PT - JOURNAL ARTICLE AU - Fulvia Gheorghita AU - Rudolf Kraftsik AU - Roger Dubois AU - Egbert Welker TI - Structural Basis for Map Formation in the Thalamocortical Pathway of the Barrelless Mouse AID - 10.1523/JNEUROSCI.1263-06.2006 DP - 2006 Sep 27 TA - The Journal of Neuroscience PG - 10057--10067 VI - 26 IP - 39 4099 - http://www.jneurosci.org/content/26/39/10057.short 4100 - http://www.jneurosci.org/content/26/39/10057.full SO - J. Neurosci.2006 Sep 27; 26 AB - Barrelless mice (BRL) homozygous for the BRL mutation that disrupts the gene coding for adenylyl cyclase type I on chromosome 11 lack spatial segregation of layer IV cortical cells and of the thalamocortical axons (TCAs) into barrel domains. Despite these morphological perturbations, a functional topographic map has been demonstrated. We reconstructed individual biocytin-injected TCAs from thalamus to barrel cortex in NOR (normal) and BRL mice to analyze to what extent the TCA arborization pattern and bouton distribution could explain the topographic representation of the whisker follicles. In BRL, the geometry of TCA is modified within layer IV as well as in infragranular layers. However, in both strains, the spatial distribution of TCA in layer IV reflects the spatial relationship of their cell bodies in the ventrobasal nucleus of the thalamus. The morphometric analysis revealed that TCAs of both strains have the same length, branch number, and number of axonal boutons in layer IV. However, in barrelless, the boutons are distributed within a larger tangential extent. Analysis of the distribution of boutons from neighboring thalamic neurons demonstrated the existence in layer IV of domains of high bouton density that in both strains equal the size and shape of individual barrels. We propose that the domains of high bouton density are at the basis of the whisker map in barrelless mice.