Long-Term Music Exposure Prevents Age-Related Cognitive Deficits in Rats Independently of Hippocampal Neurogenesis.

Cognitive decline appears across aging. While some studies report beneficial effects of musical listening and practice on cognitive aging, the underlying neurobiological mechanisms remain unknown. This study aims to determine whether chronic (6 h/day, 3 times/week) and long-lasting (4-8 months) music exposure, initiated at middle age in rats (15 months old), can influence behavioral parameters sensitive to age effects and reduce age-related spatial memory decline in rats. Spontaneous locomotor, circadian rhythmic activity, and anxiety-like behavior as well as spatial working and reference memory were assessed in 14-month-old rats and then after 4 and 8 months of music exposure (19 and 23 months old, respectively). Spatial learning and reference memory data were followed up by considering cognitive status of animals prior to music exposure (14 months old) given by K-means clustering of individual Z-score. Hippocampal cell proliferation and brain-derived neurotrophic factor (BDNF) level in the hippocampus and frontal cortex were measured. Results show that music exposure differentially rescues age-related deficits in spatial navigation tasks according to its duration without affecting spontaneous locomotor, circadian rhythmic activity, and anxiety-like behavior. Hippocampal cell proliferation as well as hippocampal and frontal cortex BDNF levels was not affected by music across aging. Cognitive improvement by music in aging rats may require distinct neurobiological mechanisms than hippocampal cell proliferation and BDNF.

[Music and neurodevelopment, the contribution of cognitive neurosciences]. / Musique et neurodéveloppement,l'apport des neurosciences cognitives.

Research in cognitive neurosciences has developed significantly and has enabled the mechanisms of neuroplasticity to be studied in order to understand the effect of music practice. In children, this research concerns mainly the impact of music learning in the setting of a music conservatory. Moreover, recent studies have also sought to measure the clinical benefits of music interventions on hospital wards, providing a scientific basis to these practices.

Altered intrinsic connectivity of the auditory cortex in congenital amusia.

Congenital amusia, a neurodevelopmental disorder of music perception and production, has been associated with abnormal anatomical and functional connectivity in a right frontotemporal pathway. To investigate whether spontaneous connectivity in brain networks involving the auditory cortex is altered in the amusic brain, we ran a seed-based connectivity analysis, contrasting at-rest functional MRI data of amusic and matched control participants. Our results reveal reduced frontotemporal connectivity in amusia during resting state, as well as an overconnectivity between the auditory cortex and the default mode network (DMN). The findings suggest that the auditory cortex is intrinsically more engaged toward internal processes and less available to external stimuli in amusics compared with controls. Beyond amusia, our findings provide new evidence for the link between cognitive deficits in pathology and abnormalities in the connectivity between sensory areas and the DMN at rest.

Morphological brain plasticity induced by musical expertise is accompanied by modulation of functional connectivity at rest.

The aim of this study was to explore whether musical practice-related gray matter increases in brain regions are accompanied by modifications in their resting-state functional connectivity. 16 young musically experienced adults and 17 matched nonmusicians underwent an anatomical magnetic resonance imaging (MRI) and a resting-state functional MRI (rsfMRI). A whole-brain two-sample t test run on the T1-weighted structural images revealed four clusters exhibiting significant increases in gray matter (GM) volume in the musician group, located within the right posterior and middle cingulate gyrus, left superior temporal gyrus and right inferior orbitofrontal gyrus. Each cluster was used as a seed region to generate and compare whole-brain resting-state functional connectivity maps. The two clusters within the cingulate gyrus exhibited greater connectivity for musicians with the right prefrontal cortex and left temporal pole, which play a role in autobiographical and semantic memory, respectively. The cluster in the left superior temporal gyrus displayed enhanced connectivity with several language-related areas (e.g., left premotor cortex, bilateral supramarginal gyri). Finally, the cluster in the right inferior frontal gyrus displayed more synchronous activity at rest with claustrum, areas thought to play a role in binding sensory and motor information. We interpreted these findings as the consequence of repeated collaborative use in general networks supporting some of the memory, perceptual-motor and emotional features of musical practice.

