Functional Magnetic Resonance Imaging (FMRI)
International Journal of Scientific and Research Publications, Volume 3, Issue 12, December 2013ISSN 2250-31531Functional Magnetic Resonance Imaging (FMRI)C. Adharsh John*B. Tech. Vishwajyothi College of EngineeringAbstract- People express their mental states, including emotions,thoughts, and desires, all the time through facial expressions,vocal nuances and gestures.Functional MRI or functional Magnetic Resonance Imaging(fMRI) is a type of specialized MRI scan. It measures thehaemodynamic response (change in blood flow) related to neuralactivity in the brain or spinal cord of humans or other animals. Itis one of the most recently developed forms of neuro-imaging.Since the early 1990s, fMRI has come to dominate the brainmapping field due to its relatively low invasiveness, absence ofradiation exposure, and relatively wide availability.fMRI’s might be the future technology to read yourthoughts and emotions. There have been claims that fMRI candetermine if you are telling the truth, what image you are lookingat, and perhaps - in the future - what you are thinking about,feeling, or your intentionsFig 2: Relationship between energy and magnetic fieldI. INTRODUCTIONThe idea that regional cerebral blood flow (CBF) could reflectneuronal activity began with experiments of Roy andSherrington at 1890 (1). This concept is the basis for allhemodynamic-based brain imaging techniques being used today.Functional MRI is a very powerful method to map brainfunctions with relatively high spatial and temporal resolution. Inorder to utilize fMRI techniques efficiently and interpret fMRIdata accurately, it is important to examine underlying physiologyand physics. In this article, we will discuss the signal source ofthe BOLD signal and improvement of BOLD fMRI techniques.Also, experimental hardware and software will be described forhelping non-experts understanding MRI.II. WHAT IS MIND READING?Our mental states shape the decisions that we make, governhow we communicate with others, and affect our performance.The ability to attribute mental states to others from their behaviorand to use that knowledge to guide our own actions and predictthose of others is known as theory of mind or mind-reading.Fig1:mind readerIn scientific basis mind reading may be defined as aneuroimaging technique which allows us to detect the brain areaswhich are involved in a task, a process or an emotion.III. PRINCIPLE OF MRINUCLEAR MAGNETIC RESONANCEWhen a nucleus with an overall magnetic moment is placedin an external magnetic field it will either line up parallel or antiparallel (often termed spin up or spin down) with the externalmagnetic field, as shown below-www.ijsrp.org
International Journal of Scientific and Research Publications, Volume 3, Issue 12, December 2013ISSN 2250-31532Fig3: Magnetic dipole momentEnergy splitting of nuclear spin states as a function of anexternal magnetic field, B0.ms 1/2 is the spin up state and ms -1/2 is the spin down state.The difference between these two energyFig 2states is proportional to the strength of the external magneticfield that the nucleus is in. As the external field increases, theenergy difference between the two states increases.The energy difference is usually related to an amount ofenergy resonant with a radio frequency pulse. When a radio pulseis applied to the system, it can flip the spin, causing thissubatomic magnetic needle to align itself antiparallel to theexternal magnetic field (the higher energy state).If a radiofrequency pulse is emitted of just the right amountof energy for the atom to absorb, the lower energy spin stateswill flip to the higher energy state. When the atoms go back tothe lower energy state, they emit a radio frequency. When manyatoms absorb and then re-emit this energy there is a detectablesignal.For regular MRI’s on our body the hydrogen nuclei in watermolecules are used. Our bodies are more than 72% water, whichis mainly found in soft tissue. A weighting is often done betweenthe absorbed and emitted radio frequency signals to determinethe different types of tissue. Then, by using s ome powerfulmathematical computations and imaging techniques, the signalsobserved are transformed into an image of what absorbed andreleased these signals.Fig 4: Brain parts affectedIV. FUNCTIONAL MRI(FMRI)For fMRIs the focus is on blood, blood flow, and how muchoxygen is in theFig 5blood. During a thought neurons are activated or are being firedin regions of the brain. These active neurons need energy andthey get it from glucose supplied by blood.Oxygen rich bloodhas about a 20% greater magnetic strength than deoxygenatedblood.Acontrast between the oxygenated and deoxygenated bloodcan be observed using magnetic resonance imaging techniques.The oxygenated blood produces the strongest signal when placedin a strong magnetic field .Radiologists interpreting fMRI scans measure the bloodflow, blood volume, and oxygen levels, which is commonlyknown as the Blood-Oxygen-Level-Dependent or BOLD signal.A computer processes the detected signal and maps it into 3-Dimages that are colored based on the measured BOLD signal .V. MIND READING USING FMRIThe brain activity is mapped into cubes called voxels, whichas similar to computer pixel (picture element). Each voxel(volumetric pixel element) represents tens of thousands ofneurons or nerve cells. Most people have the same basic regionsof the brain activated when thinking about the same object, whenthey have visited the same place, and when they perform or thinkabout doing mathematical functions such as addition orsubtraction.www.ijsrp.org
