ISMRM 23rd Annual Meeting & Exhibition • 30 May - 05 June 2015 • Toronto, Ontario, Canada

Scientific Session • fMRI Applications, Including Optogenetics

Monday 1 June 2015

Room 714 A/B

14:15 - 16:15


Victoria L. Morgan, Ph.D., T.B.A.

4:15 0131.   
Hunting the Source of a Unique Negative fMRI Signal in the Striatum Using Optogenetics
Daniel Albaugh1, Garret Stuber2, and Yen-Yu Ian Shih3
1Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 2Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States, 3BRIC, Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States

Neurovascular coupling represents a central tenet of functional MRI research. However, in the rodent striatum, the directionality of vascular responses to neural activity is not always clear. Here, we employ optogenetic-fMRI to uncover two striatal circuit mechanisms of activity-induced vasoconstriction.

14:27 0132.   Spatial Correlations of Neurovascular Coupling Studied using Single Pulse Opto-fMRI
Jack A Wells1, Isabel N Christie1, Sergey Kasparov2, Alexander Gourine3, and Mark F Lythgoe1
1Centre for Advanced Biomedical Imaging, University College London, London, London, United Kingdom, 2Department of Physiology and Pharmacology, University of Bristol, Bristol, United Kingdom, 3Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom

Despite the widespread application of fMRI, questions remain regarding the link between the measured BOLD signal and the underlying changes in neural activity. Here, we present a novel technique to investigate spatial correlations of neurovascular coupling. We use a single pulse of light (10ms) to modulate the volume of optogenetically induced action potentials in the rat cortex with concurrent fMRI. A directly proportional relationship was observed between the volume of BOLD response and the estimated volume of light-activated brain tissue, a finding which has possible implications for the design of future fMRI studies.

14:39 0133.   
Intrahippocampal and Hippocampal-Cortical Interactions Driven by Frequency Specific Optogenetic Stimulation
Russell W. Chan1,2, Alex T.L. Leong1,2, Joe S. Cheng1,2, Partick P. Gao1,2, Shu-Juan J. Fan1,2, Kevin K. Tsia2, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China

Previous studies suggested that the intrahippocampal interactions may be governed by gamma oscillations, while hippocampal-cortical interactions might be directed by low frequency oscillation and/or sharp wave-ripple. However, exactly how different frequency contributes to large-scale intrahippocampal and hippocampal-cortical interactions remains largely unknown. In this study, optogenetic functional MRI was applied to investigate the frequency-dependent hippocampal network activity. Large-scale hippocampal and cortical activations were found during 40Hz and 1Hz stimulation, respectively. This is also the first study demonstrating large-scale and widespread hippocampal-cortical activity by driving CaMKIIa-positive cells in the dorsal hippocampus. This widespread hippocampal-cortical activity suggests that the generation of low frequency oscillation in the dorsal hippocampus can modulate cortical activity.

14:51 0134.   
Uncovering the Functional Network of Medial Prefrontal Cortex in Awake Rodents using Optogenetic fMRI
Zhifeng Liang1,2, Glenn D.R. Waston2,3, Kevin D. Alloway2,3, Gangchea Lee1, Thomas Neuberger1, and Nanyin Zhang1,2
1Dept. of Biomedical Engineering, Pennsylvania State University, University Park, PA, United States, 2Center for Neural Engineering, The Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA, United States, 3Neural and Behavioral Sciences, College of Medicine, Pennsylvania State University, Hershey, PA, United States

Medial prefrontal cortex (mPFC) plays a critical role in cognition and emotion. However, mPFC functional networks cross the whole brain remains elusive, particularly in awake rodents. Here we combined optogenetics and functional magnetic resonance imaging (opto-fMRI) to reveal mPFC functional networks in awake rodents. We found optogenetic stimulations in infralimbic cortex (IL, part of mPFC) generated robust, reliable and distributed activations in awake rats, which resembled efferent anatomical projections of IL. The results expanded the applicability of opto-fMRI from sensorimotor to cognition-related networks in awake rodents, which can be utilized to investigate circuit-level mechanisms underlying mPFC-related brain functions and behaviors.

15:03 0135.   
Frequency specific optogenetic recruitment of evoked responses in the somatosensory thalamocortical circuit
Alex T.L. Leong1,2, Russell W. Chan1,2, Patrick P. Gao1,2, Joe S. Cheng1,2, Jevin W. Zhang1,2, Shu-Juan J. Fan1,2, Kevin K. Tsia2, Kenneth K.Y. Wong2, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, SAR, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, SAR, China

Timing has been postulated as one of the most important aspects of information processing in the brain, and frequency is the most intuitive of the many timing parameters. Thalamocortical circuits present a good opportunity to comprehend the importance of timing due to their well-known relay pathways to the cortex in all sensory modalities. They have oscillations that are well characterized through multisite electrical recordings during wakefulness, sleep, anesthesia and task-driven activity. The advent of optogenetics coupled with fMRI enables an unprecedented opportunity to probe the dynamics of the somatosensory thalamocortical circuit of the rat in response to differing frequency stimulation.

