Executive functions

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Higher animals, including humans use their brain to control their behavior. The cognitive processes they use are known as executive functions (also called cognitive control): They are used to choose what to do and what to control, and whether the chosen goals have been achieved. Some executive functions are basic cognitive processes such as attentional control, cognitive inhibition, inhibitory control, working memory and cognitive flexibility. Higher-order executive functions require the use of several basic executive functions and include planning and fluid intelligence (for example reasoning and problem-solving).[1][2]

Executive functions develop over time. They change during lifespan of an individual and can be improved at any time.[2] Similarly, these cognitive processes can be adversely affected by different events.[2]

Tests have been developed to assess the level of these functions. Rating scales can be used. These tests are usually performed as a part of a larger series of tests, which ain to find neurological and psychiatric disorders. An example of such a test is the Stroop test. An example of a scale is call Behaviour Rating Inventory of Executive functions.

A counterexample of this is operant and classical conditioning: With these processes, individuals are "taught" to react in a certain way to a given stimulus. In such a situation, the individual must override the response to a stimulus using executive functions.[2] This is called inhibitory control. The prefrontal cortex is necessary but not solely sufficient for executive functions;[2][3][4] other parts of the brain also have a role in mediating inhibitory control.[2][5]

Certain conditions affect cognitive control. These include addiction,[5] attention deficit hyperactivity disorder,[2][5] autism,[6] and other central nervous system disorders. Stimulus-driven behavioral responses that are associated with a particular rewarding stimulus tend to dominate one's behavior in an addiction.[5]

Hypothesized role[change | change source]

The executive system is thought to be heavily involved in handling new situations outside the domain of some of our 'automatic' psychological processes that could be explained by the reproduction of learned schemas or set behaviors. Psychologists Don Norman and Tim Shallice have outlined five types of situations in which routine activation of behavior would not be sufficient for optimal performance:[7][page needed]

  1. Those that involve planning or decision-making
  2. Those that involve error correction or troubleshooting
  3. Situations where responses are not well-rehearsed or contain new sequences of actions
  4. Dangerous or technically difficult situations
  5. Situations that require the overcoming of a strong habitual response or resisting temptation.

A prepotent response is a response for which immediate reinforcement (positive or negative) is available or has been previously associated with that response.[8] 

Executive functions are often invoked when it is necessary to override prepotent responses that might otherwise be automatically triggered by stimuli in the environment. For example, on being presented with a potentially rewarding stimulus, such as a tasty piece of chocolate cake, a person might have the automatic response to take a bite. However, where such behavior conflicts with internal plans (such as having decided not to eat chocolate cake while on a diet), the executive functions might be engaged to inhibit that response.

Although suppression of these prepotent responses is usually considered adaptive, problems for the development of the individual and the culture arise when feelings of right and wrong are overridden by cultural expectations or when creative impulses are overridden by executive inhibitions.[9] 

References[change | change source]

