EF Science

The PFC’ s extensive outputs allow for direct control of motor behavior, but they may also influence behavior indirectly by altering perceptual and cognitive representations and influencing the storage and retrieval of long-term memories.

A notable feature of the PFC is its ability to demonstrate sustained activation representing task-relevant information in the absence of sensory input, or even in the face of distracting, irrelevant sensory input

sustained activation of an individual’ s current environmental context and task goals is also necessary for flexible behavior and higher cognitive processing. The PFC likely plays a role in maintenance of these types of information as well. The maintenance of task- and goal-related information is necessary in order to define which new perceptual inputs are irrelevant (i.e., distracting) and which should be encoded and entered into the WM buffer (see also, e.g., Braver & Cohen, 2000).

I will summarize evidence supporting the view (GoldmanRakic, 1995a) that the underlying function of all the regions of the PFC is the creation and maintenance of integrated representations of all relevant information.

The type of information being maintained, rather than the type of processing, however, is the fundamental organizing principle (see Figure 1).

I suggest that attention and cognitive control are not directed actions or specific processes contained within any particular set of brain regions. Rather, what we experience and observe that we call attention and cognitive control are emergent properties dependent on the distributed representation of all types of information, both that available from present perceptual input and the information currently sustained in WM, including contextual and motivational information.

attentional selection is the consequence of biases in perceptual processing that arise directly from the representation in WM of the relative importance of one location, object, or feature over another. In this case, a domain-general attentional selection control process would not be localizable to any particular brain region.

Because working memory tests involve updating to maintain relevant information in the presence of interference, the finding that intelligence is related to working memory capacity makes it likely that intelligence is related to updating.

relations between updating and intelligence measures were undiminished, but the relations between inhibiting and intelligence and between shifting and intelligence were no longer significant.

Note that 49% to 57% of the variances in the intelligence measures were unexplained by the EFs, reflecting the fact that EFs, though important correlates of intelligence, are not the only ones.

These three EFs differentially relate to intelligence in normal young adults, with updating being the EF most closely related to intelligence.

Given that general intelligence is most closely associated with complex reasoning and problem-solving tasks (Carroll, 1993), and hence is ‘‘often taken to concern the highest-level ‘executive’ or ‘supervisory’ functions of cognition’’ (Duncan et al., 1996, p. 258), one might posit that it would relate, possibly equally, to all EFs.

SEMs revealed that when inter-EF correlations were considered, the

the current finding that not all EFs are related to psychometric intelligence suggests that traditional measures of intelligence are missing some fundamental supervisory functions.

Indeed, Salthouse et al. (2003), examining an aging sample, found substantially higher inhibiting-updating (.71), inhibiting-Gf (.73), and updating-Gf correlations (.93) than those found here.

Sternberg (1988) defined intelligence as ‘‘mental self-management’’ (p. 72) needed to adapt, select, and shape the environment, citing lack of impulse control as one cause of self-management failures.

Considering that EF are also, to a certain extent, cognitive functions, we use in this paper the terminology “non-executive cognitive functions” to refer to information-processing abilities in order to differentiate between both constructs.

among visual abilities, visual perception is a set of processes that enables recognizing, organizing, and interpreting information based on visual sensory stimulation, while visual memory refers to one’s ability to retain and recover visual representation in the absence of stimuli.

EF, in turn, refer to one’s ability to engage in objective-based behavior (Sullivan, Riccio, & Castillo, 2009). Three abilities are considered major EF: inhibition, which enables one to control inappropriate behavior and attention to distractors (selective attention); working memory that is responsible for maintaining and mentally handling information; and cognitive flexibility, which enables changing perspectives and adapting to different contexts (Diamond, 2013; Miyake et al., 2000).

functions cover “what and how much” an individual is capable of.

From this perspective, EF cover “how” an individual does something, while cognitive

even among EF-related abilities, some are more strongly associated with intelligence measures than others. For instance, in adults, working memory, and more specifically the central executive component, appears more strongly related both to Gc, and especially to Gf intelligence, while the relationship with other executive abilities is less consistent

In fact, studies have shown the contribution of Gf, together with working memory and inhibition, to solving EF traditional tests, such as the Tower of London, which assess planning (Zook, Dávalos, Delosh, & Davis, 2004).

