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Sleep is known to support the neocortical consolidation of declarative memory, including the acquisition of new language. Autism spectrum disorder (ASD) is often characterized by both sleep and language learning difficulties, but few studies have explored a potential connection between the two. Here, 54 children with and without ASD (matched on age, nonverbal ability and vocabulary) were taught nine rare animal names (e.g., pipa). Memory was assessed via definitions, naming and speeded semantic decision tasks immediately after learning (pre‐sleep), the next day (post‐sleep, with a night of polysomnography between pre‐ and post‐sleep tests) and roughly 1 month later (follow‐up). Both groups showed comparable performance at pre‐test and similar levels of overnight change on all tasks; but at follow‐up children with ASD showed significantly greater forgetting of the unique features of the new animals (e.g., pipa is a flat frog). Children with ASD had significantly lower central non‐rapid eye movement (NREM) sigma power. Associations between spindle properties and overnight changes in speeded semantic decisions differed by group. For the TD group, spindle duration predicted overnight changes in responses to novel animals but not familiar animals, reinforcing a role for sleep in the stabilization of new semantic knowledge. For the ASD group, sigma power and spindle duration were associated with improvements in responses to novel and particularly familiar animals, perhaps reflecting more general sleep‐associated improvements in task performance. Plausibly, microstructural sleep atypicalities in children with ASD and differences in how information is prioritized for consolidation may lead to cumulative consolidation difficulties, compromising the quality of newly formed semantic representations in long‐term memory., This polysomnography study examined the sleep‐associated consolidation of words for real but rare animals, in children with and without autism. Children with autism showed increased forgetting of novel features (e.g., an asp is a hairy caterpillar), relative to typical peers, one month after exposure. They also showed reduced sigma power (within the sleep spindle frequency range), and showed more general associations between overnight changes in task performance (for both novel and particularly familiar words) and sleep spindle parameters, in stark contrast to typical peers who showed selective associations between spindles and overnight changes in novel memory traces.

Sleep spindle activity in infants supports their formation of generalized memories during sleep, indicating that specific sleep processes affect the consolidation of memories early in life. Characteristics of sleep spindles depend on the infant's developmental state and are known to be associated with trait‐like factors such as intelligence. It is, however, largely unknown which state‐like factors affect sleep spindles in infancy. By varying infants’ wake experience in a within‐subject design, here we provide evidence for a learning‐ and memory‐dependent modulation of infant spindle activity. In a lexical‐semantic learning session before a nap, 14‐ to 16‐month‐old infants were exposed to unknown words as labels for exemplars of unknown object categories. In a memory test on the next day, generalization to novel category exemplars was tested. In a nonlearning control session preceding a nap on another day, the same infants heard known words as labels for exemplars of already known categories. Central–parietal fast sleep spindles increased after the encoding of unknown object–word pairings compared to known pairings, evidencing that an infant's spindle activity varies depending on its prior knowledge for newly encoded information. Correlations suggest that enhanced spindle activity was particularly triggered, when similar unknown pairings were not generalized immediately during encoding. The spindle increase triggered by previously not generalized object–word pairings, moreover, boosted the formation of generalized memories for these pairings. Overall, the results provide first evidence for a fine‐tuned regulation of infant sleep quality according to current consolidation requirements, which improves the infant long‐term memory for new experiences.

Impaired procedural learning has been suggested as a possible cause of developmental dyslexia (DD) and specific language impairment (SLI). This study examined the relationship between measures of verbal and non‐verbal implicit and explicit learning and measures of language, literacy and arithmetic attainment in a large sample of 7 to 8‐year‐old children. Measures of verbal explicit learning were correlated with measures of attainment. In contrast, no relationships between measures of implicit learning and attainment were found. Critically, the reliability of the implicit learning tasks was poor. Our results show that measures of procedural learning, as currently used, are typically unreliable and insensitive to individual differences. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=YnvV-BvNWSo

Molluscan preparations have yielded seminal discoveries in neuroscience, but the experimental advantages of this group have not, until now, been complemented by adequate molecular or genomic information for comparisons to genetically defined model organisms in other phyla. The recent sequencing of the transcriptome and genome of Aplysia californica, however, will enable extensive comparative studies at the molecular level. Among other benefits, this will bring the power of individually identifiable and manipulable neurons to bear upon questions of cellular function for evolutionarily conserved genes associated with clinically important neural dysfunction. Because of the slower rate of gene evolution in this molluscan lineage, more homologs of genes associated with human disease are present in Aplysia than in leading model organisms from Arthropoda (Drosophila) or Nematoda (Caenorhabditis elegans). Research has hardly begun in molluscs on the cellular functions of gene products that in humans are associated with neurological diseases. On the other hand, much is known about molecular and cellular mechanisms of long-term neuronal plasticity. Persistent nociceptive sensitization of nociceptors in Aplysia displays many functional similarities to alterations in mammalian nociceptors associated with the clinical problem of chronic pain. Moreover, in Aplysia and mammals the same cell signaling pathways trigger persistent enhancement of excitability and synaptic transmission following noxious stimulation, and these highly conserved pathways are also used to induce memory traces in neural circuits of diverse species. This functional and molecular overlap in distantly related lineages and neuronal types supports the proposal that fundamental plasticity mechanisms important for memory, chronic pain, and other lasting alterations evolved from adaptive responses to peripheral injury in the earliest neurons. Molluscan preparations should become increasingly useful for comparative studies across phyla that can provide insight into cellular functions of clinically important genes.