The effects of musical practice on structural plasticity: the dynamics of grey matter changes.

Intensive training and the acquisition of expertise are known to bring about structural changes in the brain. Musical training is a particularly interesting model. Previous studies have reported structural brain modifications in the auditory, motor and visuospatial areas of musicians compared with nonmusicians. The main goal of the present study was to go one step further, by exploring the dynamic of those structural brain changes related to musical experience. To this end, we conducted a regression study on 44 nonmusicians and amateur musicians with 0-26years of musical practice of a variety instruments. We sought first to highlight brain areas that increased with the duration of practice and secondly distinguish (thanks to an ANOVA analysis) brain areas that undergo grey matter changes after only limited years of musical practice from those that require longer practice before they exhibit changes. Results revealed that musical training results a greater grey matter volumes in different brain areas for musicians. Changes appear gradually in the left hippocampus and right middle and superior frontal regions, but later also include the right insula and supplementary motor area and left superior temporal, and posterior cingulate areas. Given that all participants had the same age and that we controlled for age and education level, these results cannot be ascribed to normal brain maturation. Instead, they support the notion that musical training could induce dynamic structural changes.

Autobiographical Cerebral Network Activation in Older Adults Before and After Reminiscence Therapy: A Preliminary Report.

INTRODUCTION: Reminiscence therapy (RT), which engages individuals to evoke positive memories, has been shown to be effective in improving psychological well-being in older adults suffering from PTSD, depression, and anxiety. However, its impact on brain function has yet to be determined. This paper presents functional magnetic resonance imaging (fMRI) data to describe changes in autobiographical memory networks (AMN) in community-dwelling older adults. METHODS: This pilot study used a within-subject design to measure changes in AMN activation in 11 older adults who underwent 6 weeks of RT. In the scanner, participants retrieved autobiographical memories which were either recent or remote, rehearsed or unrehearsed. Participants also underwent a clinical interview to assess changes in memory, quality of life, mental health, and affect. FINDINGS: Compared to pretreatment, anxiety decreased (z = -2.014, p = .040) and activated significant areas within the AMN, including bilateral medial prefrontal cortex, left precuneus, right occipital cortex, and left anterior hippocampus. CONCLUSION: Although RT had subtle effects on psychological function in this sample with no evidence of impairments, including depression at baseline, the fMRI data support current thinking of the effect RT has on the AMN. Increased activation of right posterior hippocampus following RT is compatible with the Multiple Trace Theory Theory (Nadel & Moscovitch, 1997).

Musical experience prior to traumatic exposure as a resilience factor: a conceptual analysis.

Resilience mechanisms can be dynamically triggered throughout the lifecourse by resilience factors in order to prevent individuals from developing stress-related pathologies such as posttraumatic stress disorder (PTSD). Some interventional studies have suggested that listening to music and musical practice after experiencing a traumatic event decrease the intensity of PTSD, but surprisingly, no study to our knowledge has explored musical experience as a potential resilience factor before the potential occurrence of a traumatic event. In the present conceptual analysis, we sought to summarize what is known about the concept of resilience and how musical experience could trigger two key mechanisms altered in PTSD: emotion regulation and cognitive control. Our hypothesis is that the stimulation of these two mechanisms by musical experience during the pre-traumatic period could help protect against the symptoms of emotional dysregulation and intrusions present in PTSD. We then developed a new framework to guide future research aimed at isolating and investigating the protective role of musical experience regarding the development of PTSD in response to trauma. The clinical application of this type of research could be to develop pre-trauma training that promotes emotional regulation and cognitive control, aimed at populations at risk of developing PTSD such as healthcare workers, police officers, and military staffs.

Korsakoff's Syndrome and Alzheimer's Disease-Commonalities and Specificities of Volumetric Brain Alterations within Papez Circuit.

