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Gillespie KM, White MJ, Kemps E, Moore H, Dymond A, Bartlett SE. The Impact of Free and Added Sugars on Cognitive Function: A Systematic Review and Meta-Analysis. Nutrients 2023; 16:75. [PMID: 38201905 PMCID: PMC10780393 DOI: 10.3390/nu16010075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
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.
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Affiliation(s)
- Kerri M. Gillespie
- School of Clinical Sciences, Faculty of Health, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia;
| | - Melanie J. White
- School of Psychology and Counselling, Faculty of Health, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia;
| | - Eva Kemps
- College of Education, Psychology and Social Work, Flinders University, Bedford Park, SA 5042, Australia;
| | - Halim Moore
- Laboratory of the Metabolic Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), Université Clermont Auvergne, 63170 Clermont-Ferrand, France;
| | - Alexander Dymond
- Mental Health and Specialist Services, Gold Coast Hospital and Health Service, Gold Coast, QLD 4215, Australia;
| | - Selena E. Bartlett
- School of Clinical Sciences, Faculty of Health, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia;
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Peters R, White D, Cleeland C, Scholey A. Fuel for Thought? A Systematic Review of Neuroimaging Studies into Glucose Enhancement of Cognitive Performance. Neuropsychol Rev 2020; 30:234-250. [PMID: 32162177 PMCID: PMC7305087 DOI: 10.1007/s11065-020-09431-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 02/17/2020] [Indexed: 01/08/2023]
Abstract
A transient improvement in cognitive performance can be observed following the ingestion of a glucose drink, a phenomenon known as the ‘glucose facilitation effect’. The effect has been studied thoroughly in the last three decades, but its neural underpinnings remain a matter of speculation. A systematic review was conducted to evaluate the current evidence from studies applying neuroimaging or neurophysiological methods to investigate the glucose enhancement effect. Eleven studies met the inclusion criteria of using neuroimaging in conjunction with cognitive outcomes. Six studies employed electroencephalography (EEG), four used functional magnetic resonance imaging (fMRI) and one employed functional near-infrared spectroscopy (fNIRS). All but one study reported modulation of neurophysiology or neuroimaging markers following glucose, while only five studies reported significant changes in cognitive outcomes. The evidence suggests that glucose administration enhances neurocognitive markers of episodic memory and attentional processes underpinned by medial temporal and frontal activation, sometimes in the absence of measurable behavioural effects. Further exploration of glucose facilitation using neuroimaging measures with increased sample sizes is warranted to replicate these findings.
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Affiliation(s)
- Riccarda Peters
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia
| | - David White
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia
| | - Carlee Cleeland
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia
| | - Andrew Scholey
- Centre for Human Psychopharmacology, Swinburne University of Technology, Melbourne, VIC, 3122, Australia.
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The impact of diet-based glycaemic response and glucose regulation on cognition: evidence across the lifespan. Proc Nutr Soc 2017; 76:466-477. [DOI: 10.1017/s0029665117000829] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The brain has a high metabolic rate and its metabolism is almost entirely restricted to oxidative utilisation of glucose. These factors emphasise the extreme dependence of neural tissue on a stable and adequate supply of glucose. Whereas initially it was thought that only glucose deprivation (i.e. under hypoglycaemic conditions) can affect brain function, it has become apparent that low-level fluctuations in central availability can affect neural and consequently, cognitive performance. In the present paper the impact of diet-based glycaemic response and glucose regulation on cognitive processes across the lifespan will be reviewed. The data suggest that although an acute rise in blood glucose levels has some short-term improvements of cognitive function, a more stable blood glucose profile, which avoids greater peaks and troughs in circulating glucose is associated with better cognitive function and a lower risk of cognitive impairments in the longer term. Therefore, a habitual diet that secures optimal glucose delivery to the brain in the fed and fasting states should be most advantageous for the maintenance of cognitive function. Although the evidence to date is promising, it is insufficient to allow firm and evidence-based nutritional recommendations. The rise in obesity, diabetes and metabolic syndrome in recent years highlights the need for targeted dietary and lifestyle strategies to promote healthy lifestyle and brain function across the lifespan and for future generations. Consequently, there is an urgent need for hypothesis-driven, randomised controlled trials that evaluate the role of different glycaemic manipulations on cognition.
