The structure of neurons in the central auditory system is vulnerable to various kinds of acoustic exposures during the critical postnatal developmental period. Here we explored long-term effects of exposure to an acoustically enriched environment (AEE) during the third and fourth weeks of the postnatal period in rat pups. AEE consisted of a spectrally and temporally modulated sound of moderate intensity, reinforced by a behavioral paradigm. At the age of 3-6 months, a Golgi-Cox staining was used to evaluate the morphology of neurons in the inferior colliculus (IC), the medial geniculate body (MGB), and the auditory cortex (AC). Compared to controls, rats exposed to AEE showed an increased mean dendritic length and volume and the soma surface in the external cortex and the central nucleus of the IC. The spine density increased in both the ventral and dorsal divisions of the MGB. In the AC, the total length and volume of the basal dendritic segments of pyramidal neurons and the number and density of spines on these dendrites increased significantly. No differences were found on apical dendrites. We also found an elevated number of spines and spine density in non-pyramidal neurons. These results show that exposure to AEE during the critical developmental period can induce permanent changes in the structure of neurons in the central auditory system. These changes represent morphological correlates of the functional plasticity, such as an improvement in frequency tuning and synchronization with temporal parameters of acoustical stimuli.
- MeSH
- akustická stimulace MeSH
- colliculus inferior cytologie fyziologie MeSH
- dendritické trny fyziologie MeSH
- dendrity fyziologie MeSH
- krysa rodu rattus MeSH
- metathalamus cytologie fyziologie MeSH
- neurony cytologie fyziologie MeSH
- neuroplasticita fyziologie MeSH
- novorozená zvířata MeSH
- potkani Long-Evans MeSH
- sluchová dráha cytologie fyziologie MeSH
- sluchové korové centrum cytologie fyziologie MeSH
- tvar buňky fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
SMI-32 antibody recognizes a non-phosphorylated epitope of neurofilament proteins, which are thought to be necessary for the maintenance of large neurons with highly myelinated processes. We investigated the distribution and quantity of SMI-32-immunoreactive(-ir) neurons in individual parts of the rat auditory system. SMI-32-ir neurons were present in all auditory structures; however, in most regions they constituted only a minority of all neurons (10-30%). In the cochlear nuclei, a higher occurrence of SMI-32-ir neurons was found in the ventral cochlear nucleus. Within the superior olivary complex, SMI-32-ir cells were particularly abundant in the medial nucleus of the trapezoid body (MNTB), the only auditory region where SMI-32-ir neurons constituted an absolute majority of all neurons. In the inferior colliculus, a region with the highest total number of neurons among the rat auditory subcortical structures, the percentage of SMI-32-ir cells was, in contrast to the MNTB, very low. In the medial geniculate body, SMI-32-ir neurons were prevalent in the ventral division. At the cortical level, SMI-32-ir neurons were found mainly in layers III, V and VI. Within the auditory cortex, it was possible to distinguish the Te1, Te2 and Te3 areas on the basis of the variable numerical density and volumes of SMI-32-ir neurons, especially when the pyramidal cells of layer V were taken into account. SMI-32-ir neurons apparently form a representative subpopulation of neurons in all parts of the rat central auditory system and may belong to both the inhibitory and excitatory systems, depending on the particular brain region.
- MeSH
- analýza rozptylu MeSH
- colliculus inferior cytologie metabolismus MeSH
- imunohistochemie MeSH
- krysa rodu rattus MeSH
- metathalamus cytologie metabolismus MeSH
- mikroskopie MeSH
- monoklonální protilátky metabolismus MeSH
- neurofilamentové proteiny metabolismus MeSH
- neurony aferentní metabolismus MeSH
- nucleus cochlearis cytologie metabolismus MeSH
- potkani Long-Evans MeSH
- přední mozek cytologie metabolismus MeSH
- sluchová dráha cytologie MeSH
- sluchové korové centrum cytologie metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- akustická stimulace MeSH
- colliculus inferior anatomie a histologie cytologie fyziologie MeSH
- elektrofyziologie MeSH
- finanční podpora výzkumu jako téma MeSH
- neurony fyziologie MeSH
- sluchová dráha cytologie fyziologie MeSH
- sluchové evokované potenciály fyziologie MeSH
- vokalizace zvířat MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
