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Open Access Highly Accessed Research article

Sensory cortex lesion triggers compensatory neuronal plasticity

Manfred Depner1, Konstantin Tziridis1, Andreas Hess2 and Holger Schulze1*

Author Affiliations

1 Experimental Otolaryngology, University of Erlangen-Nürnberg, Waldstrasse 1, 91054 Erlangen, Germany

2 Institute of Experimental and Clinical Pharmacology and Toxicology, University of Erlangen-Nürnberg, Fahrstrasse 17, 91054 Erlangen, Germany

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BMC Neuroscience 2014, 15:57  doi:10.1186/1471-2202-15-57

Published: 1 May 2014

Abstract

Background

Lesions to the human brain often cause dramatic impairments in the life of patients because of the very limited capacity of the mammalian nervous system to regenerate. On the other hand, neuronal tissue has a high capacity to reorganize itself so that loss of function due to brain damage may be compensated through neuroplastic reorganization of undamaged tissue in brain regions adjacent or contralateral to the lesion site. In this study we investigated the effect of serial lesions of the auditory cortices (AC) in both hemispheres of Mongolian gerbils on discrimination performance for fast amplitude modulated tones (AM). Healthy animals were trained to discriminate two fast AM, an ability that has previously been shown to critically depend on cortical processing. Their ability to maintain significant discrimination performance was retested after unilateral AC lesion, and again after lesion of the contralateral AC, with 15 days of continuing training in between the two lesions.

Results

After bilateral cortical ablation of both AC and 45 days of training the animals show no change in pure tone detection threshold as measured with modulation of the acoustic startle reflex which has been shown to rely on subcortical structures. In contrast to simultaneous bilateral ablation of AC that results in complete loss of AM discrimination ability in this paradigm we found compensatory plasticity that seems to be triggered by unilateral cortical ablation with subsequent training and that is able to almost fully compensate for the lost cortical functions.

Conclusions

Our results demonstrate that AM discrimination ability that normally depends on AC may be transferred to other brain regions when the brain has time to activate compensatory plasticity between the lesions of the two AC hemispheres. For this process to take place obviously one intact AC hemisphere is needed. This finding may open perspectives for new therapeutic strategies that may alleviate the impairments after multiple ischemic strokes.

Keywords:
Auditory cortex; Shuttle box; Learning; Prepulse inhibition; Deaf hearing; Mongolian gerbil