considering the movie theater metaphor as an explanatory device. This is one of my main upgrades to Baars' theater model. The mind is more like a movie theater than a live stage theater - even down to the projection room, which I'll speculate on in the future. Memories are like the frames in film; they're captured as temporal units of perception and stored in sequences for subsequent auto-associative recall. The sequences are held together by gap junctions formed as a consequence of synchronous neural firing (gamma synchrony, Hebbian learning), which always seems to accompany conscious activity. Hawkins' theory, augmented by Antanitus', makes it possible to understand how it all works. That's what my MPT model is about, pointing out this theoretical potential.
In On Intelligence, Hawkins mentions Koch as one of the few scientists willing to tackle consciousness, and one of the team that discovered the Bill Clinton neuron phenomenon, which seems to offer strong evidence for Hawkins' hierarchical regions concept of neocortical memory. However, I haven't read anything Koch has said about Hawkins' ideas anywhere on the Web. In fact, it seems the scientific community is content to wait until Hawkins proves his theory with a functional AI before offering its opinion.
I'll comment on Koch's article itself in a future post.
Thursday, August 18, 2005
Since my previous post I've been deeply engaged in another project. That engagement continues to be all consuming, so I may not be posting here for a while unless someone comments.
In the future I'll be discussing the many implications of the MPT I've recently discovered, especially regarding EEG, meditation, and the concept of the separate self. Until then...
Friday, July 22, 2005
The case of the missing gap junctions
In a recent response to Hameroff on SCR Koch cited some highly germane research findings. I didn't mention these in my article, but they strongly support my hypothesis. Koch:
Gap junctions and consciousness
A flurry of studies over the last handful years have shown that electrical gap junctions play a much larger role in cortex than previously realized (for a review, see Bennett and Zuki, 2004). The focus has been on gap junctions mediated by the Connexin family of proteins (which has at least 10 members expressed in the mammalian central nervous system); they provide a low-resistance, electrical pathway between two neurons –– hence their common alias, electrical synapses. The most important connexin of the adult brain is Cx36. These proteins link groups of local, inhibitory interneurons into large networks (forming a “hyperneuron”), restricted to specific layers in neocortex and hippocampus. Different from their conventional chemical synapses that would serve to inhibit the firing activity of their postsynaptic targets, gap junctions can cause the membrane depolarization in one interneuron to spread to others. This has given rise to the hypothesis that Cx36 gap junctions synchronize the firing of these interneurons, enabling the entire population to fire in lock step in the 30-70 Hz (gamma) range. If such synchronized and rhythmic firing is important for certain aspects of attention, perception and consciousness, then mice that lack gap junctions should show major deficits.
It has been possible to breed mice that lack the gene for the Cx35 protein. In these knockout mice, interneuron coupling is greatly reduced; this goes hand-in-hand with a loss of spike synchrony among them (however, gamma range oscillation persist, albeit at a reduced amplitude). The animals have decreased retinal function at low light levels (as expected from a loss of gap junctions in the retina) and reduced reproductive rates, but otherwise no major behavioral deficiencies; they display no obvious loss of motor coordination, and can stay on a rotating cylinder (rotorod test) as well as normal, wildtype mice.
The idea that the firing activity of groups of interneurons, possibly extending over several cortical columns, is tightly synchronized and may underlie the coalitions of neurons that are sufficient for any one conscious percept is a fascinating one to me. However, no positive evidence links neuron-to-neuron coupling in cortex via gap junctions to perception, let alone consciousness. Thus, the cautionary statement in my book, “ Not enough is known about this phenomenon to implicate it in conscious perception.” remains true today. This may always change in the future, of course.
I believe the time for change has come, in the form of Dale Antanitus' Theory of Neocortical Neuron-Astrocyte Interaction. Antanitus hypothesizes that astrocytic syncytia, groups of astrocytes connected via gap junctions, are responsible for synchronous neuronal firing. This would account for why, when the mediator of hyper-neuronal gap junctions was eliminated, gamma synchrony persisted, albeit at diminished amplitude. It suggests both neuronal and astrocytic syncytia are involved in gamma synchrony. Such redundancy is of course ubiquitous in nature and should come as no surprise; critical systems are often backed up.
There's been a lot of research into astrocytes in the past five years (e.g., 87 titles from The Journal of Neuroscience alone), but no one has yet produced a grand integrative theory as to their relationship to their neuron brothers, to my knowledge, except Antanitus. I hypothesize that his ideas are the neurophysiological basis for not only gamma synchrony but Hawkins' regions of cortex, the fundamental units of the Memory Prediction Framework, as well.
In time, after The Memory Prediction Theater is published at SCR, I hope to discuss the implications of Antanitus' theory, in the context of recent research findings, with Koch, Hameroff and others in the consciousness community.
Thursday, July 21, 2005
The question soon led me to Bernard Baars and Global Workspace. I read Baars for a couple weeks, becoming increasingly consumed, especially by the theater model he used to elaborate Global Workspace. I was just starting to really dig into the work of Stan Franklin, Baars' computer science colleague at the University of Memphis, who's developed a "conscious" software agent based on Global Workspace, when an epiphany occurred.
I happened to see something on Steve Jurvetson's blog that caught my eye. He said he'd been reading Jeff Hawkins' new book. If Steve was reading it, I thought I'd better check it out. I googled, one-clicked and was immersed within two days. I devoured the book. Easy to read. Absolutely brilliant. Totally original. The basic problem of consciousness, what Hawkins calls intelligence, solved.
Stunned, I immediately began to wonder how this Memory Prediction Framework of Hawkins' might play out in Baars' Theater of Consciousness. That's how the MPT came into being. That was November of last year. I realized today, on hearing that SCR was going to publish the hypothesis, I might be getting some questions on it, so decided to launch this blog.