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Donald Hebb's postulate only applies when two neurons are already connected. It seems you are asking more specifically, 'when two neurons are not already connected and they want to connect, how and why?' Correct? In this case, we do not know. StrangeLoop mentions it is due to the location of the neurons and the spreading of activation. Yes these might be ...


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has made it possible to have perfect input/output to the brain from a computer Perfect? Definitely not: the complexities of optogenetics of a single mm square of cortex, of a mouse lets say, are extremely complex. As Chuck mentions, many neurons/synapses may be activated by a single LASER and current technologies allow only a few different LASER ...


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Anology Taking the analogy and calculations directly, you are assuming that the fundamental computing unit of the brain is the neuron; we do not know if this is true. It could be a cortical column, a group of several neurons, the neuron, a dendritic branch (a fascinating review paper!), a synapse, receptors or neurotransmitter vesicles (how about glial ...


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Donald Hebb originally formulated what would later come to be known as spike-time dependent plasticity by famously stating "neurons that fire together wire together". In actuality, the firing has to be sequential (not simultaneous) and causal: if a neuron A fires and causes B to consequently fire, the synaptic strength between them increases. This is how the ...


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First of all I should say that I'm not a neuroscientist so take my answer with a grain of salt. Your first question was "Why can't human brains be used to do massive parallel processing in the same way computers are doing today?" I think the answer to this question has to do with the difference between the multi-core processors computers have and the nuro ...


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It is highly variable, depending on the strength and placement of the synapse (which in turn depends on synapse activity and how often the two neurons fire together, among other things). The wikipedia page here is a pretty good place to start, or if you want more detail on how that pulls together in an actual system, this paper is a good place to start.


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There is a basic epistemological problem here that was only touched upon by Chuck Sherrington - everyone is making the assumption that the brain processes the same kind of information as a digital computer. There is no real evidence to suggest that it does, in fact. A digital computer is an instantiation of a Turing machine, which is equivalent to certain ...


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The location of a sound is defined on three dimensions: distance, elevation, and azimuth. When the distance between a listener and a sound source is changed there is a change in the overall level as well as the relative levels of direct and reverberant sound energy. When the elevation is changed the overall level and the direct to reverberant ratio say ...


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First, let's take a look at the basic principles of NEF. The first two principles (Representation and Computation) do seem analogous to trained ANN models. Additionally, with the hPES learning rule that I've described here, they seem to have the same capabilities. Where the NEF really starts to shine is when it starts to describe dynamics. For a ...



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