Jeff Hawkins, "A Thousand Brains"

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Jeff Hawkins, "A Thousand Brains: A New Theory of Intelligence" (2021)

 

서평 (by Kumar Vivek)

 

이 책 'Part 1: A New Understanding of the Brain'을 읽었다. 저자가 2004년 저서 "On Intelligence"에 제시한 이론틀에 'dendritic spikes'에 대한 해석과 'reference frame' 개념을 추가해 새로 정리한 'Thousand Braiins Theoy of Intelligence'가 그 내용이다.

 

본문에서:

 

Today I no longer use the phrase "the memory prediction framework," Instead, I describe the same idea by saying that the neocortex learns a model of world, and it makes predictions based on its model. (p. 31) 

 

The brain creates a predictive model. This means that the brain continuously predicts what its input will be.... A mis-prediction causes you attend to the error and update the model. We are not aware of the vast majority of these predictions unless the input to the brain does not match. (p. 32)

 

For many years, no one knew what 90 percent of the synapses [the distal synapses] in the neocortex did. Starting around 1990, this picture changed. Scientists discovered new types of spikes that travel along the dendrites. Before, we knew of only one type of spike: it sarted at the cell body and traveled along the axion to reach other cells.... The big insight I had was that dendrite spikes are predictions. A dendrite spike occurs when a set of synapses close to each other on a distal dendrite get input at the same time, and it means that the neuron has recognized a pattern of activity in some other neurons. (p. 45) [맨 아래 사진: A typical neuron]

 

The Secret of the Cortical Column Is Reference Frames [p. 47]

 

[W]e proposed that each cortical column has a set of cells equivalent to grid cells, another set equivalenr to place cells, and another set equivalent to head direction cells, all of which were first discovered in parts of the old brain. (p. 68)

 

All Knowledge Is Stored in Reference Frames.

1. Referenc Frames Are Present Everywhere in the Neocortex.

This premise states that every column has cells that creates reference frames. I have proposed that the cells that do this are similar, but not identical, to the grid cells and place cells found in older parts of the brain.

2. Reference Frames Are Used to Model Everything We Know, Not Just Physical Objects.

3. All Knowledge Is Stored at Locations Relative to Reference Frames.

Reference frames are not an optional component of intelligence.... Every fact you know is paired with a location in a reference frame.

4. Thinking Is a Form of Movement.

Thinking occurs when the neurons invoke location after location in a reference frame, bringing to mind what we stored in each location. The succession of thoughts that we experience when thinking is analogous to the succession of sensations of ... things we see when we walk about town.... Reference frames are also the means for achieving goals. (pp. 71-3)

 

I have introduced four uses for reference frames.... Reference frames in the old brain learn maps of environments. Reference frames in the what columns of the neocortex learn maps of physical objects. Reference frames in the where columns of the neocortex learn maps of the space around our body. And finally, reference frames in the non-sensory columns of the neocortex learn maps of concepts. (p. 87)

 

Our knowledge of something is distributed among thousands of cortical columns. The columns are not redundant, and they are not exact copies of each other. Most importantly, each column is a complete sensory-moter system.... Why do we have a singular perception if we have thousands of models? ... In other words, how do our sensory inputs get bound into a singular percept? Scientists have long assumed that the varied inputs to the neocortex must converge onto a single place in the brain where something ... is perceived. This assumption is part of the hierarchy of features theory. However, the connections in the neocortex don't look like this ... the connections go in every direction. This is one of the reasons why the binding problem is considered a mistery, but we have proposed an answer: column voting. Your perception is the consensus the columns reach by voting. (p. 99)

 

 

(p. 44)