Objective: To study the ability of patients with semantic dementia to understand actions, in order to examine the contribution of semantic memory to action comprehension. Methods: The ability to comprehend symbolic and instrumental actions was assessed in 6 patients with semantic dementia and 10 healthy controls. The patients were also given the imitation test of meaningful and meaningless actions. Results: In all patients with semantic dementia, comprehension of both symbolic and instrumental actions was defective. The comprehension of symbolic actions was more impaired than that of instrumental actions. Their ability to imitate other’s actions was well preserved. Conclusion: This study showed that comprehension of action was impaired in semantic dementia, suggesting that semantic memory has an important role in comprehension of human action.

Objective: To assess the relation between serum lipids and memory in a healthy middle age cohort of women. Methods: For 326 women in the Melbourne Women’s Midlife Health Project aged 52–63 years, serum lipids were measured annually, and memory was assessed during the eighth annual visit. Results: There was a small but significant association between current low density lipoprotein cholesterol (LDL-C) concentrations and memory; for total cholesterol (TC) the association approached significance. Better memory was associated with positive changes in TC and LDL-C based on lipid measurements three years, but not six years, earlier. Memory performance was lowest among women in the lowest quartile of current LDL-C values and among women whose LDL-C levels declined over the previous three years. High density lipoprotein cholesterol (HDL-C) and triglyceride concentrations were unassociated with memory. The association between memory and TC and LDL-C was primarily related to immediate recall and not delayed recall performance on the word list task. Low cholesterol has been linked with depression, but lipid measures and self-rated mood were unrelated. Conclusions: Higher serum concentrations of LDL-C, and relatively recent increases in TC and LDL-C concentrations, are associated with better memory in healthy middle age women. Possible cognitive effects of cholesterol reduction should be considered in future studies of lipid lowering agents.

Background: “Normal” pressure hydrocephalus (NPH) is associated with injury to neurotransmitter and neuropeptide systems that recovers after surgery. This could be linked to changes in galanin, a neuropeptide with inhibitory effects on basal forebrain cognitive function. Objective: To examine changes in CSF galanin concentrations in patients with normal pressure hydrocephalus undergoing shunt surgery, and to investigate the relation between these changes and cognitive functioning. Methods: Eight patients underwent surgery for idiopathic normal pressure hydrocephalus. Lumbar CSF galanin determinations, cognitive status, and clinical status were quantified before operation and six months after. Cognition was assessed by an extensive battery of tests measuring attention, memory, speed of mental processing, visuospatial function, and frontal lobe function. Results: CSF galanin concentration decreased after surgery. This reduction correlated with improved clinical and cognitive functioning, specifically with attention and visuomotor speed, visuoconstructive and frontal functioning, and clinical status according to the NPH scale, including the sphincter and cognitive components. Conclusions: The cognitive and clinical improvement after shunt implantation correlated with CSF galanin levels, suggesting that the distribution or function of this agent involves cerebral structures that have some potential for recovery. In this study, galanin was related to several cognitive functions that may be associated with the fronto-subcortical deficits underlying cognitive dysfunction in normal pressure hydrocephalus.

Background: Diagnostic criteria of Alzheimer’s disease (AD) emphasize the integration of clinical data and biomarkers. In practice, collection and analysis of patient data vary greatly across different countries and clinics. Objective: The goal was to develop a versatile and objective clinical decision support system that could reduce diagnostic errors and highlight early predictors of AD. Methods: Novel data analysis methods were developed to derive composite disease indicators from heterogeneous patient data. Visualizations that communicate these findings were designed to help the interpretation. The methods were implemented with a software tool that is aimed for daily clinical practice. Results: With the tool, clinicians can analyze available patients as a whole, study them statistically against previously diagnosed cases, and characterize the patients with respect to having AD. The tool is able to work with virtually any patient measurement data, as long as they are stored in electronic format or manually entered into the system. For a subset of patients from the test cohort, the tool was able to predict conversion to AD at an accuracy of 93.6%. Conclusion: The software tool developed in this study provides objective information for early detection and prediction of AD based on interpretable visualizations of patient data.

Background: Episodic memory enables us to consciously recollect personally experienced past events. Memory performance is reduced in patients with mild cognitive impairment (MCI), an at-risk condition for Alzheimer’s disease (AD). Patients and methods: We used functional MRI (fMRI) to compare brain activity during memory encoding in 29 healthy elderly subjects (mean age 67.7 (SD 5.4) years) and 21 patients with MCI (mean age 69.7 (SD 7.0) years). Subjects remembered a list of words while fMRI data were acquired. Later, they had to recognise these words among a list of distractor words. The use of an event related paradigm made it possible to selectively analyse successfully encoded items in each individual. We compared activation for successfully encoded words between healthy elderly subjects and patients with MCI. Results: The main intergroup difference was found in the left hippocampus and surrounding medial temporal lobe (MTL) regions for the patients with MCI compared with healthy subjects during successful encoding. Conclusion: These results suggest that in patients with MCI, an increase in MTL activation is necessary for successful memory encoding. Hippocampal activation may help to link newly learned information to items already stored in memory. Increased activation in MTL regions in MCI may reflect a compensatory response to the beginning of AD pathology.

