Author name cluster

Lisa Conant

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

4 papers

1 author row

YNIMG Journal 2025 Journal Article

Reproducibility of fNIRS within subject for visual and motor tasks

Julie C. Wagner
Anthony Zinos
Scott A. Beardsley
Wei-Liang Chen
Lisa Conant
Marsha Malloy
Joseph Heffernan
Brendan Quirk

Functional Near Infrared Spectroscopy (fNIRS) is becoming a popular metric to noninvasively identify brain activity through assessing changes in oxygenated (HbO) and deoxygenated (HbR) hemoglobin concentration. Several aspects of fNIRS imaging are appealing for clinical applications but the reproducibility of fNIRS signals has yet to be determined over several sessions. To address this, four participants completed at least ten sessions on separate days where they performed Motor and Visual tasks while fNIRS signals were measured from 102 channels spanning the entire head. Reproducibility was quantified as the percentage of significant task related activity occurring across sessions at the channel and source levels (anatomically specific and default head models) via Region of Interest (ROI) and vertex-wise analyses. To improve source localization, digitized optode positions from each session were used with the anatomy specific source localization. Individual differences in reproducibility were present yet task-related changes in HbO were significantly more reproducible over sessions than changes in HbR (F(1, 66) = 5.03, p<0.05). Increased shifts in optode position correlated with less spatial overlap across sessions for each participant. Further steps can be taken to increase the reliability of capturing brain activity with fNIRS by improving upon data acquisition and analysis techniques.

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YNIMG Journal 2024 Journal Article

Spatial correspondence of cortical activity measured with whole head fNIRS and fMRI: Toward clinical use within subject

Anthony Zinos
Julie C. Wagner
Scott A. Beardsley
Wei-Liang Chen
Lisa Conant
Marsha Malloy
Joseph Heffernan
Brendan Quirk

Functional near infrared spectroscopy (fNIRS) and functional magnetic resonance imaging (fMRI) both measure the hemodynamic response, and so both imaging modalities are expected to have a strong correspondence in regions of cortex adjacent to the scalp. To assess whether fNIRS can be used clinically in a manner similar to fMRI, 22 healthy adult participants underwent same-day fMRI and whole-head fNIRS testing while they performed separate motor (finger tapping) and visual (flashing checkerboard) tasks. Analyses were conducted within and across subjects for each imaging approach, and regions of significant task-related activity were compared on the cortical surface. The spatial correspondence between fNIRS and fMRI detection of task-related activity was good in terms of true positive rate, with fNIRS overlap of up to 68 % of the fMRI for analyses across subjects (group analysis) and an average overlap of up to 47.25 % for individual analyses within subject. At the group level, the positive predictive value of fNIRS was 51 % relative to fMRI. The positive predictive value for within subject analyses was lower (41.5 %), reflecting the presence of significant fNIRS activity in regions without significant fMRI activity. This could reflect task-correlated sources of physiologic noise and/or differences in the sensitivity of fNIRS and fMRI measures to changes in separate (vs. combined) measures of oxy and de-oxyhemoglobin. The results suggest whole-head fNIRS as a noninvasive imaging modality with promising clinical utility for the functional assessment of brain activity in superficial regions of cortex physically adjacent to the skull.

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YNIMG Journal 2022 Journal Article

Late dominance of the right hemisphere during narrative comprehension

Vahab Youssofzadeh
Lisa Conant
Jeffrey Stout
Candida Ustine
Colin Humphries
William L. Gross
Priyanka Shah-Basak
Jed Mathis

