Biology subjects

Butters, E.

Publications and source records attributed to Butters, E..

3 recordsLinked to original sources

bioRxiv2025

Brain Network Analysis in Alzheimer's Disease and Mild Cognitive Impairment using High-Density Diffuse Optical Tomography

Dementia is associated with altered resting state connectivity, measures of which could aid in its early detection and monitoring. High-density diffuse optical tomography (HD-DOT) is well-suited to detect these alterations at scale due to its numerous practical advantages, but it has not yet been applied to dementia. In this study, we investigated resting state functional connectivity across the prefrontal cortex in individuals with Mild Cognitive Impairment (MCI, n = 22), Alzheimers Disease (AD, n = 21), and in healthy controls (n = 22). A graph theoretical approach was taken to characterise both global and local patterns of connectivity over a five-minute resting period. We found that individuals with AD and MCI exhibited denser and stronger networks, with shorter path lengths, as well as a loss of consistent key network hubs with worsening cognitive impairment. These results indicate that networks in dementia are more globally connected, albeit in a disorganised manner, perhaps reflecting the recruitment of additional connections for short-term stability which may be ultimately damaging in the long-term. Following the demonstration of HD-DOTs capacity to detect differences between healthy ageing and dementia, this work opens up new possibilities for the use of optical imaging in the study of this clinical population and HD-DOTs potential for scalable clinical use.

neuroscience↗

bioRxiv2025

Mapping functional hemodynamic and metabolic responses to dementia: a broadband spectroscopy pilot study

SignificanceBroadband near-infrared spectroscopy (bNIRS) can simultaneously monitor several chromophores including the oxidative state of cytochrome c-oxidase (oxCCO), an oxygen metabolism biomarker whose activity is altered in Alzheimers disease. Being a portable and non-invasive neuromonitoring technique, bNIRS could thus provide accessibility to brain-specific biomarkers and aid in the dementia diagnostic pathway. AimWe use bNIRS recorded functional haemodynamic and oxCCO changes to assess their relevance in Alzheimers disease dementia as potential biomarkers. ApproachUsing a visual-stimulus paradigm, we recorded functional changes in oxy-, deoxy-haemoglobin and oxCCO in three similarly aged cohorts: healthy controls (n=5), individuals with mild cognitive impairment (n=7) and individuals with Alzheimers dementia (n=7). We then selected features from these functional responses to find the best correlation with clinical cognitive markers (cognitive and behavioural test scores and clinical diagnosis) using canonical correlation analysis. ResultsWe found individual variations in peak amplitude and time-to-peak for all the stimulus-evoked bNIRS signals across the three cohorts. Canonical correlation analysis showed a strong correlation between bNIRS features and the clinical cognitive markers (r=0.902). However, repeating the same analysis by excluding the bNIRS oxCCO features leads to a significantly lower correlation (r=0.687) with the clinical markers. ConclusionsoxCCO could be a crucial biomarker, partly explaining cognitive differences with dementia. bNIRS uniquely provides a portable and non-invasive technique to monitor several chromophores simultaneously including oxCCO with potential future applications in tracking dementia progression.

bioengineering↗

bioRxiv2023

Audiotactile stimulation can improve syllable discrimination through multisensory integration in the theta frequency band

Syllables are an essential building block of speech. We recently showed that tactile stimuli linked to the perceptual centers of syllables in continuous speech can improve speech comprehension. The rate of syllables lies in the theta frequency range, between 4 and 8 Hz, and the behavioural effect appears linked to multisensory integration in this frequency band. Because this neural activity may be oscillatory, we hypothesized that a behavioural effect may also occur not only while but also after this activity has been evoked or entrained through vibrotactile pulses. Here we show that audiotactile integration regarding the perception of single syllables, both on the neural and on the behavioural level, is consistent with this hypothesis. We first stimulated subjects with a series of vibrotactile pulses and then presented them with a syllable in background noise. We show that, at a delay of 200 ms after the last vibrotactile pulse, audiotactile integration still occurred in the theta band and syllable discrimination was enhanced. Moreover, the dependence of both the neural multisensory integration as well as of the behavioral discrimination on the delay of the audio signal with respect to the last tactile pulse was consistent with a damped oscillation. In addition, the multisensory gain is correlated with the syllable discrimination score. Our results therefore evidence the role of the theta band in audiotactile integration and provide evidence that these effect may involve oscillatory activity that still persists after the tactile stimulation.

neuroscience↗