Background: Alzheimer's disease (AD) and Korsakoff's syndrome (KS) are two major neurocognitive disorders characterized by amnesia but AD is degenerative while KS is not. The objective is to compare regional volume deficits within the Papez circuit in AD and KS, considering AD progression. Methods: 18 KS patients, 40 AD patients (20 with Moderate AD (MAD) matched on global cognitive deficits with KS patients and 20 with Severe AD (SAD)), and 70 healthy controls underwent structural MRI. Volumes of the hippocampi, thalami, cingulate gyri, mammillary bodies (MB) and mammillothalamic tracts (MTT) were extracted. Results: For the cingulate gyri, and anterior thalamic nuclei, all patient groups were affected compared to controls but did not differ between each other. Smaller volumes were observed in all patient groups compared to controls in the mediodorsal thalamic nuclei and MB, but these regions were more severely damaged in KS than AD. MTT volumes were damaged in KS only. Hippocampi were affected in all patient groups but more severely in the SAD than in the KS and MAD. Conclusions: There are commonalities in the pattern of volume deficits in KS and AD within the Papez circuit with the anterior thalamic nuclei, cingulate cortex and hippocampus (in MAD only) being damaged to the same extent. The specificity of KS relies on the alteration of the MTT and the severity of the MB shrinkage. Further comparative studies including other imaging modalities and a neuropsychological assessment are required.

Time processing in neurological and psychiatric conditions.

A central question in understanding cognition and pathology-related cognitive changes is how we process time. However, time processing difficulties across several neurological and psychiatric conditions remain seldom investigated. The aim of this review is to develop a unifying taxonomy of time processing, and a neuropsychological perspective on temporal difficulties. Four main temporal judgments are discussed: duration processing, simultaneity and synchrony, passage of time, and mental time travel. We present an integrated theoretical framework of timing difficulties across psychiatric and neurological conditions based on selected patient populations. This framework provides new mechanistic insights on both (a) the processes involved in each temporal judgement, and (b) temporal difficulties across pathologies. By identifying underlying transdiagnostic time-processing mechanisms, this framework opens fruitful avenues for future research.

Boosting Autobiographical Memory and the Sense of Identity of Alzheimer Patients Through Repeated Reminiscence Workshops?

Despite severe amnesia, some studies showed that Alzheimer Disease (AD) patients with moderate to severe dementia keep a consistent, but impoverished representation of themselves, showing preservation of the sense of identity even at severe stages of the illness. Some studies suggest that listening to music can facilitate the reminiscence of autobiographical memories and that stimulating autobiographical memory would be relevant to support the self of these patients. Consequently, we hypothesized that repeated participation to reminiscence workshops, using excerpts of familiar songs as prompts would participate to the enrichment of autobiographical memories, self-representation and sense of identity. We included a group of 20 AD patients with severe dementia residing in nursing homes. Their performances were compared to a control group of 20 matched (age, education, mood) healthy residents living in the same institutions. The experiment was conducted in three phases over a 2-week period. On phase 1, an individual assessment of sense of identity was proposed to each participant. On phase 2, participants joined musical reminiscence workshops (six sessions over 2 weeks for AD patients and 3 sessions over a week for controls). During the third phase (12 days after the first assessment), individual evaluation of autobiographical memory and a second assessment of sense of identity were proposed. Our results showed that, despite their massive amnesia syndrome, autobiographical memories of AD reached at the end of the 2 weeks the number and quality of those of matched controls. Moreover, we confirmed a continuity of self-representation in AD patients with a stable profile of the answers between the first and second individual assessments of sense of identity. However, the increase in number and episodic quality of autobiographical memories was not accompanied by an enrichment of the sense of identity. In a complementary study, new patients participated in the same paradigm, but using movie extracts as prompts, and showed very similar effects. We discuss all of these results with regard to the literature showing the significant impact of repetition on the reactivation of memory traces even in very amnestic AD patients at severe stages of the disease.

Temporal aspects of the feeling of familiarity for music and the emergence of conceptual processing.

