25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Autologous Breast Reconstruction with Free Nipple–Areola Graft after Circumareolar (Skin Reducing) Mastectomy

Introduction of skin-sparing mastectomy (SSM) led to a paradigm shift in breast reconstruction. Primary reconstructions have become the therapy of choice. At the same time, immediate autologous reconstructions are oncologically safe and aesthetically pleasing. Our preferred SSM incision is the circumareolar with removal of nipple and areola (NAC). Adjustment of the skin envelope is well accomplished in mild-to-moderate ptotic breasts. We describe our technique consisting of circumareolar incision in SSM, keeping the NAC as a free graft, and immediate autologous reconstruction and immediate free NAC grafting on the flap. Aesthetic indications are slight asymmetries, ptotic breasts, large breasts where the reconstructed breast will be smaller than the original breast and where a Wise pattern is not indicated. Oncologic indications are risk-reducing mastectomies and tumors close to the NAC where resection would compromise the vitality of the NAC. We evaluated the healing of the NAC and the NAC position with regard to the breast shape. From 2019–2022, 296 autologous flaps were used for breast reconstruction. In 36 flaps, this technique was applied. Eighteen flaps were bilateral (nine patients). In total, we performed 15 inner thigh flaps and 21 DIEP flaps. No flap or NAC loss occurred. There was no wound healing complication at the breast, and no adjuvant chemotherapy or radiation therapy needed to be postponed. The advantages of this technique are (1) scar reduction with only one periareolar scar on the breast, which is also well concealed; (2) oncological safety in relation to the nipple and optimal visibility of the mastectomy cavity, which allows a meticulous mastectomy, especially important in risk-reducing mastectomies; (3) generally, fewer wound healing problems, especially fewer than with Wise pattern incision; (4) primary adjustment of the skin envelope and positioning of the NAC are easier to perform than in a secondary procedure; and (5) that the NAC is spared, and no secondary reconstruction is necessary. Disadvantages are that (1) the NAC must heal as a free graft and (2) that the sensitivity of the NAC is lower than in pedicled NAC transposition