Acute <em>In Vivo</em> Electrophysiological Recordings of Local Field Potentials and Multi-unit Activity from the Hyperdirect Pathway in Anesthetized Rats

Abstract

Converging evidence shows that many neuropsychiatric diseases should be understood as disorders of large-scale neuronal networks. To better understand the pathophysiological basis of these diseases, it is necessary to precisely characterize in which way the processing of information is disturbed between the different neuronal parts of the circuit. Using extracellular in vivo electrophysiological recordings, it is possible to accurately delineate neuronal activity within a neuronal network. The application of this method has several advantages over alternative techniques, e.g., functional magnetic resonance imaging and calcium imaging, as it allows a unique temporal and spatial resolution and does not rely on genetically engineered organisms. However, the use of extracellular in vivo recordings is limited since it is an invasive technique that cannot be universally applied. In this article, a simple and easy to use method is presented with which it is possible to simultaneously record extracellular potentials such as local field potentials and multiunit activity at multiple sites of a network. It is detailed how a precise targeting of subcortical nuclei can be achieved using a combination of stereotactic surgery and online analysis of multi-unit recordings. Thus, it is demonstrated, how a complete network such as the hyperdirect cortico-basal ganglia loop can be studied in anesthetized animals in vivo.

Subthalamic beta oscillations correlate with dopaminergic degeneration in experimental parkinsonism

“…For STN recordings, a pair of parylene insulated tungsten microelectrodes (Microprobes for Life Science, MD, USA; 1.5 MΩ impedance) was slowly inserted into the left hemisphere 1 mm above the target coordinates (AP: − 3.6, ML: +2.5, DV: − 8.0 mm). The final positioning of the electrodes in the STN was controlled by online evaluation of multi-unit activity as described previously (Haumesser et al 2017).…”

Dopamine depletion can be predicted by the aperiodic component of subthalamic local field potentials

“…We dipped 16-channel NeuroNexus probes into DiI (Invitrogen, MA, USA) and slowly inserted them into the left STN (AP, −3.6 mm; ML, − 2.5 mm; DV, −7.5 mm from the dura surface), while high-pass filtered spikes were continuously monitored for fine positioning of the electrodes upon evaluation of multiunit activity as previously described. (Haumesser et al, 2017) The correct placement of the electrode was further verified by DiI tracking and microscopic evaluation. We excluded animals with inaccurately placed electrodes or trials that lacked typical STN multiunit activity.…”

A Simple, Lightweight, and Low-Cost Customizable Multielectrode Array for Local Field Potential Recordings

“…APs identified to be produced by single neurons are called single units, whereas those from multiple neurons are multiunits ( Wickenden, 2014 ). Implanted electrodes can also collect local field potential (LFP) activity, which are synaptic currents generated through the summed synchronous synaptic activity of neurons ( Dzirasa et al, 2011 ; Harris et al, 2017 ; Haumesser et al, 2017 ). Although EEG, calcium, and LFP activity represent neural population activity, LFPs have a better spatial and temporal resolution, are stable and robust across changes in the electrode sensitivity ( Im and Seo, 2016 ; Zhang et al, 2022 ), and are less susceptible to electrode micromotion effects ( Martini et al, 2020 ).…”