The group of gifted children presented higher performance on EF tests when compared to the other two groups, but this superior performance was not observed on non-executive tests assessing other cognitive abilities.

these findings enable us to infer that the higher the intelligence measured by the Raven’s Progressive Matrices—General Scale, i.e. a Gf measure, the better the performance in most executive and non-executive measures.

The VSI group presented the best performance in verbal fluency, a complex measure of EF, which involves auditory working memory, switching and inhibition, in addition to oral language abilities (Dias & Seabra, 2014). There were, however, no differences among the groups in regard to the measures of cognitive flexibility and attention/inhibitory control. This pattern of association between intelligence and EF has been already reported in the literature

The data allow the inference that, even though there is a relationship between EF and Gf, this relationship can be understood in a generic manner and seems to be specific to certain EF abilities (Abreu et al., 2014). Looking at the measures employed in this study, a more consistent relationship took place only between Gf and complex executive ability of verbal fluency, while associations with inhibition and flexibility were weak.

The results corroborate improved general performance due to superior intelligence, that is, the g effect.

The unity and diversity of EF processes provides the opportunity to examine EF from a holistic perspective, with a focus on the combined measurement of EF, as well as from a component perspective.

cognitive retraining

Better understanding of how and when such interventions should be considered relies on clarifying how and in which respects executive functioning and slow processing speed relate to psychopathology at different levels of analysis and granularity.

Separating Speed from efficiency of EF is an important aspect of evaluating shared phenotypes for cognition (Salthouse, 1996) and thus for psychopathology.

studies of EF generally fail to consider processing speed. This is notable because hierarchal models of human cognition (e.g.(Botvinick, 2008) suggest that lower order processes, such a processing speed, inform higher order processes, such as EF.

It has been hypothesized that Speed may underlie EF

One possibility, in fact, is that Speed accounts for some of the EF effects, because EF measures are often confounded with Speed. We consider that by modeling EF and Speed simultaneously in some models. Three other hypotheses can be proposed.

The first model, here termed the “Specificity model,” proposes that different disorders are associated with different types of EF deficits.

The second, “Severity model,” proposes that EF or Speed impairment are related nonspecifically to overall severity of psychopathology rather than a specific form of psychopathology.

The third, “Dimension” model, proposes that EF or Speed deficits are related to one or more shared, underlying psychopathology liability dimensions rather than specific disorders.

Part A is generally recognized as a measure of output speed, while part B entails additional demands on scanning and motor speed in addition to switching; however it’s validity in relation to other switching measures is recognized

We refer to it as working memory for simplicity, recognizing its complexity.

PET and SPECT images can also be coregistered with anatomical MRI, but this must be obtained during a separate session and therefore, matching the scans is more difficult.

The ability to measure these neurotransmitter systems is unique to PET and SPECT imaging.

Another major drawback to PET and SPECT imaging is that these techniques have generally poor temporal resolution.

Y oga is an eight-limbed holistic system of health that includes a number of different mindbody practices. The yoga asanas are represented in the third limb of this system as organized by Patanjali (circa 400 B.C.). According to the Council for Scientific and Industrial Research (CSIR), at least 1300 different yoga postures have been described in ancient texts (Sinha, K. 2011).

After twelve weeks of training, significant changes in the mean CBF ratio were noted in the baseline (pre- yoga session) scans in the right amygdala, right dorsal medial cortex and right sensorimotor area. After twelve weeks, the activated (post- yoga session) scans showed significantly increased activity in the right dorsal frontal lobe, right prefrontal cortex, right sensorimotor cortex, right inferior frontal lobe, right superior frontal lobe and left dorsal medial frontal lobe.

