"Counting Neurons: Comparing Invasive and Noninvasive Techniques"

Abstract

This article discusses the various techniques-categorized into invasive and noninvasive-used in neuroscience research for counting neurons and estimating their density. Invasive techniques involve physically removing and staining brain tissue to count neurons, while noninvasive techniques allow for the examination of brain structure and function in live animals or humans. Examples of invasive techniques include stereology, optical fractionator, manual cell counting, confocal microscopy, and electron microscopy. Examples of noninvasive techniques include magnetic resonance imaging (MRI), electroencephalography (EEG), and functional near-infrared spectroscopy (fNIRS). The advantages and disadvantages of each technique are summarized in Table 1. Recent advancements in noninvasive NIR spectroscopic technique to estimate neuron density are highlighted. Future research and technological advancement, especially in noninvasive techniques, could lead to a better understanding of neural circuits, their function, and our daily lives.