Functional organization of the avian auditory cortex analogue. I. Topographic representation of isointensity bandwidth.
Bandwidth of auditory units in the chick forebrain (field L/Hv complex) was measured with isointensity tone stimuli. Isointensity bandwidth is topographically represented within the four-layered tonotopically organized structure. It declines continuously from rostrodorsal to caudoventral along the longitudinal axis of two-dimensional best frequency planes (frequency band laminae). Layer-specific differences along the radial axis are also obvious. In the input layer of field L and in Hv ON-response bandwidths are relatively broad. The narrower bandwidths of units in the two postsynaptic layers of field L are probably caused by lateral inhibition mechanisms, as derived from the different topographic representations of OFF-versus ON-response bandwidths. A quantitative comparison of the topographic representation of bandwidth is made with the geometry of the tonotopic organization of the chick auditory forebrain complex, as revealed by 2-deoxyglucose data in a former study. A number of possible input-output transformations are derived from this comparison.
Heil
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P
Institute of Zoology, Technical University Darmstadt, F.R.G.
Scheich
H
H
D000161:Acoustic Stimulation; D000818:Animals; D001303:Auditory Cortex / Q000033:anatomy & histology / Q000502:physiology*; D001345:Autoradiography; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology*; D002645:Chickens / Q000502:physiology*; D003847:Deoxyglucose / Q000378:metabolism; D007839:Functional Laterality; D008959:Models, Neurological; D013569:Synapses / Q000502:physiology
D003847:Deoxyglucose