  1. ↑ Malenka, RC; Nestler, EJ; Hyman, SE (2009). "Chapter 6: Widely Projecting Systems: Monoamines, Acetylcholine, and Orexin". In Sydor, A; Brown, RY (eds.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. pp. 155–157. ISBN 978-0-07-148127-4. DA has multiple actions in the prefrontal cortex. It promotes the "cognitive control" of behavior: the selection and successful monitoring of behavior to facilitate attainment of chosen goals. Aspects of cognitive control in which DA plays a role include working memory, the ability to hold information "on line" in order to guide actions, suppression of prepotent behaviors that compete with goal-directed actions, and control of attention and thus the ability to overcome distractions. ... Noradrenergic projections from the LC thus interact with dopaminergic projections from the VTA to regulate cognitive control.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Diamond, Adele (2013). "Executive functions". Annual Review of Psychology. 64: 135–168. doi:10.1146/annurev-psych-113011-143750. PMC 4084861. PMID 23020641. Core EFs are inhibition [response inhibition (self-control—resisting temptations and resisting acting impulsively) and interference control (selective attention and cognitive inhibition)], working memory, and cognitive flexibility (including creatively thinking "outside the box," seeing anything from different perspectives, and quickly and flexibly adapting to changed circumstances). ... EFs and prefrontal cortex are the first to suffer, and suffer disproportionately, if something is not right in your life. They suffer first, and most, if you are stressed (Arnsten 1998, Liston et al. 2009, Oaten & Cheng 2005), sad (Hirt et al. 2008, von Hecker & Meiser 2005), lonely (Baumeister et al. 2002, Cacioppo & Patrick 2008, Campbell et al. 2006, Tun et al. 2012), sleep deprived (Barnes et al. 2012, Huang et al. 2007), or not physically fit (Best 2010, Chaddock et al. 2011, Hillman et al. 2008). Any of these can cause you to appear to have a disorder of EFs, such as ADHD, when you do not. You can see the deleterious effects of stress, sadness, loneliness, and lack of physical health or fitness at the physiological and neuroanatomical level in the prefrontal cortex and at the behavioral level in worse EFs (poorer reasoning and problem-solving, forgetting things, and impaired ability to exercise discipline and self-control). ...
    EFs can be improved (Diamond & Lee 2011, Klingberg 2010). ... At any age across the life cycle EFs can be improved, including in the elderly and in infants. There has been much work with excellent results on improving EFs in the elderly by improving physical fitness (Erickson & Kramer 2009, Voss et al. 2011) ... Inhibitory control (one of the core EFs) involves being able to control one's attention, behavior, thoughts, and/or emotions to override a strong internal predisposition or external lure, and instead do what's more appropriate or needed. Without inhibitory control we would be at the mercy of impulses, old habits of thought or action (conditioned responses), and/or stimuli in the environment that pull us this way or that. Thus, inhibitory control makes it possible for us to change and for us to choose how we react and how we behave rather than being unthinking creatures of habit. It doesn't make it easy. Indeed, we usually are creatures of habit and our behavior is under the control of environmental stimuli far more than we usually realize, but having the ability to exercise inhibitory control creates the possibility of change and choice. ... The subthalamic nucleus appears to play a critical role in preventing such impulsive or premature responding (Frank 2006).    Diamond, Adele (2013). "Executive functions". Annual Review of Psychology. 64: 135–168. doi:10.1146/annurev-psych-113011-143750. PMC 4084861. PMID 23020641. Core EFs are inhibition [response inhibition (self-control—resisting temptations and resisting acting impulsively) and interference control (selective attention and cognitive inhibition)], working memory, and cognitive flexibility (including creatively thinking "outside the box," seeing anything from different perspectives, and quickly and flexibly adapting to changed circumstances). ... EFs and prefrontal cortex are the first to suffer, and suffer disproportionately, if something is not right in your life. They suffer first, and most, if you are stressed (Arnsten 1998, Liston et al. 2009, Oaten & Cheng 2005), sad (Hirt et al. 2008, von Hecker & Meiser 2005), lonely (Baumeister et al. 2002, Cacioppo & Patrick 2008, Campbell et al. 2006, Tun et al. 2012), sleep deprived (Barnes et al. 2012, Huang et al. 2007), or not physically fit (Best 2010, Chaddock et al. 2011, Hillman et al. 2008). Any of these can cause you to appear to have a disorder of EFs, such as ADHD, when you do not. You can see the deleterious effects of stress, sadness, loneliness, and lack of physical health or fitness at the physiological and neuroanatomical level in the prefrontal cortex and at the behavioral level in worse EFs (poorer reasoning and problem-solving, forgetting things, and impaired ability to exercise discipline and self-control). ...

    EFs can be improved (Diamond & Lee 2011, Klingberg 2010). ... At any age across the life cycle EFs can be improved, including in the elderly and in infants. There has been much work with excellent results on improving EFs in the elderly by improving physical fitness (Erickson & Kramer 2009, Voss et al. 2011) ... Inhibitory control (one of the core EFs) involves being able to control one's attention, behavior, thoughts, and/or emotions to override a strong internal predisposition or external lure, and instead do what's more appropriate or needed. Without inhibitory control we would be at the mercy of impulses, old habits of thought or action (conditioned responses), and/or stimuli in the environment that pull us this way or that. Thus, inhibitory control makes it possible for us to change and for us to choose how we react and how we behave rather than being unthinking creatures of habit. It doesn't make it easy. Indeed, we usually are creatures of habit and our behavior is under the control of environmental stimuli far more than we usually realize, but having the ability to exercise inhibitory control creates the possibility of change and choice. ... The subthalamic nucleus appears to play a critical role in preventing such impulsive or premature responding (Frank 2006).

