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1.
Brain Imaging Behav ; 2024 May 06.
Article En | MEDLINE | ID: mdl-38709432

Conscious experience and perception are restricted to a single perspective. Although evidence to suggest differences in phenomenal experience can produce observable differences in behavior, it is not well understood how these differences might influence memory. We used fMRI to scan n = 49 participants while they encoded and performed a recognition memory test for faces and words. We calculated a cognitive bias score reflecting individual participants' propensity toward either Visual Imagery or Internal Verbalization based on their responses to the Internal Representations Questionnaire (IRQ). Neither visual imagery nor internal verbalization scores were significantly correlated with memory performance. In the fMRI data, there were typical patterns of activation differences between words and faces during both encoding and retrieval. There was no effect of internal representation bias on fMRI activation during encoding. At retrieval, however, a bias toward visualization was positively correlated with memory-related activation for both words and faces in inferior occipital gyri. Further, there was a crossover interaction in a network of brain regions such that visualization bias was associated with greater activation for words and verbalization bias was associated with greater activation for faces, consistent with increased effort for non-preferred stimulus retrieval. These findings suggest that individual differences in cognitive representations affect neural activation across different types of stimuli, potentially affecting memory retrieval performance.

2.
Breast J ; 2023: 9345780, 2023.
Article En | MEDLINE | ID: mdl-37771428

Background: Patients often ask about the time taken to return to activities of daily living (ADLs) after breast surgery, but there is a lack of data to give accurate guidance. We aimed to assess the feasibility of a study to determine the time taken to return to ADLs after mastectomy with or without breast reconstruction. Materials and Methods: A prospective multicentre, self-reported questionnaire-based feasibility study of women who had undergone mastectomy ± reconstruction was performed, between Jan 2017 and Dec 2019. Women were asked to self-report when they returned to 15 ADLs with a 5-option time scale for "return to activity." Results: The questionnaire was returned by 42 patients (median [range] age: 64 [31-84]). Of these, 22 had simple mastectomy, seven mastectomy and implant reconstruction, seven mastectomy and autologous reconstruction (DIEP), and six did not specify. Overall, over 90% could manage stairs and brush hair by two weeks and 84% could get in and out of the bath by four weeks. By 1-2 months, 92% could do their own shopping and 86% could drive. 68% of women employed returned to work within four months. Compared to simple mastectomy, patients undergoing reconstruction took a longer time to return to getting in/out of bath (<2 vs. 2-4 weeks), vacuuming (2-4 weeks vs. 1-2 months), and fitness (1-2 vs. 3-4 months). There was a slower return to shopping (1-2 months vs. 2-4 weeks), driving and work (both 3-4 vs. 1-2 months), and sports (3-4 vs. 1-2 months) in autologous reconstruction compared to implant reconstruction. Conclusion: This study is feasible. It highlights slower return to specific activities (particularly strength-based) in reconstruction patients, slower in autologous compared with implant reconstruction. The impact on return to ADLs should be discussed as part of the preoperative counselling as it will inform patients and help guide their decision making. A larger study is required to confirm these results.


Breast Neoplasms , Mammaplasty , Humans , Female , Middle Aged , Mastectomy , Breast Neoplasms/surgery , Activities of Daily Living , Prospective Studies , Mammaplasty/methods , Surveys and Questionnaires , Retrospective Studies
3.
Cogn Neurosci ; 13(3-4): 147-148, 2022 07.
Article En | MEDLINE | ID: mdl-35575186

In a clever experimental design, Tallman, Clark, and Smith (this issue) tested the changes in fMRI activation and functional connectivity in the hippocampus and cortex as a function of memory age. They found that activation changed according to a power function (both increasing and decreasing) in several cortical regions but not within the hippocampus or medial temporal lobe (MTL). Further, functional connectivity increased with memory age between cortical regions but decreased for the hippocampus. Taken together, these results offer strong support for the standard consolidation model. However, they leave open the question of what role the hippocampus plays in recognition memory performance.


