found that synapsin IIa was the only synapsin isoform that could increase the reserve pool of synaptic vesicles and slow synaptic depression in neurons obtained from synapsin I/II/III triple knock-out mice. The synapsin II content of tectopulvinar terminals may make them particularly resistant to fatigue and able to follow high rates of firing. Synapsin I in tectothalamic terminals may additionally regulate plasticity. In the dLGN of synapsin I/II knockout mice, the short-term frequency-dependent facilitation of corticogeniculate EPSPs was increased, while long-term post- tetanic potentiation was decreased [36]. This change presumably occurred because fewer vesicles were tethered to retain a reserve pool. If this is correct, we would predict that tectothalamic EPSPs in synapsin I/II knockout mice would have larger initial amplitudes compared to controls, but would depress with high frequency stimulation. 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Exp Brain Res 79: 313–318. 30. von Krosigk M, Monckton JE, Reiner PB, McCormick DA (1999) Dynamic properties of corticothalamic excitatory postsynaptic potentials and thalamic PLoS ONE | www.plosone.org 12 August 2011 | Volume 6 | Issue 8 | e23781