Author: mattions

The delta. Why we are modelling.

Medium Spiny Neuron. 3D representation made using Neuronvisio.

Model of Medium Spiny Neuron. (3D representation made with Neuronvisio)

Disclaimeir: This is a long one. Get a cup of coffee and ten solid mins of your time, otherwise leave now 😉

When I meet new people and I’m asked to introduce what I do, it usually takes at least 3 minutes to give a proper overview. Usually, if the person is interested, I’ll go deeper and deeper, using an onion strategy to explain dive in the details of my subject’s research, going from a very simplified explanation to a more and more precise one.

The interesting thing is the recurrent question which arise at the end of my explanation: Why? What is the reason behind that?

I think this is a very interesting question and I have a personal answer, which I will tell you in no time. However, before that, let me introduce you a bit my research so we are on the same page. Then I will take a risk and try to generalize this to the whole modelling world.

In my Ph.D research I’m modelling the Medium Spiny Neuron of the Basal Ganglia. If you want to know why this is interesting and you want more detailed information about it just go on my academic page, otherwise here let’s just say that I’m investigating how the memory works, trying to shade some lights on the complicated business of memory and learning. In computational neuroscience we have a lot of different data, from physiology spanning to morphology to biochemical pathways. However, all this data usually belongs to quite well defined different area of expertise and they are not integrated. I’m trying to develop a coherent theory which integrate all these areas, which then we can use as a tool to understand the system.

The system I’m studying is not linear, which means a lot of different and concurrent processes influence each other, with different magnitude and at different times dynamics. The network of relations is intricate, and the different delays makes really difficult to have a static representation which can explain the situation.

This is why modelling is useful, and in my case is quantitative modelling. One of the way to try to understand this system is to create a model where we can simulate what’s going on, then run it to try to catch the emergent properties of the system and isolate them. If this approach is successful it will give us the knowledge about how the Medium Spiny Neuron should work in physiological conditions at least about some precise situation.

So what? I heard you said. Well, we have a good representation of what is going on. Which is the main idea of basic research. But there is more, so keep reading.

Let’s say the systems (in this case the Medium Spiny Neuron) can be found in pathological and then in normal conditions.

If we know how to simulate the physiological conditions and the pathological conditions then we have the possibility to understand the difference between the two. This difference or the ? (delta) ? = physiological - pathological, as I like to think about it borrowing a classic mathematical notation, is what differentiate the system in the two conditions.

This can be done also from an experimental point of view. You can replicate the two states using experiments, but given the fact the system is very complex, you can use a lot of different method to force the system into pathological conditions. Usually the system acts like a black box: you know what you put in, you can read what you’re getting out, but you don’t know what’s going on inside the box. In other words you don’t know the ?, or said in another words you don’t know why the two conditions are different.

Therefore the job of the model is try to open the box.

Now, if you know what is the ? and why it exists you have also a good indication of what is going wrong in the pathological conditions, what is missing or what is overproduced or, in more general terms, what is the bit you lack between the two systems. Then you have a starting point where to look to patch it.

I think this doesn’t apply only to computational neuroscience, but to all the models that deals with complex systems.

That’s why I think modelling is important. It will be cool to know what are the thoughts of mine 25 readers if they made up to here. Comments are open, as usual.

One or two things you should know about the desire

Htc Desire - a Droid with power. A lot of power.

It works.

It works very well.

After upgrading to the latest Android system (2.2) and resetting the phone with a data connection (I’m on O2 bolts on for internet, 7.50 £ per monthe for 500 Mb) the phone works very well.

This morning I just transferred a Pdf file from my computer (which runs ubuntu 10.04.. I mean GNU/Linux …) to the phone using bluetooth.

Just start the service, making the pc and the phone discorevable and then it was done. No black magic.

Now I’m back home, one of my job failed at the cluster. (Read my mail on HDSPA.) My internet is down ’cause virgin is having troubles for two days, right now.

So I’ve just shared the connection from my phone and I’m using it to go online, submit the failed job after correcting the problem and writing this post.

I don’t know what do you think, but I think this is sweet 🙂

Non toccate i blog

Il PD ha lanciato una campagna online contro il DDL sulle intercettazioni.
Secondo questa norma i Blog sono costretti a rettificare quanto scritto entro 48 altrimenti pagare una multa di 12 500 €.

E’ un emendamento soffocante per la libertà. Tipo che se non sei online per più di due giorni e non ricevi la notifica, puoi prendere una multa da paura.
Io la sostengo alla grandissima.

Nessuno tocchi i blog

Nessuno tocchi i blog

Via Civati.

Back in time – Easy Backup solution for linux

Making the backup is always a tricky business for me.

I always tend to postpone the moment, and that’s not a very smart procedure to keep your data safe. Thankfully, from when I discovered backintime the situation is quite different.

Back in Time Screenshot

Back in time is just a really nice and friendly graphical interface on top of rsync. The good thing is that you don’t have to worry about rsync in any way. The interface has really neat default options, like get rid of your old backup if you are short in space.

After you’ve installed you just have to pick the directory where you want to save your backup and clcik “Take Snapshot”. Then you’re done. Quick and easy.

Atheist coming out!

When I read this column I was kind of shaken.
In 2010 we still need to justify that people don’t believe.

Religion is just a business model. People believe in something that it doesn’t exist and then they are charged to do that. It’s brilliant if you run it. I’ve read this somewhere. I don’t remember who said that. I just agree.

Beware of ?0 (aleph zero)

P1010134.JPG

Volevo segnalare la rubrica di matematica tenuta da Maurizio Codogno sul post.

Oggi la storia è su ?0 e l’albergo di Hilbert. Se l’argomento vi incuriosisce c’è sempre Wikipedia per approfondire.

Se la trattazione matematica non vi suscita grandi emozioni allora pensatelo in maniera letteraria, attraverso il capolavoro di Leopardi.

L’infinito

Sempre caro mi fu quest’ermo colle
E questa siepe che da tanta parte
De’ll ultimo orrizonte il guarde esclude.
Ma sedendo e mirando interminati
Spazi di là da quella, e sovrumani
Silenzi, e profondissima quiete,
Io nel pensier mi fingo, ove per poco
Il cor non si spaura. E come il vento
Odo stormir tra queste piante, io quello
Infinito silenzio a questa voce
Vo comparando; e mi sovvien l’eterno,
E le morte stagioni, e la presente
E viva, e’l suon di lei. Così tra questa
Immensità s’annega il pensier mio:
E’l naufragar m’è dolce in questo mare.