Brain Mapping , Recognition, Psychology , Humans , Recognition, Psychology/physiology , Hippocampus/physiology , Temporal Lobe/diagnostic imaging , Temporal Lobe/physiology , Magnetic Resonance Imaging/methods
4.
Cogn Neurosci ; 13(3-4): 171-181, 2022 07.
Article En | MEDLINE | ID: mdl-35410578

Pattern separation and pattern completion are generally studied in humans using mnemonic discrimination tasks such as the Mnemonic Similarity Task (MST) where participants identify similar lures and repeated items from a series of images. Failures to correctly discriminate lures are thought to reflect a failure of pattern separation and a propensity toward pattern completion. Recent research has challenged this perspective, suggesting that poor encoding rather than pattern completion accounts for the occurrence of false alarm responses to similar lures. In two experiments, participants completed a continuous recognition task version of the MST while eye movement (Experiments 1 and 2) and fMRI data (Experiment 2) were collected. In Experiment 1, we replicated the result that fixation counts at study predicted accuracy on lure trials (consistent with poor encoding predicting mnemonic discrimination performance), but this effect was not observed in our fMRI task. In both experiments, we found that target-lure similarity was a strong predictor of accuracy on lure trials. Further, we found that fMRI activation changes in the hippocampus were significantly correlated with the number of fixations at study for correct but not incorrect mnemonic discrimination judgments when controlling for target-lure similarity. Our findings indicate that while eye movements during encoding predict subsequent hippocampal activation changes for correct mnemonic discriminations, the predictive power of eye movements for activation changes for incorrect mnemonic discrimination trials was modest at best.


Fixation, Ocular , Magnetic Resonance Imaging , Humans , Recognition, Psychology/physiology , Memory , Eye Movements
5.
J Plast Reconstr Aesthet Surg ; 75(1): 69-76, 2022 Jan.
Article En | MEDLINE | ID: mdl-34219040

BACKGROUND: Many women with increased lifetime risk of developing breast cancer, due to pathogenic gene variants or family history, choose to undergo bilateral risk reducing mastectomies (BRRM). Patient reported outcome measures (PROMS) are an increasingly important part of informed consent but are little studied in women undergoing BRRM. METHODS: We used a validated PROMS tool for breast reconstruction (BREAST-Q) in 297 women who had BRRM and breast reconstruction, 81% of whom had no malignancy (Benign Group, BG) and 19% in whom a perioperative breast cancer was diagnosed (Cancer Group, CG). 128 women also completed a Hospital Anxiety & Depression Score (HADS) questionnaire to test if preoperative HADS score could predict PROMS outcomes. RESULTS: Women in the CG had lower PROMS scores for satisfaction with their breasts, nipple reconstruction and sexual wellbeing. Both groups reported equal satisfaction with BRRM outcome and psychosocial well-being. Physical well-being PROMS of the abdomen and chest were high in women in both groups as were scores for satisfaction with the care they received. The CG group reported suboptimal quality of patient information. A higher presurgical HADS anxiety score predicted less favourable postoperative psychosocial well-being despite similar levels of satisfaction with aesthetic outcome. CONCLUSION: We show a high degree of patient reported satisfaction by woman undergoing BRRM and reconstruction. There was a negative association with a cancer diagnosis on quality of life PROMS and higher preoperative anxiety levels negatively affected postoperative psychosocial well-being. These important findings should be part of the informed consent process during preoperative counselling.


Breast Neoplasms , Mammaplasty , Breast Neoplasms/psychology , Breast Neoplasms/surgery , Female , Humans , Mammaplasty/psychology , Mastectomy , Patient Reported Outcome Measures , Patient Satisfaction , Quality of Life
6.
Sleep ; 45(3)2022 03 14.
Article En | MEDLINE | ID: mdl-34727185

STUDY OBJECTIVES: Insufficient sleep and social stress are associated with weight gain and obesity development in adolescent girls. Functional magnetic resonance imaging (fMRI) research suggests that altered engagement of emotion-related neural networks may explain overeating when under stress. The purpose of this study is to explore the effects of acute sleep restriction on female adolescents' neural responding during social evaluative stress and their subsequent eating behavior. METHODS: Forty-two adolescent females (ages 15-18 years) with overweight or obesity completed a social stress induction task in which they were told they would be rated by peers based on their photograph and profile. Participants were randomly assigned to one night of sleep deprivation or 9 h of sleep the night before undergoing fMRI while receiving positive and negative evaluations from their peers. After which, subjects participated in an ad libitum buffet. RESULTS: Sleep deprived, relative to nondeprived girls had distinct patterns of neural engagement to positive and negative evaluation in anterior, mid, and posterior aspects of midline brain structures. Moreover, a sleep deprivation-by-evaluation valence-by-caloric intake interaction emerged in bilateral dorsal anterior cingulate. Among sleep deprived girls, greater engagement during negative, but not positive, feedback was associated with lower caloric intake. This was not observed for nonsleep deprived girls. CONCLUSIONS: Results suggest an interaction between acute sleep loss and social evaluation that predicts emotion-related neural activation and caloric intake in adolescents. This research helps to elucidate the relationship between sleep loss, social stress, and weight status using a novel health neuroscience model.


