Differential Involvement of Excitatory and Inhibitory Neurons of Cat Motor Cortex in Coincident Spike Activity Related to Behavioral Context

Department of Anesthesia and Critical Care, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.34). 06/2010; 30(23):8048-56. DOI: 10.1523/JNEUROSCI.0770-10.2010
Source: PubMed


To assess temporal associations in spike activity between pairs of neurons in the primary motor cortex (MI) related to different behaviors, we compared the incidence of coincident spiking activity of task-related (TR) and non-task-related (NTR) neurons during a skilled motor task and sitting quietly in adult cats (Felis domestica). Chronically implanted microwires were used to record spike activity of MI neurons in four animals (two male and two female) trained to perform a skilled reaching task or sit quietly. Neurons were identified as TR if spike activity was modulated during the task (and NTR if not). Based on spike characteristics, they were also classified as either regular-spiking (RS, putatively excitatory) or fast-spiking (FS, putatively inhibitory) neurons. Temporal associations in the activities of simultaneously recorded neurons were evaluated using shuffle-corrected cross-correlograms. Pairs of NTR and TR neurons showed associations in their firing patterns over wide areas of MI (representing forelimb and hindlimb movements) during quiet sitting, more commonly involving RS neurons. During skilled task performance, however, significantly coincident firing was seen almost exclusively between TR neurons in a smaller part of MI (representing forelimb movements), involving mainly FS neurons. The findings of this study show evidence for widespread interactions in MI when the animal sits quietly, which changes to a more specific and restricted pattern of interactions during task performance. Different populations of excitatory and inhibitory neurons appear to be synchronized during skilled movement and quiet sitting.

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Available from: David Putrino, Dec 30, 2013
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    • "The present paper aims to compare the effect of distinct iSTDP window shapes on the structure of synaptic weights, and endeavors to clarify the role of iSTDP in tuning neuronal responses. Previous studies have shown the precise timing of spikes to convey an important part of information about stimuli in sensory pathways (Riehle et al., 1997; Jackson et al., 2003; Maldonado et al., 2008; Kilavik et al., 2009; Putrino et al., 2010). Moreover, neurons are sensitive to precise timings of spikes (Rossant et al., 2011). "
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    • "neurons were significantly more likely to display task-related spiking associations than regular spiking (RS) neurons in MI [10]. Furthermore, inhibitory interneurons in MI have been shown to interact with pyramidal cells in order to appropriately shape their patterns of task-related firing during reaching [11] [12]. "
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    • "Without sufficient spike data, the fidelity of these metrics is diminished. Second, coherent spike activity in both cortex (Constantinidis et al., 2002; Putrino et al., 2010) and striatum (Kimura et al., 2003), as well as striatal LFPs (Barnes et al., 2005), have been shown to be differentially driven by task performance, but rodent HD models show robust deficiencies in performing skilled behavioral tasks (Brooks and Dunnett, 2009). Such tasks, moreover, promote synaptic plasticity, which is compromised in cortex (Cummings et al., 2006, 2007) and striatum (Milnerwood et al., 2006) of HD models. "
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