Brain Imaging: MRI and fMRI Techniques

• Investigating Brain Functions

MRI (Magnetic Resonance Imaging)

• Involves exposing a body part to a strong magnetic field to organize protons.
• The alignment of protons allows for a highly detailed image to be formed.
• Used for detecting tumors and other abnormalities.
• Non-invasive and painless imaging technique that does not involve exposure to radiation.
• Offers high spatial resolution, allowing precise localization of brain structures.
• Can be used to detect a wide range of medical conditions including tumors, multiple sclerosis, and stroke.
• A patient is placed in a tunnel surrounded by a powerful magnet.
• Relatively expensive and time-consuming compared to other imaging techniques.
• May not be suitable for people with certain medical devices like pacemakers or metal implants.
• May not be suitable for people who experience claustrophobia or anxiety in enclosed spaces

fMRI (Functional Magnetic Resonance Imaging)

• fMRI measures the activity of neurons in the brain by measuring oxygen consumption.
• Active parts of the brain contain more oxygen-rich blood.
• Relative amounts of oxyhaemoglobin and haemoglobin affect the MRI signal differently, enabling measurement.
• Enables measuring changes in the brain during activity.

CT Scan (Computed Tomography)

• A patient is injected with a 'contrast' iodine to highlight the brain's blood vessels.
• Involves taking a quick succession of X-ray images which can be combined to produce a 3D image.
• Detects tumors, strokes, broken bones, and structural abnormalities.
• A fast and relatively cheap imaging technique.
• Can detect and diagnose medical conditions, including traumatic brain injuries, tumors, and brain bleeding.
• Involves exposure to ionizing radiation, which can increase the risk of cancer over time.
• Has a limited ability to distinguish between different types of soft tissues in the brain.

EEG (Electroencephalograph)

• Detects, amplifies, and records the brain's electrical activity using electrodes.
• Shows brain waves detected from neuron signals displayed on a graph.
• A non-invasive and painless method of recording brain activity and inexpensive
• Measures brain activity with high temporal resolution to detect real-time changes.
• Has limited spatial resolution, which means it cannot precisely locate the source of brain activity.
• Sensitive to external electrical noise, which can affect the accuracy of recordings.

PET Scan (Positron Emission Tomography)

• Based on the consumption of glucose by the brain.
• Glucose containing a radioactive tracer is taken orally or injected into the bloodstream, where it gives off positrons.
• Positron detectors generate color-coded pictures that display different neural activities.
• Identifies brain tumors, epilepsy, and blood clots.
• Uses a radioactive tracer, so precautions must be taken with pregnant women.
• Images produced are not as detailed as an MRI.

Explore MRI and fMRI techniques for brain imaging. MRI uses magnetic fields to create detailed anatomical images, while fMRI measures brain activity by detecting changes associated with blood flow. Both are crucial for neuroscience, offering non-invasive insights into brain structure and function.