Important Terms & Definitions for the Glymphatic System:

Glymphatic System

The glymphatic system is a waste clearance system in the brain that helps remove metabolic waste, toxins, and excess proteins, such as beta-amyloid, from the central nervous system. It operates primarily during sleep and relies on the flow of cerebrospinal fluid (CSF) through brain tissue to flush out interstitial waste via perivascular pathways. The system is supported by glial cells, particularly astrocytes, which help regulate fluid exchange between the cerebrospinal fluid (CSF) and interstitial fluid (ISF).

Cerebrospinal Fluid (CSF)

Cerebrospinal fluid (CSF) is a clear, colorless fluid that surrounds and cushions the brain and spinal cord. It plays a crucial role in protecting the central nervous system (CNS) by providing mechanical support, removing waste products, and maintaining a stable chemical environment.

Interstitial Fluid (ISF)

Interstitial fluid surrounds and bathes the cells in the body's tissues, providing nutrients, oxygen, and a medium for waste removal. It is a component of the extracellular fluid and plays a crucial role in maintaining cellular function and homeostasis. In the brain, interstitial fluid interacts with cerebrospinal fluid (CSF) as part of the glymphatic system, facilitating waste clearance.

Transcranial Magnetic Stimulation (TMS)

TMS (Transcranial Magnetic Stimulation) is a non-invasive brain stimulation technique that uses magnetic fields to induce electrical currents in specific areas of the brain.

Neuromodulation

Neuromodulation is the process of altering nerve activity through targeted delivery of electrical, chemical, or biological stimuli to specific areas of the nervous system. TMS is an example of neuromodulation.

Pulse Sequence

In MRI, a pulse sequence is a set of instructions for the machine on how to use magnetic fields and radio waves to take pictures of the inside of your body. It tells the MRI scanner how to interact with the hydrogen atoms in your body, which are found in water and fat, to create detailed images of your tissues. Each MRI scan type is defined by its pulse sequence, making this a fundamental concept in medical imaging.