Thesis defense Koen Kole (Donders sereis 299)
6 December 2017
Promotors: prof. dr. P.Tiesinga, Prof. dr. T. Celikel
Copromotor: Dr. S. Aschrafi
Molecules of somatosensory map plasticity
Key to answering the fundamental question of how the brain makes sense of its environment is to understand the inner workings of the (primary) sensory areas of the neocortex, which receive and process information gathered at the periphery. Experience-dependent plasticity (EDP) is the process by which neuronal communication is adapted to sustained changes in incoming information, allowing animals to adapt to the ever-changing sensory world. The rodent barrel cortex is ideally suited for studies of EDP, as sensory experience of neurons in select cortical columns can be modulated through deprivation (i.e. clipping or plucking) or stimulation of individual whiskers. The molecular mechanisms that enable barrel cortical EDP are still largely unknown. In the current thesis, I have thus aimed to obtain large-scale molecular datasets in order to investigate how sustained whisker deprivation alters transcription and translation in the corresponding cortical cellular population. I show that experience-dependent molecular changes, which show a strong laminar specificity, are related to (among other processes) synaptic communication. Molecular changes are moreover not restricted to neurons but also appear in non-neuronal cells, showing that EDP is a response on multiple cellular systems. These datasets thus provide insight into the molecular mechanisms that underlie barrel cortical EDP. I have also used electrophysiological means to investigate how sensory experience affects supragranular cross-columnar synaptic communication. The results suggest that whisker deprivation leads to depression of deprived-to-spared synapses while increasing spike thresholds and reducing firing probability in the spared column. Concluding, I have provided important datasets for the study of molecular mechanisms of EDP and have shown how sensory experience changes cross-columnar synaptic communication.