Distribution of GABAergic perikarya and terminals in the centers of the higher auditory pathway of the chicken.
The distribution of presumed GABAergic neurons and axon terminals in nuclei of the higher auditory pathway of the chicken was investigated by immunocyto-chemical methods employing antisera to the rate-limiting enzyme of GABA synthesis, glutamic acid decarboxylase, and to GABA. In the mesencephalic auditory center (MLD) about 20% of the cells reveal immunoreactivity. In contrast, the thalamic relay station nucleus ovoidalis is devoid of immunostained somata. This nucleus contains a high density of punctate immunoreactive structures presumed to be GABAergic axon terminals. In the auditory forebrain center field L and the auditory portions of the hyperstriatum ventrale, up to 8% of the cells were immunopositive. These neurons were significantly smaller than estimated from measurements of the overall cell population in these nuclei. From the two-dimensional arrangement of immunopositive neurons it is suggested that the GABAergic system in the avian auditory telencephalon consists of two separate groups of neurons: one subgroup mediating local inhibitory interactions, the other responsible for lateral inhibition between different frequency representations.
Müller
C M
CM
Institut für Zoologie, Technische Hochschule Darmstadt, Federal Republic of Germany.
D000818:Animals; D001306:Auditory Pathways / Q000166:cytology*; D005968:Glutamate Decarboxylase / Q000378:metabolism; D007124:Immunoenzyme Techniques; D008636:Mesencephalon / Q000166:cytology; D009474:Neurons / Q000166:cytology; D005680:gamma-Aminobutyric Acid / Q000032:analysis* / Q000276:immunology
D005680:gamma-Aminobutyric Acid; D005968:Glutamate Decarboxylase