Glucose effects on a continuous performance test of attention in adults

The Impact of Free and Added Sugars on Cognitive Function: A Systematic Review and Meta-Analysis

A relationship between excessive sugar consumption and cognitive function has been described in animal models, but the specific effects of sugars in humans remains unclear. This systematic review and meta-analysis aimed to evaluate the current knowledge, research characteristics, and quality of evidence of studies investigating the impacts of free and added sugars on human cognition in healthy participants. The review identified 77 studies (65 experimental trials, n = 3831; 9 cross-sectional studies, n = 11,456; and 3 cohort studies, n = 2059). All cohort studies and eight of the nine cross-sectional studies found significant positive correlations between added sugar consumption and risk of cognitive impairment. Four studies identified reduced risk of cognitive impairment associated with natural fructose-containing foods. The majority of randomised control trials assessed short-term glucose facilitation effects on cognitive outcomes. The results from these studies suggest the need for a tightly regulated blood glucose level, dependent on individualised physiological factors, for optimal cognitive function. A meta-analysis of a subset of studies that assessed the impact of glucose on recall found improvements in immediate free recall compared to controls (p = 0.002). The findings highlight the potentially detrimental effect of excessive, long-term, or prenatal added sugar consumption on cognitive function. Further research is needed to examine the specific effects of free and added sugars on cognitive function.

The Impact of Free Sugar on Human Health-A Narrative Review

The importance of nutrition in human health has been understood for over a century. However, debate is ongoing regarding the role of added and free sugars in physiological and neurological health. In this narrative review, we have addressed several key issues around this debate and the major health conditions previously associated with sugar. We aim to determine the current evidence regarding the role of free sugars in human health, specifically obesity, diabetes, cardiovascular diseases, cognition, and mood. We also present some predominant theories on mechanisms of action. The findings suggest a negative effect of excessive added sugar consumption on human health and wellbeing. Specific class and source of carbohydrate appears to greatly influence the impact of these macronutrients on health. Further research into individual effects of carbohydrate forms in diverse populations is needed to understand the complex relationship between sugar and health.

Association of Dietary Habits with Mild Cognitive Impairment among Elderly in Rural Area of North China

BACKGROUND

Recent findings suggest a possible role of diet, particularly nutrient intakes and dietary patterns, in the prevalence of mild cognitive impairment (MCI); few studies, however, have been explicitly devoted to the relationship between dietary habits and MCI.

OBJECTIVES

We aimed to explore the association between dietary habits, including meal timing, and MCI among older Chinese adults.

METHODS

This cross-sectional study involved data collected at the baseline of the Tianjin Elderly Nutrition and Cognition Cohort (TENCC) study, in which 3,111 community-dwelling older adults (326 MCI patients and 2,785 non-MCIs) from a rural area of Tianjin, China, were recruited. In March 2018 to June 2019, all participants underwent a detailed neuropsychological evaluation that allowed for psychometric MCI classification. Information on self-reported dietary behaviors was gathered via face-to-face interviews. Crude and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models.

RESULTS

In the multivariable-adjusted models, eating breakfast 4 to 6 times per week (vs. ≤3 times per week, OR: 0.45; 95% CI: 0.26, 0.75), drinking water before breakfast (yes vs. no, OR: 0.64; 95% CI: 0.51, 0.82), consuming water ≥1.5L per day (vs. <1.5L per day, OR: 0.64; 95% CI: 0.51, 0.82), and having lunch after 12:00 (vs. before 12:00, OR: 0.59; 95% CI: 0.47, 0.75) were associated with decreased risk of MCI. Participants who consumed higher amounts of cooking oil were at a higher risk of MCI (moderate vs. low, OR: 1.42; 95% CI: 1.04, 1.92; high vs. low, OR: 1.40; 95% CI: 1.07-1.83).

CONCLUSION

This study suggests that dietary habits, including breakfast frequency, daily water consumption, cooking oil consumption, and meal timing, may be associated with the risk of MCI. If replicated, these findings would open new possibilities of dietary interventions for MCI.

Effect of glucose and sucrose on cognition in healthy humans: a systematic review and meta-analysis of interventional studies

CONTEXT

Evidence suggests that plasma glucose levels may influence cognitive performance, but this has not been systematically reviewed and quantified.

OBJECTIVE

The aim of this review was to investigate the potential effects of glucose and sucrose, compared with placebo, on cognition in healthy humans.

DATA SOURCES

The electronic databases PubMed and Web of Science were searched up to December 2019. Reference lists of selected articles were checked manually.

