A picture paints a thousand words …

A picture paints a thousand words. And words are painted across our brains.  In a paper titled “Natural speech reveals the semantic maps that tile human cerebral cortex” by Huth et al, and published in Nature in April 2016, authors have mapped words to different regions of brain using functional MRI data while subjects listened to hours of narrative stories. Interestingly, despite having our individual maps, our minds are organized in similar and consistent manner, and words cluster as per semantic domains. Here is the amazing video:

Nature video on how brain maps words to different regions

Here is a screenshot of part of brain and words mapping to that region:

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(Figure Credit: Nature video on brain dictionary, April 2016)

One cannot help observing connection with current research in Natural Language Processing (NLP) in the field of Artificial Intelligence. Machine learning models such as deep recurrent neural networks can work with words. But since computer models work with numbers, words have to be first converted into numeric representation in the form of vectors. Here dimensionality of these vectors can be large. In a way, the words are being converted into spatial points in a high-dimensional spaces and then semantics becomes spatial concept. Words which are semantically similar, map to close by regions, and their relative displacements capture semantic concepts. See the following reference for technical details of word2vec (word to vector) approach:

Vector representation of words

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(Figure Credit: Tensorflow tutorial on word2vec)

It seems we are making progress in unraveling how mind works.

At the same time, a lot has yet to be discovered and understood.

How does a new born baby develop this semantic map within a matter of few years, which seems to be consistent across individuals?

And, where are our thoughts in all this?

In a semantic world, where words become colorful entities in space, perhaps our thoughts are nothing but mysterious dances in this surreal landscape.

And, where are our dreams in all this?

One can only wonder, as a wise philosopher did long time ago:

“Once upon a time, I dreamt I was a butterfly, fluttering hither and thither, to all intents and purposes a butterfly. I was conscious only of my happiness as a butterfly, unaware that I was myself. Soon I awaked, and there I was, veritably myself again. Now I do not know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man.” – Zhuangzi, 4th century BC

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