Changes in Ultrasonic Vocalizations in Senescent Rats

Biological and Acoustic Sex Differences in Rat Ultrasonic Vocalization

“…These changes to USV acoustics co-occur with non-muscular and neuromuscular changes in the larynx. Some of these changes include the following: reduced hyaluronic acid, reduced elastin densities, and increased collagen densities of the vocal fold [ 35 ]; motorneuron loss of the nucleus ambiguus [ 34 ]; deinnervation-like changes to the neuromuscular junction of the thyroarytenoid muscles [ 31 , 157 , 158 , 159 , 160 ]; reductions in muscle-twitch functions of the thyroarytenoid muscles [ 161 ]; and alterations to intrinsic laryngeal myofiber structures [ 33 , 158 , 161 , 162 ]. Although many of these changes may contribute to functional age-related deficits observed in rat larynx, as previously mentioned, USV production is a complex orchestration of many muscular subsystems that which simultaneously under age-related changes and cannot be explained by a single muscular system such as the larynx.…”

“…This review is focused on sexual dimorphism of the rat larynx and USVs; however, sex differences exist in other rodent species’ USVs (e.g., hamsters [ 12 ] and mice [ 13 , 14 , 15 , 16 ]) and sexual dimorphism of USVs is also mediated by sex differences within the central nervous system, not just the larynx [ 17 , 18 , 19 ]. Nevertheless, the rat model is widely used to study vocal communication in a variety of contexts such as social environment [ 1 , 5 , 7 , 9 , 20 , 21 , 22 , 23 ], neurogenic disorders [ 24 , 25 , 26 , 27 , 28 , 29 ], aging [ 30 , 31 , 32 , 33 , 34 , 35 ], and pharmacology [ 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ], justifying the need for a comprehensive review of the literature attuned to sex differences.…”

Middle age, a key time point for changes in birdsong and human voice.

“…The neurobiological mechanisms that contribute to voice and speech deficits in the aging population are poorly understood, limiting treatment options and motivating research investigations in animal models of vocal behavior. Neuropathological findings from rodent models of normative aging implicate neuronal cell loss in the brainstem in laryngeal dysfunction, but the contribution of higher brain centers are not known (Basken, Connor, & Ciucci, 2012; Peterson, Watts, Morris, Shelton, & Cooper, 2013; Schwarz, Thompson, Connor, & Behan, 2009; reviewed in: Lenell, Kelm-Nelson, Ciucci, & Johnson, 2018). With age-related neurodegenerative diseases such as Parkinson’s disease, deficits in dopamine modulation of corticobasal ganglia circuits contribute to vocal and limb motor deterioration in rodent models (Grant et al, 2014; Grant, Barnett, Doll, Leverson, & Ciucci, 2015).…”