This supports a model of excitatory dysfunction in mood disorders across the age spectrum

Theoretical models propose that these practices alter the interoceptive messages from the respiratory system to higher CNS centers via modulation of vagal activity

resulting in shifts in attention, perception, emotional regulation and behavior

Furthermore, fluid functioning is for the most part distinguishable from cognitive functioning associated with previously acquired knowledge available in long-term store, referred to as crystallized intelligence (gC).

As a unitary entity, however, fluid function has been described in the psychological literature under a variety of terms, including executive function, executive attention, effortful control, and working memory capacity.

By demonstrating increasing PFC activation with parametric increase in the working memory load or cognitive control demand of tasks performed during imaging, these studies have linked the PFC to fluid cognition

the term fluid cognitive functioning is utilized as a primary descriptor for these integrated aspects of cognition and is used interchangeably to some extent with the terms working memory and executive function.

PFC activation in response to diverse tasks has indicated that the integration of information in working memory, such as verbal and spatial information, or maintenance of information in working memory while executing subsidiary tasks (i.e., cognitive control functions that would seem to be the hallmark of general intelligence), is associated with greater PFC activation than that associated with either task on its own

At the very least, the analysis clearly lends itself to the conclusion that intelligence tests are not measurement invariant between cohorts and that, while some increase in general intelligence appears to have occurred, change associated with rising mean IQ is, by and large, subtest specific.

While most explanations for rising mean IQ tend to be underspecified on this point (i.e., general increases in parenting skill, education, or nutrition), others that more directly address the types of skills tested for in measures of fluid intelligence (such as increased visual-spatial complexity or selective changes in specific aspects of education associated with fluidskills development) are perhaps more likely to be shown to account for the phenomenon (Dickens & Flynn 2001b; Williams 1998).

Further examination of the deficit displayed on measures of fluid IQ in patients with frontal lesions but intact IQ as assessed by the WAIS indicates that performance is dramatically impaired by the requirement of holding multiple relations in mind simultaneously when attempting to solve problems adapted from Raven’s matrices test. Individuals with prefrontal damage exhibit no deficits on problems whose solution requires holding in mind no relations or only one relation, but exhibit a near inability to solve problems involving two or more relations

The study of fluid function under the label of EF in children, however, is a rapidly growing area of research in which the definition of EF employed is essentially identical to that used by individuals studying working memory and intelligence in adults. Specifically, when cognitive researchers working with child populations define EF as the maintenance of an appropriate problem-solving set involving mental representation of a given task and goal state within a limited-capacity central processing system (Welsh & Pennington 1988), they are describing cognitive processes that are being studied under the name of working memory in adults (e.g., Carpenter et al. 1990; Conway et al. 2002; Prabhakaran et al. 1997; 2000).

In addition, Salthouse, Atkinson, and Berish (2003) indicated that some specific executive functions (i.e., inhibition, updating, and time sharing) are potential mediators of age-related cognitive decline in normal adults, supporting the hypothesis that physical activity might serve to delay typical age-related declines in cognition.

Executive function, also known as controlled cognition, resource-demanding cognition, or executive control, is generally defined as a “higher level” or “meta-” cognitive function that manages other more basic cognitive functions (Alvarez & Emory, 2006; Baddeley, 1986; Salthouse, 2007) and the regulation of emotions and attention (Bell & Deater-Deckard, 2007; Blair & Diamond, 2008; Lewis et al., 2008) necessary for purposeful and goal-directed behaviors.

executive function in the physical activity literature is now typically described as planning, scheduling, inhibition, and working memory (Colcombe & Kramer, 2003; Hillman et al., 2006; Kramer et al., 1999).

Hughes and Graham (2002) used the classic distinction between automatic and controlled action and indicated that executive function involves planning and decision making, error correction, the implementation of a novel series of actions, performance in situations that are dangerous or technically difficult, and performance that requires overcoming a robust habitual response.

Salthouse (2005) has called for caution in using executive function as though it represents a construct that is distinct from other cognitive dimensions.

