The provided code models inhibitory synaptic interactions in the olfactory bulb (OB) network, specifically focusing on GABAergic conductance between periglomerular cells (PGCs), granule cells (GCs), and mitral cells (MCs). These conductances are mediated by GABA_A receptors, which play a crucial role in inhibitory synaptic transmission within the olfactory bulb. ### Biological Context #### 1. **Olfactory Bulb Network** The olfactory bulb is the first processing stage in the olfactory system and plays an essential role in odor detection and discrimination. It comprises various neuronal types, including mitral cells, granule cells, and periglomerular cells, among others. Mitral cells are the principal output neurons, while granule and periglomerular cells are local interneurons that modulate mitral cell activity through inhibitory synapses. #### 2. **GABAergic Inhibition** - **PGC to MC (PG→MC):** Periglomerular cells form inhibitory synapses with the dendrites of mitral cells. This interaction is crucial for shaping the response of the mitral cells to odor stimuli, potentially enhancing contrast and enabling the discrimination of similar odors. - **GC to MC (GC→MC):** Granule cells provide recurrent and lateral inhibition to mitral cells. This inhibition is non-reciprocal and involves dendrodendritic synapses, contributing to the sharpening of odor representations and facilitating pattern separation. The code aims to simulate and visualize the temporal evolution of these inhibitory synaptic conductances, expressed as GABA_A receptor-mediated conductance, which is key to understanding how inhibitory dynamics impact the processing of olfactory information. ### Key Aspects of the Model - **Conductance Variables:** The use of `GABApm` and `Ggm` variables reflects the conductance from PGCs and GCs to mitral cells, respectively. These variables represent how synaptic input modulates mitral cell activity over time. - **Temporal Window (T1, T2):** The simulations are set within a specific temporal window, allowing for the observation of conductance changes across a given interval, facilitating the analysis of dynamic synaptic interactions. - **Simulation of Two Conditions (NTCE):** The code enables the simulation of the network with and without granule cells, allowing for the distinction between the roles of glomerular layer interactions and full network interactions. By modeling these components, the code provides insights into the intricate balance of excitatory and inhibitory signals in the olfactory bulb, which is fundamental to olfactory processing at the neural circuit level.