March, 1st, 2023 by Marcio Furtado

 The human brain is one of the most complex and enigmatic structures in the universe, but it's not just humans that have fascinating brains. Small animals, such as rodents and zebrafish, have intricate neural networks that are being studied extensively to understand brain function and disorders. Electroencephalography (EEG), a that measures the electrical activity of the brain, is an essential tool in small animal research. In this article, we'll take a closer look at how EEG is performed experimentally in small animals and the exciting discoveries that are being made.

Preparing Small Animals for EEG

 Performing EEG on small animals is similar to performing EEG on humans, but it requires additional care and attention to ensure accurate results. The first step in performing EEG on small animals is to anesthetize them, which can be done using a variety of methods, including inhalation or injection. It's important to use an appropriate anesthetic and dosage to ensure that the animal remains unconscious and stable throughout the procedure.

 Once the animal is anesthetized, its head is secured in a stereotaxic frame, which ensures that the electrodes are placed in the correct location. The EEG electrodes can be inserted into the cortex or in deep brain structures.

Recording EEG Signals in Small Animals

 Once the electrodes are in place, the EEG signals are recorded using an amplifier and a computer system. The EEG signal is typically recorded from several electrode sites simultaneously, allowing researchers to obtain a more comprehensive view of the animal's brain activity. To ensure that the recorded signal is as clean and accurate as possible, it's important to minimize any noise or artifacts that may interfere with the signal. This can be achieved by reducing movement, shielding the animal from external electromagnetic fields, and avoiding electrical interference from other equipment in the room.

Analyzing EEG Signals in Small Animals

 After the EEG signals are recorded, they are analyzed using specialized software. The analysis of EEG signals in small animals can be more complex than in humans due to the smaller size of the brain and the higher levels of noise in the signal. However, the same principles apply, and the resulting EEG signal is a graphical representation of the electrical activity of the brain, with different waveforms and frequencies corresponding to different types of neural activity.

Exciting Discoveries in Small Animal Research with EEG

 EEG has numerous applications in small animal research, from the study of basic brain function to the development of new treatments for neurological and psychiatric disorders. Here are some examples of the exciting discoveries that are being made in small animal research with EEG:

1.      Studying the Neural Basis of Behavior: EEG is used to study the neural basis of behavior in small animals, exploring how the brain processes information, controls movement, and regulates emotions. By measuring the electrical activity of the brain during different behavioral tasks, researchers can gain insights into the neural circuits that underlie behavior.

2.      Developing Animal Models of Neurological and Psychiatric Disorders: Small animal research with EEG is essential for the development of animal models of neurological and psychiatric disorders, which can be used to explore the underlying mechanisms of these disorders and test new treatments.

3.      Testing the Efficacy of Treatments: EEG is used to test the efficacy of new treatments for neurological and psychiatric disorders in small animals. By measuring the effects of treatments on the brain activity of small animals, researchers can determine whether the treatment is effective and whether it has any adverse effects. For example, EEG has been used to evaluate the effects of drugs that target epilepsy in rats, providing insight into the mechanisms underlying this disorder and helping to develop new treatments. Similarly, EEG has been used to evaluate the effects of deep brain stimulation, a technique used to treat movement disorders such as Parkinson's disease. By measuring the changes in brain activity caused by deep brain stimulation, researchers can determine whether the treatment is effective and optimize the stimulation parameters to achieve the best results.

4.      Studying Brain Development: EEG is also used to study brain development in small animals, exploring how the brain changes during the early stages of life. For example, EEG has been used to study the development of the visual system in zebrafish, providing insight into the neural mechanisms underlying visual processing.

 In conclusion, EEG is a powerful tool for studying the brain in small animals, enabling researchers to explore the neural basis of behavior, develop animal models of neurological and psychiatric disorders, test the efficacy of treatments, and study brain development. By combining EEG with other techniques such as optogenetics and functional imaging, researchers can gain an even deeper understanding of the brain and make exciting discoveries that may lead to new treatments for neurological and psychiatric disorders.