A simulation study on the effects of dendritic morphology on layer V PFC pyramidal cell firing behavior

• Main Authors: Maria Psarrou, Alexandra Tzilivaki
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2014-03-01
• Series: Frontiers in Systems Neuroscience
• Subjects: Dendrites; morphology; firing pattern; pyramidal cell; PFC; Single neuron modeling
• Online Access: http://journal.frontiersin.org/Journal/10.3389/conf.fnsys.2014.05.00023/full

The majority of neuronal cells found in the cerebral cortex are pyramidal neurons. Their function has been associated with higher cognitive and emotional functions. Pyramidal neurons have a characteristic structure, consisting of a triangular shaped soma whereon descend two extended and complex dendritic trees, and a long bifurcated axon. All the morphological components of the pyramidal neurons exhibit significant variability across different brain areas and layers. Pyramidal cells receive numerous synaptic inputs along their structure, integration of which in space and in time generates local dendritic spikes that shape their firing pattern. In addition, synaptic integration is influenced by voltage-gated and ion channels, which are expressed in a large repertoire by pyramidal neurons. Electrophysiological categories of pyramidal cells can be established, based on the action potential frequency, generated from a fixed somatic stimulus: (1) cells that fire repetitive action potentials (Regular Spiking – RS), (2) cells that fire clusters of 2 – 5 action potentials with short ISIs (Intrinsic Bursting – IB), and (3) cells that fire in repetitive clusters of 2 – 5 action potentials with short ISIs (Repetitive Oscillatory Bursts – ROB). In vitro and in silico scientific studies, correlate the firing patterns of the pyramidal neurons to their morphological features. <br/> <br/>This study provides a quantitatively analysis via compartmental neuronal modelling of the effects of dendritic morphology and distribution and concentration of ionic mechanisms, along the basal and/or apical dendrites on the firing behavior of a 112-set of layer V rat PFC pyramidal cells. We focus on how particular morphological and passive features of the dendritic trees shape the neuronal firing patterns. Our results suggest that specific morphological parameters (such as total length, volume and branch number) can discriminate the cells as RS or IB, regardless of what is the distribution and concentration of ionic mechanisms along the dendritic trees. Moreover, varying combinations of the basal, the apical or both dendritic tree plexus produce different cell type percentages. Consequently, it appears that variations on the dendritic size and dendritic topology of the pyramidal cells influence their firing patterns and subsequently may influence the information coding that these neurons support. <br/>