Miyake et al. (2000a) suggested that because it is impossible to find a “pure” executive function measure, multiple neuropsychological measures should be used to minimize “task impurity” and to assess the broad construct. Another solution is to be clear in understanding the subcomponent(s) that are assessed by a particular behavioral measure (Jurado & Rosselli, 2007) and to use care in not overgeneralizing to the broader construct of executive function

the WCST is sensitive to frontal lobe damage and is purported to assess the executive functions of switching, inhibition, updating, and selective attention (Alvarez & Emory, 2006; Greve et al., 2005).

To perform the TMT successfully requires a variety of abilities, including number recognition, visual scanning with a motor component, and mental flexibility

In addition, performance on the TMT-B has increased requirements (as compared with the TMT-A) in terms of task-set inhibition ability, cognitive flexibility, and the ability to maintain a response set (Arbuthnott & Frank, 2000; Kortte, Horner, & Windhan, 2002). To isolate the executive function requirements of the TMT-B from the general processes of perceiving and responding, the difference between TMT-B and TMT-A or the ratio of TMT-B to TMT-A has typically been used as the measure of executive function (Arbuthnott & Frank, 2000; Salthouse et al., 2003).

This is likely to be indicative of the relatively recent interest in executive function in exercise psychology and is illustrative of how little data we actually have available on the effects of physical activity on executive function.

Several hypotheses have been proposed to explain posited PA-related effects on cognitive and academic performance. Regular PA alters neurogenesis and angiogenesis and enhances central nervous system metabolism. 20 Furthermore, it

has been suggested that regular PA increases the availability of certain growth factors, such as brain-derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF). All these systems and factors are involved with the maintenance and plasticity of the structure and function of the brain, 20 21 and thus with learning and memory

The majority of the studies included in the current review assessed the effects of PA in children aged 6–12 years. Seven studies reported children aged 5 years or younger, 44 51 52 64 77 79 80 and 13 studies included youths (ie, older than 12 years) in their studies. 37 39 43

The shortest intervention duration was 1 week, 54 62 79 and the longest spanned a period of 9 years.

Stratifying the evidence synthesis at the level of outcome for academic performance we conclude that there is strong evidence for beneficial effects of PA on maths performance (beneficial effects on 86% of the outcomes), but inconclusive evidence for language performance (beneficial effect on 27% of the outcomes).

The majority of the intervention studies implemented PA sessions of at least 30 min (n=41).

Many studies applied interventions that were delivered 5 days a week (n=28). The lowest frequency was 1 43 44 and the highest frequency was 6 days per week. 36 65 Most studies (n=34) assessed the effects of PA consisting primarily of aerobic exercise.

Six studies assessed the effects of motor demanding or cognitively engaging activities. 31 43 44 53 54 70 Three of these studies implemented PA games specifically tailored to challenge core executive functions in a gross-motor fashion. 43 44 54 The majority of studies implemented separate PA sessions, whereas 14 studies delivered physically active academic lessons. 42 48 51 62 66 77–80 83 85 87

The intervention also showed small significant beneficial effects on attentional performance and impulse control after 1and 2 years, which were not sustained into the third year. After 9 years, children in the intervention group had significantly higher qualification scores for upper school

Most studies reporting intervention effects on cognitive performance, assessed domains of executive functions (in particular inhibition, working memory , updating, attention, task switching, and planning), speed of information processing, fluid and crystallised intelligence.

In particular, enhanced performance accuracy and increased P3 amplitude were observed in tasks requiring higher amounts of attention, inhibition and cognitive flexibility . T asks requiring less executive control were unaffected by the FITKids intervention.

Subramanian et al 65 reported beneficial effects of structured PA versus unstructured physical and creative sedentary activities in 12- to 17-year-olds on tasks measuring attention, concentration, non-verbal fluency , and mental flexibility

Although we found no evidence for beneficial effects on cognitive performance or overall academic performance, we found strong evidence for beneficial effects of PA on maths performance.

Cognitive/academic performance can theoretically improve through biological or psychosocial pathways, 20 and an interplay between the two is possible and probable.

beneficial effects on maths performance assessed intervention programmes with a minimal frequency of three sessions per week and a minimal programme duration of two school years.