We tested whether the emergence of familiarity to a melody may trigger or co-occur with the processing of the concept(s) conveyed by emotions to, or semantic association with, the melody. With this objective, we recorded ERPs while participants were presented with highly familiar and less familiar melodies in a gating paradigm. The ERPs time locked to a tone of the melody called the "familiarity emergence point" showed a larger fronto-central negativity for highly familiar compared with less familiar melodies between 200 and 500 msec, with a peak latency around 400 msec. This latency and the sensitivity to the degree of familiarity/conceptual information suggest that this component was an N400, a marker of conceptual processing. Our data suggest that the feeling of familiarity evoked by a musical excerpt could be accompanied by other processing mechanisms at the conceptual level. Coupling the gating paradigm with ERP analyses might become a new avenue for investigating the neurocognitive basis of implicit musical knowledge.

Do Musicians Have Better Mnemonic and Executive Performance Than Actors? Influence of Regular Musical or Theater Practice in Adults and in the Elderly.

The effects of musical practice on cognition are well established yet rarely compared with other kinds of artistic training or expertise. This study aims to compare the possible effect of musical and theater regular practice on cognition across the lifespan. Both of these artistic activities require many hours of individual or collective training in order to reach an advanced level. This process requires the interaction between higher-order cognitive functions and several sensory modalities (auditory, verbal, visual and motor), as well as regular learning of new pieces. This study included participants with musical or theater practice, and healthy controls matched for age (18-84 years old) and education. The objective was to determine whether specific practice in these activities had an effect on cognition across the lifespan, and a protective influence against undesirable cognitive outcomes associated with aging. All participants underwent a battery of cognitive tasks that evaluated processing speed, executive function, fluency, working memory, verbal and visual long-term memories, and non-verbal reasoning abilities. Results showed that music and theater artistic practices were strongly associated with cognitive enhancements. Participants with musical practice were better in executive functioning, working memory and non-verbal reasoning, whereas participants with regular acting practice had better long-term verbal memory and fluency performance. Thus, taken together, results suggest a differential effect of these artistic practices on cognition across the lifespan. Advanced age did not seem to reduce the benefit, so future studies should focus on the hypothetical protective effects of artistic practice against cognitive decline.

New Long-Term Encoding in Severely Amnesic Alzheimer's Disease Patients Revealed Through Repeated Exposure to Artistic Items.

BACKGROUND: Encoding of new information is considered to be impossible in people with Alzheimer's disease (PWAD) at a moderate to severe stage. However, a few case studies reported new learning under special circumstances, especially with music. OBJECTIVE: This article aims at clarifying PWAD's learning capacities toward unknown material under more ecological settings, which is repeated exposure without encoding instruction. METHODS: Twenty-three PWAD (Age: m = 84.6(5.2), 5≤MMSE≤19) underwent presentations of unknown artistic pieces (targets) through 8 daily individual sessions. These sessions were followed by a test session, during which their knowledge of the targets was assessed through a verbal and behavioral scale (the sense of familiarity scale) against a series of unknown items (distractors). RESULTS: Through this design, we were able to objectify encoding of three types of targets (verses, paintings, and music) against distractors the day after exposure sessions, and 2 months after the last presentation (study 1). Music and paintings were eventually well-encoded by most participants, whereas poems encoding was poorer. When compared to distractors, target items were significantly better recognized. We then compared the recognition of target paintings against two types of painting distractors, either perceptually or semantically related (study 2). The targets were better recognized than all three painting distractors, even when they were very close to the targets. CONCLUSION: Despite massive anterograde amnesia, our results clearly showed that recognition-based learning without conscious memory of the encoding context is preserved in PWAD at a severe stage, revealed through an increasing sense of familiarity following repeated exposure. These findings could open new perspective both for researchers and clinicians and improve the way we understand and care for PWAD living in healthcare facilities.

Age-related changes in the cerebral substrates of cognitive procedural learning.