Magnetic Resonance Imaging , Overweight , Adolescent , Female , Humans , Obesity/complications , Obesity/diagnostic imaging , Sleep , Sleep Deprivation/complications , Sleep Deprivation/diagnostic imaging
7.
Br J Surg ; 108(8): 908-916, 2021 08 19.
Article En | MEDLINE | ID: mdl-34059874

BACKGROUND: Future innovations in science and technology with an impact on multimodal breast cancer management from a surgical perspective are discussed in this narrative review. The work was undertaken in response to the Commission on the Future of Surgery project initiated by the Royal College of Surgeons of England. METHODS: Expert opinion was sought around themes of surgical de-escalation, reduction in treatment morbidities, and improving the accuracy of breast-conserving surgery in terms of margin status. There was emphasis on how the primacy of surgical excision in an era of oncoplastic and reconstructive surgery is increasingly being challenged, with more effective systemic therapies that target residual disease burden, and permit response-adapted approaches to both breast and axillary surgery. RESULTS: Technologies for intraoperative margin assessment can potentially half re-excision rates after breast-conserving surgery, and sentinel lymph node biopsy will become a therapeutic procedure for many patients with node-positive disease treated either with surgery or chemotherapy as the primary modality. Genomic profiling of tumours can aid in the selection of patients for neoadjuvant and adjuvant therapies as well as prevention strategies. Molecular subtypes are predictive of response to induction therapies and reductive approaches to surgery in the breast or axilla. CONCLUSION: Treatments are increasingly being tailored and based on improved understanding of tumour biology and relevant biomarkers to determine absolute benefit and permit delivery of cost-effective healthcare. Patient involvement is crucial for breast cancer studies to ensure relevance and outcome measures that are objective, meaningful, and patient-centred.


This article describes how future innovations in science and technology influence the management of breast cancer from a surgical perspective. This work was undertaken in response to the Commission on the Future of Surgery project initiated by the Royal College of Surgeons of England.


Breast Neoplasms/surgery , Mastectomy, Segmental/trends , Female , Forecasting , Humans , Mastectomy, Segmental/methods
8.
Br J Surg ; 108(5): 534-541, 2021 05 27.
Article En | MEDLINE | ID: mdl-34043774

BACKGROUND: Prepectoral implant-based breast reconstruction with acellular dermal matrix has become an increasingly popular option for selected patients. There are no randomized data to demonstrate short- or long-term outcomes. Cohort studies to date have demonstrated safety, but risk factors for complications are unknown. METHODS: A prospective cohort study of all patients undergoing prepectoral implant-based breast reconstruction between 2013 and 2019. Clinical factors and those related to reconstruction were analysed in relation to complications and implant loss using univariable and multivariable logistic regression. RESULTS: A total of 469 reconstructions were undertaken in 289 women; the majority of reconstructions were performed using a one-stage direct-to-implant technique with acellular dermal matrix. Median follow-up was 21 (range 2-71) months. Minor complications were seen after 11·2 per cent of reconstructions, major complications after 5·9 per cent, and the rate of implant loss by 3 months was 3·1 per cent. In the final multivariable model, sentinel node biopsy (odds ratio (OR) 5·06, 95 per cent c.i. 2·00 to 12·80), axillary clearance (OR 6·67, 1·17 to 37·94) and adjuvant radiotherapy (OR 7·11, 1·60 to 31·61) were independent risk factors for development of a major complication, and sentinel node biopsy (OR 4·32, 1·23 to 15·22) for implant loss. CONCLUSION: Prepectoral implant-based breast reconstruction has acceptable medium-term results but careful patient selection is advised.