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Sibille KT, Bartsch F, Reddy D, Fillingim RB, Keil A. Increasing Neuroplasticity to Bolster Chronic Pain Treatment: A Role for Intermittent Fasting and Glucose Administration? THE JOURNAL OF PAIN 2016; 17:275-81. [PMID: 26848123 DOI: 10.1016/j.jpain.2015.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/27/2015] [Accepted: 11/05/2015] [Indexed: 10/22/2022]
Abstract
UNLABELLED Neuroplastic changes in brain structure and function are not only a consequence of chronic pain but are involved in the maintenance of pain symptoms. Thus, promotion of adaptive, treatment-responsive neuroplasticity represents a promising clinical target. Emerging evidence about the human brain's response to an array of behavioral and environmental interventions may assist in identifying targets to facilitate increased neurobiological receptivity, promoting healthy neuroplastic changes. Specifically, strategies to maximize neuroplastic responsiveness to chronic pain treatment could enhance treatment gains by optimization of learning and positive central nervous system adaptation. Periods of heightened plasticity have been traditionally identified with the early years of development. More recent research, however, has identified a wide spectrum of methods that can be used to "reopen" and enhance plasticity and learning in adults. In addition to transcranial direct current stimulation and transcranial magnetic stimulation, behavioral and pharmacological interventions have been investigated. Intermittent fasting and glucose administration are two propitious strategies, that are noninvasive, inexpensive to administer, implementable in numerous settings, and might be applicable across differing chronic pain treatments. Key findings and neurophysiological mechanisms are summarized, and evidence for the potential clinical contributions of these two strategies toward ameliorating chronic pain is presented. PERSPECTIVE Neuroplastic changes are a defining feature of chronic pain and a complicating factor in treatment. Noninvasive strategies to optimize the brain's response to treatment interventions might improve learning and memory, increase the positive adaptability of the central nervous system, and enhance treatment outcomes.
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Affiliation(s)
- Kimberly T Sibille
- Department of Aging and Geriatric Research, University of Florida, Gainesville, Florida; Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, Florida.
| | - Felix Bartsch
- Department of Aging and Geriatric Research, University of Florida, Gainesville, Florida; Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, Florida; Department of Psychology, University of Florida, Gainesville, Florida
| | - Divya Reddy
- Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, Florida
| | - Roger B Fillingim
- Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, Florida
| | - Andreas Keil
- Department of Psychology, University of Florida, Gainesville, Florida
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Stollery B, Christian L. Glucose improves object-location binding in visual-spatial working memory. Psychopharmacology (Berl) 2016; 233:529-47. [PMID: 26576942 PMCID: PMC4710657 DOI: 10.1007/s00213-015-4125-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 10/19/2015] [Indexed: 12/23/2022]
Abstract
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.
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Affiliation(s)
- Brian Stollery
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol, BS8 1TU, UK.
| | - Leonie Christian
- School of Experimental Psychology, University of Bristol, 12a Priory Road, Bristol, BS8 1TU UK
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Abstract
Previous research has produced discrepant findings as to whether glucose administration effects lead to enhanced recollection or arise only under dual-task conditions. The aim of the present research was to address these issues by firstly employing an alternative cognitively demanding paradigm that has been linked to hippocampal function, i.e. the Process Dissociation Procedure (PDP). A second aim was to use this paradigm to explore whether glucose affects qualitative aspects of memory function. To achieve these aims, the PDP task was administered to participants who had either consumed a glucose (25 g) or aspartame-sweetened control drink. Results demonstrated glucose facilitation effects only under difficult task conditions and with no such effect emerging for the process of recollection. The present results support the contention that the beneficial effects of glucose arise under hippocampally driven, cognitively demanding task conditions, and that this effect enhances quantitative but not qualitative aspects of recognition memory.
