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1.
Front Psychol ; 15: 1325237, 2024.
Article in English | MEDLINE | ID: mdl-38984273

ABSTRACT

Introduction: The COVID-19 pandemic, with over 83 million confirmed cases and 1.8 million deaths, has raised concerns about long-term cognitive issues, especially in populations facing disparities. Despite a few years since Peru's first COVID-19 wave, the cognitive effects on adults remain unclear. This study is the first in Peru to explore COVID-19's impact on general cognition and executive function. Methods: A retrospective cross-sectional study compared individuals with COVID-19 history to controls, assessing general cognition, verbal fluency, attention, and executive function. Among 240 assessed, 154 met the study inclusion criteria, with about 60% female and an average age of 38.89 ± 16.001 years. Groups included controls (n = 42), acute phase (AP, n = 74) (1-14 days of symptoms), and hyperinflammatory phase (HP, n = 38) (>14 days of symptoms). Results: Significant cognitive differences were observed. The HP group exhibited lower general cognitive performance (p = 0.02), working memory (p = 0.01), and executive function (planning; p < 0.001; flexibility; p = 0.03) than controls. Those with <14 days of illness (AP vs. HP) had deficits in general cognitive performance (p = 0.02), working memory (p = 0.02), and planning (p < 0.001), mainly during the hyperinflammatory phase, showing differences in working memory (p = 0.003) and planning (p = 0.01). Gender differences emerged, with males in the HP phase having poorer working memory (p = 0.003) and planning (p = 0.01). Discussion: This study underscores COVID-19's negative impact on cognitive function, even in mild cases, with potential heightened effects in men during acute or hyperinflammatory phases. The findings provide Peru's first evidence, highlighting the vulnerability of populations facing socioeconomic disparities.

2.
J Alzheimers Dis ; 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38875030

ABSTRACT

Background: Aging is a complex and natural process. The physiological decline related to aging is accompanied by a slowdown in cognitive processes, which begins shortly after individuals reach maturity. These changes have been sometimes interpreted as a compensatory sign and others as a fingerprint of deterioration. Objective: In this context, our aim is to uncover the mechanisms that underlie and support normal cognitive functioning in the brain during the later stages of life. Methods: With this purpose, a systematic literature search was conducted using PubMed, Scopus, and Web of Science databases, which identified 781 potential articles. After applying inclusion and exclusion criteria, we selected 12 studies that examined the brain oscillations patterns in resting-state conditions associated with cognitive performance in cognitively unimpaired older adults. Results: Although cognitive healthy aging was characterized differently across studies, and various approaches to analyzing brain activity were employed, our review indicates a relationship between alpha peak frequency (APF) and improved performance in neuropsychological scores among cognitively unimpaired older adults. Conclusions: A higher APF is linked with a higher score in intelligence, executive function, and general cognitive performance, and could be considered an optimal, and easy-to-assess, electrophysiological marker of cognitive health in older adults.

3.
Front Public Health ; 11: 1284692, 2023.
Article in English | MEDLINE | ID: mdl-38145063

ABSTRACT

Millions of dollars have been lost in dementia research over the last 30 years owing to unsuccessful clinical trials aimed at finding an effective treatment for the condition. Although two promising drugs have been identified, the research effort is insufficient. The dehumanization of patients and the pressure to publish have led to a decline in the quality and usefulness of scientific research. One way to tackle these problems is establishing close contact with those who put their faith in researchers. Fine-tuning the participation of patients with dementia and caregivers in research design and improving their connection and communication with researchers could positively contribute to enhancing the perspectives and designing strategies for scientists in order to generate a new and enriching vision. The Walking the Talk for Dementia event showed that people can still live with dementia despite their condition. Approximately 300 people participated in the all-week "Santiago's Camino" symposium. People living with dementia, caregivers, healthcare professionals, activists, clinicians, and researchers participated in this event. The "Walking the Talk for Dementia" (WTD) event vividly demonstrated a strong commitment to upholding Global Brain Health Institute's (GBHI) core values of Authenticity, Fairness, Openness, Respect, Courage, and Empathy (A FORCE) to advance equity in brain health. These values provide clear guidance for their advocacy initiatives aimed at mitigating the global impact of dementia. Research and development are essential across scientific fields, especially in clinical contexts where involving patients and caregivers is critical. The WTD initiative exemplifies this aspect by bringing together researchers, caregivers, and dementia patients on the Camino de Santiago in Spain.


