Activity of brainstem cholinergic neurons during 22 kHz ultrasonic vocalization in rats /

Adult rats emit 22 kHz ultrasonic alann calls in aversive situations. This type of call IS a component of defensive behaviour and it functions predominantly to warn conspecifics about predators. Production of these calls is dependent on the central cholinergic system. The laterodorsal tegmental nucleus (LDT) and pedunculopontine tegmental nucleus (PPT) contain largely cholinergic neurons, which create a continuous column in the brainstem. The LDT projects to structures in the forebrain, and it has been implicated in the initiation of 22 kHz alarm calls. It was hypothesized that release of acetylcholine from the ascending LDT terminals in mesencephalic and diencephalic areas initiates 22 kHz alarm vocalization. Therefore, the tegmental cholinergic neurons should be more active during emission of alarm calls. The aim of this study was to demonstrate increased activity of LDT cholinergic neurons during emission of 22 kHz calls induced by air puff stimuli. Immunohistochemical staining of the enzyme choline acetyltransferase identified cell bodies of cholinergic neurons, and c-Fos immunolabeling identified active cells. Double labeled cells were regarded as active cholinergic cells. There were significantly more (pcells in the LDT of vocalizing animals than in control (non-vocalizing air puffed and naIve non-airpuffed) animals. Although the numbers were low, there were also significantly more (pcells, which are selectively active in the LDT during emission of 22 kHz alarm calls.

Letter - E.C. Schmon to Arthur A. Schmon, 13 May 1919

The letter describes a day Eleanore Celeste spent downtown and many friends she ran into during her outing. She then mentions an article she read that states most troops will be out of France by July 1st. This letter is labelled number 278.

Letter - E.C. Schmon to Arthur A. Schmon, 12 November 1918

Eleanore Celeste is currently substituting at Lafayette St. School and she writes "of all the schools that I have substituted in, I like this the best." She hears about the end of the war and tells a story of how she was dancing and jumping when another teacher entered and she was so embarrassed she ran into a closet.