Ask HN: What data structure does our brain use?

There has been done a lot of work on this issue specifically to the mental lexicon, of lexemes/entities of language, and its storage. A lot of it was based on psychological testing, for example reaction times when words are presented that are somehow associated etc.

I guess that, while on a neurological level storage of different types of memory might work similar, the 'data structure' is perhaps different.

Short answer: A graph.

All data structures are simplified graphs.

The state of the physical universe is a massive graph in which interconnected objects are themselves massive assemblies of graphs of atoms and the atoms are graphs of subatomic particles. It's graphs all the way down. The properties of all systems - physical, chemical, economic, biological - emerge from the interactions between simple connected elements.

My opinion is that all knowledge is representable as a connected graph. The disconnect between our computers and our minds arises from the fact that brains are categorically not numerical machines but graph processing and pattern recognition engines. Neural networks are the underlying hardware and, with the typical elegance of nature, these are also graphs.

It should be possible to build a graph based language. The basic "Elements" [SICP] are easy to realise:

1. Primitive Expressions are graph nodes. They have identity and not much else.

2. Means of combination. Graphs can be added, subtracted etc.

3. Abstraction. A graph can be abstracted into a single node. We have no problem looking at a complex assembly of components as a single entity.

Since Google and Facebook are two massive platforms whose value arise from direct interaction with planet-scale graphs with billions of nodes, would these platforms be easier to build if our computers were more graph oriented? I would like to believe so.

Our insights in memory formation are still limited. The most studied candidate is LTP/D[1], the change of weights of synapses between neurons. Memory formation is a complex process though. While LTP can be induced with a short burst of spikes, its stabilization and maintainance depends on a sizeable number of molecules and genes. We still don't know at what level the memories may be stored, it could be the level of single synapses, groups of synapses, the level of single neurons or ensembles of neurons.

There are experiments involving fear memory that have shown that a fearful event can be "stored" in an ensemble of identifiable neurons, and even be turned on and off [2].

Then there are brain rhythms and sleep. Memories would become overwritten if they were stored in the same circuits over and over, so there are various theories about how memories are transferred to various parts of the cortex via coordinated rhytmic activity or sleep.

Closer to your question, the data structure that our serial thinking brain uses is language. We think, reason and communicate using it. Language has a tree-like syntax, but semantics are an unsolved problem. There is even a theory that suggests that brain rhythms may encode "sentences" into thoughts via neuronal oscillations[3].

1: http://en.wikipedia.org/wiki/Long-term_potentiation

2: http://www.silvalab.com.cnchost.com/silvapapers/ZhouNN2009.p...

3: http://osiris.rutgers.edu/BuzsakiHP/Publications/PDFs/Buzsak...

The right response is that science doesn't know yet.