Therefore, the main observation that potentiation is

Therefore, the main observation that potentiation is High Content Screening restricted to IB cells and depression is restricted to RS cells holds for both in vivo and ex vivo data. Our LSPS experiments were performed in mice

while the in vivo intracellular recordings were performed in rats. Could the species difference alter the comparability of the results? It is possible that slight quantitative differences might be species-related, but the main qualitative result does not appear to be. When we repeated the extracellular receptive field study in mice we observed the same evolution of receptive fields across the different layers following deprivation. The main difference between plasticity in mice and rats was that potentiation occurred in LVa in rats but not in mice. One possible explanation for this would be the presence of fewer C59 IB cells in LVa of mice. Some laboratories have reported a clear layer separation of thick tufted and thin slender cells in S1 (Groh et al., 2010 and Meyer et al., 2010). In other studies, including the present one, thin slender regular spiking neurons were observed in LVb (Schubert et al., 2007). At the very

least, all studies so far conclude that the distributions of pyramidal neuron types are not uniform throughout LV. Therefore, it is reasonable to hypothesize that the differences observed extracellularly between LVa and LVb result in part from differences in the percentage of RS and IB cells. If most cells in LVa of the mouse are of the RS type, we would not expect to see potentiation Liothyronine Sodium from the extracellular studies and indeed we do not. If

LVa in the rat contains a mixture of RS and IB cells, as we found from our classification, then one would expect to see potentiation from the extracellular studies, which is the case. Synaptic plasticity varies with layer in sensory cortices, a factor that might be explained by the different connections within each layer (Wang and Daw, 2003). Synaptic plasticity affects receptive field organization both in supra- and infragranular barrel cortex neurons (Jacob et al., 2007). However IB cells and RS cells, which we show in this study to be differently potentiated during deprivation, share the same layer and largely the same connections including input from LII/III neurons. What then could be the mechanisms that drive their distinct forms of experience-dependent plasticity? The basal level of activity differs between RS and IB cells (de Kock et al., 2007), IB cells having larger spontaneous and evoked activity. Postsynaptic spike pattern and frequency influences the sign and amplitude of synaptic plasticity in vitro in cortical LII/III (Froemke et al., 2006 and Zilberter et al., 2009) and LV pyramidal cells (Birtoli and Ulrich, 2004 and Letzkus et al., 2006).

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