Executive Functions in Health and Disease

Elkhonon Goldberg, Elkhonon Goldberg

• Publisher: Academic Press
• Year: 2017
• ISBN:
  9780128037058
• Topic: Psychology
• Subtopic: Physiological Psychology
• Index: Psychology

Executive Functions in Health and Disease provides a comprehensive review of both healthy and disordered executive function. It discusses what executive functions are, what parts of the brain are involved, what happens when they go awry in cases of dementia, ADHD, psychiatric disorders, traumatic injury, developmental disorders, cutting edge methods for studying executive functions and therapies for treating executive function disorders. It will appeal to neuropsychologists, clinical psychologists, neuroscientists and researchers in cognitive psychology.

• Encompasses healthy executive functioning as well as dysfunction
• Identifies prefrontal cortex and other brain areas associated with executive functions
• Reviews methods and tools used in executive function research
• Explores executive dysfunction in dementia, ADHD, PTSD, TBI, developmental and psychiatric disorders
• Discusses executive function research expansion in social and affective neuroscience, neuroeconomics, aging and criminology
• Includes color neuroimages showing executive function brain activity

Part I

Executive Functions in Health

Outline

Chapter 1 Prefrontal Executive Functions Predict and Preadapt

Chapter 2 The Cellular Mechanisms of Executive Functions and Working Memory: Relevance to Mental Disorders

Chapter 3 Gene Expression in the Frontal Lobe

Chapter 4 A Functional Network Perspective on the Role of the Frontal Lobes in Executive Cognition

Chapter 5 Neural Network Models of Human Executive Function and Decision Making

Chapter 6 Crucial Role of the Prefrontal Cortex in Conscious Perception

Chapter 7 Neurodevelopment of the Executive Functions

Chapter 8 Executive Functions and Neurocognitive Aging

Chapter 9 Assessment of Executive Functions in Research

Chapter 1

Prefrontal Executive Functions Predict and Preadapt

Joaquín M. Fuster, Semel Institute, School of Medicine, University of California Los Angeles, Los Angeles, CA, United States

Abstract

The prefrontal cortex plays a critical role in the temporal organization of behavior and language within the broad neurobiological framework of the perception–action (PA) cycle, the circular processing of information that regulates the adaptation of the organism to its environment. That temporal organizing role of the prefrontal cortex is supported by three major executive functions that constitute the essential dynamic components of the cognitive control of behavior and language: (1) executive attention, (2) working memory, and (3) decision-making. The three functions are teleonomic in that they have a critical future perspective toward goal or reward. In this chapter, after discussion of the PA cycle and of the physiological role of the prefrontal cortex in it, executive attention, working memory, and decision-making are empirically placed in both cycle and cortex with the available experimental evidence.

Keywords

Prefrontal cortex; perception–action cycle; cognitive control; prospective executive function; attention; working memory; decision-making

Introduction

Based on the theory of evolution and his experience with the effects of brain lesions, Jackson, the father of neurology, was the first to postulate the hierarchical organization of the nervous system, which he considered both a representational and a coordinating system at all levels, from top to bottom (Jackson, 1882). To exemplify the identity of representational and executive neural substrates, he used the motor cortex. Here, the same assemblies of cells that represent a movement are in charge of its execution. By “representation” in this cortex he meant, of course, the executive memory of skeletal movement, which we may call “phyletic memory” because it is genetically inherited and common to all members of the species. In the frontal lobe, at the top of the executive motor hierarchy, Jackson placed the “highest centers” for the representation and execution of complex movement, the highest nerve agencies for the memory and coordination of the actions of the “whole organism.” He was obviously referring to premotor and prefrontal areas. Thus, extending his hierarchical principle to those cortical regions, he attributed the representation and coordination of purposeful and goal-directed actions. Language was one among them, which he called more specifically as the “capacity to propositionise” (Jackson, 1915). Luria, later (1966), would not only make that capacity a fundamental fontal function but also extend it to the coordination of all forms of complex action, in other words, to what Lashley (1951) had termed the “syntax of action.”

To “propositionise” is to make propositions, which for Jackson meant the commonly accepted ability to construct grammatical sentences with words and ideas. In modern times, however, based on a large body of clinical evidence, it can be confidently asserted that the propositions that higher frontal cortex makes include also proposals, in other words, schemes or plans of action, transcending language, to be executed in the more or less distant future. Luria (1966), probably more clearly than anybody else, attributed to higher frontal cortex the capacity to implement those proposals by organizing complex and purposeful goal-directed behavior in the temporal domain. As a logical consequence, the incapacity to formulate and carry out plans is now universally recognized as a pathognomonic symptom of substantial prefrontal damage (Fuster, 2015). From this, incapacity derives the general notion that as part of its role in the temporal organization of behavior, the normal prefrontal cortex opens the organism to its future, by predicting events, including its own actions, and by preadapting the organism to those events before they happen.