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Affiliation(s)
- Karen R Brandt
- Department of Psychology, University of Roehampton, London, UK
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Glucose, relational memory, and the hippocampus. Psychopharmacology (Berl) 2015; 232:2113-25. [PMID: 25527036 DOI: 10.1007/s00213-014-3842-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 12/08/2014] [Indexed: 12/14/2022]
Abstract
RATIONALE Many studies suggest that glucose can temporarily enhance hippocampal-dependent memories. As the hippocampus plays a key role in associative learning, we examined the influence of glucose on verbal paired associate memory. OBJECTIVE This study examines how glucose modifies performance on a relational memory task by examining its influence on learning, subsequent forgetting and relearning. METHODS A selective reminding procedure was used to show high and low imagability paired associates to 80 participants, who were seen twice. On the first session, they received 25 g glucose pre-learning, 25 g glucose post-learning or placebo. On the second session, 1 week later, they received 25 g glucose or placebo. Cued-recall was evaluated after each learning trial, 1 week later to assess forgetting and after an opportunity to relearn the material forgotten. RESULTS Glucose did not influence paired associate acquisition. Those given glucose pre-learning tended to forget less material the following week, and independently, glucose at retrieval facilitated cued-recall. Both forms of facilitation were equally apparent on low and high imagability pairs. The benefit of glucose pre-learning was eliminated once the paired associates had been seen again, but the benefit of glucose at retrieval extended into the second relearning trial. CONCLUSIONS The discussion considers the cognitive processes and hippocampal basis for paired associate learning and retention and the implications for glucose's mode of action. It is proposed that glucose during encoding serves to make the delayed memories initially more available, whereas its influence during delayed retrieval makes available memories temporarily more accessible.
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Glucose administration and cognitive function: differential effects of age and effort during a dual task paradigm in younger and older adults. Psychopharmacology (Berl) 2015; 232:1135-42. [PMID: 25288513 DOI: 10.1007/s00213-014-3750-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Accepted: 09/15/2014] [Indexed: 10/24/2022]
Abstract
RATIONALE Current research suggests that glucose facilitates performance on cognitive tasks which possess an episodic memory component and a relatively high level of cognitive demand. However, the extent to which this glucose facilitation effect is uniform across the lifespan is uncertain. METHODS This study was a repeated measures, randomised, placebo-controlled, cross-over trial designed to assess the cognitive effects of glucose in younger and older adults under single and dual task conditions. Participants were 24 healthy younger (average age 20.6 years) and 24 healthy older adults (average age 72.5 years). They completed a recognition memory task after consuming drinks containing 25 g glucose and a placebo drink, both in the presence and absence of a secondary tracking task. RESULTS AND CONCLUSIONS Glucose enhanced recognition memory response time and tracking precision during the secondary task, in older adults only. These findings do not support preferential targeting of hippocampal function by glucose, rather they suggest that glucose administration differentially increases the availability of attentional resources in older individuals.
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Scholey A, Savage K, O'Neill BV, Owen L, Stough C, Priestley C, Wetherell M. Effects of two doses of glucose and a caffeine-glucose combination on cognitive performance and mood during multi-tasking. Hum Psychopharmacol 2014; 29:434-45. [PMID: 25196040 PMCID: PMC4265209 DOI: 10.1002/hup.2417] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 04/23/2014] [Accepted: 05/12/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND This study assessed the effects of two doses of glucose and a caffeine-glucose combination on mood and performance of an ecologically valid, computerised multi-tasking platform. MATERIALS AND METHODS Following a double-blind, placebo-controlled, randomised, parallel-groups design, 150 healthy adults (mean age 34.78 years) consumed drinks containing placebo, 25 g glucose, 60 g glucose or 60 g glucose with 40 mg caffeine. They completed a multi-tasking framework at baseline and then 30 min following drink consumption with mood assessments immediately before and after the multi-tasking framework. Blood glucose and salivary caffeine were co-monitored. RESULTS The caffeine-glucose group had significantly better total multi-tasking scores than the placebo or 60 g glucose groups and were significantly faster at mental arithmetic tasks than either glucose drink group. There were no significant treatment effects on mood. Caffeine and glucose levels confirmed compliance with overnight abstinence/fasting, respectively, and followed the predicted post-drink patterns. CONCLUSION These data suggest that co-administration of glucose and caffeine allows greater allocation of attentional resources than placebo or glucose alone. At present, we cannot rule out the possibility that the effects are due to caffeine alone Future studies should aim at disentangling caffeine and glucose effects.