Breast Implantation/methods , Breast Implants/adverse effects , Mammaplasty , Acellular Dermis , Adult , Aged , Breast Neoplasms/surgery , Cohort Studies , Female , Follow-Up Studies , Humans , Middle Aged , Radiotherapy, Adjuvant , Risk Factors , Sentinel Lymph Node Biopsy , Young Adult
9.
Learn Mem ; 28(4): 109-113, 2021 04.
Article En | MEDLINE | ID: mdl-33723030

Binding visual features into coherent object representations is essential both in short- and long-term memory. However, the relationship between feature binding processes at different memory delays remains unexplored. Here, we addressed this question by using the Mnemonic Similarity Task and a delayed-estimation working memory task on a large sample of older adults. The results revealed that higher propensity to misbind object features in working memory is associated with lower lure discrimination performance in the mnemonic similarity task, suggesting that shared feature binding processes underlie the formation of coherent short- and long-term visual object memory representations.


Aging/physiology , Discrimination, Psychological/physiology , Memory, Long-Term/physiology , Memory, Short-Term/physiology , Visual Perception/physiology , Aged , Female , Humans , Male
10.
Hippocampus ; 31(4): 408-421, 2021 04.
Article En | MEDLINE | ID: mdl-33432734

Episodic memory depends on the computational process of pattern separation in order to establish distinct memory representations of similar episodes. Studies of pattern separation in humans rely on mnemonic discrimination tasks, which have been shown to tax hippocampal-dependent pattern separation. Although previous neuroimaging research has focused on hippocampal processing, little is known about how other brain regions, known to be involved in recognition memory performance, are involved in mnemonic discrimination tasks. Conversely, neuroimaging studies of pattern separation with whole-brain coverage lack spatial resolution to localize activation to hippocampal subfields. In this study, 48 healthy young adult participants underwent whole-brain high-resolution functional MRI (fMRI) scanning while completing a mnemonic discrimination task. A priori region-of-interest analyses revealed activation patterns consistent with pattern separation in distinct hippocampal subregions, particularly in the subiculum. Connectivity analyses revealed a network of cortical regions consistent with the memory retrieval network where fMRI activation was correlated with hippocampal activation. An exploratory whole-brain analysis revealed widespread activation differentially associated with performance of the mnemonic discrimination task. Taken together, these results suggest that a network of brain regions contribute to mnemonic discrimination performance, with the hippocampus and parahippocampal cortex as a hub in the network displaying clear signals consistent with pattern separation and regions such as the dorsal medial prefrontal cortex particularly important for successful lure discrimination.


Hippocampus , Memory, Episodic , Brain/diagnostic imaging , Brain Mapping , Hippocampus/diagnostic imaging , Hippocampus/physiology , Humans , Magnetic Resonance Imaging , Recognition, Psychology/physiology , Young Adult
11.
Behav Res Ther ; 136: 103784, 2021 01.
Article En | MEDLINE | ID: mdl-33316579

A cognitive intervention that may reduce weight and caloric intake is inhibitory control training (ICT; having individuals repeatedly withhold dominant responses to unhealthy food images). We conducted a randomized controlled trial where 100 individuals with overweight or obesity were assigned to complete a generic (n = 48) or food-specific ICT (n = 52) training four times per week for four weeks. Weight and caloric intake were obtained at baseline, four-weeks, and 12-weeks. Participants also completed high-calorie and neutral go/no-go tasks while N2 event-related potential (ERP) data, a neural indicator of inhibitory control, was measured at all visits. Results from mixed model analyses indicate that neither weight, caloric intake, nor N2 ERP component amplitude towards high-calorie foods changed at post-testing or at the 12-week follow up. Regression analyses suggest that individuals with smaller N2 difference amplitudes to food may show greater weight loss and reductions in caloric intake after a generic ICT, while individuals with larger N2 difference amplitudes to food may show greater weight loss and reductions in caloric intake after a food-specific ICT. Overall, multiple food-specific or generic ICT sessions over the course of a four-week period do not affect overall weight loss, caloric intake, or N2 ERP amplitude.


Feeding Behavior , Overweight , Adult , Energy Intake , Evoked Potentials , Humans , Obesity/therapy , Overweight/therapy
12.
Brain Imaging Behav ; 15(1): 177-189, 2021 Feb.
Article En | MEDLINE | ID: mdl-32128716

