MRI and fMRI: Brain Imaging Techniques

<p>7 and 10 Tesla scanners are now used in research. (A)</p> Signup and view all the answers

<p>White matter properties (C)</p> Signup and view all the answers

<p>It assesses metabolic activity and blood flow. (A)</p> Signup and view all the answers

<p>Increased hippocampal volume. (C)</p> Signup and view all the answers

<p>White matter tracts and their integrity. (B)</p> Signup and view all the answers

<p>PiB (A)</p> Signup and view all the answers

<p>Higher spatial and temporal resolutions. (A)</p> Signup and view all the answers

<p>Exposure to ionizing radiation. (D)</p> Signup and view all the answers

<p>BOLD response in the posterior occipital regions occurs after visual stimulation. (D)</p> Signup and view all the answers

<p>Initial dip in blood oxygenation followed by increased oxygen supply. (C)</p> Signup and view all the answers

<p>Randomized block design. (C)</p> Signup and view all the answers

<p>V5 (MT) (C)</p> Signup and view all the answers

<p>MT (D)</p> Signup and view all the answers

<p>V4 (C)</p> Signup and view all the answers

<p>Inability to recognize faces (A)</p> Signup and view all the answers

<p>They allow for an optimized statistical power to detect responses (B)</p> Signup and view all the answers

<p>It captures fluctuations in brain networks while participants rest (C)</p> Signup and view all the answers

<p>Patterns of fMRI responses and brain similarity (A)</p> Signup and view all the answers

<p>V1 (B)</p> Signup and view all the answers

<p>They show clear overlaps in brain regions affected (D)</p> Signup and view all the answers

<p>They elicit responses in both medial and lateral occipital cortex (C)</p> Signup and view all the answers

<p>Long wait times between events in scanning (D)</p> Signup and view all the answers

MRI uses strong magnetic fields to align the protons in water molecules within the brain. The difference in alignment between parallel and anti-parallel protons generates signals that are measured to create detailed images of the brain.

fMRI is a technique that measures brain activity by detecting changes in blood flow. When a brain area is more active, it requires more oxygenated blood. fMRI detects these changes in blood flow creating images of brain activity.

Diffusion Tensor Imaging (DTI) is a technique that uses MRI to visualize water diffusion in the brain's white matter. Water diffuses more easily along axons than across them, providing information about the direction and integrity of neuronal connections.

Higher magnetic field strengths in MRI scanners (e.g., 7T and 10T) provide better image resolution and sensitivity, allowing for deeper insights into brain structure and function.

By studying brain anatomy (structure) using techniques like MRI, scientists can understand how different brain areas are connected and how they contribute to specific functions. This knowledge informs research on brain development, disease, and learning.

A region in the brain that specializes in processing visual motion.

A brain region that responds selectively to color information.

The ability to recognize faces.

The inability to recognize faces due to damage to the fusiform gyrus.

A brain region located in the fusiform gyrus, responsible for face recognition.

A type of fMRI design where events occur randomly, allowing for the measurement of brain responses to specific events.

A statistical method used to analyze brain activity patterns across multiple trials and conditions.

The study of brain activity patterns during periods of rest, revealing the presence of functional networks.

The ability of fMRI to detect brain activity while someone imagines specific actions or experiences.

The ability of fMRI to distinguish between brain responses to different categories of stimuli.

Anatomical atlases provide detailed anatomical maps, allowing researchers to precisely identify regions of interest within individuals. This enables the measurement of functional activity in specific areas.

By comparing brain structures across groups, researchers can investigate differences associated with various conditions, such as neurological disorders or cognitive abilities.

The hippocampus, a brain region involved in memory, is larger in London taxi drivers compared to controls. This suggests that extensive spatial navigation experience can lead to structural adaptations in this area.

Diffusion Tensor Imaging (DTI) allows the visualization and measurement of white matter tracts, revealing connections between brain regions. Studies have shown that the integrity of specific white matter pathways, particularly in the ventral visual stream, is compromised in individuals with prosopagnosia (face blindness).

Positron Emission Tomography (PET) is a brain imaging technique that measures metabolic activity by detecting the release of positrons from radioactive isotopes injected into the body. This allows researchers to investigate brain activity associated with specific tasks or conditions.

A common PET tracer uses water labeled with radioactive oxygen. When injected, the unstable isotope releases positrons which collide with electrons, generating gamma rays. The scanner detects these rays, allowing researchers to locate their source and infer metabolic activity.

PET can be used to assess blood flow changes during visual tasks. By comparing blood flow patterns when a subject fixates on a central cross versus when they view a checkerboard pattern, researchers can identify brain regions exhibiting increased activity.

PiB, a PET tracer, specifically binds to beta-amyloid plaques, a characteristic of Alzheimer's disease. Imaging using PiB can help diagnose and monitor the progression of AD.

fMRI is a brain imaging technique that measures BOLD (Blood-Oxygen-Level Dependent) signal, which reflects changes in blood oxygenation related to neuronal activity.

Block designs are frequently used in fMRI studies due to the slow nature of the BOLD signal. In block designs, one condition is presented for a prolonged period followed by another condition, allowing researchers to compare the BOLD signal across different conditions.