Picture free recall performance linked to the brain's structural connectome

Memory functions are highly variable between healthy humans. The neural correlates of this variability remain largely unknown.; Here, we investigated how differences in free recall performance are associated with DTI-based properties of the brain's structural connectome and with grey matter volumes in 664 healthy young individuals tested in the same MR scanner.; Global structural connectivity, but not overall or regional grey matter volumes, positively correlated with recall performance. Moreover, a set of 22 inter-regional connections, including some with no previously reported relation to human memory, such as the connection between the temporal pole and the nucleus accumbens, explained 7.8% of phenotypic variance.; In conclusion, this large-scale study indicates that individual memory performance is associated with the level of structural brain connectivity

Plasticity in the sensorimotor cortex induced by Music-supported therapy in stroke patients: a TMS study.

Playing a musical instrument demands the engagement of different neural systems. Recent studies about the musician"s brain and musical training highlight that this activity requires the close interaction between motor and somatosensory systems. Moreover, neuroplastic changes have been reported in motor-related areas after short and long-term musical training. Because of its capacity to promote neuroplastic changes, music has been used in the context of stroke neurorehabilitation. The majority of patients suffering from a stroke have motor impairments, preventing them to live independently. Thus, there is an increasing demand for effective restorative interventions for neurological deficits. Music-supported Therapy (MST) has been recently developed to restore motor deficits. We report data of a selected sample of stroke patients who have been enrolled in a MST program (1 month intense music learning). Prior to and after the therapy, patients were evaluated with different behavioral motor tests. Transcranial Magnetic Stimulation (TMS) was applied to evaluate changes in the sensorimotor representations underlying the motor gains observed. Several parameters of excitability of the motor cortex were assessed as well as the cortical somatotopic representation of a muscle in the affected hand. Our results revealed that participants obtained significant motor improvements in the paretic hand and those changes were accompanied by changes in the excitability of the motor cortex. Thus, MST leads to neuroplastic changes in the motor cortex of stroke patients which may explain its efficacy

Multimodal imaging of brain reorganization in hearing late learners of sign language

The neural plasticity underlying language learning is a process rather than a single event. However, the dynamics of training - induced brain reorganization have rarely been examined, especially using a multimodal magnetic resonance imaging approach, which allows us to study the relationship between functional and structural changes. We focus on sign language acquisition in hearing adults who underwent an 8‐month long course and five neuroimaging sessions. We assessed what neural changes occurred as participants learned a new language in a different modality - as reflected by task‐based activity, connectivity changes, and co‐occurring structural alterations. Major changes in the activity pattern appeared after just 3 months of learning, as indicated by increases in activation within the modality‐independent perisylvian language network, together with increased activation in modality‐dependent parieto‐occipital, visuospatial and motion‐sensitive regions. Despite further learning, no alterations in activation were detected during the following months. However, enhanced coupling between left‐lateralized occipital and inferior frontal regions was observed as the proficiency increased. Furthermore, an increase in gray matter volume was detected in the left inferior frontal gyrus which peaked at the end of learning. Overall, these results showed complexity and temporal distinctiveness of various aspects of brain reorganization associated with learning of new language in different sensory modality

Considering the Purposes of Moral Education with Evidence in Neuroscience: Emphasis on Habituation of Virtues and Cultivation of Phronesis

In this paper, findings from research in neuroscience of morality will be overviewed to consider the purposes of moral education. Particularly, I will focus on two main themes in neuroscience, novel neuroimaging and experimental investigations, and Bayesian learning mechanism. First, I will examine how neuroimaging and experimental studies contributed to our understanding of psychological mechanisms associated with moral functioning while addressing methodological concerns. Second, Bayesian learning mechanism will be introduced to acquire insights about how moral learning occurs in human brains. Based on the overviewed neuroscientific research on morality, I will examine how evidence can support the model of moral education proposed by virtue ethics, Neo-Aristotelian moral philosophy in particular. Particularly, two main aims of virtue ethics-based moral education, habituation of virtues and cultivation of phronesis, will be discussed as the important purposes of moral education based on neuroscientific evidence