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Affiliation(s)
- Andrew Scholey
- Centre for Human Psychopharmacology, Swinburne UniversityMelbourne, VIC, Australia,
*Correspondence to: A. Scholey, Centre for Human Psychopharmacology, Swinburne University, Melbourne, VIC 3122, Australia. Tel: +61(0)3 9214 8932 E-mail:
| | - Karen Savage
- Centre for Human Psychopharmacology, Swinburne UniversityMelbourne, VIC, Australia
| | | | - Lauren Owen
- Centre for Human Psychopharmacology, Swinburne UniversityMelbourne, VIC, Australia
| | - Con Stough
- Centre for Human Psychopharmacology, Swinburne UniversityMelbourne, VIC, Australia
| | | | - Mark Wetherell
- Department of Psychology, Northumbria UniversityNewcastle-upon-Tyne, UK
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Li YK, Hui CLM, Lee EHM, Chang WC, Chan SKW, Leung CM, Chen EYH. Coupling physical exercise with dietary glucose supplement for treating cognitive impairment in schizophrenia: a theoretical model and future directions. Early Interv Psychiatry 2014; 8:209-20. [PMID: 24224943 DOI: 10.1111/eip.12109] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 10/10/2013] [Indexed: 01/09/2023]
Abstract
AIMS Metabolic dysregulation may disrupt the complex neuroprotective mechanisms essential for brain health. Recent studies have pointed out the possible aetiological role of metabolic dysregulation in the onset of schizophrenia and the associated cognitive impairment. In this paper, we aimed to generate a theoretical model of how a combination of physical exercise and dietary glucose supplement may help to alleviate cognitive impairment in schizophrenia. METHODS Literature on metabolic dysregulation, especially insulin resistance, in relation to the onset of schizophrenia and the associated cognitive impairment is reviewed. The cognitive enhancement effects of physical exercise and dietary glucose supplement are then summarised. Finally, we propose a theoretical model based on the concerted effects of physical exercise and glucose supplement. RESULTS In general, the joint action of physical exercise and dietary glucose supplement could up-regulate glucose and insulin transport into the brain, as well as augmenting the release of insulin growth factor-1 and brain-derived neurotrophic factor. Physical exercise and glucose supplement could enhance energy supply and neuroplasticity in brain, subsequently leading to potential cognitive enhancement in schizophrenia. However, glucose supplement is not suitable for patients with abnormal metabolic profile. CONCLUSIONS The combination of physical exercise and glucose supplement has potential therapeutic values in treating cognitive impairment in schizophrenia. Further research is necessary to investigate the optimal patterns of exercise and doses of glucose for treating cognitive impairment in schizophrenia.
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Affiliation(s)
- Yuet-Keung Li
- Department of Psychiatry, University of Hong Kong, Hong Kong
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Brown LA, Riby LM. Glucose enhancement of event-related potentials associated with episodic memory and attention. Food Funct 2014; 4:770-6. [PMID: 23536104 DOI: 10.1039/c3fo30243a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Previous studies have reported that increasing glycaemia by a glucose-containing drink enhances memory functioning. The aim of the present study was to extend this literature by examining the effects of glucose on episodic memory as well as attention processes, and to investigate associated event-related potential (ERP) markers. Fifteen minutes after treatment (25 g glucose or placebo drink), 35 participants performed an old/new recognition memory task and a Stroop colour naming task. Consistent with previous research, when controlling for glucose regulation, cognitive facilitation was observed behaviourally for verbal memory, but there was also a trend towards attentional facilitation. Furthermore, across both domains, it was the most demanding task conditions that exhibited glucose sensitivity. In support of the behavioural results, the analysis of ERPs across treatment groups revealed an enhanced left-parietal old/new effect related to recollection, and also suggested modulation of attentional processes. The results suggest that glucose may facilitate attention as well as memory.
