The Source of Spontaneous Activity in the Main Olfactory Bulb of the Rat

In vivo, most neurons in the main olfactory bulb exhibit robust spontaneous activity. This paper tests the hypothesis that spontaneous activity in olfactory receptor neurons drives much of the spontaneous activity in mitral and tufted cells via excitatory synapses.Single units were recorded in vivo from the main olfactory bulb of a rat before, during, and after application of lidocaine to the olfactory nerve. The effect of lidocaine on the conduction of action potentials from the olfactory epithelium to the olfactory bulb was assessed by electrically stimulating the olfactory nerve rostral to the application site and monitoring the field potential evoked in the bulb.Lidocaine caused a significant decrease in the amplitude of the olfactory nerve evoked field potential that was recorded in the olfactory bulb. By contrast, the lidocaine block did not significantly alter the spontaneous activity of single units in the bulb, nor did it alter the field potential evoked by electrical stimulation of the lateral olfactory tract. Lidocaine block also did not change the temporal patters of action potential or their synchronization with respiration.Spontaneous activity in neurons of the main olfactory bulb is not driven mainly by activity in olfactory receptor neurons despite the extensive convergence onto mitral and tufted cells. These results suggest that spontaneous activity of mitral and tufted is either an inherent property of these cells or is driven by centrifugal inputs to the bulb

Sense of Place among Atlanta Public Housing Residents

For almost two decades now, cities around the country have been demolishing traditional public housing and relocating residents to subsidized private market rental housing. In this paper, we examine sense of place, consisting of both community and place attachment, among a sample of Atlanta public housing residents prior to relocation (N = 290). We find that 41% of the residents express place attachment, and a large percentage express some level of community attachment, though residents of senior public housing are far more attached than residents of family public housing. Positive neighborhood characteristics, such as collective efficacy and social support, are associated with community attachment, and social support is also associated with place attachment. Negative neighborhood characteristics, such as social disorder and fear of crime, are not consistently associated with sense of place. We argue that embodied in current public housing relocation initiatives is a real sense of loss among the residents. Policy makers may also want to consider the possibilities of drawing upon residents’ sense of place as a resource for renovating and revitalizing public housing communities rather than continuing to demolish them and relocating residents to other neighborhoods