Diffusion MRI and Pharmacological Enhancement of Motor Recovery after Stroke

The primary goal of these studies is to enhance recovery of motor function following stroke and to understand the relationship between dMRI measures and the cellular, functional, and behavioral changes acutely and chronically following rehabilitation. We hypothesize that dMRI will be a sensitive tool to identify microstructural changes acutely and chronically following stroke and that promoting mitochondria biogenesis will lead to better functional recovery and induce structural and functional plasticity following rehabilitative training. Towards this goal, we used a combination of sensitive behavioral, immunohistochemical and mitochondrial-related molecular markers, and diffusion magnetic resonance imaging (dMRI) to investigate the time course of acute and chronic stroke effects. We were able to detect acute changes in dMRI metrics and correlate those changes with functional and morphological plasticity following stroke. Our work has shown that mean kurtosis, a dMRI metric, increased acutely after stroke and persists days poststroke in the lesion core. We found strong correlations between mean diffusivity and astrogliosis in the perilesional stroke area. There were no correlations between dendritic and axonal surface densities and dMRI metrics acutely following stroke. However, behavioral-induced and learning-induced neural plasticity was not detected with dMRI changes chronically in perilesional grey matter or white matter. Our studies have revealed mitochondria dysfunction that persists for at least six days post stroke in ipsilesional cortex and striatum following a focal sensorimotor (SMC) ischemic lesion. Therefore, we proposed that pharmacologically enhancing mitochondria function and biogenesis would promote recovery after stroke when administered early after stroke. We found that giving a drug known to induce mitochondria biogenesis, formoterol, a FDA approved long-lasting β2-adrenergic receptor agonist, twenty-four hours after SMC ischemic lesions caused a full restoration of markers of mitochondria function in the striatum three days post stroke and stimulates a partial recovery of functional markers in the cortex six days post-stroke. Our studies revealed that animals given formoterol (0.1mg/kg) combined with motor rehabilitative training (RT) daily for 15 days leads to better recovery of motor function than animals given vehicle treatment and RT. These data demonstrate that stimulating mitochondria biogenesis acutely after stroke enhances functional motor recovery

FUNCTIONAL CONNECTIVITY PATTERNS ASSOCIATED WITH AGING, PHYSICAL ACTIVITY, AND GENETIC RISK FOR ALZHEIMER’S DISEASE IN HEALTHY HUMAN BRAIN NETWORKS.

Leisure time physical activity (PA) and exercise training help to improve and maintain cognitive function in healthy older adults and in adults with the APOE-ε4 allele, a genetic risk for Alzheimer’s Disease (AD). Earlier work finding increased functional connectivity in the Default Mode Network (DMN) after a 12-week walking intervention in 16 older adults with mild cognitive impairment is presented in Chapter 3. The primary dissertation study investigating differences in brain function depending on PA level and genetic risk for AD prior to changes in cognition is presented in Chapters 4-6. Useable resting state and anatomical MRI scans were collected from 69 healthy adults (22-51 years) as well as saliva for APOE genotyping (carriers defined as homozygotes or heterozygotes of the ɛ4 allele) and responses to the Paffenbarger Physical Activity Questionnaire (High PA >1500 kcal, Low PA <1500 kcal per week). The following network measures of functional connectivity were calculated: global efficiency; node strength of Default Mode Network (DMN) and Fronto-Parietal Network (FPN) hubs and hippocampal subsections; and long-range connectivity of the medial prefrontal cortex (mPFC) and posterior cingulate cortex (PCC) in the DMN. Multiple linear regression analysis revealed statistically significant results for the long-range connectivity of the left PCC, a prominent hub of the DMN, and left mPFC. The differences in projected trajectories of the connectivity are potentially reflective of the compensatory time-course in our participants based on interactions of PA level and APOE status. The Low PA non-carriers had a positive slope indicating increased connectivity with age while carriers and non-carriers in the High PA category had horizontal aging trajectories. PA is associated with cognitive reserve (CR), a term describing the protection and adaptation of cognitive processes through neural efficiency and compensation mechanisms, and it is possible the Low PA non-carriers exhibited compensatory increases in connectivity of the left mPFC-PCC earlier than High PA study participants due to lower levels of CR. The promising findings that rs-fMRI can be used as an early detection of brain changes sensitive to PA levels and APOE-ɛ4 status are critical to the research and treatment of AD

The future of functionally-related structural change assessment

The brain is continually changing its function and structure in response to changing environmental demands. Magnetic resonance imaging (MRI) methods can be used to repeatedly scan the same individuals over time and in this way have provided powerful tools for assessing such brain change. Functional MRI has provided important insights into changes that occur with learning or recovery but this review will focus on the complementary information that can be provided by structural MRI methods. Structural methods have been powerful in indicating when and where changes occur in both gray and white matter with learning and recovery. However, the measures that we derive from structural MRI are typically ambiguous in biological terms. An important future challenge is to develop methods that will allow us to determine precisely what has changed. © 2011 Elsevier Inc