Classifying heterogeneity of spontaneous up-states: A method for revealing variations in firing probability, engaged neurons and Fano factor

Atypical “seizure-like” activity in cortical reverberating networks in vitro can be caused by LPS-induced inflammation: a multi-electrode array study from a hundred neurons

“…To investigate the underlying properties of this activity, we performed a statistical analysis of the neuron type (excitatory or inhibitory, see Becchetti et al, 2012) and a classification of the durations of the acquired bursts (see Gullo et al, 2012). We found that, on average, the number of engaged neurons was not changing before and after LPS (not shown), but on the contrary, it was the number of elicited spikes (SN, in each burst) that was strongly increasing for both neuronal types (clusters).…”

“…During a typical whole experiment of 14 h, we computed the data in sequential time segments of 2 h in control (6 h) and after the LPS application (8 h). Each burst was characterized by how many spikes were elicited from burst onset up to its end; we then computed the temporal histogram of the SN (SNTH: Gullo et al, 2010, 2012) and plotted it by averaging all data in each 2 h time segment and among all the neurons belonging to the same cluster (see Materials and Methods). The SNTH data plots observed in control (untreated) and in LPS are shown in Figures 2A,B , respectively: for excitatory cluster: thin lines and open circles and for inhibitory cluster: thick lines and closed circles.…”

“…The global network burst structure was analyzed with standard techniques (see Ham et al, 2008) as well as procedures recently developed by us (Gullo et al, 2012). Briefly, we applied a running window of variable duration (10 ms to 1 s) in order to search for the start and end of the burst duration and collect all of the spikes which were precisely tagged to the engaged excitatory and inhibitory neurons already designated as previously explained above.…”

“…Contrary to the in vivo network counterpart that is governed by a sensory input and a up- and down-state behavior (see Chen et al, 2013), it is well known that cultured neuronal network activity is reverberating, and long-term data recording can be performed by using in vitro multi-site electrophysiology, fully established from many years (Keefer et al, 2001; Beggs and Plenz, 2003, 2004; Gramowski et al, 2004; Tateno et al, 2005; Eytan and Marom, 2006; Gullo et al, 2009, 2010, 2012). …”

Neurological Diseases from a Systems Medicine Point of View

“…As two-photon microscopy allows for penetration of tissues to the range of a few mm [ 137 ], this approach is still beyond typical mammalian brain size. To overcome these limitations, new methods have been developed, allowing to remove the lipids of the tissue by electrophoresis, leading to transparent organs [ 138 , 139 ].…”