NEOCORTICAL CIRCUITS. specifications

Transcription

1 NEOCORTICAL CIRCUITS specifications

2 where are we coming from? human-based computing using typically human faculties associating words with images -> labels for image search locating objects in images -> database for computer vision provide common sense facts -> for more "intelligent" computing lure millions into playing that game nature-inspired computing annealing genetic algorithms swarm intelligence limitations to "computers" problems no "computer" can solve problems that require unreasonable resources brain-inspired computing

3 brain-inspired computing stagnant artificial intelligence the human brain an (almost everywhere) identical 6-layer structure in the neocortex with a columnar organization genetically determined dedicated areas hierarchically connected laminar computing machine, massively parallel, special algorithms memory the neocortex stores sequences of patterns the neocortex recalls patterns auto-associatively the neocortex stores patterns in an invariant form the neocortex stores patterns in a hierarchy structure of the brain the neocortex: flows, interconnect, operation overall architecture with the hippocampus on top hierarchical temporal memory towards a mathematical theory of cortical micro-circuits brain-computer interfacing: non-invasive probing, transducers, invasive probes

4 simplified brain architecture hippocampus learns long-term memories and sends the info to the cortex cerebral cortex the old long term memory for events, places, objects parahippocampal gyrus prefrontal cortex olfactory cortex hippocampus amgydala striatum limbic system the old motor system the old timer auditory cortex somatosensory cortex hypothalamus basal ganglia cerebellum visual cortex thalamus sensory organs motor cortex motor organs

5 the hippocampus: on top of it all unexpected patterns get passed higher and higher up so truly new experiences will reach the hippocampus aging example: - fitting into past memories so less and less is seen as new without the hippocampus no new things can be learned unlike the neocortex, the hippocampus has heterogeneous structure with specialized regions. only form permanent memories if experience it over and over, in reality or by thinking of it, so that it gets passed down to cortex. touch audition vision

6 Hawkins' model (of the world) causes beliefs people cars buildings words songs ideas world senses patterns cause cause cause cause cause cause representations of causes cortex our intelligent machine what should the intelligent machine do? 1 discover causes in the world 2 infer novel input 3 predict future 4 direct motor behavior

7 the world intelligent machine 1 discover causes in the world 2. infer novel input 3. predict future 4. direct motor behavior causes sensory data representation of causes each node: discovers causes (of its input), passes beliefs up, predictions down each node: stores common sequences, changing sensory data forms stable beliefs at top stable beliefs at top form changing sensory predictions benefits of "hierarchical" structure 1) shared representations lead to generalization and efficiency 2) hierarchy matches spatial and temporal hierarchy of causes in world 3) belief propagation techniques ensure all nodes quickly reach mutually compatible beliefs 4) affords mechanism for attention

8 how does each node discover causes? 1) learn common spatial patterns 2) learn common sequences of spatial patterns ad 1:things that happen at the same time are likely to have a common cause common patterns: remember uncommon patterns: ignore ad 2:things that happen consecutively might have a common cause common sequence: assign to cause time common sequence: assign to cause uncommon sequence: ignore

9 simple htm vision system (32x32 pixels) Level 3 Level 2 Level 1 4 pixels

10 columnar organization of the microcircuit upward flow: converging inputs arrive at layer 4. form a passing connection in layer 6 layer4 sends axons to 2 and 3, layer 2,3 send often axons up to the next higher region. L1 L2 L3 L4 L5 L6

11 columnar organization of the microcircuit L1 L2 L3 L4 L5 L6 downward flow: -layer 6 cells to layer 1 of lower regions. - layer 1 spreads this input out, - picked up on by dendrites of layers 2,3, 5 - axons from 2 and 3 form synapses in 5 and excite cells in 5 and 6

12 columnar organization of the microcircuit

13 timing circuit motor functions nonspecific thalamus

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16 Mapping between neocortex hierarchy and HTM hierarchy.