Transient circuits in development

The young brain is structurally different from the adult brain. For example before and during the critical period a transient neuronal circuit is present in cortex. This circuit is formed by subplate neurons (SP). Because after the critical period – when subplate neurons are no longer present – only limited plasticity is present, it is possible that this circuit participates in types of synaptic plasticity that occur only during the critical period. Thus, the disappearance of this circuit might be what ends the critical period. Our previous work and the work of others showed that loss of subplate neurons during development leads to severe developmental malformations (Kanold et al., Science 2003, Kanold & Shatz Neuron  2006, Kanold 2009, Tolner et al 2012).

 
Our current work focuses on elucidating on how this and other early circuits shape the functional organization of the brain and how these circuits control the critical period. Using in vitro circuit mapping approaches we showed that SP neurons receive thalamic inputs and provide excitatory input to layer 4 (Zhao, Kao, Kanold, 2009)thus forming a crucial relay of thalamic (and thus sensory)activity (Zhao et al. 2009, Viswanathan et al 2012). Moreover we showed that even at the earliest ages there is a close and dynamic interaction between circuits in the developing cortical plate and SP neurons (Viswanathan et al. 2012, Meng et al. 2014).
 
Patrick Kanold
Department of Biology