PMID- 37017309 OWN - NLM STAT- MEDLINE DCOM- 20230420 LR - 20230614 IS - 1522-1598 (Electronic) IS - 0022-3077 (Print) IS - 0022-3077 (Linking) VI - 129 IP - 5 DP - 2023 May 1 TI - Basal ganglia neurons in healthy and parkinsonian primates generate recurring sequences of spikes. PG - 1010-1020 LID - 10.1152/jn.00265.2022 [doi] AB - The spiking activity of basal ganglia neurons can be characterized by summary statistics such as the average firing rate, or by measures of firing patterns, such as burst discharges, or oscillatory fluctuations of firing rates. Many of these features are altered by the presence of parkinsonism. This study examined another distinct attribute of firing activity, i.e., the occurrence of repeating sequences of interspike intervals (ISIs). We studied this feature in extracellular electrophysiological recordings that were made in the basal ganglia of rhesus monkeys, before and after they had been rendered parkinsonian by treatment with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Neurons in both pallidal segments and in the subthalamic nucleus tended to fire in repeating sequences, typically two ISIs long (i.e., involving three spikes). In recordings that were 5,000 interspike intervals long, 20%-40% of spikes participated in one of many sequences with each ISI replicating the sequence pattern with a timing error of