The article describes the results of the investigation of the mechanisms of logical-grammatical constructions comprehension in students 7-8 y.o. with and without language acquisition disorders. Computer-administered tests were used to assess the ability to comprehend logical-grammatical constructions, as well as the tests of serial organization of speech and movement (traditional and computer-based) and the tests for assessment of the level of visual-spatial perception strategies. Neuropsychological syndrome analysis allowed to conclude that the difficulties of logical-grammatical constructions comprehension are linked to the deficit of visualspatial perception, which is the common point of view for Russian neuropsychology. 

Also, the experimental evidences were found, that the understanding of logicalgrammatical construction is closely linked to the serial organization of speech and movements. The character of this connection differs from the character of the connection between the understanding of logical-grammatical constructions and the level of visual-spatial strategies perception, which highlights that these two groups of functions provide different contributions to the process of comprehension of grammatically complex sentences. These findings are interpreted using the theory of systemic dynamic localization of higher mental functions by Vygotsky-Luria, the model of the three levels of language organization by A.R. Luria and the model of the three levels of syntax by T.V. Akhutina. It is considered that the operations of grammatical re-structuring of complex sentences ontogenetically relate closely to the functions of serial organization of movements and develop on the neighbouring anatomical substrate (posterior parts of frontal cortex). The other aspect of the process of logical-grammatical constructions comprehension, which includes finding of the «reference point», and generation of asymmetrized «quasi-spatial» structure of the sentence, where the thematical roles are assigned, is linked in the same way to the functions of visual-spatial perception and the anatomical substrate of these functions (temporal-parietal-occipital zone).