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Affiliation(s)
- Louise A Brown
- Division of Psychology, School of Social Sciences, Nottingham Trent University, Burton Street, Nottingham, NG1 4BU, UK.
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Lamport DJ, Lawton CL, Mansfield MW, Moulin CA, Dye L. Type 2 diabetes and impaired glucose tolerance are associated with word memory source monitoring recollection deficits but not simple recognition familiarity deficits following water, low glycaemic load, and high glycaemic load breakfasts. Physiol Behav 2014; 124:54-60. [DOI: 10.1016/j.physbeh.2013.10.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 10/23/2013] [Indexed: 11/24/2022]
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Scholey A, Macpherson H, Sünram-Lea S, Elliott J, Stough C, Kennedy D. Glucose enhancement of recognition memory: differential effects on effortful processing but not aspects of 'remember-know' responses. Neuropharmacology 2012; 64:544-9. [PMID: 22766389 DOI: 10.1016/j.neuropharm.2012.06.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/13/2012] [Accepted: 06/15/2012] [Indexed: 11/25/2022]
Abstract
The administration of a glucose drink has been shown to enhance cognitive performance with effect sizes comparable with those from pharmaceutical interventions in human trials. In the memory domain, it is currently debated whether glucose facilitation of performance is due to differential targeting of hippocampal memory or whether task effort is a more important determinant. Using a placebo-controlled, double-blind, crossover 2(Drink: glucose/placebo) × 2(Effort: ± secondary task) design, 20 healthy young adults' recognition memory performance was measured using the 'remember-know' procedure. Two high effort conditions (one for each drink) included secondary hand movements during word presentation. A 25 g glucose or 30 mg saccharine (placebo) drink was consumed 10 min prior to the task. The presence of a secondary task resulted in a global impairment of memory function. There were significant Drink × Effort interactions for overall memory accuracy but no differential effects for 'remember' or 'know' responses. These data suggest that, in some circumstances, task effort may be a more important determinant of the glucose facilitation of memory effect than hippocampal mediation. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Andrew Scholey
- Centre for Human Psychopharmacology, Swinburne University, Melbourne VIC 3122, Australia.
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Riby LM, Law AS, Mclaughlin J, Murray J. Preliminary evidence that glucose ingestion facilitates prospective memory performance. Nutr Res 2011; 31:370-7. [DOI: 10.1016/j.nutres.2011.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Revised: 04/27/2011] [Accepted: 04/27/2011] [Indexed: 11/30/2022]
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Parent MB, Krebs-Kraft DL, Ryan JP, Wilson JS, Harenski C, Hamann S. Glucose administration enhances fMRI brain activation and connectivity related to episodic memory encoding for neutral and emotional stimuli. Neuropsychologia 2011; 49:1052-1066. [DOI: 10.1016/j.neuropsychologia.2011.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 02/07/2011] [Accepted: 02/09/2011] [Indexed: 10/18/2022]
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Smith MA, Hii HL, Foster JK, van Eekelen JAM. Glucose enhancement of memory is modulated by trait anxiety in healthy adolescent males. J Psychopharmacol 2011; 25:60-70. [PMID: 19939878 DOI: 10.1177/0269881109348164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Glucose administration is associated with memory enhancement in healthy young individuals under conditions of divided attention at encoding. While the specific neurocognitive mechanisms underlying this 'glucose memory facilitation effect' are currently uncertain, it is thought that individual differences in glucoregulatory efficiency may alter an individual's sensitivity to the glucose memory facilitation effect. In the present study, we sought to investigate whether basal hypothalamic-pituitary-adrenal axis function (itself a modulator of glucoregulatory efficiency), baseline self-reported stress and trait anxiety influence the glucose memory facilitation effect. Adolescent males (age range = 14-17 years) were administered glucose and placebo prior to completing a verbal episodic memory task on two separate testing days in a counter-balanced, within-subjects design. Glucose ingestion improved verbal episodic memory performance when memory recall was tested (i) within an hour of glucose ingestion and encoding, and (ii) one week subsequent to glucose ingestion and encoding. Basal hypothalamic-pituitary-adrenal axis function did not appear to influence the glucose memory facilitation effect; however, glucose ingestion only improved memory in participants reporting relatively higher trait anxiety. These findings suggest that the glucose memory facilitation effect may be mediated by biological mechanisms associated with trait anxiety.
