The convergence principle 1/3

We are living a time of great discoveries about the last unexplored continent, the brain. Neuroscience, neuropsychology and cognitive robotics teach us a lot about how the interaction of millions of cell can lead to what we are.  If we look at a specific part of the brain, the cortex, we are able to understand the core principle of cognition. As a researcher on cognitive robotics, the ideas of Damasio (Synthetic talk here) are directly applicable to modeling the cortex of a robot. His research demonstrates the convergence-divergence zones, according to which sensory-motor modalities are linked together through a hierarchy of cortical maps.  

Take as example the concept of a banana:

• you have a clear mental image of a banana (vision)
• you can mime how you would open it (motor)
• you have a clear idea of how it tastes (odor)
• you can say, read and hear “banana” 

However, I was able to evoke all those mental representations by just one word.  This word that you read somehow activated a whole network of cortical areas in a specific manner to remind you of what a banana is. Since the case of reading may be a bit complicated to figure out, let’s assume that I was talking to you. I said “banana”, the corresponding sound wave entered your hears and was encoded as a neural raw representation. This representation is going to activate the primary auditory areas and the signal which will in turn send information to higher level areas which receive input from other modalities as well, the motor act of your mouth that would produce this sound for example. The three areas would be connected like shown on the picture above:
 

Over-simple example of hierarchical organization of cortical areas

 Note that the connections are bidirectional, which means that a specific pattern of activity in the amodal area is triggering in a feedback way the sensory areas. Concretely this means that hearing the word “banana” will trigger your motor system to say it (at some point you will probably ^^’) and that by silently pronouncing it you may still mentally hear it.

My job consists in building on this basic principle, so that one day robots can be conscious that the concept of a banana is buried deep in their mind…