Subject(s)
Dementia , Humans , Dementia/therapy , Caregivers , Health Personnel , Empathy , Communication
4.
Comput Biol Med ; 167: 107626, 2023 12.
Article in English | MEDLINE | ID: mdl-37918262

ABSTRACT

BACKGROUND: Infant crying is the first attempt babies use to communicate during their initial months of life. A misunderstanding of the cry message can compromise infant care and future neurodevelopmental process. METHODS: An exploratory study collecting multimodal data (i.e., crying, electroencephalography (EEG), near-infrared spectroscopy (NIRS), facial expressions, and body movements) from 38 healthy full-term newborns was conducted. Cry types were defined based on different conditions (i.e., hunger, sleepiness, fussiness, need to burp, and distress). Statistical analysis, Machine Learning (ML), and Deep Learning (DL) techniques were used to identify relevant features for cry type classification and to evaluate a robust DL algorithm named Acoustic MultiStage Interpreter (AMSI). RESULTS: Significant differences were found across cry types based on acoustics, EEG, NIRS, facial expressions, and body movements. Acoustics and body language were identified as the most relevant ML features to support the cause of crying. The DL AMSI algorithm achieved an accuracy rate of 92%. CONCLUSIONS: This study set a precedent for cry analysis research by highlighting the complexity of newborn cry expression and strengthening the potential use of infant cry analysis as an objective, reliable, accessible, and non-invasive tool for cry interpretation, improving the infant-parent relationship and ensuring family well-being.


Subject(s)
Algorithms , Crying , Humans , Infant, Newborn , Infant , Acoustics , Brain/diagnostic imaging , Kinesics
5.
Int J Mol Sci ; 24(22)2023 Nov 17.
Article in English | MEDLINE | ID: mdl-38003628

ABSTRACT

Despite decades of intense research, disease-modifying therapeutic approaches for Alzheimer's disease (AD) are still very much needed. Apart from the extensively analyzed tau and amyloid pathological cascades, two promising avenues of research that may eventually identify new druggable targets for AD are based on a better understanding of the mechanisms of resilience and vulnerability to this condition. We argue that insulin-like growth factor I (IGF-I) activity in the brain provides a common substrate for the mechanisms of resilience and vulnerability to AD. We postulate that preserved brain IGF-I activity contributes to resilience to AD pathology as this growth factor intervenes in all the major pathological cascades considered to be involved in AD, including metabolic impairment, altered proteostasis, and inflammation, to name the three that are considered to be the most important ones. Conversely, disturbed IGF-I activity is found in many AD risk factors, such as old age, type 2 diabetes, imbalanced diet, sedentary life, sociality, stroke, stress, and low education, whereas the Apolipoprotein (Apo) E4 genotype and traumatic brain injury may also be influenced by brain IGF-I activity. Accordingly, IGF-I activity should be taken into consideration when analyzing these processes, while its preservation will predictably help prevent the progress of AD pathology. Thus, we need to define IGF-I activity in all these conditions and develop a means to preserve it. However, defining brain IGF-I activity cannot be solely based on humoral or tissue levels of this neurotrophic factor, and new functionally based assessments need to be developed.


Subject(s)
Alzheimer Disease , Insulin-Like Growth Factor I , Humans , Alzheimer Disease/metabolism , Apolipoprotein E4/metabolism , Brain/metabolism , Diabetes Mellitus, Type 2/metabolism , Insulin-Like Growth Factor I/metabolism , Animals
6.
Behav Sci (Basel) ; 13(10)2023 Sep 28.
Article in English | MEDLINE | ID: mdl-37887457

