Moderate hypoglycaemia after learning does not affect memory consolidation and brain activation during recognition in non‐diabetic adults

Warren, R. E.; Sommerfield, Andrew J.; Greve, Andrea; Allen, Kate V.; Deary, Ian J.; Frier, Brian M.

doi:10.1002/dmrr.799

Cited by 6 publications

(3 citation statements)

References 41 publications

(45 reference statements)

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“…Consolidation was studied by inducing hypoglycaemia (blood glucose 2.5mmol/l) within 20 to 40 minutes of completing a learning task, 12 and appeared to be unaffected by hypoglycaemia as recall remained intact after euglycaemia had been restored. However, consolidation may have been completed before the hypoglycaemia was induced, and because of the simplicity of the task, it is possible that recognition was being tested rather than memory.…”

Section: Specific Cognitive Functions Affected By Acute Hypoglycaemiamentioning

confidence: 99%

The effects of acute hypoglycaemia on cognitive function in type 1 diabetes

Inkster

Frier

2012

Diabetes & Vascular Disease

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Throughout life with type 1 diabetes mellitus people with the condition are exposed to multiple episodes of hypoglycaemia associated with insulin therapy. Hypoglycaemia affects several domains of cognitive function. Studies in non-diabetic adults and in people with type 1 diabetes have shown that almost all domains of cognitive function are impaired to some degree during acute hypoglycaemia, with complex tasks being more greatly affected. The specific cognitive functions of attention and memory are both profoundly impaired during hypoglycaemia. These cognitive processes are fundamental to the performance of many day to day tasks. Their impairment disrupts everyday life and raises safety concerns for the pursuit of activities such as driving. Mood and emotion are also negatively affected by hypoglycaemia, resulting in tense tiredness, while motivation is reduced, and anger may be generated in some individuals. Hypoglycaemia can cause embarrassing social situations, and may lead to chronic anxiety and depression in people with type 1 diabetes. At present few therapeutic measures can modify or ameliorate the effects of hypoglycaemia on cognitive function, so instigation of measures to prevent exposure to hypoglycaemia is of major clinical importance, while preserving good glycaemic control.

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Section: Specific Cognitive Functions Affected By Acute Hypoglycaemiamentioning

confidence: 99%

The effects of acute hypoglycaemia on cognitive function in type 1 diabetes

Inkster

Frier

2012

Diabetes & Vascular Disease

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“…Studies that have examined brain activation in response to sensory stimulation or cognitive challenges using BOLD fMRI during hypoglycemic conditions in nondiabetic subjects (11–13) have shown that hypoglycemia reduces regional brain BOLD activation. This reduction in BOLD response during hypoglycemia has been attributed to low glucose levels causing decreases in neuronal activity, glucose oxidative metabolism, cerebral blood flow, neurovascular coupling, and/or neuronal recruitment (12).…”

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confidence: 99%

Brain Activation During Working Memory Is Altered in Patients With Type 1 Diabetes During Hypoglycemia

et al. 2011

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OBJECTIVETo investigate the effects of acute hypoglycemia on working memory and brain function in patients with type 1 diabetes.RESEARCH DESIGN AND METHODSUsing blood oxygen level–dependent (BOLD) functional magnetic resonance imaging during euglycemic (5.0 mmol/L) and hypoglycemic (2.8 mmol/L) hyperinsulinemic clamps, we compared brain activation response to a working-memory task (WMT) in type 1 diabetic subjects (n = 16) with that in age-matched nondiabetic control subjects (n = 16). Behavioral performance was assessed by percent correct responses.RESULTSDuring euglycemia, the WMT activated the bilateral frontal and parietal cortices, insula, thalamus, and cerebellum in both groups. During hypoglycemia, activation decreased in both groups but remained 80% larger in type 1 diabetic versus control subjects (P < 0.05). In type 1 diabetic subjects, higher HbA1c was associated with lower activation in the right parahippocampal gyrus and amygdala (R2 = 0.45, P < 0.002). Deactivation of the default-mode network (DMN) also was seen in both groups during euglycemia. However, during hypoglycemia, type 1 diabetic patients deactivated the DMN 70% less than control subjects (P < 0.05). Behavioral performance did not differ between glycemic conditions or groups.CONCLUSIONSBOLD activation was increased and deactivation was decreased in type 1 diabetic versus control subjects during hypoglycemia. This higher level of brain activation required by type 1 diabetic subjects to attain the same level of cognitive performance as control subjects suggests reduced cerebral efficiency in type 1 diabetes.

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“…The association between BGL and BOLD response lies at hand as neuronal activity in the human brain mainly relies on glucose metabolism (Fox and Raichle 2007;Fox et al 1988;Pellerin 1994;Paulson et al 2010). Investigations of effects of BGL on the intensity of the BOLD response during fMRI experiments hitherto mainly focused on BGL significantly lower than those found in 'life-like' situations (Driesen et al 2007;Anderson et al 2006;Warren et al 2008;Schafer et al 2012). These insulin clamp studies give rise to BGL that would usually lead to clinical treatment for hypoglycemia.…”

Section: Introductionmentioning

confidence: 99%

Prolonged fasting impairs neural reactivity to visual stimulation

et al. 2014

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Previous literature has shown that hypoglycemia influences the intensity of the BOLD signal. A similar but smaller effect may also be elicited by low normal blood glucose levels in healthy individuals. This may not only confound the BOLD signal measured in fMRI, but also more generally interact with cognitive processing, and thus indirectly influence fMRI results. Here we show in a placebo-controlled, crossover, double-blind study on 40 healthy subjects, that overnight fasting and low normal levels of glucose contrasted to an activated, elevated glucose condition have an impact on brain activation during basal visual stimulation. Additionally, functional connectivity of the visual cortex shows a strengthened association with higher-order attention-related brain areas in an elevated blood glucose condition compared to the fasting condition. In a fasting state visual brain areas show stronger coupling to the inferior temporal gyrus. Results demonstrate that prolonged overnight fasting leads to a diminished BOLD signal in higher-order occipital processing areas when compared to an elevated blood glucose condition. Additionally, functional connectivity patterns underscore the modulatory influence of fasting on visual brain networks. Patterns of brain activation and functional connectivity associated with a broad range of attentional processes are affected by maturation and aging and associated with psychiatric disease and intoxication. Thus, we conclude that prolonged fasting may decrease fMRI design sensitivity in any task involving attentional processes when fasting status or blood glucose is not controlled.

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Moderate hypoglycaemia after learning does not affect memory consolidation and brain activation during recognition in non‐diabetic adults

Cited by 6 publications

References 41 publications

The effects of acute hypoglycaemia on cognitive function in type 1 diabetes

The effects of acute hypoglycaemia on cognitive function in type 1 diabetes

Brain Activation During Working Memory Is Altered in Patients With Type 1 Diabetes During Hypoglycemia

Prolonged fasting impairs neural reactivity to visual stimulation

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