| BSTju-restricted neuron | McDonald (McDonald) | This subdivision consists of neurons with small, ovoid perikarya (9-13 micrometers in diameter) and several thin dendrites that give rise to numerous, wavy branches (Fig. 2, cell C). Dendritic branches, which have a dense covering of spines, are restricted to the confines of this small region (Fig. 2). Axons originate from the perikaryon or the proximal portion of a primary dendrite but can only be followed for a short distance before they leave the section or cease to impregnate. They usually emit one or more thin,
beaded collaterals that appear to remain confined to the subdivision. Collator note: see also Larriva-Sahd, 2004. | synonym | | These bipolar neurons correspond to the cell type “restricted to the confines of this small region,” described by McDonald (1983)... | Larriva-Sahd J. | Mihail Bota |
|
| BNSTALG Type II neuron | Hammack et al. (Hammack) | Type II neurons were the most abundant of BNSTALG neurons, accounting for 55% of all recorded cells. These neurons had a Vm of -58.0 &plusm; 0.5 mV and an Rm of 377.4 & 15.7 MOhms.. Type II neurons also exhibited a depolarizing sag in response to hyperpolarizing current injection that was similar to that described for Type I neurons. However, in contrast to Type I neurons, the amplitude and rate of onset of the rebound depolarization observed at the termination of the hyperpolarizing current
injection were always much larger than the degree of depolarizing rectification observed. Significantly, the amplitude of the rebound depolarization often surpassed action potential threshold and triggered a rebound burst of action potentials (see Fig. 2B, Type II), suggesting that Type II neurons express additional active currents that could be modulated by prior membrane hyperpolarization. After the initial burst of action potentials, Type II neurons either fire in a regular pattern (Fig. 2A, Type II), fire in bursts, or stop firing altogether (accommodate). The variability of this second response is likely explained by the differential expression of outward rectifying currents and calcium-dependent potassium currents, and/or differences in the properties of the calcium currents that generate the initial burst. These differences suggest that even within Type II neurons there is heterogeneity in their physiological responses. | partially corresponds | | Collator note: Type II neurons appear to be distributed over several anterior BST regions. We chose "overlap" relationship, because no systematic study was made to unequivocally map this neuron-type over the possible morphological types. Moreover, the bipolar neurons can be further subdivided in several subtypes, depending on the route of their axons. See also Larriva-Sahd, 2004. | Hammack S.E., Mania E. & Rainnie D.G. | Mihail Bota |
|