STUDY SELECTION

Randomized controlled trials or crossover trials that compared glucose or sucrose with placebo for effects on cognition were eligible.

DATA EXTRACTION

Potentially eligible articles were selected independently by 2 authors. Risk of bias was assessed through the Cochrane Collaboration tool. Standardized mean differences (SMDs) were obtained from random-effects meta-analyses for a subsample of studies that reported the same outcomes.

RESULTS

Thirty-seven trials were identified, of which 35 investigated the effect of glucose consumption compared with placebo on cognition. Two studies found no effect of glucose on cognition, while the others found mixed results. Only 3 of the 37 studies investigated the effects of sucrose intake, reporting mixed results. Meta-analyses revealed a significantly positive effect of glucose compared with control, but only when a verbal performance test (immediate word recall) was used in parallel-design studies (SMD = 0.61; 95%CI, 0.20-1.02; I2 = 0%). Twenty-four studies were classified as having high risk of bias for the selection procedure.

CONCLUSIONS

A limited body of evidence shows a beneficial effect of glucose in individuals performing immediate verbal tasks. High-quality trials with standardized cognitive measurements are needed to better establish the effect of glucose or sucrose on cognition.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42019122939.

Non-nutritive Sweeteners and Glycaemic Control

PURPOSE OF REVIEW

The consumption of foods and beverages containing non-nutritive sweeteners (NNS) has increased worldwide over the last three decades. Consumers' choice of NNS rather than sugar or other nutritive sweeteners may be attributable to their potential to reduce weight gain.

RECENT FINDINGS

It is not clear what the effects of NNS consumption are on glycaemic control and the incidence of type 2 diabetes. This review aims to examine this question in epidemiological, human intervention and animal studies. It is not clear that NNS consumption has an effect on the incidence of type 2 diabetes or on glycaemic control even though there is some evidence for the modification of the microbiome and for interaction with sweet taste receptors in the oral cavity and the intestines' modification of secretion of glucagon-like peptide-1 (GLP-1), peptide YY (PYY), ghrelin and glucose-dependent insulinotropic polypeptide (GIP), which may affect glycaemia following consumption of NNS. In conclusion, long-term studies of NNS consumption are required to draw a firm conclusion about the role of NNS consumption on glycaemic control.

Motoric self-regulation by sled dogs and pet dogs and the acute effect of carbohydrate source in sled dogs

Inhibitory control is a term used to envelop a collection of processes that allow an organism to refrain from engaging in an inappropriate prepotent or responsive behavior. Studies have examined the propensity of inhibitory control by nonhuman animals, from the cognitively complex processes involved in self-control to potentially less cognitively taxing processes such as motoric self-regulation. Focusing on canines, research has suggested that the domestication process as well as experiences during ontogeny contribute to inhibitory control. Diet may also play an important role in an individual's ability to self-regulate. This study examined this possibility by investigating motoric self-regulation in sled dogs, using three well-established tasks (i.e., A-not-B Bucket, Cylinder, and A-not-B Barrier tasks), performed after consumption of one of three dietary treatments with different glycemic index values. We also compared the performance of sled dogs during these tasks with results previously obtained from pet dogs. Overall, the results show many similarities in the performance of sled dogs and pet dogs on the motoric self-regulation tasks, with the notable exception that sled dogs may have a stronger spatial perseveration during the A-not-B Bucket task. Previous research findings reporting a lack of correlation among these tasks are also supported. Finally, during the early postprandial phase (period after consumption), dietary treatments with different glycemic index values did not influence self-regulatory performance for sled dogs.

Glycemic impact of non-nutritive sweeteners: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND/OBJECTIVES

Nonnutritive sweeteners (NNSs) are zero- or low-calorie alternatives to nutritive sweeteners, such as table sugars. A systematic review and meta-analysis of randomized controlled trials was conducted to quantitatively synthesize existing scientific evidence on the glycemic impact of NNSs.

SUBJECTS/METHODS

PubMed and Web of Science databases were searched. Two authors screened the titles and abstracts of candidate publications. The third author was consulted to resolve discrepancies. Twenty-nine randomized controlled trials, with a total of 741 participants, were included and their quality assessed. NNSs under examination included aspartame, saccharin, steviosides, and sucralose. The review followed the PRISMA guidelines.