The study conclusions suggested that their findings provided evidence for a more efficient use of neural resources underlying executive functions after participation in PA interventions, reflected in enhanced neural activity in regions supporting attention and working memory functions. 49

PA intervention may result in a more adult-like recruitment of prefrontal brain regions, which is important for many aspects of executive functions.

To establish the effect of combining academic content and PA, there should be at least three groups: (a) the intervention group that combines PA with academic content; (b) the non-active control group that only receives the same academic content as the intervention group, but without PA; (c) the active control group that only receives the PA component.

One high-quality study 54 suggested larger effects of coordinative or perceptual– motor forms of exercise on cognitive performance, particularly on executive functions, than aerobic exercise.

V ariability of practice that is central to coordination and perceptual–motor exercise training, for example, may be an interface between motor and cognitive development promotion. 9

Regarding moderators, it is likely that some children may benefit more from additional PA such as children with low PA levels or overweight children.

Interrupting and limiting sedentary time with standing desks or short activity bouts may be more feasible in the school setting and, therefore, a promising form of intervention.

Based on 11 high-quality intervention studies, we found inconclusive evidence of a beneficial effect of PA interventions on cognitive and overall academic performance in children. However, based on academic outcomes related to mathematics, we found strong evidence for beneficial effects of PA.

The information about the world has to be there, but it also has to be structured in such a way that there is a non-miraculous explanation of how it got there, how it is maintained, and how it actually achieves the preselective effects that are its raison d'être.

Unlike the merely Skinnerian creatures who survive because they are lucky, we Popperian creatures survive because we're smart--of course we're just lucky to be smart, but that's better than just being lucky

actions that were better for their agents.

when you give someone a pair of scissors, you enhance their potential to arrive more safely and swiftly at Smart Moves

Specifically, the interaction between motor coordination and EF had significant effects on language, as the association between EF and language was positive and significant at low and moderate levels of motor skills, but not at high levels of motor skills.

In contrast, the S-RCD group’s poor performance on the planning component remained significant after controlling for phonological processing. Findings suggest reading comprehension difficulties are linked to executive dysfunction; in particular, poor strategic planning/organizing may lead to reading comprehension problems.

Executive Functions—Working Memory Sentence Span (Swanson, Cochran, & Ewers, 1989; based on Daneman & Carpenter, 1980) On this test, the examiner reads a set of sentences and asks a question about one of them. The child answers and then remembers the last word of each sentence. The number of sentences increases by one sentence with each set. The score for total number of words recalled was used in analyses.Spatial Span (WISC-III–Process Instrument; WISC-III-PI; Kaplan, Fein, Kramer, Delis, & Morris, 1999) This measure uses a spatial span board, upon which 10 blue cubes are mounted in a random order. The researcher taps cubes (one cube per second) in a specified sequence, and the child is asked to replicate the sequence, both forward and backward. Scaled scores from the Backward Span trial were used in analyses.Digit Span (WISC-IV; Wechsler, 2003) Children are asked to repeat aurally presented digit strings, both forward and backward. Scaled scores from the Backward Span trial were used in analyses.

Executive Functions—Planning, Organization, Self-Monitoring Elithorn Mazes (WISC-III-PI; Kaplan et al., 1999) This measure requires the child to examine a visually presented maze and choose a single path that passes through circles within a “lattice” of lines in an inverted triangular structure, without backtracking. The measure provides information about strategic planning and response organization skills. Scaled scores were used in analyses.Trail Making (Delis-Kaplan Executive Function System; D-KEFS; Delis, Kaplan, & Kramer, 2001) The entire D-KEFS Trail Making Test was administered; however, scaled scores from Trial 4: Number/Letter Sequencing, for which the participant was required to switch back and forth between connecting numbers and letters in sequence, were used in analyses.Tower (D-KEFS; Delis et al., 2001) The Total Achievement Score from the Tower Test, a measure of a novel problem solving that requires planning and organization, was also administered. For this task, participants must move disks varying in size across three pegs to build a designated tower using the fewest number of moves possible.