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12

There is a huge body of literature on axon growth cone guidance which will give you some insights into how the biology works. Unfortunately, incorporating it all into a model is probably going to make it unwieldy unless your express purpose is to model the physiology, which doesn't seem like the case. Here are some references: Hong K, Nishiyama M. ...


6

For the dentate gyrus, which is probably more closely analogous to a feedforward hidden layer in a memory network, here are some answers: Axon and dendrite connectivity is essentially local and can probably be assumed to be initially random within that local region. That is, a neuron integrating into the DG at the midpoint (along the long hippocampal ...


6

Another reason for reduced plasticity in adults is that learning something different in the presence of an existing knowledge structure is more difficult than learning from a "blank slate". In a sense, you get interference from the known language (for example). One person who has developed this argument computationally is Jay McClelland in the context of ...


6

Although LTP might be necessary for brain plasticity, I would doubt that it is also sufficient. There is quite a lot of literature about homeostatic plasticity (for a review, see Turrigiano & Nelson, 2004) and synaptic scaling (for another review, see Turrigiano, 2008) which seem to be necessary to keep LTP working in the long run. References ...


6

Sadly (or should I be happy that Google is this awesome? Not to mention the rate of scientific progress!), all I really had to do to come up with an answer was perform a Google search for "learning transcranial magnetic stimulation". The first hit, a ScienceDaily page (Ruhr-University Bochum, 2011) page, lists some journal references (Mix, Benali, Eysel, ...


6

Interesting question! I performed a fairly extensive search in Google Scholar and Scopus using various keyword searches, including, but not limited to "color blindness and plasticity", "color blind and brain", "dichromates brain", and "monochromates brain". Strikingly, I found nothing. The reason is aptly explained by Solomon & Rosa, 2014 and I quote ...


5

One great example of such plasticity is the ability of early-blind people to utilize their V1 area to read Braille: Functional relevance of cross-modal plasticity in blind humans (Cohen et al., 1997) Excerpt from the abstract: We conclude that blindness from an early age can cause the visual cortex to be recruited to a role in somatosensory ...


5

Yes, the visual cortex is plastic, even in adults: We measured adaptation in the responses of populations of cat V1 neurons to stimulus ensembles with markedly different statistics of stimulus orientation. We found that adaptation served two homeostatic goals. First, it maintained equality in the time-averaged responses across the population. ...


4

Assuming you're getting at a related idea to your other recent question (Does a more ergonomic and user friendly interface/device make the human brain work less?), I wouldn't worry about user friendliness causing mental atrophy by precluding the need for thought. Thought continues well beyond matters of control to matters of application and optimization. ...


4

In adult mouse cortex, synaptic spines can last anywhere from days to months. I'm not sure that any such work has been done on human Broca's area, but keep in mind that many synapses are experience dependent. One study found that fear conditioning and fear extinction lead, respectively, to synapse formation and elimination. So the lifetime of a synapse ...


3

The concept of mental rotation was introduced by Shepard & Metzler (1971). The 3D assemblages of cubes were part of their original experiment. Vandenburg and Kuse (1978) later developed a paper-and-pencil test based on this prior experiment, named the Vandenberg and Kuse’s Mental Rotation Test (VMRT). The study which Bavelier most likely refers to is ...


2

The truth is, we don't fully know. There are likely a number of factors. One of them seems to be the Brain Derived Neurotrophic Factor (BDNF). This molecule seems to be involved with maintaining and encouraging neuron growth. In Rats with a transgenically accelerated rise in BDNF levels, the critical period began earlier, and finished earlier as well (Huang ...


2

The time required to learn Braille may vary depending on factors such as age, partial/full and early/late blindness and individual differences (see here), but what has come out of studies such as this is that visual deprivation appears to speed up Braille learning. In the study I cite, all subjects received the same degree of training, but individuals who ...


2

Consider that elimination of such a phenomena is not ideal. It's been proposed that actual neuronal networks exist under the tension of synchronous decoupling. http://www.sciencedirect.com/science/article/pii/S0896627308001281 To answer your question though, you probably should consider that reciprocal connections might not be between two individual ...


1

I can't speak to color blindness, but a little about the neural correlates of color processing in general. There has been some thought that macaque V4 (non-primary or extrastriate visual cortex) and the human V4 topologue may be responsible for color processing--some studies have found wavelength-specific cells in V4, but other studies have found no greater ...


1

The ability of dopamine to work on different time scales is discussed by Schultz. More generally, the basic idea of prediction error reinforcement based learning and DA is that the prediction error signal "propagates back in time". There is some doubt for how temporally precise this DA signal actually is, and if DA is fast enough to support RPE TD learning. ...


1

What you mean is that you want teenage existentialist angst to last for life? The neuroplasticity of younger children comes at a cost, which is not really knowing ones place in the world, because the world model you are building is constantly changing. Getting a world model broadly settled then enables you to move on in life and do more. If we retained the ...



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