Globus Pallidus External Segment Neuron Classification in Freely Moving Rats: A Comparison to Primates

Abstract

Globus Pallidus external segment (GPe) neurons are well-characterized in behaving primates. Based on their firing properties, these neurons are commonly divided into two distinct groups: high frequency pausers (HFP) and low frequency bursters (LFB). However, no such characterization has been made for behaving rats. The current study characterizes and categorizes extracellularly recorded GPe neurons in freely moving rats, and compares these results to those obtained by extracellular recordings in behaving primates using the same analysis methods. Analysis of our data recorded in rats revealed two distinct neuronal populations exhibiting firing-pattern characteristics that are similar to those obtained in primates. These characteristic firing patterns are conserved between species although the firing rate is significantly lower in rats than in primates. Significant differences in waveform duration and shape were insufficient to create a reliable waveform-based classification in either species. The firing pattern analogy may emphasize conserved processing properties over firing rate per-se. Given the similarity in GPe neuronal activity between human and non-human primates in different pathologies, our results encourage information transfer using complementary studies across species in the GPe to acquire a better understanding of the function of this nucleus in health and disease.

Arkypallidal Cells Send a Stop Signal to Striatum

“…1G). This is consistent with labeled Protos in awake mice (Dodson et al, 2015), and with the majority subpopulation in many GPe studies in awake monkeys and rats (DeLong, 1971; Raz et al, 2000; Gage et al, 2010; Benhamou et al, 2012). Identified Arkys were more irregularly active (Fig.…”

Pharmacologic MRI (phMRI) as a tool to differentiate Parkinson's disease–related from age-related changes in basal ganglia function

“…In addition, the GPe receives dopaminergic inputs as well, although the functional significance of these inputs is not fully understood (Parent et al, 2001). Data collected from both rodent and primate studies indicate that a lower average firing rate has been observed in the rodent GP compared to the primate GPe, while firing patterns were very similar (Benhamou et al, 2012). The phMRI responses observed in the GPe following dopaminergic stimulations appear to parallel previously reported neurophysiological data.…”

A novel tri-component scheme for classifying neuronal discharge patterns

“…Since FF and AF are sensitive to Poissonian noise and to across trial variability (Churchland et al, 2010), these metrics are able to detect local variations in pattern or rate. Two additional novel metrics, post spike suppression (PSP) (Benhamou et al, 2012) and residual metrics (Maimon and Assad, 2009) were also assessed, but were found to be not particularly useful. Because current metrics, including CV, LVr, and density histogram (Leblois et al, 2010), were found here to be inadequate for delineating burstiness, we developed a new burst discrimination metric.…”