The central topic of this chapter is the future perspective of the three major executive functions of the prefrontal cortex: (1) executive attention, (2) working memory, and (3) decision-making. All three are functionally intertwined and share common biological objectives or teleonomic goals (Monod, 1971), which include the adaptation of the organism to predictable changes in its internal or external environment. Accordingly, in this chapter, I will outline and support the prospective aspects of each of those functions. I will preface the discussion of the three functions with a brief presentation of the general biological principle they obey. That principle is the perception–action (PA) cycle, which is the circular cybernetic processing of information that regulates the relationships between nervous system and environment in goal-directed behavior and language.

The PA Cycle

Biologist Uexküll (1926) remarked that living organisms adapt to their environment by a circular flow of information that runs through the environment and the brain, with a structural sensing interface (“mark organ”) and an effector interface (“action organ”). The sea anemone senses the chemistry of the water for nutrients, which reflexively mobilize their “action organ” toward them for their ingestion. It is a simple feed-forward reflex arc (Fig. 1.1). However, in the brain of higher organisms, Uexküll noted that there is internal feedback that bypasses the environment through the brain and from the “action organ” that flows back into the “mark organ.” That internal feedback provides the brain with a measure of additional supraordinate control of the cycle.

Figure 1.1 Uexküll’s diagram of the adaptation of the organism to its environment. He writes (A) “The inner world is divided into two parts; one, that receives the impressions, faces the world-as-sensed, and the other, that distributes the effects, faces the world of action.” (B) “In the highest animals, however, the creature’s own action-rule penetrates further into the world-as-sensed, and there, assumes direction and control (my italics) … A new circle (red arrow) is introduced within the animal’s own central organ for the support of the external function-circle, and this connects the action organ with the mark-organ.” From Uexküll (1926). Theoretical Biology. New York: Harcourt, Brace & Co, 155–157.

In the primate brain, that adaptation cycle, with its internal feedback countercycle, evolves into a hierarchy of concentric cycles of cerebral structures and processes that adjust the animal to its external environment while satisfying immediate and future biological needs. At the highest level of that hierarchy, the cycle involves the cerebral cortex, which harbors networks for processing information from sensory to motor areas through associative cortex. The cycle has received various names from neurologists and neuroscientists; I favor the PA cycle denomination to emphasize the cognitive, memory-related, aspect of sensation in its higher circuits. Essentially, in the integration of complex goal-directed behavior, the PA cycle functions as follows (Fig. 1.2). Inputs from the environment or the internal milieu are processed through cognitive networks or cognits (Fuster, 2009) of posterior cortex (parietal–temporal–occipital, PTO). The output from that processing flows into the prefrontal cortex, where, through executive cognitive networks, it informs consequent action upon the environment; that action is effected through the premotor cortex, the basal ganglia, and the pyramidal system. The action produces changes in the environment, which are processed through the senses and fed back into posterior cortex toward further action. Thus, the entire cycle works as a self-correcting and guiding cybernetic system that regulates behavior and language toward their goals. It is important to note that the cycle can be set in motion by events anywhere within it, in the cortex or in the environment (external or internal milieu), obviating the need for a “center of will” or “central executive.”

Figure 1.2 Circuitry of the PA cycle through cortex and environment. A perceptual hierarchy of cognits (cognitive neuronal networks) is depicted on the left and an executive one on the right (The top-left compartment, PTO, includes both unimodal and multimodal association cortex). Major feed-forward connectivity runs through thick arrows. Thin arrows mark intracortical feedback connections that play important roles in cognitive control. PA, perception–action; PTO, parietal–temporal–occipital. Bottom left: Uexkull’s internal feedback in lower animals (red arrow), which in the human cycle at right is represented by the red arrow from prefrontal to PTO cortex. That arrow symbolizes schematically essential components of the three executive functions subsumed by cognitive control (executive attention, working memory, and decision-making).

As in lower organisms, however, there is internal countercyclical feedback from effectors to receptors in the primate brain. That internal feedback, I argue in this chapter, has future-oriented functions that modulate the PA cycle in anticipation of predicted percepts, actions, and rewards. In both the human and nonhuman primate, those are the executive functions of the prefrontal cortex to be discussed below. Their essential infrastructural support is made of corticocortical connections from that cortex upon posterior perceptual cortex and the cognitive networks of this cortex. In the aggregate, those functions constitute what has been termed “cognitive control” (Miller & Cohen, 2001) argued at the service of the temporal organization of goal-directed behavior (Fuster, 2001).

Based on their work on insects and fish, von Holst and Mittelsteadt (1950) were the first to postulate the predictive properties of the internal feedback from executive to sensing sectors of the brain (red arrow in Figs. 1.1 and 1.2). They called that internal feedback “reafference.” According to them, it consisted of signals from the motor system, which, immediately before the execution of a reflex motor response to sensory stimulation, flowed back into the sensory system to refine that response and to integrate it wit...