Blocking sequential subcircuits in their hyperglutamatergic CSTC loop halts tics

Interesting discovery in 2015: breaking any step in the CSTC loop stop tics in TS model in mice.

Each drug class alleviates tics in the Ticcy mice, suggesting a hyperglutamatergic CSTC “tic circuit” could exist in TS wherein cortical/amygdalar pyramidal projection neurons׳ glutamatergic overexcitation of both striatal output neurons and nigrostriatal dopaminergic modulatory neurons unbalances their circuit integration to excite striatothalamic output and create tics, and illuminating new TS drug strategies.

In simple English

There is a loop circuit in the brain that consists of several brain areas connected sequentially: Cortex -> Striatum -> Thalamus -> Cortex.

Breaking a connection in that loop by a drug that inhibits neurotransmission at any step stops tics.

This suggests presence of “tic circuit” that restarts itself due to excessive amount of glutamatergic signalling and inability to suppress that signalling by inhibitory neurotransmission.

Reference

1. “Hyperglutamatergic cortico-striato-thalamo-cortical circuit” breaker drugs alleviate tics in a transgenic circuit model of Tourette׳s syndrome, 2015 / Brain Research