International Journal of Scientific and Research Publications, Volume 3, Issue 12, December 2013ISSN 2250-3153Radiologists cannot use fMRI to determine each neuron’sfunction, but they can get a mapping of active parts of the brainand they are getting better at interpreting these maps.Fig6Fig %:a birdWhen you are thinking about something (let's say a bird),fMRI can show which voxels are activated (let's say voxels 3352-20 and 34-12-40). Mind reading through functional MRI isinverting this relationship: if fMRI shows you are activatingvoxels 33-52-20 and 34-12-40, we can assure thatyou arethinking about a bird.VI. EXPERIMENTAL SETUP OF ANIMAL FMRIIn order to perform MRI experiments, it is necessary to havea magneticFig 7resonanceimager, which can be obtained from MRImanufacturers.3APPAATUS REQUIREDAn integrated MRI system consists of a magnet, gradient andshim coil(s) (often integrated), a console, radiofrequency (RF)and gradient amplifiers, and RF coils.(i) The most expensive item is a super-conducting magnet.Strength of magnetic field (Bo) is defined as a unit of Tesla (1Tesla ( 10,000 gauss) is equivalent to about 20,000 times theearth’s magnetic field). Typical magnetic fields for humanresearch range between 1.5 T(ii) A gradient coil set inserted into the magnet boregenerates linear magnetic fields along x,y, and z directions.(iii) Console consists of receivers that detect, amplify,demodulate, and digitize the MRsignals detected by the RF coil,and a set of electronics that can generate a pattern of RF andgradient pulses (which are sent to the amplifiers) for thegeneration of the appropriate imaging signals from the sample. Acomputer controls both of these processes in the console(iv) RF coils are used to transmit RF pulses for excitationof water and detect RF signalsfrom water. For whole brainstudies, a homogenous head coil should be used, while a smallsurface coil can be used for localized brain studies.Anesthetized (or awake) rat is inserted into the center ofmagnet borefor fMRI studies. To monitoranimal conditions,end-tidal CO2 level, body temperature, and blood pressure arecontinuously monitored, and blood gases are repeatedlymeasured. Several changes were made in rats surroundings ,liketemperature, light&heat etc.& different BOLD signals wereobtained.fMRI time courses of spin-echo BOLD signal in the primarysomatosensory region of rat. Color indicates a cross-correlationvalue. Localized activation is observed at the forelimbThese datas are passed through fmri data processingsoftwares.fMRI data processing software can be obtained fromvarious sources (AFNI, Brain Voyager, FIESTA?, SPM,Stimulate, etc). Processing software contain various statisticalmethods as well as visualization methods.VII. APPLICATIONS OF THIS TECHNOLOGYMind Controlled WheelchairFig 9Fid 8:appartuswww.ijsrp.org
International Journal of Scientific and Research Publications, Volume 3, Issue 12, December 2013ISSN 2250-3153A little different from the Brain-Computer Typing machine,this thing works by mapping brain waves when you think aboutmoving left, right, forward or back, and then assigns that to awheelchair command of actually moving left, right, forward orback.The result of this is that you can move the wheelchairsolely with the power of your mind. It will be truly helpful forthe paralysed and disabled people.4IN COMMUNICATION FIELDA future where we are surrounded with mobile phones, carsand online services that can read our minds and react to ourmoods. Even we can drive cars without streeing.CRIMINAL BRAINMAPPPING & LIE DETECTORDevelopment of this technology will become an helpful aidin reading intentions of criminals on scientific basis and toinvestigate crimes.WORLD WITHOUT INPUT DEVICESIN MEDICAL FIELDFig 12: GeneralPhysicians perform fMRI to:Examine the anatomy of the brain.-Determine precisely which part of the brain is handling criticalfunctions such as thought, speech, movement and sensation,which is called brain mapping.-Help assess the effects of stroke, trauma or degenerative disease(such as Alzheimer's) on brain function.- Monitor the growth and function of brain tumours. Guide theplanning of surgery, radiation therapy, or other surgicaltreatments for the brain.VIII. ADVANTAGES & DEMERITSADVANTAGESFig 10 :brain features in a mri scan reportFig 12: reportHuge time is spent in input data to computers. By usingthis technology input can be given directly from mind tosystem,Leading to tremendous changes in industrial,health,&educational fields.www.ijsrp.org