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Affiliation(s)
- Michael A Smith
- School of Paediatrics and Child Health, University of Western Australia, Princess Margaret Hospital for Children, Perth, Western Australia, Australia.
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Smith MA, Riby LM, Eekelen JAMV, Foster JK. Glucose enhancement of human memory: a comprehensive research review of the glucose memory facilitation effect. Neurosci Biobehav Rev 2010; 35:770-83. [PMID: 20883717 DOI: 10.1016/j.neubiorev.2010.09.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 09/16/2010] [Accepted: 09/21/2010] [Indexed: 11/25/2022]
Abstract
The brain relies upon glucose as its primary fuel. In recent years, a rich literature has developed from both human and animal studies indicating that increases in circulating blood glucose can facilitate cognitive functioning. This phenomenon has been termed the 'glucose memory facilitation effect'. The purpose of this review is to discuss a number of salient studies which have investigated the influence of glucose ingestion on neurocognitive performance in individuals with (a) compromised neurocognitive capacity, as well as (b) normally functioning individuals (with a focus on research conducted with human participants). The proposed neurocognitive mechanisms purported to underlie the modulatory effect of glucose on neurocognitive performance will also be considered. Many theories have focussed upon the hippocampus, given that this brain region is heavily implicated in learning and memory. Further, it will be suggested that glucose is a possible mechanism underlying the phenomenon that enhanced memory performance is typically observed for emotionally laden stimuli.
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Affiliation(s)
- Michael A Smith
- Department of Psychology, Northumbria University, Ellison Place, Newcastle upon Tyne, NE1 8ST, UK.
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Owen L, Finnegan Y, Hu H, Scholey AB, Sünram-Lea SI. Glucose effects on long-term memory performance: duration and domain specificity. Psychopharmacology (Berl) 2010; 211:131-40. [PMID: 20523971 DOI: 10.1007/s00213-010-1876-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 04/21/2010] [Indexed: 10/19/2022]
Abstract
RATIONAL Previous research has suggested that long-term verbal declarative memory is particularly sensitive to enhancement by glucose loading; however, investigation of glucose effects on certain memory domains has hitherto been neglected. Therefore, domain specificity of glucose effects merits further elucidation. OBJECTIVES The aim of the present research was to provide a more comprehensive investigation of the possible effects of glucose administration on different aspects of memory by 1) contrasting the effect of glucose administration on different memory domains (implicit/explicit memory; verbal/non-verbal memory, and recognition/familiarity processes), 2) investigating whether potential effects on memory domains differ depending on the dose of glucose administered (25 g versus 60 g), 3) exploring the duration of the glucose facilitation effect (assessment of memory performance 35 min and 1 week after encoding). METHODS A double-blind between-subjects design was used to test the effects of administration of 25 and 60 g glucose on memory performance. RESULTS Implicit memory was improved following administration of 60 g of glucose. Glucose supplementation failed to improve face recognition performance but significantly improved performance of word recall and recognition following administration of 60 g of glucose. However, effects were not maintained 1 week following encoding. CONCLUSIONS Improved implicit memory performance following glucose administration has not been reported before. Furthermore, the current data tentatively suggest that level of processing may determine the required glucose dosage to demonstrate memory improvement and that higher dosages may be able to exert effects on memory pertaining to both hippocampal and non-hippocampal brain regions.
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Affiliation(s)
- Lauren Owen
- NICM Centre for the Study of Natural Medicines and Neurocognition, Brain Sciences Institute, Melbourne, VIC, 3122, Australia.
