Research in the neurosciences is a constantly evolving field of study, and neurophysiological techniques continue to progress in conjunction with advancements in the technology of what it takes to examine the animal brain. At the forefront of these developments is Neuralynx©, the main provider of sophisticated electrophysiology systems and high-performance data acquisition hardware and software, with applications in both research and clinical contexts.
The primary goal of electrophysiological recording is to detect and measure communication signals between neurons in real time. Electrophysiology is a tool that allows scientists and researchers to examine the neural bases and neuronal network correlates of simple and complex behaviors, which can tell us a lot about how the brain functions and which brain regions are activated during specific activities. For instance, electrophysiological recording is a widely applied technique in the study of spatial orientation and navigation among rodents, such as grid cell experiments. Experiments such as these typically examine grid cells, place cells, and head direction of the hippocampus and medial entorhinal cortex, which are all part of the brain’s neural network that tells us our position in space. These cell types and regions of the brain are extensively studied by obtaining electrophysiological recordings from rodents during experimental maze trials.
Electrophysiological recordings are achieved by installing electrodes in the animal brain, which come in devices of different varieties and techniques depending on one’s need. The principal types of electrodes are solid conductors such as discs or needles, tracings on printed circuit boards, or hollow tubes such as glass pipettes that are filled with an electrolyte solution. Electrophysiological activity can be recorded inside the cell if the tool is small enough to do so, and scientists can also make use of whole-cell recording, perforated patch recording, and patch recording. Aside from intracellular activity, electrophysiological recording techniques also include single-unit and multi-unit recording, detecting the activity of several nearby cells simultaneously. Currently, technology allows electrodes to be chronically-implanted onto the rodent brain to record brain activity during particular behaviors and can last up to several weeks.
These electrophysiological techniques allow the recording of brain communication across three levels of information processing and communication–microscopic (ion channels, spiking neurons, and neuronal assemblies as the neural substrate); mesoscopic (oscillatory electroencephalographic activity at different scales, which reflect neural networks); and macroscopic (large-scale activation and synchronization for integrative information processes). Currently, modern physiological methods range from single-neuron and neuronal ensemble recordings to recordings of field potentials within discrete brain regions as well as multiple brain areas (Kolev, 2011; Vertes & Stackman Jr., 2011).