ABSTRACT

BACKGROUND: Latin American countries have been profoundly affected by COVID-19. Due to the alarming incidence of identified cases, we intended to explore which psychosocial elements may influence poor adherence to the mandatory control measures among the population. OBJECTIVE: We aimed to assess Peruvians' knowledge, attitudes, and vulnerability perception during the coronavirus outbreak. METHOD: We collected data from 225 self-selected participants using a web-based cross-sectional survey. RESULTS: The overall respondents were between 18 and 29 years old (56.8%), female (59.5%), belonged to educated groups, and graduated professionals (69.3%), most of them. Logistic regression showed that Knowledge is highly associated with education (p = 0.031), occupation (p = 0.002), and age (p = 0.016). Our study identified that, although people reported adequate Knowledge by identifying expected symptoms and virus transmission ways in COVID-19 disease. There is a significant perceived susceptibility to contracting the mentioned virus, displaying stigmatized behavior (59.1%) and fear of contracting the virus from others (70.2%). Additionally, it is reported to lack people's confidence in national health authorities regarding sanitary responses (62.7%), preparedness for the disease (76.9%), and the lack of adequate measures to deal with it (51.1%). CONCLUSION: We found that age, education, and occupation modulate Knowledge. At the same time, only age affected Perception and Attitude. Public policies should consider specific guidelines on knowledge translation and risk communication strategies for both containing psychological responses promptly and ensuring compliance with general control measures by the population.

7.
Front Neurosci ; 17: 1266873, 2023.
Article in English | MEDLINE | ID: mdl-37799341

ABSTRACT

Introduction: Even though infant crying is a common phenomenon in humans' early life, it is still a challenge for researchers to properly understand it as a reflection of complex neurophysiological functions. Our study aims to determine the association between neonatal cry acoustics with neurophysiological signals and behavioral features according to different cry distress levels of newborns. Methods: Multimodal data from 25 healthy term newborns were collected simultaneously recording infant cry vocalizations, electroencephalography (EEG), near-infrared spectroscopy (NIRS) and videos of facial expressions and body movements. Statistical analysis was conducted on this dataset to identify correlations among variables during three different infant conditions (i.e., resting, cry, and distress). A Deep Learning (DL) algorithm was used to objectively and automatically evaluate the level of cry distress in infants. Results: We found correlations between most of the features extracted from the signals depending on the infant's arousal state, among them: fundamental frequency (F0), brain activity (delta, theta, and alpha frequency bands), cerebral and body oxygenation, heart rate, facial tension, and body rigidity. Additionally, these associations reinforce that what is occurring at an acoustic level can be characterized by behavioral and neurophysiological patterns. Finally, the DL audio model developed was able to classify the different levels of distress achieving 93% accuracy. Conclusion: Our findings strengthen the potential of crying as a biomarker evidencing the physical, emotional and health status of the infant becoming a crucial tool for caregivers and clinicians.

8.
Front Neurol ; 14: 1198882, 2023.
Article in English | MEDLINE | ID: mdl-37614974

ABSTRACT

Respect is a feeling of admiration for someone. It forms one of the core values of the Global Brain Health Institute (GBHI), which strives to protect the world's aging populations from threats to brain health. These values guide us as we advocate for reducing the global impact of dementia. By taking a values-based approach to brain health, we can drive global changes for millions of people. Respect fortifies gratitude and embraces diversity. Philosophical discussions of the ideas support the assertion that respect is crucial in everyday conversations and actions as well as in personal, social, political, and moral spheres. No one can become a leader unless they genuinely respect and care about the success of each team member. Diversity, equity, and inclusivity form the fundamental cornerstones of respect. Understanding this core value of respect will ensure altruistic behavior among the leaders that may help mitigate racism, cultural insults, gender discrimination, stigmatization, religious hatred, and, worst of all, poor leadership abilities that have been the disconcerting examples of disrespect in recent years. We present the underlying neurobiology of respect and its impact on equity and leadership.

