A theoretical investigation of medium spiny neuron dynamics

by Mr Jan Pieczkowski (CBR, Stockholm University)

Monday 8 Jun 2015, 13:15 → 14:00 Europe/Stockholm

Fantum (Fantum)

A detailed, biophysically plausible compartmental model of a striatal medium spiny projection neuron (MSN) has recently been developed in our group. A previous version of the model has been confirmed to reproduce experimental findings [Evans et al. (2012)]. The updated model uses more accurate ion channels. Moreover, it features a complex, physiologically realistic dendritic tree as its morphology was reconstructed from slice recordings. While it maintains its ability to reproduce experimental findings, this added complexity makes it harder to understand single-cell dynamics, let alone how this might influence the dynamics of a network consisting of these neurons. The goal of this study is therefore to investigate how the synchronisation properties are affected under a regime of different conditions. It has long been established that the so-called phase-response curve can help to classify neurons with regard to their Hodgkin type, a classification that can directly be related to synchronisation between such neurons. In a recent study, Chen et al. (2013) have found that modulation of the SK (small-current calcium-activated potassium) SK channel can change an MSN's Hodgkin type. Their model, on the other hand, only used a single-compartment Hodgkin-Huxley type model and therefore did not account for dendritic effects. We determine here which class our neuron model falls into, and which effect the location of stimulation in the dendritic tree might have on the dynamics. Additionally, we modulate specific channel conductances like SK, and KIR (potassium inward-rectifying current), to see if this modulation is sufficient to switch the Hodgkin type.