Small fruit fly brains are scanned before removing an 8-nanometer slice with an ion beam. Each fly brain tissue has , slices and one brain takes years. Similar research with mice uses special devices, which are the equivalent of 50 to of these beams at once. Composites are being made where pictures of large slices can zoom in to see detail. As with the middle scale, in fact, software is not good at the untangling and individual visual work by humans is better, but extremely slow.
One group uses a public video game called Brainflight to dis entangle axons. Game players fly along axons through these composite pictures and attempt to untangle the path of individual neurons. This same type of crowd sourcing has been used with protein folding. The largest product is a mouse retina cube with neurons and , synapses.
A million of these products would equal a mouse brain. There is much debate about which level will produce the most useful information. Many think that the middle level is most relevant to describing brain circuits. There is certainly a question of what the fMRI is telling us because of the limitations already described. The smallest views are interesting to describe types of neuroplasticity, but are too small to describe brain circuits that can extend across the entire brain.
There are increasing number of projects attempting to make an accurate approximation of neuronal connections in computer simulations to see if this can predict neuronal behavior. Previously a 3D map of a small piece of mouse brain was simulated based on slices. New much larger expensive simulations are ongoing. The largest European computer simulation project is , times larger; its first publication was this week. The large European project funded for a billion dollars has just produced its first major paper with a presentation of a brain simulation.
This project constructs a supercomputer simulation of a small region of the mouse brain 0. It has been praised by some and, recently, publicly, attacked by neuroscientists in a letter to a journal as a waste of money. It was produced over twenty years with existing data by 82 scientists in 12 institutions. It simulates 31, neurons and their 37 million synapses using different types of brain cells and millions of connections.
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An algorithm was built predicting how synapses would form and work. The first neurons were produced by actual recorded data and then the algorithm produced the 31, other neurons and their connections. The algorithm predicted locations of 40 million synapses and then calculated pruning. The project takes models of different kinds of neurons and their shapes; it positions them at different depths.
It calculates where they would all touch each other.
It first produced million touches. Synapses are given a stimulating or inhibiting character.
Five rules of connectivity decide which touches are reasonable and then the algorithm pruned deletes the rest. The result after pruning is 37 million touches or synapses. Experiments with several simulations were performed with these synapses. Possible ion flow through the 37 million synapses was calculated from data for a small number of the neurons. The data was extrapolated to all of the neurons in the simulation. This was then compared with electron microscope data. Another simulation studied possible calcium effects.
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Previous simulations showed bursts similar to sleep not asynchronous awake behavior. When the simulation calculated calcium for awake animals, it became asynchronous like real brains. Another simulation was of sensory fibers coming into the cortex such as touch information. Neurons were found that fired in three beats or triplets. All of this type of activity has been observed before in the real brain and the simulation identified specific neuron types for the activity.
It is an expensive, interesting project. It is not clear if the assumptions of the algorithm are accurate, nor the results. Each will have to be tested over time. Some scientists feel it is a beginning of something.
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Others feel nothing is learned and it is an expensive waste. Some problems are obvious even to the directors of the project—no glia, complex neuroplasticity, brain waves, cytokines or blood vessels.
While neuronal connections are fascinating and fantastic, they are hardly the entire story. Many posts have been written about the fantastic dynamic levels of activity with astrocytes, microglia, oligodendrocytes and immune cells. The hope for the connectome researchers is that mind is a creation of brain, which is thought to be a computer of some type. It is spurred by the philosophy that there is no mind and no meaning in the universe, but rather only random molecules bumping into each other and creating an illusion of mind through physical forces.
The latest and best current science shows a large amount of evidence consistent with the new paradigm that mind exists as an integral part of nature like matter and forms of energy. While the work being done to map the brain is extremely valuable and interesting, it is necessary to point out dramatic and potentially insurmountable obstacles in this quest to reduce mind to neural connections.
Searching for the Mind with Jon Lieff, M. So poo-pooing the brain scan as being too ambiguous is nonsense according to a specialist with 83, data points to back him. Amen's talk is available on you tube. Thanks for sharing your thoughts, Sharon. I haven't seen Dr. You're exactly right that according to Dr. Amen, the scans his centers offer can provide information that affects treatment. Unfortunately neuroimaging scientists do not share his view, for reasons I outlined in my article. Amen's group has yet to provide convincing evidence to change the views of mainstream scientists.
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As for the head injury, yes it would absolutely make sense to treat with rehabilitation rather than medication. That said, we typically don't need a brain scan to know that someone had a head injury. Just like with psychiatric symptoms, we would know that based on the person's report. A doctor who prescribed medication without considering the need for a rehab program simply wouldn't be providing good care.
For most of the conditions that are assessed with those 83, scans, we just don't know enough about the brain to use those scans in a meaningful way. They can't tell us if someone has a psychiatric condition, or doesn't have one, or which condition, or certainly not which subtype of a specific diagnosis. I wish there were more reason to be optimistic about psychiatric brain imaging but unfortunately there is not! As a doctorate-level academic, you should know that there are a LOT of pathologies that can affect cognition I recently saw a patient admitted for acute psychosis.
Lo and behold, a CT scan demonstrated large ring-enhancing lesions in the cerebrum.
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A diagnosis of lymphoma was eventually made, saving this patient's life. If the scan had never been performed, and treatment had remained purely psychopharmacological, a young life would have been lost. Cherry-picking the example of "head injury," which is indeed easy to diagnose without a scan, willfully disregards the wide range of conditions that are not diagnosable without imaging.
I find myself wondering if you're just feigning ignorance of this to prove an ideological point. I'm glad you shared this story, Dogstar. They illustrate exactly the point I'm making in the article: Brain scans are a powerfully useful tool for detecting "large ring-enhancing lesions" and other visible conditions. They are not useful for understanding psychiatric conditions without a clear structural basis.
Thanks for reading. Surely if something is wrong with the way someone thinks or behaves and initial assessment or therapy doesn't make much of a difference and that person spends a long time waiting for therapies, diagnoses, trying different meds, suffering anxiety, depression, OCD to the detriment of their quality of life and even suicide attempts, then why on earth not look at the brain to see if there is something organic going on?
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Of course I realize a scan isn't likely to diagnose a mental health condition or personality disorder, but what if an previously unknown malformation, cyst or injury could be causing a problem? Many desperate people and their families would welcome such an investigation. Hi, Jeanne. I appreciate your thoughts. Yes, brain imaging to look for a visible issue like you described would be a perfectly appropriate use of neuroimaging.
I'd imagine doctors order a brain scan when there are symptoms suggesting something imageable might be present e. I guess the problem with using imaging for mental health screening is that it would require tremendous expense and additional risks without much of a benefit since so few scans would yield anything helpful.