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Szego EM, Janáky T, Szabó Z, Csorba A, Kompagne H, Müller G, Lévay G, Simor A, Juhász G, Kékesi KA. A mouse model of anxiety molecularly characterized by altered protein networks in the brain proteome. Eur Neuropsychopharmacol 2010; 20:96-111. [PMID: 20015620 DOI: 10.1016/j.euroneuro.2009.11.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 09/25/2009] [Accepted: 11/12/2009] [Indexed: 02/06/2023]
Abstract
Recently, several attempts have been made to describe changes related to certain anxiety states in the proteome of experimental animal models. However, these studies are restricted by limitations regarding the number and correct identification of separated proteins. Moreover, the application of a systems biology approach to discover the molecular mechanisms of anxiety requires genetically homogenous inbred animal models. Therefore, we developed a novel mouse model of anxiety using a combination of crossbreeding (inbred for 35 generations) and behavioral selection. We found significant changes in 82 proteins in the total brain proteome compared to the control proteome. Thirty-four of these proteins had been previously identified in other anxiety, depression or repeated psychosocial stress studies. The identified proteins are associated with different cellular functions, including synaptic transmission, metabolism, proteolysis, protein biosynthesis and folding, cytoskeletal proteins, brain development and neurogenesis, oxidative stress, signal transduction. Our proteomics data suggest that alterations in serotonin receptor-associated proteins, in the carbohydrate metabolism, in the cellular redox system and in synaptic docking are all involved in anxiety.
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Affiliation(s)
- Eva M Szego
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, Budapest, Pázmány P. stny. 1/c, Hungary
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Decreases in recollective experience following acute alcohol: a dose-response study. Psychopharmacology (Berl) 2010; 208:67-74. [PMID: 19911170 DOI: 10.1007/s00213-009-1709-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Accepted: 10/21/2009] [Indexed: 10/20/2022]
Abstract
RATIONALE Acute alcohol intoxication induces a selective impairment of recognition memory associated with conscious recollection whilst recognition based on familiarity is left intact. OBJECTIVES We aimed to further elucidate the acute effects of alcohol on recognition memory by assessing three different doses of alcohol and examining the way in which this affected the recollection and familiarity components of recognition memory in comparison to a placebo group. METHODS A double-blind independent design was used, and participants received either alcohol (0.4, 0.6 or 0.8 g/kg) or a placebo drink. Participants encoded word pairs with depth of processing manipulated under generate and read conditions. Recognition memory was assessed and recollective awareness was examined through use of the remember-know procedure. RESULTS Alcohol produced a dose-dependent reduction in recognition memory associated with recollection, evidenced by decreases in the number of correctly recognised items with 'remember' responses compared to placebo. Recognition based on a familiarity, evidenced by 'know' responses, showed no differences between groups or pattern of reduction compared to the placebo group. However, a negative correlation was found between recognition based on familiarity and levels of intoxication. CONCLUSIONS Alcohol-induced impairments in recognition memory occur in a dose-dependent manner, specifically driven by reductions in recognition associated with conscious awareness.
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Smith MA, Riby LM, Sünram-Lea SI, van Eekelen JAM, Foster JK. Glucose modulates event-related potential components of recollection and familiarity in healthy adolescents. Psychopharmacology (Berl) 2009; 205:11-20. [PMID: 19274454 DOI: 10.1007/s00213-009-1509-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 02/27/2009] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Behavioural evidence supports the notion that oral glucose ingestion enhances recognition memory judgements based on recollection, but not familiarity. The present study sought to clarify and extend upon these behavioural findings by investigating the influence of glucose administration on event-related potential (ERP) components that are thought to be differentially mediated by recollection and familiarity processes in healthy adolescents. METHODS In a within-subjects design, participants performed a recognition memory task, during which time electroencephalogram (EEG) was recorded, subsequent to ingestion of either (a) glucose or (b) placebo in a counterbalanced order. RESULTS Response times during the recognition memory task were observed to be faster for the glucose condition, relative to a placebo control. Further, glucose ingestion was associated with an enhanced left parietal old/new ERP effect (a marker of recollection) and an enhanced mid-frontal old/new ERP effect (known to be mediated by familiarity). DISCUSSION These findings (a) support the results of previous research that the 'glucose memory facilitation effect' can be extended to healthy adolescents, but (b) suggest that glucose enhances both the recollection and familiarity components of recognition memory. The observed ERP profile has important implications for the proposal that glucose specifically targets the hippocampus in modulating cognitive performance.