The purpose of this study was to examine the effects of after-school sedentary screen time on children's brain activation in reward and cognitive control regions in response to pictures of high- and low-calorie foods. Thirty-two children participated in a randomized crossover study with counterbalanced treatment conditions. Conditions took place on separate days after school and included three hours of active or sedentary play. After each condition, neural activation was assessed using functional magnetic resonance imaging (fMRI) while participants completed a go/no-go task involving pictures of high- and low-calorie foods. General response inhibition was also measured using the Stroop task. Hunger was measured upon arrival to the testing facility and just prior to fMRI scans. Mixed effects models were used to evaluate main effects and interactions. Significant stimulus by condition interactions were found in the right superior parietal cortex, and left anterior cingulate cortex (Ps ≤ 0.05). High-calorie pictures elicited significantly more activation bilaterally in the orbitofrontal cortex compared to low-calorie pictures (Ps ≤ 0.05). Stroop task performance diminished significantly following the sedentary condition compared to the active (P ≤ 0.05). Subjective feelings of hunger were not different between conditions at any point. Sedentary screen time was associated with significantly decreased response inhibition and a reversed brain activation pattern to pictures of high- and low-calorie foods compared to active play, in areas of the brain important to the modulation of food intake. Decreased attention, and impulse control following sedentary screen time may contribute to disinhibited eating that can lead to overweight and obesity.


Magnetic Resonance Imaging , Screen Time , Attention , Brain/diagnostic imaging , Child , Cross-Over Studies , Cues , Food , Humans , Reward , Schools
13.
Front Psychol ; 11: 528079, 2020.
Article En | MEDLINE | ID: mdl-33364992

Computer users are often the last line of defense in computer security. However, with repeated exposures to system messages and computer security warnings, neural and behavioral responses show evidence of habituation. Habituation has been demonstrated at a neural level as repetition suppression where responses are attenuated with subsequent repetitions. In the brain, repetition suppression to visual stimuli has been demonstrated in multiple cortical areas, including the occipital lobe and medial temporal lobe. Prior research into the repetition suppression effect has generally focused on a single repetition and has not examined the pattern of signal suppression with repeated exposures. We used complex, everyday stimuli, in the form of images of computer programs or security warning messages, to examine the repetition suppression effect across repeated exposures. The use of computer warnings as stimuli also allowed us to examine the activation of learned fearful stimuli. We observed widespread linear decreases in activation with repeated exposures, suggesting that repetition suppression continues after the first repetition. Further, we found greater activation for warning messages compared to neutral images in the anterior insula, pre-supplemental motor area, and inferior frontal gyrus, suggesting differential processing of security warning messages. However, the repetition suppression effect was similar in these regions for both warning messages and neutral images. Additionally, we observed an increase of activation in the default mode network with repeated exposures, suggestive of increased mind wandering with continuing habituation.

14.
Surg Oncol ; 33: 100-107, 2020 Jun.
Article En | MEDLINE | ID: mdl-32561074

INTRODUCTION: Tamoxifen is a widely used hormonal based therapy for breast cancer in the adjuvant and metastatic setting, prolonging overall and recurrence-free survival. There has been increasing interest in the potential for novel "off-target" effects of tamoxifen and its metabolite N-desmethyltamoxifen across a number of cancer types. We aim to review the current literature regarding the potential use of tamoxifen in other primary malignancies. METHOD: A qualitative systematic review was performed according to the PRISMA guidelines using pre-set search criteria across the PubMed, Cochrane and Scopus databases from 1985 to 2019. Additional results were generated from included papers references. RESULTS: A total of 324 papers were identified, of which 47 were included; a further 29 articles were obtained from additional referencing to give a total of 76 articles. Clinical trials have demonstrated benefits with the use of tamoxifen in isolation and combination, specifically in patients with advanced non-resectable malignancy, however results are not consistent across the literature. In vivo data consistently suggests that off target effects of tamoxifen are mediated through the ceramide pathway or through inhibition of protein kinase C (PKC). CONCLUSIONS: With increased focus upon the potential of repurposing drugs, tamoxifen may be a candidate for repurposing in the wider cancer setting. There is evidence to suggest that the ceramide or PKC pathway could act as a therapeutic target for tamoxifen or alternative chemotherapeutics and merits further investigation.


