Classification of extracellularly recorded neurons by their discharge patterns and their correlates with intracellularly identified neuronal types in the frontal cortex of behaving monkeys

Abstract

Neurons in the cerebral cortex are not homogeneous. However, neuronal types have been ignored in most previous work studying neuronal processes in behaving monkeys. We propose a new method to identify neuronal types in extracellular recording studies of behaving monkeys. We classified neurons as either bursting or non-bursting, and then classified the bursting neurons into three types: (i) neurons displaying a burst of many spikes (maximum number of spikes within a burst; NSB max > or = 8) at a high discharge rate (maximum interspike interval; ISI max < 5 ms); (ii) neurons displaying a burst of fewer spikes (NSB max < or = 5) at a high discharge rate (ISI max < 5 ms); and (iii) neurons displaying a burst of a few spikes (NSB max < or = 7) at relatively long ISIs (ISI max > 5 ms). We found that the discharge patterns of the four groups corresponded to those of regular spiking (RS), fast spiking (FS), fast rhythmic bursting (FRB) and intrinsic bursting (IB) neurons demonstrated in intracellular recording studies using in vitro slice preparations, respectively. In addition, we examined correlations with the task events for neurons recorded in the frontal eye field and neuronal interactions for pairs of neurons recorded simultaneously from a single electrode. We found that they were substantially different between RS and FS types. These results suggest that neurons in the frontal cortex of behaving monkeys can be classified into four types based on their discharge patterns, and that these four types contribute differentially to cortical operations.

Neuronal Signal Dynamics during Preparation and Execution for Behavioral Shifting in Macaque Posterior Parietal Cortex

“…According to a previous study (Katai et al, 2010), we classified each of the SR neurons into two cell types, a putative regular spiking (pRS) neuron or a putative burst spiking (pBS) neuron, on the basis of interspike intervals (ISI). If the ISIs smaller than 5 msec accounted for less than 5% of all the ISIs recorded from the neuron, the neuron was classified as a pRS neuron.…”

Attentional Modulation of Firing Rate Varies with Burstiness across Putative Pyramidal Neurons in Macaque Visual Area V4

“…These should be distinguished from narrow spiking neurons that lack burst firing, which are instead likely to correspond to fast-spiking interneurons. One recent study (Katai et al, 2010) has used spiking statistics to distinguish among four different cell classes in the frontal cortex of the behaving primate. Their study identified these with classes previously defined in slice (intrinsically bursting (IB), regular spiking (RS), fast spiking (FS), and fast rhythmic bursting (FRB)).…”

“…However, recent studies in the awake primate that have examined spiking statistics in more detail have revealed a diversity of firing patterns across neocortical regions (Maimon and Assad, 2009) as well as across neurons recorded within individual cortical areas (Bair et al, 1994; Friedman-Hill et al, 2000; Compte et al, 2003; Joelving et al, 2007; Katai et al, 2010). Indeed, many intracellular recording studies have used discharge patterns such as bursting to distinguish among different neocortical neuronal classes (McCormick et al, 1985; Nowak et al, 2003).…”

Towards the automatic classification of neurons

“…Spike shape and timing were identified as key physiological features, notably firing rate, fast after-hyperpolarization depth of the first spike, as well as half-height width and latency from stimulus of the second spike. Other similar studies reported analogous distinctive electrophysiological parameters, namely rise, duration, and decay of the first two spikes, plus firing rate and spike duration at 10 Hz [21,58]. …”