Auditory cortical efferent actions upon inferior colliculus unitary activity in the guinea pig

Neural sensitivity to novel sounds in the rat's dorsal cortex of the inferior colliculus as revealed by evoked local field potentials

“…As very few ICd neurons display intrinsic onset discharge patterns (Sun and Wu, 2008), the sound-driven onset responses are likely caused by synaptic inhibition after the initial excitation. This possibility is supported by results showing that activation of cortical neurons can elicit long-lasting inhibition following initial excitation in ICd neurons (Bledsoe et al, 2003;Syka and Popelár, 1984;Torterolo et al, 1998). Existence of the show results obtained at 10% pDev while the bottom panel represent results at 30% pDev.…”

Divergent response properties of layer-V neurons in rat primary auditory cortex

“…Such a system could play a significant role in modifying A1 responses to reflect level of arousal, context, experience, learning, etc. (Kilgard and Merzenich, 1998a,b;Rauschecker, 1999;Sakai and Suga, 2001;Suga et al, 2000;Sun et al, 1989;Syka and Popular, 1984;Torterolo et al, 1998;Weingberger, 1998;Ehret, 2001, 2002;Yan and Suga, 1998;Suga, 1997, 2000;Zhou and Jen, 2000a,b).…”

“…Recent studies demonstrate that the corticotectal system, through ''egocentric selection'' mechanisms , adjusts collicular firing in the frequency, amplitude, time and spatial domains to make it more like its own and effectively shape its own input Sun et al, 1989;Syka and Popular, 1984;Torterolo et al, 1998;Yan and Ehret, 2001;Yan and Suga, 1998;Suga, 1997, 2000;Zhou and Jen, 2000a,b). Such a focused positive feedback loop serving to modify the ascending stream of sensory information would only seem possible if the descending information from layer-V neurons is itself tuned.…”

Projections from auditory cortex contact ascending pathways that originate in the superior olive and inferior colliculus

“…Stimulation of auditory cortex has been shown to have excitatory, inhibitory, or mixed effects on cells in the IC (Mitani et al, 1983;Syka and Popelár, 1984;Goldstein-Daruech et al, 2002;Bledsoe et al, 2003;Torterolo et al, 1998;reviewed by Casseday et al, 2002;Suga and Ma, 2003). For cells in the ICc, cortical stimulation can affect spontaneous or sound-evoked activity and can alter the cell's selectivity for various parameters of an acoustic stimulus (Mitani et al, 1983;Sun et al, 1996;Yan and Suga, 1996a, b;1999;Jen et al, 2001;Ma and Suga, 2001;Jen and Zhou, 2003;Zhou and Jen, 2005;Yan et al, 2005).…”