Antineoplastic Agents, Hormonal/therapeutic use , Apoptosis , Autophagy , Drug Repositioning , Neoplasms/drug therapy , Tamoxifen/therapeutic use , Acid Ceramidase/antagonists & inhibitors , Acid Ceramidase/metabolism , Ceramides/metabolism , Chemotherapy, Adjuvant , Glucosylceramides/antagonists & inhibitors , Glucosylceramides/metabolism , Humans , Neoplasms/metabolism , Protein Kinase C/antagonists & inhibitors , Protein Kinase C/metabolism , Signal Transduction , Tamoxifen/analogs & derivatives
15.
Clin Transl Oncol ; 22(6): 870-877, 2020 Jun.
Article En | MEDLINE | ID: mdl-31473984

PURPOSE: Circulating tumour cells (CTCs) are a marker of poor prognosis and are associated with increased risk of venous thromboembolism in metastatic breast cancer (MBC). We aimed to determine if the presence of CTCs and plasma markers of hypercoagulability [thrombin-antithrombin III (TAT), fibrinogen and D-dimer] are biomarkers of survival in MBC. METHODS/PATIENTS: In a prospective study of MBC patients, CTC (CellSearch®) enumeration and plasma TAT, fibrinogen and D-dimer measured prior to commencement of treatment for disease progression were correlated to overall survival. RESULTS: At study completion, of 50 MBC patients recruited (median age 59 years, range 36-82), 40 patients had died (median survival 417 days, range 58-2141). CTCs (≥ 1/7.5 ml) were identified in 16 patients (median number of cells per 7.5 ml, 3 (range 1-31) and were associated with systemic hypercoagulability (medians TAT: 8.1 vs. 5.2 ng/ml, p = 0.03; fibrinogen: 4.3 vs. 3.1 g/l, p = 0.03; D-dimer: 1327 vs. 683 ng/ml, p = 0.0001). At 1 year, of 16 patients with ≥ 1 CTC, 7 had died (44%), compared to 5 of 26 (19%) patients in the no-CTC group. The presence of ≥ 1 CTC was associated with a trend for reduced overall survival (median 455 days vs. 614 days, p = 0.15). Plasma TAT inversely correlated with survival and was significantly higher in patients dying within 1 year (median 9.8 vs. 5.2 ng/ml, p = 0.004) whilst D-dimer showed a trend for reduced 1-year survival (median 1211 vs. 817 ng/ml, p = 0.06). MBC patients with combined high D-dimer (≥ 895 ng/ml) and CTC positivity (≥ 1/7.5 ml whole peripheral blood) had significantly reduced survival (p = 0.04). CONCLUSIONS: The correlation between CTCs, hypercoagulability and reduced survival in MBC suggests the coagulation system supports tumour cell metastasis and is, therefore, a potential therapeutic target.


Breast Neoplasms/blood , Breast Neoplasms/mortality , Neoplastic Cells, Circulating/metabolism , Thrombophilia/blood , Adult , Aged , Aged, 80 and over , Antithrombin III , Biomarkers, Tumor/blood , Breast Neoplasms/pathology , Female , Fibrin Fibrinogen Degradation Products/metabolism , Fibrinogen/metabolism , Humans , Middle Aged , Neoplasm Metastasis , Peptide Hydrolases/blood , Prognosis , Survival Rate
16.
Brain Imaging Behav ; 14(1): 308-319, 2020 Feb.
Article En | MEDLINE | ID: mdl-30719618

Obese adults have been shown to have poorer white brain matter integrity relative to normal-weight peers, but few studies have tested whether white matter integrity is compromised in overweight and obese adolescents. Also, it is unclear if age interacts with body mass to affect white matter integrity in adolescents. We used Automated Fiber Quantification, a tractography method, to compare fractional anisotropy between normal-weight and overweight/obese adolescents in the corpus callosum, corticospinal tract, cingulum, inferior fronto-occipital fasciculus, and uncinate fasciculus. Further, we tested whether any differences were moderated by age. Forty-seven normal-weight and forty overweight/obese adolescents were scanned using a diffusion tensor imaging (DTI) scan sequence. Overweight/obese compared to normal-weight adolescents had decreased white matter integrity in the superior frontal corpus callosum, left and right uncinate fasciculi, left inferior fronto-occipital fasciculus, and left corticospinal tract, which may be related to heightened reward processing. Overweight/obese compared to normal-weight adolescents had increased white matter integrity in the orbital and anterior frontal corpus callosum, right inferior fronto-occipital fasciculus, left cingulum, and left corticospinal tract, which may be related to heightened attentional processing. As age increased, six tracts showed poorer white matter integrity as body mass index percentile (BMI%) increased, but three tracts showed greater white matter integrity as BMI% increased. Future research examining associations between white matter integrity and neural indices of food-related reward and attention are needed to clarify the functional significance of white matter integrity discrepancies between normal-weight and overweight/obese adolescents.


