Main Question or Discussion Point
Is neural oscillation the only method in which we can analyze and communicate with the brain?
To a large extent things like this are a function of location rather than "oscillations". Electrically stimulating a precise spot can, in fact, give someone things like the experience of blue or sadness.I'm specifically interested in bi-directional methods for communicating and analyzing the brain.
For instance, the ability to analyze brain patterns and understand that the subject is looking at the color blue or experiencing sadness. And in the other direction, the ability to stimulate or activate the brain in such a way that the subject perceives the color blue or feels sadness.
This is what I'm talking about except that after Penfield they began implanting depth electrodes so they could both send and receive signals from points in the limbic system. The electrodes are very thin and they are stripped of insulation at regular intervals so that each electrode can either send or receive at different points along its length. I think they might put as many as ten in the suspect hemisphere to locate the seizure focus as precisely as possible. Penfield was limited to triggering seizures from the cortex. The focus might be far removed from the point where the seizure activity reaches the cortex, so surface stimulation isn't all that reliable.Do you mean something like this? I can smell burnt toast (just a dramatization)
(interview, see around 2:11)
http://www.ncbi.nlm.nih.gov/pubmed/149734772. Do neurons only really matter in large clusters? (e.g., does a single neuron control anything?)
For humans it's very difficult as doing anything that records with higher resolution than current methods requires getting rid of the skull. For electrical signals, the skull acts as a spatial filter, smearing together signals that are separated spatially. The effects are greater for higher frequency oscillations, as higher frequency oscillations tend to be less coherent across space than lower frequency oscillations. Other methods like fMRI give better spatial resolution, but much worse temporal resolution (and fMRI uses blood oxygen level as a proxy for neural activity. And needs a lot of liquid helium.)My limited knowledge of this field suggests that neural oscillation is currently the most precise and unobtrusive method for analyzing neural activity -- even if it’s limited to clusters of thousands or millions. I was curious if there were other methods -- equally unobtrusive and ideally much more precise -- under development?
This is done in brain slice preparations and in animal experiments using sharp electrodes implanted into the brain (or with more fancy imaging techniques). It gives you a different type of information; whether it is useful depends on the question you are asking.Here are a few more questions:
1. EEG and MEG detect the activity of thousands or millions of neurons. I imagine this is a limitation of both the technology and approach. Would it be useful to measure the activity of a single neuron?
As far as I am aware, it depends on the brain area, and what type of processing is occurring - but we're only just starting to unravel the neural code really...2. Do neurons only really matter in large clusters? (e.g., does a single neuron control anything?)
What level of detail of neural activity would you want to record? Firing of every cell? Release of neurotransmitter at every synapse? Dendritic spiking? Gap junctional communication? Glial processes? Gene expression? I would imagine on a low level, it would vary hugely between individuals, but at a much higher level, similarities would be observed.1. Consider the possibility of mapping or recording the neural activity required to learn a single word. Would this process be similar amongst a large portion of the population or is it highly specific to each individual?
I would say not exactly, because the the activity of the brain doesn't just depend on the input, but also on the brain's current state, which is constantly changing. However, if you could make your artificial stimulus in a way to account for this, then I guess perhaps theoretically...2. Could it be possible to stimulate the brain so that it mimics the previously recorded neural activity? And if so, would that result in the subject learning the word?