Show Reference: "Cerebral Origins of the Auditory Projection to the Superior Colliculus of the Cat"

Cerebral Origins of the Auditory Projection to the Superior Colliculus of the Cat Hearing Research (March 2013), doi:10.1016/j.heares.2013.02.008 by Nicole Chabot, Jeffrey G. Mellott, Amee J. Hall, Emily L. Tichenoff, Stephen G. Lomber
@article{chabot-et-al-2013,
    abstract = {The superior colliculus ({SC}) is critical for directing accurate head and eye movements to visual and acoustic targets. In visual cortex, areas involved in orienting of the head and eyes to a visual stimulus have direct projections to the {SC}. In auditory cortex of the cat, four areas have been identified to be critical for the accurate orienting of the head and body to an acoustic stimulus. These areas include primary auditory cortex (A1), the posterior auditory field ({PAF}), the dorsal zone of auditory cortex ({DZ}), and the auditory field of the anterior ectosylvian sulcus ({fAES}). Therefore, we hypothesized that these four regions of auditory cortex would have direct projections to the {SC}. To test this hypothesis, deposits of wheat germ agglutinin conjugated to horseradish peroxidase ({WGA}-{HRP}) were made into the superficial and deep layers of the {SC} to label, by means of retrograde transport, the auditory cortical origins of the corticotectal pathway. Bilateral examination of auditory cortex revealed that the vast majority of the labeled cells were located in the hemisphere ipsilateral to the {SC} injection. In ipsilateral auditory cortex, nearly all the labeled neurons were found in the infragranular layers, predominately in layer V. The largest population of labeled cells was located in the {fAES}. Few labeled neurons were identified in A1, {PAF}, or {DZ}. Thus, in contrast to the visual system, only one of the auditory cortical areas involved in orienting to an acoustic stimulus has a strong direct projection to the {SC}. Sound localization signals processed in primary (A1) and other non-primary ({PAF} and {DZ}) auditory cortices may be transmitted to the {SC} via a multi-synaptic corticotectal network. \^{a}º Corticotectal neurons originate primarily from the ipsilateral infragranular layers. \^{a}º The dominant corticotectal projections emerged from ipsilateral and contralateral {fAES}. \^{a}º Few, if any, direct corticotectal inputs to the {SC} from A1, {DZ} or {PAF} were observed. \^{a}º {fAES} projects via a direct route to the {SC} while A1, {DZ}, and {PAF} have multisynaptic networks to {SC}.},
    author = {Chabot, Nicole and Mellott, Jeffrey G. and Hall, Amee J. and Tichenoff, Emily L. and Lomber, Stephen G.},
    doi = {10.1016/j.heares.2013.02.008},
    issn = {03785955},
    journal = {Hearing Research},
    keywords = {auditory, auditory-processing, biology, sc},
    month = mar,
    posted-at = {2013-03-19 12:51:42},
    priority = {2},
    title = {Cerebral Origins of the Auditory Projection to the Superior Colliculus of the Cat},
    url = {http://dx.doi.org/10.1016/j.heares.2013.02.008},
    year = {2013},
    pages = {33--45},
    volume = 300
}

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Neurons in the superficial SC are almost exclusively visual in most species.

The auditory field of the anterior ectosylvian sulcus (fAES) has strong corticotectal projections (in cats).

Some cortical areas are involved in orienting towards auditory stimuli:

  • primary auditory cortex (A1)
  • posterior auditory field (PAF)
  • dorsal zone of auditory cortex (DZ)
  • auditory field of the anterior ectosylvian sulcus (fAES)

Only fAES has strong cortico-tectal projections.