RESULTS

Meta-analysis was performed to estimate and track the trajectory of blood glucose concentrations over time after NNS consumption, and to test differential effects by type of NNS and participants' age, weight, and disease status. In comparison with the baseline, NNS consumption was not found to increase blood glucose level, and its concentration gradually declined over the course of observation following NNS consumption. The glycemic impact of NNS consumption did not differ by type of NNS but to some extent varied by participants' age, body weight, and diabetic status.

CONCLUSIONS

NNS consumption was not found to elevate blood glucose level. Future studies are warranted to assess the health implications of frequent and chronic NNS consumption and elucidate the underlying biological mechanisms.

The Effects of Carbohydrates, in Isolation and Combined with Caffeine, on Cognitive Performance and Mood-Current Evidence and Future Directions

This review examines the effects of carbohydrates, delivered individually and in combination with caffeine, on a range of cognitive domains and subjective mood. There is evidence for beneficial effects of glucose at a dose of 25 g on episodic memory, but exploration of dose effects has not been systematic and the effects on other cognitive domains is not known. Factors contributing to the differential sensitivity to glucose facilitation include age, task difficulty/demand, task domain, and glucoregulatory control. There is modest evidence to suggest modulating glycemic response may impact cognitive function. The evidence presented in this review identifies dose ranges of glucose and caffeine which improve cognition, but fails to find convincing consistent synergistic effects of combining caffeine and glucose. Whilst combining glucose and caffeine has been shown to facilitate cognitive performance and mood compared to placebo or glucose alone, the relative contribution of caffeine and glucose to the observed effects is difficult to ascertain, due to the paucity of studies that have appropriately compared the effects of these ingredients combined and in isolation. This review identifies a number of methodological challenges which need to be considered in the design of future hypothesis driven research in this area.

Macronutrient composition of a morning meal and the maintenance of attention throughout the morning

BACKGROUND

At present, the impact of macronutrient composition and nutrient intake on sustained attention in adults is unclear, although some prior work suggests that nutritive interventions that engender slow, steady glucose availability support sustained attention after consumption. A separate line of evidence suggests that nutrient consumption may alter electroencephalographic markers of neurophysiological activity, including neural oscillations in the alpha-band (8-14 Hz), which are known to be richly interconnected with the allocation of attention. It is here investigated whether morning ingestion of foodstuffs with differing macronutrient compositions might differentially impact the allocation of sustained attention throughout the day as indexed by both behavior and the deployment of attention-related alpha-band activity.

METHODS

Twenty-four adult participants were recruited into a three-day study with a cross-over design that employed a previously validated sustained attention task (the Spatial CTET). On each experimental day, subjects consumed one of three breakfasts with differing carbohydrate availabilities (oatmeal, cornflakes, and water) and completed blocks of the Spatial CTET throughout the morning while behavioral performance, subjective metrics of hunger/fullness, and electroencephalographic (EEG) measurements of alpha oscillatory activity were recorded.

RESULTS

Although behavior and electrophysiological metrics changed over the course of the day, no differences in their trajectories were observed as a function of breakfast condition. However, subjective metrics of hunger/fullness revealed that caloric interventions (oatmeal and cornflakes) reduced hunger across the experimental day with respect to the non-caloric, volume-matched control (water). Yet, no differences in hunger/fullness were observed between the oatmeal and cornflakes interventions.

CONCLUSION

Observation of a relationship between macronutrient intervention and sustained attention (if one exists) will require further standardization of empirical investigations to aid in the synthesis and replicability of results. In addition, continued implementation of neurophysiological markers in this domain is encouraged, as they often produce nuanced insight into cognition even in the absence of overt behavioral changes. ClinicalTrials.gov Identifier: NCT03169283.

Executive functioning and diabetes: The role of anxious arousal and inflammation

Individuals who perform poorly on measures of the executive function of inhibition have higher anxious arousal in comparison to those with better performance. High anxious arousal is associated with a pro-inflammatory response. Chronically high anxious arousal and inflammation increase one's risk of developing type 2 diabetes. We sought to evaluate anxious arousal and inflammation as underlying mechanisms linking inhibition with diabetes incidence. Participants (N=835) completed measures of cognitive abilities, a self-report measure of anxious arousal, and donated blood to assess interleukin-6 (IL-6) and glycated hemoglobin (HbA1c). Individuals with low inhibition were more likely to have diabetes than those with high inhibition due to the serial pathway from high anxious arousal to IL-6. Findings remained when entering other indicators of cognitive abilities as covariates, suggesting that inhibition is a unique cognitive ability associated with diabetes incidence. On the basis of our results, we propose several avenues to explore for improved prevention and treatment efforts for type 2 diabetes.

