In his 1981 book “Fundamentals to a Pharmacology of the Mind”, Corneliu Giurgea, writes in the Introduction that the term “integrative activity of the nervous system” is to be taken in “the sense given by Sherrington as the ensemble of those central nervous system-processes that combine ‘elementary reflexes into movement patterns having obvious purposes.'” (p. xiii)
In the first chapter, he describes “brain integrative activity” more deeply and in referring especially to the higher telencephalic activity, as “the ensemble of operations through which the brain accomplishes its chief function, i.e. to acquire new experiences and memories, to retrieve previous ones, and to assume their interactions, thereby organizing, at physiological level, our future and reorganizing the traces of past events left upon us.” (p. 13)
Giurgea believed the view of “brain integrative activity” could be defined by two fundamental aspects: the mental unity and the consciousness level. (p. 15)
He defines “mental activity” as the following: “Mental activity is a unitarian one and is based on the entirety of the processes taking place in both brain hemispheres and that underlie in all details the capacity to learn and recall memories. Perceptual integrations, transcortical and commissural connections, information selection and codification.
Giurgea defines “consciousness level” as something that “may evolve from emotional arousal or simple awakeness to deep sleep or coma. It is the behavioral electrophyiological, and mental expression of a definite state of cortical tonus that modulates peripheral reactivities.” And the “central tonus” is “regulated by innate mechanisms, depending on sensorial inputs and their repercussions on reticular and limbic basic activities but also on acquired, learned mechanisms such as the so-called ‘shortened’ conditional reflexes.” (p. 15)
He then goes on to say that “mental unity and consciousness level are only two facets of the same telencephalic activity at a given moment” and that because the ability to learn can be modulated by various types of stimulation of regions such as the reticular, hippocampus, or amygdala, that consciousness is therefore, “a highly integrated brain activity, depending not only on individual neurons but also on the functional processes and operations that make them act as they do.” (p. 15) And so he summarizes that while consciousness derives from the firing of these neurons, it is about the process through which they fire and “not directly through the material they contain.
It is from this perspective, that the book follows the Pavlovian point of view, “according to which learning and memory in humans are phenomena that can relevantly, if not exhaustively, be correlated to animal studies on conditioned reflexes, i.e. to high nervous activity.”
While I will not go further in depth in this post about the Pavlovian concepts, it may help you understand the framework in which all of the experiments on the nootropic concept were based. For example, there are certain things generally accepted within the Pavlovian school, such as “that the central nervous system (CNS) operates with two fundamental processes (excitation and inhibition), one basic mechanism (the reflex), and two fundamental properties (reactivity and plasticity).
I will zoom out here and go back to the Preface and cover some of the other concepts that combined to form the full concept of the “higher brain integrative activity.”
Before Pavlov there was no way to study the cerebral hemispheres because all of the known physiology of the nervous system was learned about through reflex actions. This forced Pavlov and his school (of which Giurgea was a part), to pursue psychology, which allowed for the application of physiologic methods to the cerebral cortex. Pavlov’s work was based on that of Hughlings Jackson and so was the Sherringtonian integrative concept. They were both based on Jackson’s concept of how the “simplest spinal reflex ‘thinks’, so to say in terms of movements and not of muscles” (Sherrington, 1931, P. 21)
Charles Sherrington’s book, The Integrative Activity of the Nervous System (IANS), had a goal to explain “how the nervous system welds a collection of disparate body parts and organs into a unified individual. Sherrington postulated that the reflex is the simplest unit of nervous integration. He introduced the concept of the synapse as the site where elementary reflexes interact to enable more complex and unified behavior and argued that a synaptic nervous system facilitated the evolution of the cerebrum and cerebellum.” Sherrington’s book, IANS, is said to have done for the understanding of the neurological basis of behavior, what Newton’s “Principia Mathematica” did for the understanding of physics.
Higher integrative brain activity in Giurgea’s use” is a phrase that combines three prior concepts: “the pavlovian “higher nervous activity,” the Sherringtonian “Integrative Action of the Nervous System” and the term used by Konorski, “Integrative Activity of the Brain.” (p. xiv)
This is along the lines of Buser’s (1976) “higher functions of the nervous system” meaning “functions that are not sensory receptive or motor projective.”
This also applies to structures in the Penfield’s (1966) uncommitted cortex that includes activities related to attention, will, learning and memory, thinking, etc. What these terms emphasize together is the “common physiological nature, at all CNS levels, of the fundamental integrative mechanisms and the specific differences that enable higher brain structures to assume the physiological basis of mental activity.” (p. xv)
This meant that higher brain activity can be studied. “Higher brain integrative activity includes mental noetic, cognitive activities but also fundamental mechanisms that underpin these functions and that might not result directly in mentally conscious of unconscious events.”
The integration is “extremely complex and multifaceted.”
Giurgea believes that the higher brain integrative activity is “essentially related to the telencephalon and that a selective telencephalic psychopharmacology…might be considered as one of the future lines of research contributing to a pharmacological control of the mind.” (p. xv)
Drugs that are used to treat neurosis and psychosis are called psychotropics. And in the pharmacology of higher brain integrative activity, Giurgea’s group created nootropics, to create substances which can directly target control the higher processes of the mind. (p. xvi)