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Affiliation(s)
- Michael A Smith
- School of Paediatrics and Child Health, University of Western Australia, Princess Margaret Hospital for Children, G. P. O. Box D 184, Perth, Western Australia, 6840, Australia.
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Scholey AB, Sünram-Lea SI, Greer J, Elliott J, Kennedy DO. Glucose administration prior to a divided attention task improves tracking performance but not word recognition: evidence against differential memory enhancement? Psychopharmacology (Berl) 2009; 202:549-58. [PMID: 18979086 DOI: 10.1007/s00213-008-1387-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Accepted: 09/30/2008] [Indexed: 11/27/2022]
Abstract
RATIONALE The cognition-enhancing effects of glucose administration to humans have been well-documented; however, it remains unclear whether this effect preferentially targets episodic memory or other cognitive domains. OBJECTIVES The effect of glucose on the allocation of attentional resources during memory encoding was assessed using a sensitive dual-attention paradigm. MATERIALS AND METHODS One hundred and twenty volunteers (mean age 21.60, SD 4.89, 77 females) took part in this randomised, double-blind, placebo-controlled, parallel groups study where each consumed a 25-g glucose drink or a placebo. Half of the participants in each drink condition attempted to track a moving on-screen target during auditory word presentation. The distance between the cursor and the tracking target was used as an index of attentional cost during encoding. Effects of drink and tracking on recognition memory and drink on tracking performance were assessed. Self-rated appetite and mood were co-monitored. RESULTS Co-performing the tracking task significantly impaired memory performance irrespective of drink condition. In the placebo-tracking condition, there was a cost to tracking manifest as greater deviation from target during and immediately following word presentation. Compared with placebo, the glucose drink significantly improved tracking performance during encoding. There were significant time-related changes in thirst and alertness ratings but these were not differentially affected by drink or tracking conditions. CONCLUSION Tracking but not memory was enhanced by glucose. This finding suggests that, under certain task conditions, glucose administrations does not preferentially enhance memory performance. One mechanism through which glucose acts as a cognition enhancer is through allowing greater allocation of attentional resources.
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Affiliation(s)
- Andrew B Scholey
- NICM Centre for Study of Natural Medicines and Neurocognition, Brain Sciences Institute, Swinburne University, Melbourne, VIC 3122, Australia.
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Sunyer B, Diao WF, Kang SU, An G, Boddul S, Lubec G. Cognitive Enhancement by SGS742 in OF1 Mice Is Linked to Specific Hippocampal Protein Expression. J Proteome Res 2008; 7:5237-53. [DOI: 10.1021/pr800594b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Berta Sunyer
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Wei-Fei Diao
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Sung Ung Kang
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Gunyong An
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Sanjay Boddul
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - Gert Lubec
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
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Glucoregulatory and order effects on verbal episodic memory in healthy adolescents after oral glucose administration. Biol Psychol 2008; 79:209-15. [PMID: 18555581 DOI: 10.1016/j.biopsycho.2008.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 03/27/2008] [Accepted: 05/02/2008] [Indexed: 11/21/2022]
Abstract
The ingestion of oral glucose has been observed to facilitate memory performance in both elderly individuals and in young adults. However, fewer studies have investigated the effect of glucose on memory in children or adolescents. In the present study, the ingestion of a glucose laden drink was observed to enhance verbal episodic memory performance in healthy adolescents under conditions of divided attention, relative to a placebo drink. Further analyses found that this glucose memory facilitation effect was observed only in adolescents exhibiting better glucoregulatory efficiency. These findings demonstrate that the glucose memory facilitation effect can be generalised to younger individuals. The importance of controlling for treatment order in within-subjects designs investigating the glucose memory enhancement effect is also discussed.
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