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## Pathophysiology  ### Animal models  A face-valid animal model of tics has been a very important but elusive goal. McCairn and colleagues have now published their important work characterizing a nonhuman primate tic model \citep{26796690}. \cite{26796690}.  Unilateral, temporary disinhibition of the nucleus accumbens (NA)—the ventral, more limbic-connected part of the striatum—produces vocalizations in monkeys that resemble vocal tics in human patients. The vocalizations sometimes were associated with local field potential (LFP) spikes in the NA, but not always; in the absence of local LFP spikes, phase coupling in the alpha frequency band between NA, anterior cingulate and primary motor cortex tended to be stronger. By contrast, disinhibition of the (more traditionally motor) dorsolateral putamen led to repetitive movements that the authors call "myoclonic tics," whose phenomenology is less similar on its face to that of tics, and which were regularly preceded by LFP spikes.   ### Pathological studies