Biology subjects

Hardwick, R.

Publications and source records attributed to Hardwick, R..

4 recordsLinked to original sources

bioRxiv2024

Multisensory approach in Mental Imagery: ALE meta-analyses comparing Motor, Visual and Auditory Imagery

Mental Imagery is a topic of longstanding and widespread scientific interest. Individual studies have typically focused on a single modality (e.g. Motor, Visual, Auditory) of Mental Imagery. Relatively little work has considered directly comparing and contrasting the brain networks associated with these different modalities of Imagery. The present study integrates data from 439 neuroimaging experiments to identify both modality-specific and shared neural networks involved in Mental Imagery. Comparing the networks involved in Motor, Visual, and Auditory Imagery identified a pattern whereby each form of Imagery preferentially recruited higher level associative brain regions involved in the associated real experience. Results also indicate significant overlap in a left-lateralized network including the pre-supplementary motor area, ventral premotor cortex and inferior parietal lobule. This pattern of results supports the existence of a core network that supports the attentional, spatial, and decision-making demands of Mental Imagery. Together these results offer new insights into the brain networks underlying human imagination. HighlightsO_LIMeta-Analyses of Motor, Visual, and Auditory modalities of Imagery were compared C_LIO_LIEach modality recruited high level areas related to associated real-life experience C_LIO_LIA core network of pre-SMA, PMv and IPL were recruited by all imagery modalities C_LIO_LIResults emphasize attentional, spatial, & executive aspects of Mental Imagery C_LI

neuroscience↗

bioRxiv2023

A control policy can be adapted to task demands during both motor execution and motor planning

Movement planning consists of several processes related to the preparation of a movement such as decision making, target selection, application of task demands, action selection and specification of movement kinematics. These numerous processes are reflected in the reaction time, which is the time that it takes to start executing the movement. However, not all the processes that lead to motor planning increase reaction time. In this paper, we wanted to test whether tuning the control policy to task demands contributes to reaction time. Taking into account that the tuning of the control policy differs for narrow and wide targets, we used a timed response paradigm in order to track the amount of time needed to tune the control policy appropriately to task demands. We discovered that it does not take any time during motor planning and even that it can occur indistinguishably during motor planning or during motor execution. That is, the tuning the control policy was equally good when the narrow or wide target was displayed before than when it was displayed after the start of the movement. These results suggest that the frontier between motor planning and execution is not as clear cut as it is often depicted. New & NoteworthyMovement preparation consists of different processes such as target selection, and movement parameters selection. We investigate the time that it takes to tune movement parameters to task demands. We found that the brain does this instantaneously and that this can even happen during movement. Therefore, this suggests that there exists an overlap during movement planning and execution.

neuroscience↗

bioRxiv2020

Mass spectrometric characterisation of the circulating peptidome following oral glucose ingestion in control and gastrectomised patients.

Meal ingestion triggers secretion of a variety of gut and endocrine peptides, several of which are routinely measured in research studies by commercial immunoassays. We developed an LC-MS/MS based assay for parallel monitoring of multiple peptides in small volumes of human plasma, providing the benefit of analysing exact peptide sequences rather than immuno-reactivity, and potential advantages of cost and sample volumes for measuring multiple peptide hormones. The method involves acetonitrile precipitation of larger proteins, followed by solid phase extraction and nano-LC-MS/MS using an untargeted approach on an orbitrap mass spectrometer. Analysis of plasma from control subjects and patients who have undergone gastrectomy with Roux-en-Y reconstruction, revealed elevated levels of a number of peptides following glucose ingestion. These included GLP-1(7-36), GLP-1(9-36), glicentin, oxyntomodulin, GIP(1-42), GIP(3-42), PYY(1-36), PYY(3-36), neurotensin, insulin and C-peptide, as well as motilin, which decreased following glucose ingestion. Results showed good correlation with those peptides measured previously by immunoassay in the same samples. The gastrectomy group had higher, but non-glucose-dependent, circulating levels of peptides from PIGR and DMBT1. Overall, the method is fast, generic, reproducible and inexpensive, and requires only small plasma samples, making it potentially adaptable for multiplexed measurement of a variety of peptides.

biochemistry↗

bioRxiv2018

Genomic evidence supports a clonal diaspora model for metastases of esophageal adenocarcinoma

Continual evolution of cancer makes it challenging to predict clinical outcomes. Highly varied and unpredictable patient outcomes in esophageal adenocarcinoma (EAC) prompted us to question the pattern and timing of metastatic spread. Whole genome sequencing and phylogenetic analysis of 396 samples across 18 EAC cases demonstrated a stellate pattern on the phylogenetic trees in 90% cases. The age-dependent trinucleotide signature, which can serve as a molecular clock, was absent or reduced in the stellate branches beyond the trunk in most cases (p<0.0001). Clustering of lymph nodes and distant metastases (n=250) demonstrated samples sharing a common clonal origin were widely dispersed anatomically. Metastatic subclones at autopsy were present in tissue and blood samples from earlier time-points. We infer that metastasis occurs rapidly across multiple sites, constituting a model of metastatic spread we term clonal diaspora. This has implications for understanding metastatic progression, clinical staging and patient management.

genomics↗