9.
Sci Rep ; 13(1): 9489, 2023 06 11.
Article in English | MEDLINE | ID: mdl-37303002

ABSTRACT

Electroencephalography (EEG) can detect changes in cerebral activity during spaceflight. This study evaluates the effect of spaceflight on brain networks through analysis of the Default Mode Network (DMN)'s alpha frequency band power and functional connectivity (FC), and the persistence of these changes. Five astronauts' resting state EEGs under three conditions were analyzed (pre-flight, in-flight, and post-flight). DMN's alpha band power and FC were computed using eLORETA and phase-locking value. Eyes-opened (EO) and eyes-closed (EC) conditions were differentiated. We found a DMN alpha band power reduction during in-flight (EC: p < 0.001; EO: p < 0.05) and post-flight (EC: p < 0.001; EO: p < 0.01) when compared to pre-flight condition. FC strength decreased during in-flight (EC: p < 0.01; EO: p < 0.01) and post-flight (EC: ns; EO: p < 0.01) compared to pre-flight condition. The DMN alpha band power and FC strength reduction persisted until 20 days after landing. Spaceflight caused electrocerebral alterations that persisted after return to earth. Periodic assessment by EEG-derived DMN analysis has the potential to become a neurophysiologic marker of cerebral functional integrity during exploration missions to space.


Subject(s)
Space Flight , Humans , Astronauts , Eye , Brain , Electroencephalography
10.
Cells ; 12(11)2023 05 25.
Article in English | MEDLINE | ID: mdl-37296598

ABSTRACT

Aging is a physiological process accompanied by a decline in cognitive performance. The cholinergic neurons of the basal forebrain provide projections to the cortex that are directly engaged in many cognitive processes in mammals. In addition, basal forebrain neurons contribute to the generation of different rhythms in the EEG along the sleep/wakefulness cycle. The aim of this review is to provide an overview of recent advances grouped around the changes in basal forebrain activity during healthy aging. Elucidating the underlying mechanisms of brain function and their decline is especially relevant in today's society as an increasingly aged population faces higher risks of developing neurodegenerative diseases such as Alzheimer's disease. The profound age-related cognitive deficits and neurodegenerative diseases associated with basal forebrain dysfunction highlight the importance of investigating the aging of this brain region.


Subject(s)
Alzheimer Disease , Basal Forebrain , Animals , Aging/physiology , Cholinergic Neurons , Cognition , Mammals
12.
Article in English | MEDLINE | ID: mdl-36834292

ABSTRACT

The coronavirus (COVID-19) pandemic, confinement, fear, lifestyle changes, and worldwide health care impacted almost all diseases. Reports from countries outside Latin America revealed differences in migraine patients. In this study, we describe and compare the immediate changes in migraine symptoms associated with COVID-19 quarantine in patients from Argentina, Mexico, and Peru. An online survey was conducted from May to July 2020. The survey was answered by 243 migraine patients, with questions related to sociodemographic data, quarantine conditions, changes in working conditions, physical activity, coffee intake, healthcare access, acute migraine medication use, symptoms of anxiety, depression, and fear of COVID-19. The results show that 48.6% of migraine patients experienced worsened symptoms, 15.6% improved, and 35.8% remained unchanged. Worsening migraine symptoms were associated with staying at home during the lockdown. Intake of analgesics was associated with an increase in migraine symptoms of 18 times relative to those who did not increase their intake. Migraine symptoms improved when the number of sleep hours was increased, and we observed an improvement when patients decreased analgesic intake. The uncertainty about the end of the pandemic, the news, and social media are three items that contributed to the worsening of migraine symptoms in patients in the three investigated countries. Confinement during the first pandemic wave in Latin America harmed migraine patients who stayed home during the lockdown.


Subject(s)
COVID-19 , Migraine Disorders , Humans , Pandemics , Latin America , SARS-CoV-2 , Communicable Disease Control , Health Services Accessibility , Analgesics/therapeutic use , Migraine Disorders/drug therapy
13.
Brain Sci ; 12(12)2022 Nov 24.
Article in English | MEDLINE | ID: mdl-36552073

ABSTRACT

In neuropsychological evaluation, verbal fluency is a crucial measure of cognitive function, but this measure requires standardized and normative data for use. The present study aimed to obtain validation and normative data for the verbal fluency task in the Peruvian population, with participants ranging from 6 to 94 years and varying in age, educational level, and sex. We recruited 2602 healthy individuals and used linear regression analysis to determine the effect of age, sex, and educational level. We also evaluated internal consistency between categories and phonological tasks with Cronbach's alpha and Pearson's correlation analysis and calculated test-retest reliability after three months. We found significant effects of age, educational level, and sex on phonological and semantic fluency. Participants with more than 12 years of education had the highest scores overall. Regarding age, middle-aged participants (between 31 and 40 years old) had the highest scores; scores gradually decreased outside of this age range. Regarding sex, men performed better than women. These results will increase the ability of clinicians to precisely determine the degree to which verbal fluency is affected in patients of different ages and educational levels.

