In vivo analysis of Purkinje cell firing properties during postnatal mouse development

Abstract

Arancillo M, White JJ, Lin T, Stay TL, Sillitoe RV. In vivo analysis of Purkinje cell firing properties during postnatal mouse development. J Neurophysiol 113: 578 -591, 2015. First published October 29, 2014 doi:10.1152/jn.00586.2014.-Purkinje cell activity is essential for controlling motor behavior. During motor behavior Purkinje cells fire two types of action potentials: simple spikes that are generated intrinsically and complex spikes that are induced by climbing fiber inputs. Although the functions of these spikes are becoming clear, how they are established is still poorly understood. Here, we used in vivo electrophysiology approaches conducted in anesthetized and awake mice to record Purkinje cell activity starting from the second postnatal week of development through to adulthood. We found that the rate of complex spike firing increases sharply at 3 wk of age whereas the rate of simple spike firing gradually increases until 4 wk of age. We also found that compared with adult, the pattern of simple spike firing during development is more irregular as the cells tend to fire in bursts that are interrupted by long pauses. The regularity in simple spike firing only reached maturity at 4 wk of age. In contrast, the adult complex spike pattern was already evident by the second week of life, remaining consistent across all ages. Analyses of Purkinje cells in alert behaving mice suggested that the adult patterns are attained more than a week after the completion of key morphogenetic processes such as migration, lamination, and foliation. Purkinje cell activity is therefore dynamically sculpted throughout postnatal development, traversing several critical events that are required for circuit formation. Overall, we show that simple spike and complex spike firing develop with unique developmental trajectories.

Altered cerebellar connectivity in autism and cerebellar-mediated rescue of autism-related behaviors in mice

“…2a and Supplementary Fig s. 3 and 4). The observed frequency of PN activity was consistent with reductions in PN firing rates in zebrin-expressing cerebellar domains 22–24 . To further confirm the efficacy of cerebellar modulation in vivo, we combined the above chemogenetic strategy with single-unit recordings from RCrusI in anesthetized animals (Supplementary Figs.…”

An optimized surgical approach for obtaining stable extracellular single-unit recordings from the cerebellum of head-fixed behaving mice

“…We have also performed the surgery and successfully acquired single-unit Purkinje cell recordings in outbred Swiss Webster mice (Arancillo et al, 2015). Purkinje cells were isolated from the anterior vermis (lobules I-V), central vermis (lobule VI), and posterior vermis (lobules VIII–IX) usually at a depth of up to 2.5 mm below the surface of the cerebellum (Fig.…”

“…We were able to hold single units for more than 300 seconds, which is critical when examining the dynamic properties of Purkinje cell spike patterns during behavior (Sauerbrei et al, 2015). Long spike trains are valuable since they allow for specific calculations such as simple spike CV and CV2 (CV: 0.79 ± 0.06, CV2: 0.58 ± 0.04; see also White et al, 2014; Arancillo et al, 2015). Using the surgical steps that we delineated for maintaining the visibility of bregma, we could successfully target the cerebellar nuclei using standard stereotaxic coordinates (Paxinos and Franklin, 2001).…”

“…Our group adapted the setup by making minor modifications (Arancillo et al, 2015). The main tools required for the surgery are dissection scissors (Fine Science Tools, Foster City, CA, USA; FST#14082-09), #55 forceps (FST #11255-20), and Dumont AA forceps (FST #11210-10), which we use for reflecting tissue, teasing apart fascia when access is needed, and lifting off any tissue debris from the surgical site.…”

“…The signals may be collected from populations of neurons using electrode arrays (Buzsaki, 2004; Khodagholy et al, 2015), tetrodes (Gao et al, 2012; Chaumont et al, 2013; Sauerbrei et al, 2015), or single electrodes to collect either local field potentials (LFPs; Miller and Wilson, 2008; Servais and Cheron, 2005) or action potentials from single cells (Bryant et al, 2009; White et al, 2014). For recording from individual neurons, signals can be acquired by using whole-cell techniques in which the electrode penetrates the cell to measure the internal milieu and cell membrane properties (Long and Lee, 2012), or the electrode can be placed in very close proximity to a cell of interest to record extracellular signals (Arancillo et al, 2015). In either case, the preparation has to be very stable in order to hold the cell for a sufficient length of time so that an adequate number of spikes can be collected for statistical analyses.…”