It was less than 24 hours ago since the last post echoing an article on the NYT on memristors, and two more articles have appeared on both the NYT and CNN with the reports of the announcement, made on Tuesday by HP, that it would commercialize a new computer memory technology with Hynix, the South Korean chip maker. Read the rest of this entry »

It was 1965 when Gordon Moore (co-founder of Intel) made the observation that the number of transistors per square inch of integrated circuits roughly doubled each year, starting from the time of introduction of these devices. What was in 1965 an observation become a law postulating that this trend would not come to a stop. Unfortunately, the limits of physics have caused a recent slowdown in the rhythm at which semiconductor companies can miniaturize transistors. Yesterday, an article on the NYT focused on a fresh announcement by Rice University and HP on a fundamental discovery able to overcome the barrier to the continued miniaturization of electronic components. Read the rest of this entry »

While building mammalian-sized whole brain systems is surely one of the most important research avenues in the new AI wave, with the promise of revolutionize both mobile robotics and more traditional data mining applications, much can be learned from isolating the functional principles encapsulated in small networks of neurons in non-mammalian species. Read the rest of this entry »

Neuromorphic engineers are studying the nervous system and trying to emulate its function and organization in their computational and robotics systems. They are hoping to match (or perhaps even exceed) the human brain in vision, hearing, pattern recognition and learning tasks (Boahen 2005). Read the rest of this entry »

Note: This posting summarizes some arguments I presented at the 2010 IEEE Symposium on Circuits and Systems. The complete presentation is available at this link.

In an earlier posting I presented arguments of why the idea of the memristor as a fourth fundamental circuit element is likely to be wrong. However, regardless of whether or not the memristor is considered as a fundamental circuit element, one may ask if it is technically correct to say that the researchers from HPLabs actually did discover a memristor. Read the rest of this entry »

During the first week in June, the 4th international BCI Meeting was held outside beautiful Monterey, California. This being my first BCI conference, I was excited to find out what innovations in the field were either in development or already being implemented. The organizers mentioned that the number of meeting participants had grown exponentially since its last gathering five years ago, a trend that mimics the number of BCI publications produced each year. A PubMed search for “brain-computer interface” gave 209 results for 1990-2009, whereas from 2006-2010 the same search yielded 507 results in just four years. Read the rest of this entry »

After writing several memristor models with SPICE last week, I decided to post a short tutorial here on the subject. I’ll concentrate on modeling the memristor introduced in the Nature Nanoletters’ article Memristive Switching mechanism for metal/oxide/metal nanodevices by Yang et al., published in July 2008. More specifically the model is an enhanced version of the one derived in the article CNN Using Memristors for Neighborhood Connections (IEEE CNNA 2010) by me and Mika Laiho. Read the rest of this entry »

Insightful people have noted that the brain has been difficult to understand from simple measurements because of its relative irreducibility to single neuron dynamics, suspected to be a result of emergent properties.  Line up a few hundred million transistors very carefully and you get a fast but ’stupid’ processor; bag a bunch of proteins with a lipid membrane and you’re still far from a functioning cell; the list goes on.  Something about the whole, goes the cliche, is greater than the sum of its parts.  I’ve traditionally only heard about this concept as it applies to neuroscience, but I recently came across a great quote from D’Arcy Thompson that could use some fresh air on the Internet.  In terms of cell biology, he warns against thinking of a multicellular organism in terms of its constituent cells, arguing instead that the biophysics is better understood in terms of the whole tissue and the interactions between its pieces.  I’m not sure whether or not this was added in the revised edition of On Growth and Form (1942), but I’d like to think that this was written in the first edition, published in 1917: Read the rest of this entry »

If you had doubts before starting to read Neurdon, I think that by now you have come to the realization that there are as many neuroscientists that use computers than computer scientists that want to “use” neuroscience. This post is another example of the latter: Steve Furber, Professor of Computer Engineering at the University of Manchester and leader of the team that designed the the 32bit ARM microprocessor, is trying to build a large-scale neural simulator out of ARM processors. Read the rest of this entry »

Note: This posting summarizes some arguments I presented at the 2010 IEEE Symposium on Circuits and Systems. The complete presentation is available at this link.

Much of the recent interest in HP’s finding the “missing” memristor has been based on the presumption that it is correctly interpreted as the “4^th fundamental circuit element” after the resistor, capacitor, and inductor. The original argument from Leon Chua was that there were four ways to link the variables of charge and current to the variables of flux-linkage and voltage. The resistor, capacitor, and inductor represent three ways to link these variables while the memristor was postulated as representing the “missing” link connecting charge and flux-linkage. This may seem like a reasonable argument at first glance but it is not without flaws. Read the rest of this entry »