Reading CTs

If you have a CT scan that you have never been able to make sense of, check out this site...CT Scan Page You can get to know your own brain anatomy by identifying structures and understanding what functions they are responsible for.
For example, roll the curser over "Amygdala" and identify the same structure on your own scan.. this is the region responsible for emotional coding particularly when related to survival (fear, anger and pleasure) and deciding what aspect should be stored as memory and where.

And another really helpful neuroanatomy site MedWayne Diagradiology Great for getting a feel of what you are looking at on brain scans and orientating yourself around brain anatomy using sulci and gyrus, (the folds and valleys that look very dark on the scans)

fMRI Activation map and Subtraction

Activation maps — FMRIB Centre, University of Oxford
This Oxford webpage guides you through a simple fMRI experiment

To highlight a particular region's activation scientifically, a subtraction technique between a simulated and a control run of the experiment is frequently used. This minimises risk of misinterpreting activation from another area, a region that is not of significant interest to the experiment or study.

fMRI, the basics

fMRI or functional MRI is technique that can map brain areas activated by a task or sensory input. fMRI can be used for clinical or research purposes and like most of the devices I am mentioning, is non invasive, though uncomfortable. fMRI like most neuroimaging uses an understanding of principles of electromagnetism to infer the brain's activity. Taking advantage of the known orientation of atoms and a constant magnetic field in the MRI scanner allows scientists to see changes in blood flow associated with brain activity, then infer the activations that must be the source. The intensity of an MRI signal is determined by the level of magnetic resonance, specifically what is called the BOLD effect (blood oxygenation level dependent). All materials have some effect on magnetic fields depending on it's susceptibility or "magnetic moment". Blood that is oxygen rich differs in how it effects a magnetic field from deoxygenated blood. Oxygenated blood is diamagnetic, it tends to take a position at right angles to lines of magnetic force. Deoxygenated hemoglobin (blood) takes a position parallel and proportional to the the intensity of whaever local magnetic field is present. The MRI, with its created and constant field is able to set up an environment where a difference in as little of 3% change in oxygen levels of the blood is detected and imaged.
Typically a high resolution MRI is done to be used as a backdrop before redoing the MRI with BOLD scans at lower resolutions and the participant engaging in an activity. A person in the MRI can wear special goggles or glasses to show the images of their brain. Images are made slice by slice, combined in the computer to form 3-D pictures of the brain. Final images will show the areas of activity during the experiment.

MRI

MRI is brilliant for imaging our bodies, it does so non-invasively meaning theres no injections or cutting. You do however, have to stay extremely still in a very uncomfortable environment. It is well worth the discomfort when you get to see your body, inside-out.

Radiofrequency, RF waves are a form of electromagnetic energy and can excite the protons in living tissue. The protons get excited to a higher energy level, then a photon (light), is released as the proton 'relaxes' back to it's resting energy level. Protons act like tiny magnets with their own associated field which can cancel out. This along with all the noise generated by protons in areas that are not the focus, make the information the photons are sending out very difficult to pick up and interpret. An analogy is a room full of people talking at the same time, each person is saying something meaningful, but the room from a distance sounds like a meaningless cloud of noise. By setting up an external magnetic field, an environment is set up in which protons will line up either upward or downward, parallel to the field. A net magnetic field is then created by the protons with a strength that is proportionate to the strength of the magnet. The stronger the magnet, the more protons align, the less noise from "other voices".
RF pulses help each proton to rotate and move in unison at 90degrees to the magnetic field. Aligning to 90degrees from the field, reexcites the protons to higher energy states which takes to steps to return to a resting state from.

10% of your brain

Why do people (which people??) say that humans only use 10% of the brain? This has become a modern myth with no discernable origin. It is completely and utterly untrue. WE USE ALL OF OUR BRAINs and there is nothing scientific to back up the widely pronounced claim. I am a fan of science fiction but not of fiction posing as science!! Corporations have used this claim as a marketing strategy (american airlines and this ad for satellite tv, for example). Its a bit surprising that no one in any of the companies that represented this "information" or any of the individuals that have said the statement flippantly (likely to make a point in an argument) had the thought to find a source or any reasonable proof. Why do we as humans like to consider ourselves stunted, physically unable to fulfill our potential?
I have a few guesses at the distant origins of this statement, perhaps it is a made up statistic originally used to demonstrate the difference between how much of the brain lights up when consciously attending to something when not consciously attending. The running, accepted theory is it is a misinterpretation of Pierre Flourens, the french physiologist who was the first to notice that lobotomies didnt affect all the functions of bird and rat brains in the 1800s. This led to the understanding of localised brain activity from structures in the brain evolved for specialised activity.Why would our brains evolve to this size if, it isn't all used?
George Orwell said, "Myths which are believed in tend to become true..." and if our brains at their current size of about 3lbs had 90% of it removed.. we would have a brain that is equivalent in size and weight to a sheep's brain. Don't be a sheep, keep using 100% just like you already do.

Explicit versus Implicit control

Implicit control over brain activation is learned through the normal development and acquisition of new skills. Unaware, we implicitly control brain activation with every voluntary action performed. Every perspective a mind takes activates particular brain mechanisms.

Explicit control over brain activity is that which must be deliberately controlled. A subject must be conscious and take charge over brain activation through deliberate choices. An example given by Christopher DeCharms (2008) is the case whereby one can learn to control activation (pain in DeCharms study) in a region of their brain by exerting exactly the type of thought that will maximize or minimize its activation. It will be interesting to observe to what extent people can learn greater explicit control over their brain activation in an area of their brain by training and the consequences of such training. Charms noted that real-time functional MRI has the potential to bring normally non-conscious brain processes into our conscious awareness. This will transform implicit control of brain activation into explicit control.
Click here for DeCharms full pdf article of the pain study

Critical Reasoning for Neuroscience

Okay, so the brain is incredible. Its vast, and can hold more information in better ways than the best computer. That may change soon click and read.. "When will computer hardware match the human brain?" for more thoughts along those lines. What extent are the nuances of our behaviour and emotional responses governed by functionally

specific parts of the brain? What behaviours and environmental or chemical influences give rise to disorder, or shut down a specific functionality?

I highly recommend reading this blog entry on some tips for critical neuroscience reasoning. Ketyov reminds us some important things to keep in mind when researching or listening to anything related to neuroscience. Over estimating the specificity of language for one, leads to many problems.

Its important to keep in mind that metaphor and similar forms of descriptive language are not caused by a specific "metaphor" region of the brain but are meaningful and effectively descriptive because they activate networks of activity across the brain, for eg, from different sense operators like sensation of sun on the skin to the face recognition region (fusiform gyrus) when thinking of "Juliet as the Sun".