Interestingly, whilst the properties of HT bursting induced by Cch are broadly similar to those of HT bursting induced by mGluR activation, there is one notable distinction between the two types of activity. Specifically, whilst mGluR-induced HT bursting is overtly associated with dendritic Ca2+ spikes (Fig. 1C) (see above), this is rarely the case for mAChR-induced HT bursting (Fig. 2). Rather, HT bursting in this context seems to be generated by a prominent spike afterdepolarization (ADP) (Lörincz et al. 2008) (Fig. 2B). This ADP appears to be generated by Na+ channels (Hughes et al. 2004) and whilst also being present following mGluR1a activation (Fig. 1C, top right, arrowheads), it possesses a much greater amplitude and functional significance following mAchR activation (Fig. 2B, bottom).
