**2. The development of functional systems in the brain**

Based on the theories of Sechenov [4] and Pavlov [5], Luria [1] conceptualises higher mental processes as complex reflex activities, responsible for reflecting and working with the outside world. Following Vygotsky [6, 7], Luria suggests that these reflex processes are social in origin, mediate in structure and voluntary in mode of function [8].

In this dynamic view of neurological development and functioning, the natural reflexes of the child become radically organised as a result of the handling of objects. New motor patterns, for example, are formed so that the child's movements are able to match the properties of the objects with which he or she interacts. Similar principles apply in the development of human perception, which would be formed under the direct influence of the objective world of things, the majority of which have a social origin [9].

As the brain and the nervous system form the basis for human adaptation to the social and physical demands of the environment, the social and interactive conditions in human development would lead to the formation of highly complex systems of reflex connections. To be capable of reflecting, the external world requires the combined working of many receptors in the formation of new functional systems [10]. In this ongoing process of organisation and reorganisation, the development of higher mental functions would be based on the creation of new, intermediate structures of mental processes and the development of new interfunctional relationships directed towards the performance of new tasks, as well as the performance of previous tasks by new methods.

Luria suggests [1, 2] that the performance of increasingly complex tasks would require the development of increasingly complex mediate structures in the brain. A mediate structure would thus be a characteristic feature of all mental processes. Speech would also play a decisive role in the mediation of mental processes [11]. The higher mental functions would be based on mediate structures and would be neurolinguistic in character [3], as they would be both formed and mediated, with the intimate participation of speech.

Luria's theories have had direct influence into the literature on the neurological basis of speech, language and developmental learning disabilities, both directly through his writings and through the neurological principles he advocated [12–22]. Luria's theories have formed the basis for the development of assessment procedures such as the Luria-Nebraska Neuropsychological Battery [23, 24] and NEPSY [25] and have also had a strong influence on the Cognitive Assessment System developed by Das and Naglieri [26, 27], as well as into assessment procedures more generally [28–31].

While Luria did not refer to learning disabilities directly, others have seen the relevance of Luria's theories to procedures for diagnosis and remediation [27, 32–37]. Luria's work has influenced the work of a number of theorists and practitioners who approach learning disabilities from a neuropsychological standpoint (for example, see [38–45]), and his influence can also be traced into instructional approaches based on fluency and automaticity in language, reading, writing and spelling [46–61], such as the fluency-based programme described in this chapter.