14.
J Alzheimers Dis ; 90(2): 599-608, 2022.
Article in English | MEDLINE | ID: mdl-36155510

ABSTRACT

BACKGROUND: Cognitive impairment and dementia may result from a combination of modifiable and nonmodifiable risk and protective factors, such as the environment, educational attainment, time devoted to cognitively stimulating activities, and physical activity. OBJECTIVE: This study aimed to investigate the mediating role of sociodemographic characteristics and lifestyle factors in the years of education and cognitive performance in Peruvian adults. METHODS: This cross-sectional study included 1,478 subjects assessed by Addenbrooke's Cognitive Examination Revised (ACE-R). Using mediation models, we evaluated the mediation role of parents' educational level, reading time (RT), and physical activity time (PAT) in the years of education (IYE) and cognitive performance. RESULTS: People who reported having lived in an urban area during their childhood are estimated to have, on average, 2.085 years more formal education than those who lived in rural areas. In addition, 49% of cognitive performance scores are explained by the mediation effect of reading and physical activity time in the IYE. This implies that higher levels of education, mediated by RT and PAT per week, are 1.596 units associated with higher scores on the ACE-R. CONCLUSION: Despite the fact that nonmodifiable factors (i.e., childhood residence area, parents' educational level) seem to exert an effect on older adults' cognition, their influence is mediated by other factors that are indeed modifiable (i.e., reading time, physical activity engagement). In this sense, lifestyle changes could help prevent or decrease the risk of cognitive impairment and reduce the disease's impact on vulnerable environments in Latin American and Caribbean countries.


Subject(s)
Cognitive Dysfunction , Life Style , Humans , Aged , Child , Cross-Sectional Studies , Peru/epidemiology , Cognition , Cognitive Dysfunction/psychology
15.
Geroscience ; 44(4): 2243-2257, 2022 08.
Article in English | MEDLINE | ID: mdl-35604612

ABSTRACT

Sleep disturbances are common during aging. Compared to young animals, old mice show altered sleep structure, with changes in both slow and fast electrocorticographic (ECoG) activity and fewer transitions between sleep and wake stages. Insulin-like growth factor I (IGF-I), which is involved in adaptive changes during aging, was previously shown to increase ECoG activity in young mice and monkeys. Furthermore, IGF-I shapes sleep architecture by modulating the activity of mouse orexin neurons in the lateral hypothalamus (LH). We now report that both ECoG activation and excitation of orexin neurons by systemic IGF-I are abrogated in old mice. Moreover, orthodromical responses of LH neurons are facilitated by either systemic or local IGF-I in young mice, but not in old ones. As orexin neurons of old mice show dysregulated IGF-I receptor (IGF-IR) expression, suggesting disturbed IGF-I sensitivity, we treated old mice with AIK3a305, a novel IGF-IR sensitizer, and observed restored responses to IGF-I and rejuvenation of sleep patterns. Thus, disturbed sleep structure in aging mice may be related to impaired IGF-I signaling onto orexin neurons, reflecting a broader loss of IGF-I activity in the aged mouse brain.