Objective: To determine how cortical compensation occurs in higher cognitive systems during the recovery phase of diffuse axonal injury (DAI). Design: 12 right-handed patients with a magnetic resonance imaging (MRI) lesion pattern compatible with pure DAI were identified. Pure DAI was defined as finding of traumatic microbleeds on T2*-weighted gradient-echo images in the absence of otherwise traumatic or non-traumatic MRI abnormalities. 12 matched healthy controls were also enrolled. Functional magnetic resonance imaging (fMRI) was used to assess brain activation during a working memory test (Paced Visual Serial Attention Test (PVSAT)). Results: No significant group differences were observed in reaction times for the PVSAT. Although patients with pure DAI committed a few errors during the PVSAT, controls respond correctly to each probe. Controls showed activations in the left frontal gyrus, left parietal gyrus and right inferior parietal gyrus. Patients with pure DAI showed activations in the left inferior frontal gyrus, right inferior frontal gyrus and right middle frontal gyrus. Between-group analysis of the PVSAT task showed significantly greater activation of the right inferior frontal gyrus (BA 45) and right middle frontal gyrus (BA 9) in patient with pure DAI versus controls. Conclusions: Patients with pure DAI require compensatory activation of the contralateral (right) prefrontal region to carry out activities similar to healthy controls. These findings provide further evidence for the adaptive capacity of neuronal systems and brain plasticity during the recovery stages of DAI.

Objectives: To determine the relative impact of hydrocephalus and spinal dysraphism in young adults on intellectual and cognitive functioning. Sub-groups of patients with congenital hydrocephalus and/or spina bifida were assessed between 1995 and 2003. The entry criteria were that individuals should have (i) intact global function, (ii) average verbal intelligence (or above), and (iii) should not have clinical depression. There were three sub-groups: patients with hydrocephalus and spina bifida, patients with hydrocephalus without spina bifida, and patients with spina bifida without hydrocephalus. Methods: Patients were neuropsychologically assessed as part of their normal clinical assessment during their annual medical review. Each individual completed a screening battery assessing global functioning, verbal intelligence, and mood. In addition they completed additional tests including measures of emotional intelligence, memory, attention, and executive function. Results were analysed to compare the performance of the patient sub-groups and to compare them to a healthy control group. Results: Patients with hydrocephalus (with or without spina bifida) were significantly impaired on the vast majority of all test scores as compared to patients with spina bifida and healthy controls. They were particularly poor on measures assessing executive function. By contrast for patients with spina bifida with no associated hydrocephalus, the significant majority of all test scores fell within the average range or above. Conclusions: The neuropsychological profile of patients with hydrocephalus is one of relative impairment and this is so whether or not spina bifida is present. In spina bifida alone, in the absence of hydrocephalus, cognitive function is relatively spared.

The purpose of this study was to define magnetic resonance imaging (MRI) correlates of normal brain ageing, with the specific objective of investigating whether the size of the hippocampus is selectively correlated with age related memory performance in non-demented individuals in their ninth and tenth decades of life.Hippocampal size was estimated using MRI based volumetry and qualitative visual assessment in 102 community dwelling individuals aged between 81 and 94 years. Participants were evaluated on a variety of clinical and experimental instruments, including a comprehensive neuropsychological test battery. All participants underwent neurological examination, an extensive medical history was obtained, and an informant confirmed details of each participant's functional ability.Both visual and volumetric hippocampal measures were identified as robust predictors of memory performance, even when the influence of age related illnesses and sociodemographic variables was accounted for. When the sample was reduced to include the most cognitively healthy participants who were rated by an informant as showing no evidence of cognitive decline, the left hippocampal measures remained significant predictors of delayed retention of verbal material.These findings suggest that hippocampal volumes are selectively correlated with memory functioning in both normal and successful ageing.

The trends in medical publishing are towards electronic versions and the use of the English language. The objective of this study was to compare general practitioners' ability to retain information when reading on paper versus on screen, and in their mother tongue versus in the English.Randomized controlled trial of 114 Scandinavian general practitioners. They read a review article for 10 minutes either on paper/in English, on screen/in English, on paper/in their mother tongue, or on screen/in their mother tongue. Afterwards they completed a questionnaire with six open questions from the article. The main outcome measure was sum score on a scale from 0 (no correct answers) to 13 (all questions answered correctly).We found no difference between readers of paper and screen versions (median (interquartile range) 4 (2-6) vs. 4 (2-5), p = 0.97). Those who read their mother tongue scored significantly higher than those who read English (4 (3-6) vs. 3 (2-4), p = 0.01).The medium (paper vs. screen) does not influence the ability of general practitioners to retain medical information. Doctors best retain medical information when reading it in their mother tongue.