Invasive Neuroimaging

Sometime we need to go inside the skull to figure out how the brain is behaving. While surgery is needed, the signals can be a lot clearer.

Levels of Invasiveness

There are multiple levels we can stick recording electrodes

Microelectrode Arrays

Microelectrode arrays are small arrays of electrodes that are used to measure the electrical activity of neurons in the brain. They are typically made from materials such as silicon or silicon nitride, and are designed to be implanted in the brain to record the activity of individual neurons or small groups of neurons.

Microelectrode arrays are used in a variety of research and clinical settings, including in studies of brain function, the development of brain-computer interfaces, and the treatment of neurological disorders. They can provide valuable information about the electrical activity of neurons, which can be used to understand how the brain works and develop new treatments for brain disorders.

Microelectrode arrays are typically very small, with individual electrodes measuring just a few micrometers in diameter. This allows them to be implanted in the brain without causing significant damage to the tissue. The arrays are typically connected to wires or cables that are used to transmit the electrical signals from the electrodes to recording or stimulating devices.

Spike Sorting

Now that we can record single or multi-unit activity over time, what’s next?

Spike sorting is the process of identifying and separating the action potentials, or “spikes,” of individual neurons in an electrophysiological recording. This process is typically done using computer algorithms, which analyze the electrical signals recorded by electrodes and identify the spikes of individual neurons.

Spike sorting is an important step in the analysis of electrophysiological data, as it allows researchers to study the activity of individual neurons, rather than the activity of the population as a whole. This can provide valuable information about how the brain works and how individual neurons contribute to brain function.

Spike sorting algorithms typically work by identifying the characteristic shape and timing of a neuron’s action potentials. These features are used to distinguish the spikes of different neurons, allowing the algorithm to “sort” the spikes into different groups, corresponding to individual neurons.