Cognitive procedural learning occurs in three qualitatively different phases (cognitive, associative, and autonomous). At the beginning of this process, numerous cognitive functions are involved, subtended by distinct brain structures such as the prefrontal and parietal cortex and the cerebellum. As the learning progresses, these cognitive components are gradually replaced by psychomotor abilities, reflected by the increasing involvement of the cerebellum, thalamus, and occipital regions. In elderly subjects, although cognitive studies have revealed a learning effect, performance levels differ during the acquisition of a procedure. The effects of age on the learning of a cognitive procedure have not yet been examined using functional imaging. The aim of this study was therefore to characterize the cerebral substrates involved in the learning of a cognitive procedure, comparing a group of older subjects with young controls. For this purpose, we performed a positron emission tomography activation study using the Tower of Toronto task. A direct comparison of the two groups revealed the involvement of a similar network of brain regions at the beginning of learning (cognitive phase). However, the engagement of frontal and cingulate regions persisted in the older group as learning continued, whereas it ceased in the younger controls. We assume that this additional activation in the older group during the associative and autonomous phases reflected compensatory processes and the fact that some older subjects failed to fully automate the procedure.

Preservation of Musical Memory Throughout the Progression of Alzheimer's Disease? Toward a Reconciliation of Theoretical, Clinical, and Neuroimaging Evidence.

Through this review of 25 clinical and experimental works on long-term musical memories in Alzheimer's disease (AD) patients, we attempt to clarify the conceptual understanding of musical memories, identify their evolution across the stages of the pathology, and propose possible explanations concerning the neural and cognitive mechanisms that underpin the preservation and impairment of certain musical memories. After clarifying the different kind of musical memories, we investigated their alterations throughout AD's progression from mild to severe stages. Both procedural and retrograde semantic memory seem relatively spared in AD, while episodic memory appears to be impaired early. Moreover, partial preservation of music encoding in AD can be revealed through paradigms that are especially designed for AD patients (relying on behavioral cues, using adapted settings, etc.). Although seldomly used, they would definitely help understanding the preserved capacities in every stage of AD. However, more research is needed to better understand this phenomenon and assess its specificity to music or other types of supports. These findings could lead to multiple applications in care settings and research designs, bringing more nuanced understanding of how long-term musical memory degrades throughout the course of AD, and should encourage us to prioritize patients' preserved cognitive abilities in current AD recreational and care programs.

Helping caregivers of people with dementia: a need to renew theoretical frameworks in France.

Research and care have improved a lot for persons with dementia (PWD) in France. However, most studies are essentially descriptive, and very few researches have focused on theoretical framework that may help understand and help their caregivers (CG). Yet, some approaches exist, and have proven to be efficient in other countries. The main interest of such approaches is the possibility to match health professionals' conception of CG and their situation, and thus allowing to better describe their situation, their difficulties and their expectations, and thus offer a caring the closest possible from their needs. Four main approaches will be discussed : 1) stress coping, the most used model in CG's care that allows to assess the principal stressors in CG's role, and to figure out the best ways to cope with these; 2) person centered care, which claims that making the CG more competent in their role decreases their burden; 3) role transition theory for which the difficulties come from the fact that CG's role is mostly unexpected, and their way of embracing it modifies their perception of themselves and their relative with dementia; 4) senses framework characterizes CG and PWD through their relationship, and offers a vision that includes difficulties and ways to cope with them, as well as satisfactions they experiment in the caregiving relationship. We will see through these theoretical frameworks which elements are the most relevant to take into account, their similarities and differences as well as the possible applications for health practitioners.

How motor, cognitive and musical expertise shapes the brain: Focus on fMRI and EEG resting-state functional connectivity.

Brain activity and structure are shaped by life experiences. This plasticity has often been demonstrated with different types of expertise by using functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). Experts showed domain-specific functional neural changes during completion of a task when compared to non-experts. However, all of these results are task-dependent and even though they have proven useful for understanding neural interactions and their direct relation to individual skill, studying brain plasticity without any task might provide complementary information about functional cerebral reorganization due to expertise at the whole-brain level and might facilitate comparison across studies. Resting-state functional MRI and EEG makes it possible to explore the functional traces of expertise in the brain by measuring temporal correlations of blood oxygen level-dependent (BOLD) and spontaneous neural activity fluctuations at rest. Since these correlations are thought to reflect a prior history co-activation of brain regions, we propose reviewing studies that focused on the effects of expertise in the motor, cognitive and musical domains on brain plasticity at rest, to determine whether there is a domain-specific neural signature of expertise. After highlighting expertise-related changes within resting-state networks for each domain, we discuss their specificity to the trained activity and the methodological considerations concerning different conditions and analyses used between studies.

