# Non-invasive measures of multisensory cortical feedforward and feedback influences

> **NIH NIH R01** · MASSACHUSETTS GENERAL HOSPITAL · 2020 · $544,729

## Abstract

Non-invasive measures of multisensory cortical feedforward and feedback influences
 The objective of this research is to develop and apply advanced multimodal neuroimaging methods to
examine how information flows between brain areas, by using crossmodal modulation of human auditory
processing as a test case. A hierarchical organization of feedforward (FF) and feedback (FB) connections among
primate sensory areas has been established based on anatomical and functional connectivity patterns across
cortical layers. For example, information from other sensory systems could modulate sound processing in
auditory cortices (AC) through direct FF inputs, lateral inputs from other sensory cortices, and/or FB effects from
higher-level polymodal areas (e.g., superior temporal sulcus STS). However, the exact way each of these
mechanisms contributes to perception and cognition is an important open question. A critical barrier for resolving
this question has been the lack of non-invasive techniques to make detailed inferences on FF and FB influences
in cortical information processing. Such techniques are also needed to achieve better tools for the diagnosis and
follow-up of disorders involving abnormal FF and FB processes, including aphasia, dyslexia, or autism. Recent
studies suggest that functional FF and FB influences could be indirectly inferred from the local direction of
magneto- and electroencephalography (MEG, EEG) source current estimates, as well as from frequency-band
specific directed functional connectivity measures. Furthermore, recent developments in ultra-high field
functional magnetic resonance imaging (fMRI) make it possible sample small voxels (< 1 mm3) at different depths
of cortex, potentially enabling inferences of FF and FB type laminar activation patterns. These approaches could
provide critical pieces of information regarding the hierarchical role of an area among other cortical areas,
something that is not available in conventional measures of cortical activation patterns. Based on these scientific
premises, our Aim 1 is to combine measures of source current direction and effective connectivity derived from
MEG/EEG (Subaim 1a) with intracortical depth (or “laminar”) analyses of 7T fMRI signals recorded
simultaneously with high-density EEG data (Subaim 1b). We will compare the results with predictions based on
studies of non-human primate models. Our Aim 2 is to develop novel methods for examining the neuronal
mechanisms of crossmodal entrainment of AC activations in humans, including an extension of the source
direction analysis to oscillatory activity. To achieve this, we will combine analyses of MEG/EEG source estimates
(Subaim 2a) and analyses of simultaneously acquired laminar-resolution 7T fMRI and high-density EEG data
(Subaim 2b). For both Aims, we will validate our non-invasive results by using direct brain recordings from
patients with epilepsy who have intracranial electrodes implanted for medical reasons. These techniques
re...

## Key facts

- **NIH application ID:** 9954040
- **Project number:** 5R01DC016765-03
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** SEPPO PENTTI AHLFORS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $544,729
- **Award type:** 5
- **Project period:** 2018-07-01 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9954040

## Citation

> US National Institutes of Health, RePORTER application 9954040, Non-invasive measures of multisensory cortical feedforward and feedback influences (5R01DC016765-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9954040. Licensed CC0.

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