International Journal of Scientific and Research Publications, Volume 3, Issue 12, December 2013ISSN 2250-3153fMRI and MRI machines are harmless with virtually no sideeffects. However they are not for those who have claustrophobiaor any metal pins or rods in their bodies.They are effective to determine areas of thought, brainfunction, and the health of brain tissue, as well as analyzingemotion.Short acquisition time of imagesMapping of complex functions (emotions, motor control,specialized language functions,.) is possible.DEMERITSTAPPING OF BRAINS FOR FUTURE CRIMESFreedom of right to think any time,any thing at any wheregets destroyes. Chances of misusing this technology to tap one’sthoughts will lead to dangerONLY SIMPLEX MODE OF COMMUNICATION POSSIBLEOnly signals from brain can be detected.Signals to braincannot be propagated.CALIBRATION VARY FROM PERSON TO PERSONIndividual brains differ, so scientists need to study asubject's patterns before they can train a computer to identifythose patterns or make predictions.APPARATUS REQUIRED ARE COSTLIER & HUGE.5IX. CONCLUSIONFunctional magnetic resonance images (fMRIs) arebecoming popular in both the consumer and research arenas. Bigbusinesses use fMRIs to determine consumer preferences andwhich movie scenes viewers prefer. Smaller businesses utilizethe machines as lie detector tests. However, the technique offMRI is being most utilized for clinical and basic research bymany different professions.Imaging brain activity is a source of data that providesinsights into individual characteristics.This technology is going to be a mojor tool for scientist’s inthe development of next generation computers working onartificial .co.uk/arts/links/fmri.phpPrinciples of Functional MRI(pdf) Seong-Gi Kim, Ph.D. Departmentof Neurobiology, University of Pittsburgh Medical Schoolhttp://www.physicscentral.com/fmri.htmA Primer on MRI and Functional MRI(pdf) (version 2.1, 6/21/01) DouglasC. Noll, Ph.D. Departments of Biomedical Engineering and RadiologyUniversity of Michigan, Ann Arbor, MI 48109-2125AUTHORSFirst Author – C.Adharsh john, Btech : Vishwajyothi college ofEngineering, Mail:adhajohn@gmail.com, Phno:91-9633315206www.ijsrp.org
Functional MRI or functional Magnetic Resonance Imaging (fMRI) is a type of specialized MRI scan. It measures the haemodynamic response (change in blood flow) related to neural activity in the brain or spinal cord of humans or other an
magnetic resonance imaging (fMRI) and two related techniques, resting-state fMRI (rs-fMRI) and real-time fMRI (rt-fMRI), to the diagnosis and treatment of behavioral problems and psychiatric disorders. It also explains how incorporating neuroscience
Spring 2007 fMRI Analysis Course 1 Outline MR Basic Principles Spin Hardware Sequences Basics of BOLD fMRI Susceptibility and BOLD fMRI A few trade-offs Spring 2007 fMRI Analysis Course 2 Basics of BOLD fMRI Spring 2007 fMRI Analysis Course 3 The MR room Spring 2007 fMR
Director, fMRI Research Center Columbia University Health Sciences NI Basement www.fmri.org Neuroscience 2004 Functional Brain Imaging Hirsch, J., et al Columbia fMRI I. Hypothesis of functional specificity II. Brain Mapping Techniques 1. Positron Emission Tomography, PET 2. Functional Magnetic Resonance Imaging
Principles of functional Magnetic Resonance Imaging 5 s Publication Year The Growth of fMRI FIGURE 1.1 The yearly number of publications in PubMed that mention the term ‘fMRI’ either in its title or abstract between 1993 to 2012. teams with experti
Functional magnetic resonance imaging (fMRI) has become a mainstream neuroimaging modality in the assessment of patients being evaluated for brain tumour and epilepsy . principles and state-of-the-art clinical applications of fMRI
Functional magnetic resonance imaging (functional MRI or fMRI) 39 Using fMRI to analyze activation patterns within a brain area 42 Using fMRI to examine activity relationships between brain areas 44 Optical brain imaging 45 . Principl
Functional magnetic resonance imaging (fMRI) has quickly become the preferred technique for imaging normal brain activity, especially in the typically developing child. This technique takes advantage of specific magnetic properties and phys
Literary Theory and Schools of Criticism Introduction A very basic way of thinking about literary theory is that these ideas act as different lenses critics use to view and talk about art, literature, and even culture. These different lenses allow critics to consider works of art based on certain assumptions within that school of theory. The different lenses also allow critics to focus on .
