TY - JOUR T1 - Patterns of dendritic basal field orientation of pyramidal neurons in the rat somatosensory cortex JF - eneuro JO - eNeuro DO - 10.1523/ENEURO.0142-18.2018 SP - ENEURO.0142-18.2018 AU - Ignacio Leguey AU - Ruth Benavides-Piccione AU - ConcepciĆ³n Rojo AU - Pedro LarraƱaga AU - Concha Bielza AU - Javier DeFelipe Y1 - 2018/12/17 UR - http://www.eneuro.org/content/early/2018/12/14/ENEURO.0142-18.2018.abstract N2 - The study of neuronal dendritic orientation is of interest because it is related to how neurons grow dendrites to establish the synaptic input that neurons receive. The dendritic orientations of neurons in the nervous system vary, ranging from rather heterogeneously distributed (asymmetric) to homogeneously distributed (symmetric) dendritic arbors. Here we analyze the dendritic orientation of the basal dendrites of intracellularly labeled pyramidal neurons from horizontal sections of layers II-VI of the hindlimb somatosensory cortex of 14-day-old rats (P14). We used circular statistics and proposed two new graphical descriptive representations of the neuron. We found that the dendritic pattern of most neurons was asymmetric. Furthermore, we found that there is a mixture of different types of orientations within any given group of neurons in any cortical layer. In addition, we investigated whether dendritic orientation was related to the physical location within the brain with respect to the anterior, dorsal, posterior and ventral directions. Generally, there was a preference towards the anterior orientation. A comparison between layers revealed that the preference for the anterior orientation was more pronounced in neurons located in layers II, III, IV and Va than for the neurons located in layers Vb and VI. The dorsal orientation was the least preferred orientation in all layers, except for layers IV and Va where the ventral orientation had the lowest preference. Therefore, the orientation of basal dendritic arbors of pyramidal cells is variable and asymmetric, although a majority has a single orientation with a preference for the anterior direction in P14 rats.Significance Statement It is thought that the dendritic arborizations of pyramidal cells are oriented to make contact with relevant synaptic inputs. It could be expected that these arborizations are distributed uniformly around the soma. We used circular statistics and two new graphical descriptive representations of the neuron to study the orientation of basal dendritic arbors in the rat somatosensory cortex. We observed that the basal dendritic pattern of most neurons was asymmetric and that was a mixture of different types of orientations within any given group of neurons in any cortical layer. Nevertheless, we found a large proportion of cells showing a preference for the anterior orientation axis, suggesting that these cells have a preference for an axonal system oriented in this direction. ER -