The Effects of Breakfast and Breakfast Composition on Cognition in Adults

Extensive literature has addressed the acute cognitive effects of breaking a fast. Recent reviews in this line of work have synthesized available research on the cognitive consequences of fasting compared with nutrient intake and the cognitive effects of macronutrient consumption. These largely have been inconclusive, possibly in part because of selection criteria limiting the scope of studies covered. The purpose of the current review is to integrate the results of the literature examining the cognitive effects of breakfast and breakfast composition in adults with the use of a flexible definition of breakfast, specifically, any caloric intake after a fasting period of ≥8 h. This review includes 38 studies that examine the acute cognitive impact of breakfast and 16 studies that examine the effects of breakfast composition. Results suggest that healthy adults show a small but robust advantage for memory (particularly delayed recall) from consuming breakfast. Largely equivocal results emerge for attention and motor and executive function; there were no effects from breakfast on language. Regarding breakfast composition, a smaller number of studies and widely disparate methodology addressing this question preclude definitive conclusions about the effects of cognition. A subset of this literature examines these questions in the context of glucoregulation; the findings emphasize the importance of considering differences in glucoregulation in research designs, even among healthy cohorts. The limitations of this literature include methodologic differences, such as the use of different tests to measure cognitive constructs, as well as the effects of timing in test administration.

Glucose improves object-location binding in visual-spatial working memory

RATIONALE

There is evidence that glucose temporarily enhances cognition and that processes dependent on the hippocampus may be particularly sensitive. As the hippocampus plays a key role in binding processes, we examined the influence of glucose on memory for object-location bindings.

OBJECTIVE

This study aims to study how glucose modifies performance on an object-location memory task, a task that draws heavily on hippocampal function.

METHODS

Thirty-one participants received 30 g glucose or placebo in a single 1-h session. After seeing between 3 and 10 objects (words or shapes) at different locations in a 9 × 9 matrix, participants attempted to immediately reproduce the display on a blank 9 × 9 matrix. Blood glucose was measured before drink ingestion, mid-way through the session, and at the end of the session.

RESULTS

Glucose significantly improves object-location binding (d = 1.08) and location memory (d = 0.83), but not object memory (d = 0.51). Increasing working memory load impairs object memory and object-location binding, and word-location binding is more successful than shape-location binding, but the glucose improvement is robust across all difficulty manipulations. Within the glucose group, higher levels of circulating glucose are correlated with better binding memory and remembering the locations of successfully recalled objects.

CONCLUSIONS

The glucose improvements identified are consistent with a facilitative impact on hippocampal function. The findings are discussed in the context of the relationship between cognitive processes, hippocampal function, and the implications for glucose's mode of action.

Interactions between sleep habits and self-control

Good sleep habits and effective self-control are important components of successful functioning. Unfortunately chronic sleep loss and impaired self-control are common occurrences for many individuals which can lead to difficulty with daily self-control issues such as resisting impulses and maintaining attentive behavior. Understanding how self-control is depleted and how good sleep habits may help replenish and maintain the capacity for self-control is an important issue. A sleep-deprived individual who has expended the necessary resources for self-control is at an increased risk for succumbing to impulsive desires, poor attentional capacity, and compromised decision making. To date, few studies have investigated how sleep and self-control are inter-related. The goal of this mini-review is to explore the intersection between sleep habits and self-control and encourage researchers to focus on a new area of research that integrates what are at present largely separate areas in psychology and human neurosciences.

Do specific dietary constituents and supplements affect mental energy? Review of the evidence

The numbers of marketing claims and food, beverage, and drug products claiming to increase mental energy have risen rapidly, thus increasing the need for scientific specificity in marketing and food label claims. Mental energy is a three-dimensional construct consisting of mood (transient feelings about the presence of fatigue or energy), motivation (determination and enthusiasm), and cognition (sustained attention and vigilance). The present review focuses on four dietary constituents/supplements (Ginkgo biloba, ginseng, glucose, and omega-3 polyunsaturated fatty acids) to illustrate the current state of the literature on dietary constituents and mental energy. The strongest evidence suggests effects of Ginkgo biloba on certain aspects of mood and on attention in healthy subjects, as well as associations between omega-3 polyunsaturated fatty acids and reduced risk of age-related cognitive decline. Limitations of the current data and challenges for future research are discussed.