Obesity/physiopathology , Overweight/physiopathology , White Matter/physiopathology , Adolescent , Anisotropy , Brain/physiopathology , Corpus Callosum/physiopathology , Diffusion Magnetic Resonance Imaging/methods , Diffusion Tensor Imaging/methods , Female , Humans , Male , Nerve Net/physiopathology , Neural Pathways/physiopathology
17.
Trends Cogn Sci ; 23(11): 938-951, 2019 11.
Article En | MEDLINE | ID: mdl-31597601

The hippocampus is critical for learning and memory, relying in part on pattern separation processes supported by the dentate gyrus (DG) to prevent interference from overlapping memory representations. In 2007, we designed the Mnemonic Similarity Task (MST), a modified object recognition memory task, to be highly sensitive to hippocampal function by placing strong demands on pattern separation. The MST is now a widely used behavioral task, repeatedly shown to be sensitive to age-related memory decline, hippocampal connectivity, and hippocampal function, with specificity to the DG. Here, we review the utility of the MST, its relationship to hippocampal function, its utility in detecting hippocampal-based memory alterations across the lifespan, and impairments associated with clinical pathology from a variety of disorders.


Hippocampus/physiology , Memory Disorders/physiopathology , Memory and Learning Tests , Pattern Recognition, Visual/physiology , Recognition, Psychology/physiology , Hippocampus/physiopathology , Humans
18.
Neuroimage Clin ; 23: 101803, 2019.
Article En | MEDLINE | ID: mdl-30991304

Increased fMRI food cue reactivity in obesity, i.e. higher responses to high- vs. low-calorie food images, is a promising marker of the dysregulated brain reward system underlying enhanced susceptibility to obesogenic environmental cues. Recently, it has also been shown that weight loss interventions might affect fMRI food cue reactivity and that there is a close association between the alteration of cue reactivity and the outcome of the intervention. Here we tested whether fMRI food cue reactivity could be used as a marker of diet-induced early changes of neural processing in the striatum that are predictive of the outcome of the weight loss intervention. To this end we investigated the relationship between food cue reactivity in the striatum measured one month after the onset of the weight loss program and weight changes obtained at the end of the six-month intervention. We observed a significant correlation between BMI change measured after six months and early alterations of fMRI food cue reactivity in the striatum, including the bilateral putamen, right pallidum, and left caudate. Our findings provide evidence for diet-induced early alterations of fMRI food cue reactivity in the striatum that can predict the outcome of the weight loss intervention.


Corpus Striatum/physiopathology , Cues , Obesity/physiopathology , Weight Loss , Weight Reduction Programs , Adult , Aged , Body Mass Index , Female , Food , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Treatment Outcome , Young Adult
20.
Sleep ; 42(4)2019 04 01.
Article En | MEDLINE | ID: mdl-30649528

STUDY OBJECTIVES: Sleep is an important behavior that affects appetite and eating in adolescents. Our study examined food-related neural activation in brain regions associated with food reward and inhibition in adolescents under sleep-restricted and well-rested conditions. METHODS: In this within-subjects study, 52 adolescents (ages 12-18; 46% female; M age = 15.96 years, SD = 1.56) with normal weight (NW; N = 29, M body mass index % [BMI%] = 54.55, SD = 24.54) or overweight/obesity (OV/OB; N = 23, M BMI% = 93.78, SD = 4.60) spent 5 hours in bed at home each night for five consecutive nights and 9 hours in bed at home each night for 5 consecutive nights, with the first day of each condition occurring 4 weeks apart. The morning following each sleep modification period, functional magnetic resonance imaging (fMRI) data were collected while participants performed an inhibitory (go/no-go) task with food stimuli. RESULTS: We found significantly greater activation in brain regions associated with inhibition in adolescents with NW in response to food cues when sleep restricted. No increase in inhibition-related neural activation was observed in adolescents with OV/OB when sleep restricted. We also found neural activation consistent with greater reward processing associated with food cues following sleep restriction regardless of weight status. CONCLUSIONS: These findings suggest that chronic sleep restriction may increase the likelihood of suboptimal dietary behavior for adolescents with OV/OB because they do not experience increased inhibition-related neural responding to counter possible increased reward-related neural responding following sleep restriction.


Appetite/physiology , Brain Mapping , Cues , Eating/psychology , Obesity/physiopathology , Adolescent , Body Mass Index , Body Weight , Brain/physiology , Child , Female , Food/statistics & numerical data , Humans , Magnetic Resonance Imaging/methods , Male , Reward , Sleep/physiology
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