Technology in the modern laboratory
fMRI (functional Magnetic Resonance Imaging) This technique identifies the role of different areas of the brain. It does this by detecting higher and lower magnetic susceptibilities in the blood, which indicate whether the blood is newly oxygenated or not. Real time scans are possible which aid treatments such as surgery and are of great value as a diagnostic tool.
See http://www.fmrib.ox.ac.uk/fmri_intro/brief.html for more or http://www.dcn.ed.ac.uk/bic/research/structural.asp for a British University applying the technique.
MagnetoEncephaloGraphy (or MEG) detects the magnetic fields associated with brain activity without using X-rays. It sends no signals into the brain so is entirely safe. It enables a functional image of the brain to be shown. This helps show what activity the brain is undertaking, and where in the brain this comes from. It helps show where problems (eg epilepsy or migraine) is coming from.
See http://www.magres.nottingham.ac.uk/meg/index.phtml for a UK university working at the forefront of this technology. Or see http://www.aston.ac.uk/lhs/research/facilities/meg/faq.jsp and see http://www.aston.ac.uk/lhs/research/groups/nrg/nrg_projects.jsp for some of their valuable work in humans.
EIT (Electrical Impedance Tomography), is mobile and cheap. It registers electrical resistance in disease-affected areas. The main benefit is therefore to trace the movement of blood and other fluids. Developments will hopefully lead to this being a cheap, portable method of imaging the brain in full 3-D detail.
See http://dnl.ucsf.edu/users/tferree/docs/IEEE2002.pdf for the detailed interpretation of info from EIT.
SPECT (Single Photon-Emission Computed Tomography) enables doctors to build 3D images of the brain by detecting details about the flow of blood. This shows brain function and is vital for detection of illnesses. This is done by radioactive labelling blood.
Powerful new microscopes and other technologies make studies of actual human tissue very valuable to serious researchers, while making animal research obsolete
TOP : Highly detailed slide of human brain tissue taken post-mortem.
BOTTOM : F-dopa PET in Parkinson’s disease before (a) and after (b) dopamine cell implantation
PET (Positron emission tomography) scans detect radiation from positrons, and enable a detailed picture of the illness to be constructed. This is vital for patients with brain dysfunction for which the cause has not been determined.
MRS (Magnetic Resonance Spectroscopy) Enables chemical analysis of the brain without surgery, by distinguishing the chemical nature of the part of the brain being scanned. This is done by detecting the magnetic resonance in that part of the brain and analysing the data this shows.
EROS Uses lasers which can pass through the skull, to image the brain. They are fired from dozens of different directions at once, and the technique measures differences in the way they reflect. The differences are caused by the fluid in the brain cells, and reveal vital information about the condition of the different parts of the brain.
TMS (Transcranial magnetic stimulation) stimulates or calms parts of the brain using magnetic impulses. Higher frequencies stimulate, lower ones calm. This enables doctors to calm brain areas and assess the affect on symptoms, therefore identifying brain areas linked with specific illnesses. Long-term imbalances in the brain can be identified.
Without autopsies, the progress in neurology would be almost non existent. This method has focused on real patients and the real nature of their brains, and full records of their condition have been compared with the findings. As microscopes become more powerful, the method becomes more effective.
In vitro study involves studying human brain tissue and understanding the chemical interactions and detailed information about the biology of it. It also compares healthy tissue with unhealthy tissue to show the difference, and has already helped enormously with development of treatments.
Computer modelling is becoming more advanced each year. With the information from autopsy, in vitro studies and technological imaging, knowledge of the brain and activity in it is more detailed than ever. The healthy brain, and the brain afflicted by illnesses can now be modelled and the complex interactions can be modelled.
The human brain is unlike any other, with additional areas, different proportions, and is organised differently. The only way the function of the human brain has been understood has been through clinical (human) study.
Studies have shown that the same areas in different animal and human brains play different roles as well: damage to the corresponding parts of monkey and human brains has been shown do cause different symptoms.
In the early 1800s the speech centres of the brain were located through autopsies and observing patients – work which would have been impossible through vivisection as animals lack the same speech process more obviously than they lack other processes.
Research into human brain function is only really possible through studying humans – either in life or at post mortem. As a recognised neurologist explains:
“The study of the brain, if it is to bear fruit, must be made on man, i.e. at the bedside and in the post-mortem theatre; …The utmost that can be learned from experiments on the brains of animals is the topography of the animal’s brain, and it must still remain for the science of human anatomy and clinical investigation to enlighten us in regard…of our own species; and in fact, it is from the department of clinical investigation and post-mortem study that so far all of our best brain localizations have been secured.”