Effects of acute alcohol intoxication and paroxetine on aggression in men

BACKGROUND

The purpose of this study was to examine the role of the serotonin (5-HT) system in alcohol-related aggression.

METHODS

Specifically, we experimentally examined the effects of 5-HT augmentation on alcohol-related aggression in men (n = 56). After consuming either alcohol (mean blood alcohol concentration of 0.10%) or a placebo (no alcohol) drink, and taking either 20 mg of paroxetine (Paxil) or a placebo pill, participants were provided the opportunity to administer electric shock to a (faux) opponent during a task disguised as a reaction-time game. Aggression was defined as the intensity of shock chosen and the frequency with which an extreme (clearly painful) shock was chosen. We predicted that 5-HT augmentation would be associated with lower aggressive behavior overall, and also reduce the aggression facilitating effects of acute alcohol intoxication.

RESULTS

The results indicated that alcohol intoxication increased aggression, particularly under low provocation. Paroxetine decreased aggression, particularly during high provocation. These effects, however, occurred independently of each other.

CONCLUSIONS

The effect of alcohol on extreme aggression was moderated by previous aggression history, with more aggressive individuals showing greater alcohol-related increases in extreme aggression.

An investigation of the effects of saccharides on the memory performance of middle-aged adults

OBJECTIVES

To investigate the effects of glucose, or a combination of saccharides, or a placebo on the memory performance of middle-aged adults.

DESIGN

A double-blind, placebo controlled design was used. A population-based sample of 45 men and women (aged 40-63 years) completed a series of memory tasks following administration of a single dose of either glucose, a combination of saccharides or placebo. Memory tasks included immediate and delayed recall, recognition, short-term memory, working memory, and a test of general cognitive ability.

RESULTS

There were no statistically significant effects of treatments on any of the outcome measures.

CONCLUSION

The pattern of means in the combination of saccharides group suggests potential enhancement effects of memory performance in middle-aged adults that deserves further investigation.

The physiology of willpower: linking blood glucose to self-control

Past research indicates that self-control relies on some sort of limited energy source. This review suggests that blood glucose is one important part of the energy source of self-control. Acts of self-control deplete relatively large amounts of glucose. Self-control failures are more likely when glucose is low or cannot be mobilized effectively to the brain (i.e., when insulin is low or insensitive). Restoring glucose to a sufficient level typically improves self-control. Numerous self-control behaviors fit this pattern, including controlling attention, regulating emotions, quitting smoking, coping with stress, resisting impulsivity, and refraining from criminal and aggressive behavior. Alcohol reduces glucose throughout the brain and body and likewise impairs many forms of self-control. Furthermore, self-control failure is most likely during times of the day when glucose is used least effectively. Self-control thus appears highly susceptible to glucose. Self-control benefits numerous social and interpersonal processes. Glucose might therefore be related to a broad range of social behavior.

Acute effects of macronutrient manipulations on cognitive test performance in healthy young adults: A systematic research review

The potential for foods to exert effects on behaviour is increasingly recognised. Previous studies have incorporated both well-known and lesser-known cognitive tests in the evaluation of relationships between macronutrient interventions and mental performance. Systematic review methodology was used to identify studies of macronutrient effects on cognition, limited to acute effects in young, fasted, healthy adults. Thirty-one studies met the inclusion criteria, yielding a total of 134 outcome measures. The studies reviewed displayed a predominance of soluble glucose manipulations, and a paucity of complex carbohydrate, protein or fat manipulations. Memory performance was most commonly measured, but verbal fluency, attention, reaction time, psychomotor skill and problem solving were also assessed. Significant differences in performance tended to occur under circumstances of more intense cognitive demand and after delays. Memory emerged as the most sensitive cognitive modality to macronutrient manipulations. Tasks identified as sensitive included Serial Sevens, Free Word Recall and Cued Word Recall, with tentative support for the Word Recognition Task. Findings also suggested that visuo-spatial memory may be influenced by macronutrient manipulations.

Progressive dehydration causes a progressive decline in basketball skill performance

PURPOSE

To determine the effect of 1, 2, 3, and 4% dehydration (DEH) versus euhydration (EUH) on basketball performance in adult male players.