Musical Expertise Increases Top-Down Modulation Over Hippocampal Activation during Familiarity Decisions.

The hippocampus has classically been associated with episodic memory, but is sometimes also recruited during semantic memory tasks, especially for the skilled exploration of familiar information. Cognitive control mechanisms guiding semantic memory search may benefit from the set of cognitive processes at stake during musical training. Here, we examined using functional magnetic resonance imaging, whether musical expertise would promote the top-down control of the left inferior frontal gyrus (LIFG) over the generation of hippocampally based goal-directed thoughts mediating the familiarity judgment of proverbs and musical items. Analyses of behavioral data confirmed that musical experts more efficiently access familiar melodies than non-musicians although such increased ability did not transfer to verbal semantic memory. At the brain level, musical expertise specifically enhanced the recruitment of the hippocampus during semantic access to melodies, but not proverbs. Additionally, hippocampal activation contributed to speed of access to familiar melodies, but only in musicians. Critically, causal modeling of neural dynamics between LIFG and the hippocampus further showed that top-down excitatory regulation over the hippocampus during familiarity decision specifically increases with musical expertise - an effect that generalized across melodies and proverbs. At the local level, our data show that musical expertise modulates the online recruitment of hippocampal response to serve semantic memory retrieval of familiar melodies. The reconfiguration of memory network dynamics following musical training could constitute a promising framework to understand its ability to preserve brain functions.

[Pure amusia reavealing an ischaemic lesion of right temporal planum. Participation of the right temporal lobe in perception of music]. / Amusie isolée révélatrice d'une lésion ischémique du planum temporal droit. Rôle du lobe temporal dans l'appréhension de la musique.

Amusia is the impaired perception and performance of music due to brain lesions that do not affect motor or sensory skills. Amusia is usually associated with other neuropsychological disorders. We report an exceptional case of pure amusia of sudden onset in a professional choir conductor, following right-sided temporal planum infarction revealing internal carotid occlusion. We describe this patient's symptoms in relation to published observations and to the conclusions of PET scanning. This clinical case confirms that singing disorders and impaired timbre and melodic perception are particularly linked to the right temporal lobe, whereas rhythm perception involves the left temporal lobe.

Dementia beyond 2025: Knowledge and uncertainties.

Given that there may well be no significant advances in drug development before 2025, prevention of dementia-Alzheimer's disease through the management of vascular and lifestyle-related risk factors may be a more realistic goal than treatment. Level of education and cognitive reserve assessment in neuropsychological testing deserve attention, as well as cultural, social, and economic aspects of caregiving. Assistive technologies for dementia care remain complex. Serious games are emerging as virtual educational and pleasurable tools, designed for individual and cooperative skill building. Public policies are likely to pursue improving awareness and understanding of dementia; providing good quality early diagnosis and intervention for all; improving quality of care from diagnosis to the end of life, using clinical and economic end points; delivering dementia strategies quicker, with an impact on more people. Dementia should remain presented as a stand-alone concept, distinct from frailty or loss of autonomy. The basic science of sensory impairment and social engagement in people with dementia needs to be developed. E-learning and serious games programs may enhance public and professional education. Faced with funding shortage, new professional dynamics and economic models may emerge through coordinated, flexible research networks. Psychosocial research could be viewed as an investment in quality of care, rather than an academic achievement in a few centers of excellence. This would help provide a competitive advantage to the best operators. Stemming from care needs, a logical, systems approach to dementia care environment through organizational, architectural, and psychosocial interventions may be developed, to help reduce symptoms in people with dementia and enhance quality of life. Dementia-friendly environments, culture, and domesticity are key factors for such interventions.