Cav2.3 (R-Type) Calcium Channels Are Critical for Mediating

Comment from

Marco Weiergräber

on

In response:

Cav2.3 (R-type) calcium channels are critical for mediating

anticonvulsive and neuroprotective properties of lamotrigine in vivo

by Dibue and Schneider (Epilepsia, July 2015)

In a response letter Dibue and Schneider (Epilepsia, July 2015) confirm the type of analysis criticized by Weiergräber and Papazoglou (Epilepsia, July 2015). In their response Dibue and Schneider argue that other “some investigators including ourselves choose to include the nominal bandwidth (fivefold or greater) when using these transmitters to gain insight into higher frequency bands ((Raver SM et al. (2013); Black SW et al. (2014)) and to sample at a higher rate to avoid aliasing.” First, this serves as no scientific explanation. Second, the references given do not support the gamma analysis of Dibue et al., (Epilepsia, 2013) at all. In both studies (Raver et al. (2013) and Black et al. (2014)), gamma was analyzed up to 60 and 80 Hz respectively, which is critical using the F20EET transmitter but can be accepted. However, in contrast to Dibue et al. (2013) in both references the Nyquist-Shannon limit of 125 Hz has not been violated. Dibue et al. (2013) analyzed up to 500 Hz which does not provide real analytical gamma data. In their response, Dibue and Schneider (2015) argue that they decided to sample at a higher rate. This is a general misunderstanding of the telemetry system. Sampling beyond the nominal sampling rate of the transmitter (i.e. 250 Hz) does not generate real data points. Instead the system interpolates. Thus, any data beyond the Nyquist-Shannon limit are unreliable or actually are fictive.

The authors are adviced to contact the technical service and/or scientists of the telemetry manufacturer Data Science International for clarification. It should also be stated clearly that screening the literature definitely shows that no violations of the Nyquist-Shannon limit are actually published using the F20-EET transmitter or other radiotelemetry transmitter types, despite the ones discussed here.

References

Dibue M, Kamp MA, Alpdogan S, et al. Cav2.3 (R-type) calcium channels are critical for mediating anticonvulsive and neuroprotective properties of lamotrigine in vivo. Epilepsia 2013;54: 1542–1550.

Weiergräber M. and Papazoglou A. Cav2.3 R-type Ca2+ channels in anticonvulsive treatment. Epilepsia 2015;56:1180–1181.

Raver SM, Haughwout SP, Keller A. Adolescent cannabinoid exposure permanently suppresses cortical oscillations in adult mice. Neuropsychopharmacology 2013;38:2338–2347.

Black SW, Morairty SR, Chen TM, et al. GABAB agonism promotes sleep and reduces cataplexy in murine narcolepsy. J Neurosci 2014;34:6485–6494.