Decoding the auditory corticofugal systemsIntroductionRoles of the auditory corticofugal systemsSensory processingMotor behaviorAutonomic functionState dependent changesThe corticofugal systemsThalamus and medial geniculate bodyMidbrain and inferior colliculusMedullaNon-auditory brain stemStriatumPrinciples of the corticofugal projectionsDensityTopographyDivergenceSublaminar originsAxon structureThematic perspectiveFeedbackReciprocityParityExecutive controlHegemonyQuestions for the futureParallel pathwaysAscending and descending interactionsSpecies differencesAnatomical substratesAcknowledgmentsReferencesDecoding the auditory corticofugal systemsqJeffery A. Winer*Division of Neurobiology, Department of Molecular and Cell Biology, Room 285 Life Sciences Addition,University of California at Berkeley, Berkeley, CA 94720-3200, USAReceived 17 June 2005; accepted 20 June 2005Available online 25 January 2006AbstractThe status of the organization of the auditory corticofugal systems is summarized. These are among the largest pathways in the brain,with descending connections to auditory and non-auditory thalamic, midbrain, and medullary regions. Auditory corticofugal influencethus reaches sites immediately presynaptic to the cortex, sites remote from the cortex, as in periolivary regions that may have a centrif-ugal role, and to the cochlear nucleus, which could influence early central events in hearing. Other targets include the striatum (possiblepremotor functions), the amygdala and central gray (prospective limbic and motivational roles), and the pontine nuclei (for precerebellarcontrol). The size, specificity, laminar origins, and morphologic diversity of auditory corticofugal axons is consonant with an interpre-tation of multiple roles in parallel descending systems.Ó 2005 Elsevier B.V. All rights reserved.0378-5955/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved.doi:10.1016/j.heares.2005.06.014Abbreviations: AA, amygdala, anterior nucleus; AAF, anterior auditory field; ABm, amygdala, basomedial nucleus; ACe, amygdala, central nucleus;AD, dorsal cochlear nucleus, anterior part; AES, anterior ectosylvian sulcus area; AI, auditory cortex, primary area; AII, auditory cortex, second area;AL, amygdala, lateral nucleus; ALe, ansa lenticularis; AlP, anterolateral periolivary nucleus; Am, amygdala; Ame, amygdala, medial nucleus; Av,anteroventral cochlear nucleus; AvA, anteroventral cochlear nucleus, anterior division; AvS, anteroventral cochlear nucleus, small cell cap; C, caudal; Ca,caudate nucleus; CC, caudal cortex of the inferior colliculus; Cl, claustrum; CG, central gray; CN, central nucleus of the inferior colliculus; Cu, cuneiformnucleus; D, dorsal nucleus of the medial geniculate body or dorsal; DD, deep dorsal nucleus of the medial geniculate body; DC, dorsal cortex of theinferior colliculus; DCa, caudal dorsal nucleus of the medial geniculate body; DF, dorsal cochlear nucleus, fusiform cell layer; DI–DIV, cortex of theinferior colliculus, layers I–IV; DL, dorsal nucleus of the lateral lemniscus; DlP, dorsolateral periolivary nucleus; DM, dorsal cochlear nucleus, molecularlayer; DmP, dorsomedial periolivary nucleus; DS, dorsal superficial nucleus of the medial geniculate body; DZ, dorsal auditory zone (suprasylvian fringe);EC, external cortex of the inferior colliculus; ED, posterior ectosylvian gyrus, dorsal part; EI, posterior ectosylvian gyrus, intermediate part; En,entopeduncular nucleus; EV, posterior ectosylvian gyrus, ventral part; GP, globus pallidus; ICa, internal capsule; IL, intermediate nucleus of the laterallemniscus; In, insular cortex; IT, intercollicular tegmentum; La, amygdala, lateral nucleus; LC, lateral cortex of the inferior colliculus; LD, lateral dorsalnucleus; LP, lateral posterior nucleus; LT, lateral nucleus of the trapezoid body; LS, lateral superior olive; M, medial division; MR, mesencephalicreticular formation; MS, medial superior olive; MT, medial nucleus of the trapezoid body; NB, nucleus of the brachium of the inferior colliculus; Ov, parsovoidea of the ventral division of the medial geniculate body; P, auditory cortex, posterior area; PA, posterior cochlear nucleus, anterior division; Pl,paralemniscal area; PN, pontine nuclei; Pu, putamen; Pul, pulvinar nucleus; Pv, posteroventral cochlear nucleus; PvO, posteroventral cochlear nucleus,octopus cell area; Ro, rostral pole nucleus of the inferior colliculus; RP, rostral pole of the medial geniculate body; Sa, nucleus sagulum; SC, superiorcolliculus; SL, suprageniculate nucleus, lateral part; SM, suprageniculate nucleus, medial part; SNc, substantia nigra, pars compacta; SNr, substantianigra, pars reticulata; Sp, subparafascicular nucleus; SpN, suprapeduncular nucleus; Te, temporal cortex; TL, lateral nucleus of the trapezoid body; TM,medial nucleus of the trapezoid body; TV, ventral nucleus of the trapezoid body; V, pars lateralis of the ventral division or ventral; Ve, auditory cortex,ventral area; VL, ventral nucleus of the lateral lemniscus; Vl, ventrolateral nucleus of the medial geniculate body; VmP, ventromedial periolivary nucleus;VP, auditory cortex, ventral posterior area; 35, parahippocampal cortex, area 35; 36, parahippocampal cortex, area 36DOI of original article: 10.1016/j.heares.2005.06.007.qThis is a corrected version of the paper originally published in HEARES Vol. 207, Issue 1–2, September 2005, pp. 1–9. The publisher regrets that thepresentation of the original publication was not up to the standards of the journal.*Tel.: +1 510 643 8227; fax: +1 510 643 6791.E-mail address: [email protected]/locate/hearesHearing Research 212 (2006) 1–81. IntroductionThe classical view of sensory processing begins with aperipheral receptor epithelium which is topographicallyorganized and whose ganglion cells establish maps in thebrain (Weinberg, 1997). At subsequent synaptic stations,the receptive fields (RFs) created at early stages are trans-formed through divergence and convergence , forms of con-nectional recombination that permit new features toemerge (Martin, 1994) and which likely enable perceptualdecisions (Dykes, 1983). The classical perspective inter-prets this process of feature extraction and progressiveincreases in RF size and complexity as integrative, andas a basis for subsequent binding within (Tr eisman,1996) and between (Driver and Spence, 1998) modalities.Within the cerebral cortex intricate pathways abound forfurther analytic