Subject(s)
Hypothalamic Area, Lateral , Insulin-Like Growth Factor I , Animals , Mice , Orexins/metabolism , Insulin-Like Growth Factor I/metabolism , Hypothalamic Area, Lateral/metabolism , Sleep/physiology , Neurons/metabolism
16.
Cells ; 11(4)2022 02 17.
Article in English | MEDLINE | ID: mdl-35203366

ABSTRACT

Aging is accompanied by a decline in cognition that can be due to a lower IGF-I level. We studied response facilitation induced in primary somatosensory (S1) cortical neurons by repetitive stimulation of whiskers in young and old mice. Layer 2/3 and 5/6 neurons were extracellularly recorded in young (≤ 6 months of age) and old (≥ 20 month of age) anesthetized mice. IGF-I injection in S1 cortex (10 nM; 0.2 µL) increased whisker responses in young and old animals. A stimulation train at 8 Hz induced a long-lasting response facilitation in only layer 2/3 neurons of young animals. However, all cortical neurons from young and old animals showed long-lasting response facilitation when IGF-I was applied in the S1 cortex. The reduction in response facilitation in old animals can be due to a reduction in the IGF-I receptors as was indicated by the immunohistochemistry study. Furthermore, a reduction in the performance of a whisker discrimination task was observed in old animals. In conclusion, our findings indicate that there is a reduction in the synaptic plasticity of S1 neurons during aging that can be recovered by IGF-I. Therefore, it opens the possibility of use IGF-I as a therapeutic tool to ameliorate the effects of heathy aging.


Subject(s)
Insulin-Like Growth Factor I , Somatosensory Cortex , Aging , Animals , Insulin-Like Growth Factor I/pharmacology , Mice , Neuronal Plasticity/physiology , Vibrissae
17.
Mol Psychiatry ; 27(4): 2182-2196, 2022 04.
Article in English | MEDLINE | ID: mdl-35115701

ABSTRACT

Maladaptive coping behaviors are probably involved in post-traumatic stress disorders (PTSD), but underlying mechanisms are incompletely understood. We now report that mice lacking functional insulin-like growth factor I (IGF-I) receptors in orexin neurons of the lateral hypothalamus (Firoc mice) are unresponsive to the anxiolytic actions of IGF-I and develop PTSD-like behavior that is ameliorated by inhibition of orexin neurons. Conversely, systemic IGF-I treatment ameliorated PTSD-like behavior in a wild-type mouse model of PTSD (PTSD mice). Further, systemic IGF-I modified the GABA/Glutamate synaptic structure in orexin neurons of naïve wild-type mice by increasing the dephosphorylation of GABA(B) receptor subunit through inhibition of AMP-kinase (AMPK). Significantly, pharmacological inhibition of AMPK mimicked IGF-I, normalizing fear behavior in PTSD mice. Thus, we suggest that IGF-I enables coping behaviors by balancing E/I input onto orexin neurons in a context-dependent manner. These observations provide a novel therapeutic approach to PTSD through modulation of AMPK.


Subject(s)
Insulin-Like Growth Factor I , Stress Disorders, Post-Traumatic , AMP-Activated Protein Kinases , Adenosine Monophosphate/metabolism , Adenosine Monophosphate/therapeutic use , Adenylate Kinase/metabolism , Animals , Insulin-Like Growth Factor I/metabolism , Mice , Neurons/metabolism , Orexins/metabolism , Stress Disorders, Post-Traumatic/drug therapy , Stress Disorders, Post-Traumatic/metabolism , gamma-Aminobutyric Acid/metabolism
18.
F1000Res ; 11: 663, 2022.
Article in English | MEDLINE | ID: mdl-36636477

ABSTRACT

Background: Pleiotropic actions of insulin and insulin-like growth factor I (IGF-I) in the brain are context- and cell-dependent, but whether this holds for their receptors (insulin receptor (IR) and IGF-I receptor (IGF-IR), respectively), is less clear. Methods: We compared mice lacking IR or IGF-IR in glial fibrillary astrocytic protein (GFAP)-expressing astrocytes in a tamoxifen-regulated manner, to clarify their role in this type of glial cells, as the majority of data of their actions in brain have been obtained in neurons. Results: We observed that mice lacking IR in GFAP astrocytes (GFAP IR KO mice) develop mood disturbances and maintained intact cognition, while at the same time show greater pathology when cross-bred with APP/PS1 mice, a model of familial Alzheimer´s disease (AD). Conversely, mice lacking IGF-IR in GFAP astrocytes (GFAP-IGF-IR KO mice) show cognitive disturbances, maintained mood tone, and show control-dependent changes in AD-like pathology. Conclusions: These observations confirm that the role of IR and IGF-IR in the brain is cell-specific and context-dependent.