PET and fMRI studies suggest that auditory narrative comprehension is supported by a bilateral multilobar cortical network. The superior temporal resolution of magnetoencephalography (MEG) makes it an attractive tool to investigate the dynamics of how different neuroanatomic substrates engage during narrative comprehension. Using beta-band power changes as a marker of cortical engagement, we studied MEG responses during an auditory story comprehension task in 31 healthy adults. The protocol consisted of two runs, each interleaving 7 blocks of the story comprehension task with 15 blocks of an auditorily presented math task as a control for phonological processing, working memory, and attention processes. Sources at the cortical surface were estimated with a frequency-resolved beamformer. Beta-band power was estimated in the frequency range of 16-24 Hz over 1-sec epochs starting from 400 msec after stimulus onset until the end of a story or math problem presentation. These power estimates were compared to 1-second epochs of data before the stimulus block onset. The task-related cortical engagement was inferred from beta-band power decrements. Group-level source activations were statistically compared using non-parametric permutation testing. A story-math contrast of beta-band power changes showed greater bilateral cortical engagement within the fusiform gyrus, inferior and middle temporal gyri, parahippocampal gyrus, and left inferior frontal gyrus (IFG) during story comprehension. A math-story contrast of beta power decrements showed greater bilateral but left-lateralized engagement of the middle frontal gyrus and superior parietal lobule. The evolution of cortical engagement during five temporal windows across the presentation of stories showed significant involvement during the first interval of the narrative of bilateral opercular and insular regions as well as the ventral and lateral temporal cortex, extending more posteriorly on the left and medially on the right. Over time, there continued to be sustained right anterior ventral temporal engagement, with increasing involvement of the right anterior parahippocampal gyrus, STG, MTG, posterior superior temporal sulcus, inferior parietal lobule, frontal operculum, and insula, while left hemisphere engagement decreased. Our findings are consistent with prior imaging studies of narrative comprehension, but in addition, they demonstrate increasing right-lateralized engagement over the course of narratives, suggesting an important role for these right-hemispheric regions in semantic integration as well as social and pragmatic inference processing.

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YNICL Journal 2020 Journal Article

Sensitivity of functional connectivity to periaqueductal gray localization, with implications for identifying disease-related changes in chronic visceral pain: A MAPP Research Network neuroimaging study

Sonja J. Fenske
Douglas Bierer
Gisela Chelimsky
Lisa Conant
Candida Ustine
Ke Yan
Thomas Chelimsky
Jason J. Kutch

Previous studies examining the resting-state functional connectivity of the periaqueductal gray (PAG) in chronic visceral pain have localized PAG coordinates derived from BOLD responses to provoked acute pain. These coordinates appear to be several millimeters anterior of the anatomical location of the PAG. Therefore, we aimed to determine whether measures of PAG functional connectivity are sensitive to the localization technique, and if the localization approach has an impact on detecting disease-related differences in chronic visceral pain patients. We examined structural and resting-state functional MRI (rs-fMRI) images from 209 participants in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network study. We applied three different localization techniques to define a region-of-interest (ROI) for the PAG: 1) a ROI previously-published as a Montreal Neurological Institute (MNI) coordinate surrounded by a 3 mm radius sphere (MNI-sphere), 2) a ROI that was hand-traced over the PAG in a MNI template brain (MNI-trace), and 3) a ROI that was hand-drawn over the PAG in structural images from 30 individual participants (participant-trace). We compared the correlation among the rs-fMRI signals from these PAG ROIs, as well as the functional connectivity of these ROIs with the whole brain. First, we found important non-uniformities in brainstem rs-fMRI signals, as rs-fMRI signals from the MNI-trace ROI were significantly more similar to the participant-trace ROI than to the MNI-sphere ROI. We then found that choice of ROI also impacts whole-brain functional connectivity, as measures of PAG functional connectivity throughout the brain were more similar between MNI-trace and participant-trace compared to MNI-sphere and participant-trace. Finally, we found that ROI choice impacts detection of disease-related differences, as functional connectivity differences between pelvic pain patients and healthy controls were much more apparent using the MNI-trace ROI compared to the MNI-sphere ROI. These results indicate that the ROI used to localize the PAG is critical, especially when examining brain functional connectivity changes in chronic visceral pain patients.

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