    Figure 4: Executive functions and related terms
  3. ↑ Alvarez, Julie A.; Emory, Eugene (2006). "Executive function and the frontal lobes: A meta-analytic review". Neuropsychology Review. 16 (1): 17–42. doi:10.1007/s11065-006-9002-x. PMID 16794878. S2CID 207222975.
  4. ↑ Malenka, RC; Nestler, EJ; Hyman, SE (2009). "Chapter 13: Higher Cognitive Function and Behavioral Control". In Sydor, A; Brown, RY (eds.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. p. 315. ISBN 978-0-07-148127-4. However, damage to the prefrontal cortex has a significant deleterious effect on social behavior, decision making, and adaptive responding to the changing circumstances of life. ... Several subregions of the prefrontal cortex have been implicated in partly distinct aspects of cognitive control, although these distinctions remain somewhat vaguely defined. The anterior cingulate cortex is involved in processes that require correct decision-making, as seen in conflict resolution (eg, the Stroop test, see in Chapter 16), or cortical inhibition (eg, stopping one task and switching to another). The medial prefrontal cortex is involved in supervisory attentional functions (eg, action-outcome rules) and behavioral flexibility (the ability to switch strategies). The dorsolateral prefrontal cortex, the last brain area to undergo myelination during development in late adolescence, is implicated in matching sensory inputs with planned motor responses. The ventromedial prefrontal cortex seems to regulate social cognition, including empathy. The orbitofrontal cortex is involved in social decision making and in representing the valuations assigned to different experiences.
  5. ↑ 5.0 5.1 5.2 5.3 Malenka, RC; Nestler, EJ; Hyman, SE (2009). "Chapter 13: Higher Cognitive Function and Behavioral Control". In Sydor, A; Brown, RY (eds.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York: McGraw-Hill Medical. pp. 313–321. ISBN 978-0-07-148127-4.  • Executive function, the cognitive control of behavior, depends on the prefrontal cortex, which is highly developed in higher primates and especially humans.
     • Working memory is a short-term, capacity-limited cognitive buffer that stores information and permits its manipulation to guide decision-making and behavior. ...
    These diverse inputs and back projections to both cortical and subcortical structures put the prefrontal cortex in a position to exert what is often called "top-down" control or cognitive control of behavior. ... The prefrontal cortex receives inputs not only from other cortical regions, including association cortex, but also, via the thalamus, inputs from subcortical structures subserving emotion and motivation, such as the amygdala (Chapter 14) and ventral striatum (or nucleus accumbens; Chapter 15). ...
    In conditions in which prepotent responses tend to dominate behavior, such as in drug addiction, where drug cues can elicit drug seeking (Chapter 15), or in attention deficit hyperactivity disorder (ADHD; described below), significant negative consequences can result. ... ADHD can be conceptualized as a disorder of executive function; specifically, ADHD is characterized by reduced ability to exert and maintain cognitive control of behavior. Compared with healthy individuals, those with ADHD have diminished ability to suppress inappropriate prepotent responses to stimuli (impaired response inhibition) and diminished ability to inhibit responses to irrelevant stimuli (impaired interference suppression). ... Functional neuroimaging in humans demonstrates activation of the prefrontal cortex and caudate nucleus (part of the striatum) in tasks that demand inhibitory control of behavior. Subjects with ADHD exhibit less activation of the medial prefrontal cortex than healthy controls even when they succeed in such tasks and utilize different circuits. ... Early results with structural MRI show thinning of the cerebral cortex in ADHD subjects compared with age-matched controls in prefrontal cortex and posterior parietal cortex, areas involved in working memory and attention.
  6. ↑ Solomon, Marjorie (13 November 2007). "Cognitive control in autism spectrum disorders". International Journal of Developmental Neuroscience. 26 (2): 239–47. doi:10.1016/j.ijdevneu.2007.11.001. PMC 2695998. PMID 18093787.
  7. ↑ Norman, DA; Shallice, T (1980). "Attention to action: Willed and automatic control of behaviour". In Gazzaniga, MS (ed.). Cognitive neuroscience: a reader. Oxford: Blackwell (published 2000). p. 377. ISBN 978-0-631-21660-5.
  8. ↑ Barkley, Russell A.; Murphy, Kevin R. (2006). Attention-Deficit Hyperactivity Disorder: A Clinical Workbook. Vol. 2 (3rd ed.). New York, NY: Guilford Press. ISBN 978-1-59385-227-6. OCLC 314949058.
  9. ↑ Cherkes-Julkowski, Miriam (2005). The DYSfunctionality of Executive Function. Apache Junction, AZ: Surviving Education Guides. ISBN 978-0-9765299-2-7. OCLC 77573143.

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