Plasticity of the adult auditory system based on corticocortical and corticofugal modulations

Selective Corticofugal Modulation on Sound Processing in Auditory Thalamus of Awake Marmosets

“…The importance of corticofugal modulation on auditory processing and perception is well recognized (He, 2003b; Nunez and Malmierca, 2007; Suga, 2020; Terreros and Delano, 2015; Winer, 2006; Winer et al, 2001; Wood et al, 2017). However, previous studies which applied cortical activation or inactivation have found that corticofugal influence can be either suppressive or facilitatory, leading to controversy in the field (He, 2003b; Suga, 2020).…”

“…In contrast, in the visual system (Andolina et al, 2007;Kalil and Chase, 1970;Macchi et al, 1986;Sininger et al, 1999;Tsumoto et al, 1978;Wang et al, 2018;Yuan et al, 1985Yuan et al, , 1986 and in barrel somatosensory system (Ghazanfar et al, 2001;Temereanca and Simons, 2004), studies report an enhancement of point to point homologous projections along with a suppression at non-homologous projections (Kalil and Chase, 1970;Macchi et al, 1986;Singer, 1977;Temereanca and Simons, 2004;Tsumoto et al, 1978;Usrey and Sherman, 2019;Yuan et al, 1985Yuan et al, , 1986. This finding has been further supported in a highly specialized auditory system, that of awake bats, where activation of A1 demonstrated improved sound processing at subcortical levels (Suga, 2020). This raises the possibility that differences in previous studies arise from different brain states (Bartlett and Wang, 2007;Constantinople and Bruno, 2011;Haider et al, 2013;Long and Lee, 2012).…”

“…The copyright holder for this preprint this version posted March 14, 2021. ; https://doi.org/10.1101/2021.03.13.435231 doi: bioRxiv preprint / corticofugal studies in auditory system were carried out in anesthetized animals (Amato et al, 1969;He, 1997He, , 2003bHe et al, 2002;Ryugo and Weinberger, 1976;Villa et al, 1991;Watanabe et al, 1966), where the auditory cortex was suppressed to some degree (He, 1997). In this case, manipulation of A1 demonstrated some degree of modulation of spectral, intensity and spatial aspects of onset response during auditory processing (He, 2003a;Nunez and Malmierca, 2007;Suga, 2020;Terreros and Delano, 2015;Winer, 2006;Winer et al, 2001). Although sustained responses are crucial for temporal processing (Wang et al, 2008), and especially important for speech and music processing (Rosen, 1992;Wang, 2000), the effect of corticothalamic modulation on sustained response remains unknown.…”

Cortical Stimulation Induces Excitatory Postsynaptic Potentials of Inferior Colliculus Neurons in a Frequency-Specific Manner

“…The auditory cortex sends large numbers of descending projections to most auditory nuclei in the thalamus, midbrain, and low brainstem (Weedman and Ryugo, 1996;Druga et al, 1997;Winer et al, 1998Winer et al, , 2001Rouiller and Welker, 2000;Schofield and Coomes, 2005). These corticofugal projections comprise a feedback system that enables cortex-oriented modulation or control of the neural processing of incoming sound information (Syka and Popelár, 1984;Suga et al, 2000;Jen et al, 2002;Xiong et al, 2009;Bajo et al, 2010;Bajo and King, 2013;Terreros and Delano, 2015;Suga, 2020).…”

“…Following the pioneering work by Suga and his colleagues (Yan and Suga, 1996;Suga et al, 1997;, a surge of studies over the last quarter-century has established a highly specific corticofugal function. Specifically, cortical neurons implement differential modulation of the auditory responses of subcortical neurons depending on the functional relationship of cortical and subcortical neurons, facilitation when cortical and subcortical neurons have similar tunings, and suppression when they have different ones (Suga, 2020). This cortex-oriented modulation is seen across various domains i.e., frequency, amplitude, and time (Yan and Suga, 1996;Ma and Suga, 2001;Yan and Ehret, 2002;Zhou and Jen, 2007), various processing centers i.e., thalamus, midbrain, and cochlear nucleus (Zhang and Suga, 2000;Zhou and Jen, 2000;Luo et al, 2008;Liu et al, 2010) and various species i.e., bats, gerbils and mice Zhou and Jen, 2000;Sakai and Suga, 2002;Yan and Ehret, 2002).…”