METHODS

Seventeen 17- to 28-yr-old male basketball players completed 3 h of interval treadmill walking (40 degrees C and 20% relative humidity) with or without fluid replacement. Subjects completed six trials in random order: 1) EUH with a carbohydrate-electrolyte solution (CES), 2) EUH control (flavored water with 0% carbohydrate and 18 mM sodium), 3) 1% DEH, 4) 2% DEH, 5) 3% DEH, and 6) 4% DEH. After a 70-min recovery period, subjects performed a sequence of continuous basketball drills designed to simulate a fast-paced game. Measures of overall skill performance during the 80-min game included 1) total time to complete basketball-specific movement drills (sprinting, defensive slides, sprinting-defensive slides combination, and repetitive jumping drills) and 2) total number of shots (foul-line and baseline jump shots, layups, three-point, 15-ft, free throws) made per game.

RESULTS

Performance during all timed and shooting drills declined progressively as % DEH increased. Total time to complete basketball-specific movement drills was slower (1%: + 7 +/- 6; 2%: + 20 +/- 5 (P < 0.05); 3%: + 26 +/- 7 (P < 0.005); 4%: + 57 +/- 9 (P < 0.0001) s), and fewer shots were made during DEH versus EUH control (1%: -5 +/- 1; 2%: -6 +/- 2 (P < 0.05); 3%: -8 +/- 2 (P < 0.005); 4%: -10 +/- 1 (P < 0.0001) shots made). There were no significant differences in performance between CES and EUH control.

CONCLUSION

Basketball players experienced a progressive deterioration in performance as DEH progressed from 1 to 4%. The threshold, or % DEH at which the performance decrement reached statistical significance, was 2% for combined timed and shooting drills.

Dehydration impairs vigilance-related attention in male basketball players

PURPOSE

To determine the effects of dehydration (DEH) on attentional vigilance in male basketball players.

METHODS

The Test of Variables of Attention (TOVA; Universal Attention Disorders) was administered to 11 male basketball players (17-28 yr) at baseline (test 1), after walking (50% V O2max) in the heat (40 degrees C and 20% relative humidity) (test 2), and then after a simulated basketball game (test 3). Tests 2 and 3 were performed while subjects were either DEH (1-4%) or euhydrated (EUH). The TOVA consisted of target-infrequent and target-frequent conditions, simulating static and dynamic (such as a basketball game) environments, respectively. TOVA measures included errors of omission (OE) and commission (CE), response time (RT), and sensitivity.

RESULTS

During the target-infrequent half of test 3, EUH resulted in significantly better sensitivity (+0.4+/-1.2 vs -0.9+/-1.3), faster RT (-8+/-20 vs +16+/-28), and fewer OE (-0.4+/-0.7 vs +1.3+/-2.4) compared with DEH. During the target-frequent half, EUH resulted in significantly fewer OE (-4+/-15 vs +5+/-7) and CE (-1.9+/-3.2 vs 0.6+/-1.4) in test 2 and greater sensitivity (+0.7+/-2.6 vs -0.7+/-1.1) and faster RT (-21+/-28 vs +5+/-31) than DEH in test 3.

CONCLUSION

Vigilance-related attention of male basketball players was impaired by DEH, especially during the target-frequent condition of the TOVA. These results suggest that fluid replacement is essential to prevent the decline in vigilance that occurs with DEH in highly dynamic environments. Therefore, basketball players should be advised to maintain EUH for optimal concentration and attentional skills during competition.

Sustained and Transient Attention in the Continuous Performance Task

One of the most frequently applied methods to study abnormal cognition is the Continuous Performance Task (CPT). It is unclear, however, which cognitive functions are engaged in normal CPT performance. The aims of the present study were to identify the neurocognitive functions engaged in the main variants of the CPT and to determine to what extent these variants differentially engage these functions. We hypothesized that the main CPT versions (CPT-X, CPT-AX, CPT-Identical Pairs) can be distinguished by whether they demand sustained or transient attention and sustained or transient response preparation. Transient attention to objects like letters or digits, that is, the need to switch attention to different objects from trial to trial, impairs target detection accuracy relative to sustained attention to a single object. Transient response preparation, that is, the possibility to switch response preparation on and off from trial to trial, improves response speed relative to having to sustain response preparation across all trials. Comparison of task performance and Event-Related brain Potentials (ERPs) of healthy participants obtained in the main CPT variants confirmed these hypotheses. Behavioral and ERP measures indicated worse target detection in the CPT-AX than in the CPT-X, consistent with a higher demand on transient attention in that task. In contrast, behavioral and ERP measures indicated higher response speed in the CPT-AX than in the CPT-X, associated with more response preparation in advance of the targets. This supports the idea of increased transient response preparation in the CPT-AX. We conclude that CPTs differ along at least two task variables that each influences a different cognitive function.