Subject(s)
Alzheimer Disease , Receptor, IGF Type 1 , Animals , Mice , Alzheimer Disease/metabolism , Astrocytes , Carrier Proteins/metabolism , Insulin , Insulin-Like Growth Factor I/metabolism , Receptor, IGF Type 1/metabolism
19.
Front Aging Neurosci ; 13: 682388, 2021.
Article in English | MEDLINE | ID: mdl-34539376

ABSTRACT

It is known that aging is frequently accompanied by a decline in cognition. Furthermore, aging is associated with lower serum IGF-I levels that may contribute to this deterioration. We studied the effect of IGF-I in neurons of the horizontal diagonal band of Broca (HDB) of young (≤6 months old) and old (≥20-month-old) mice to determine if changes in the response of these neurons to IGF-I occur along with aging. Local injection of IGF-I in the HDB nucleus increased their neuronal activity and induced fast oscillatory activity in the electrocorticogram (ECoG). Furthermore, IGF-I facilitated tactile responses in the primary somatosensory cortex elicited by air-puffs delivered in the whiskers. These excitatory effects decreased in old mice. Immunohistochemistry showed that cholinergic HDB neurons express IGF-I receptors and that IGF-I injection increased the expression of c-fos in young, but not in old animals. IGF-I increased the activity of optogenetically-identified cholinergic neurons in young animals, suggesting that most of the IGF-I-induced excitatory effects were mediated by activation of these neurons. Effects of aging were partially ameliorated by chronic IGF-I treatment in old mice. The present findings suggest that reduced IGF-I activity in old animals participates in age-associated changes in cortical activity.

20.
J Neurosci ; 41(22): 4768-4781, 2021 06 02.
Article in English | MEDLINE | ID: mdl-33911021

ABSTRACT

Insulin-like growth factor-I (IGF-I) signaling plays a key role in learning and memory processes. While the effects of IGF-I on neurons have been studied extensively, the involvement of astrocytes in IGF-I signaling and the consequences on synaptic plasticity and animal behavior remain unknown. We have found that IGF-I induces long-term potentiation (LTPIGFI) of the postsynaptic potentials that is caused by a long-term depression of inhibitory synaptic transmission in mice. We have demonstrated that this long-lasting decrease in the inhibitory synaptic transmission is evoked by astrocytic activation through its IGF-I receptors (IGF-IRs). We show that LTPIGFI not only increases the output of pyramidal neurons, but also favors the NMDAR-dependent LTP, resulting in the crucial information processing at the barrel cortex since specific deletion of IGF-IR in cortical astrocytes impairs the whisker discrimination task. Our work reveals a novel mechanism and functional consequences of IGF-I signaling on cortical inhibitory synaptic plasticity and animal behavior, revealing that astrocytes are key elements in these processes.SIGNIFICANCE STATEMENT Insulin-like growth factor-I (IGF-I) signaling plays key regulatory roles in multiple processes of brain physiology, such as learning and memory. Yet, the underlying mechanisms remain largely undefined. Here we demonstrate that astrocytes respond to IGF-I signaling, elevating their intracellular Ca2+ and stimulating the release of ATP/adenosine, which triggers the LTD of cortical inhibitory synapses, thus regulating the behavioral task performance related to cortical sensory information processing. Therefore, the present work represents a major conceptual advance in our knowledge of the cellular basis of IGF-I signaling in brain function, by including for the first time astrocytes as key mediators of IGF-I actions on synaptic plasticity, cortical sensory information discrimination and animal behavior.


Subject(s)
Adenosine/metabolism , Astrocytes/metabolism , Neuronal Plasticity/physiology , Receptor, IGF Type 1/metabolism , Somatosensory Cortex/physiology , Animals , Behavior, Animal/physiology , Down-Regulation , Learning/physiology , Long-Term Synaptic Depression/physiology , Male , Memory/physiology , Mice , Mice, Inbred C57BL , Pyramidal Cells/physiology
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