15:15 0136.   Characterizing cortical responses to the stimulation of single mechanoreceptive afferents using fMRI at 7 T
Rosa Maria Sanchez Panchuelo1, Rochelle Ackerley2, Paul Glover1, Richard Bowtell1, Francis McGlone3, Johan Wessberg2, and Susan Francis1
1University of Nottingham, Nottingham, United Kingdom, 2University of Gothenburg, Gothenburg, Sweden, 3Liverpool Johns Moore University, Liverpool, United Kingdom

We successfully performed microstimulation of single afferents in the environment of an ultra-high field (7T) MR scanner and collected high resolution fMRI data depicting the response to intraneural microstimulation (INMS). fMRI data were acquired during INMS of 11 different afferents across four subjects. We compare the cortical responses elicited by INMS of single afferents with those produced by mechanical stimulation of each afferent’s receptive field. We show that INMS and vibrotactile stimulation engage sensory related brain areas, and that INMS activates additional brain networks. INMS responses were localized within the expected area of digit representation in primary somatosensory cortex.

15:27 0137.   Odor-evoked fMRI maps are coupled to calcium-sensitive dye imaging patterns of input activity in the olfactory bulb
Basavaraju G Sanganahalli1, Michelle R Rebello2, Peter Herman1, Gordon M Shepherd3, Justus V Verhagen2,4, and Fahmeed Hyder1,5
1Diagnostic Radiology, Yale University, New Haven, CT, United States, 2The John B. Pierce Laboratory, Yale University, New Haven, CT, United States,3Neurobiology, Yale University, New Haven, CT, United States, 4Neurobiology, Yale University, CT, United States, 5Biomedical Engineering, Yale University, New Haven, CT, United States

To improve functional understanding of odor-evoked glomerular activity patterns revealed by BOLD signal and to relate how input activities of glomeruli reflected by calcium imaging relate to bulk neuropil activity of fMRI, we designed a study to image the same rats with fMRI first and then with calcium imaging. Excellent correspondence between odor-evoked fMRI maps and calcium-sensitive dye imaging patterns of input activity suggests input activity is a dominant part of neuropilar activity in glomeruli. In conclusion, multi-modal functional imaging of rat olfactory bulb with odorant stimulation provides new opportunities for gaining insights into complexities of neuropilar activities.

15:39 0138.   MEG and fMRI localization of infrasonic and low-frequency sound
Markus Weichenberger1, Rüdiger Brühl2, Martin Bauer2, Robert Kühler2, Albrecht Ihlenfeld2, Johannes Hensel2, Christian Koch2, Bernd Ittermann2, Simone Kühn1, and Tilmann Sander2
1Max Planck Institute for Human Development, Berlin, Germany, 2Physikalisch-Technische Bundesanstalt (PTB), Braunschweig und Berlin, Germany

Infrasound is a potential hazard to human health. This multimodal study is targeting the perception of infrasound and low-frequency sound in humans. Sinusoidal acoustic stimuli of seven frequencies (8, 12, 20 , 40, 63, 125, 250 Hz) were individually calibrated for 15 volunteers and applied while conducting a MEG and fMRI study. Location and amplitude of the activated brain area were analyzed for both modalities showing different frequency dependencies. Although the reception of the infrasound is mainly tactile only brain activation in the region of the auditorial cortex was found.

15:51 0139.   Encoding Self-Motion and External Motion during Pursuit Eye Movement, A Study at 9.4T
F. Molaei-Vaneghi1,2, Jonas Bause1, Philipp Ehses1, Klaus Scheffler1, and Andreas Bartels2
1High Field Magnetic Resonance, Max-Planck Institute for Biological Cybernetics, Tübingen, Baden-Württemberg, Germany, 2Center for Integrative Neuroscience (CIN), Vision and Cognition Lab, Tübingen, Baden-Württemberg, Germany

Here we propose to use ultra-high-field (9.4T) human fMRI in order to answer two questions: firstly, is there a differential involvement of cortical layers in the processing of retinal motion and of objective motion in high-level visual areas? Second: is there a columnar organisation segregating retinal and objective motion processing? A differential laminar response profile to the two motion types would provide important cues with regards to the hierarchy of processing involved in different areas, with modulation of upper, middle, or lower layers speaking for feedback, bottom-up or output sources of the different signals, respectively. A columnar segregation would indicate specialized and segregated circuits within a given area.

16:03 0140.   
Endogenous GABA Concentration and Haemodynamic Responses to Graded Visual Contrast
Mark Mikkelsen1, C. John Evans1, Alan J. Stone1,2, Esther A. H. Warnert1, and Krish D. Singh1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom, 2FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom

Concentration of the neurotransmitter γ-aminobutyric acid (GABA) is known to predict task-related BOLD and CBF responses. Here, we simultaneously measured BOLD and CBF in the visual cortex whilst employing a graded visual contrast paradigm to investigate GABA’s potential association with properties of haemodynamic contrast tuning. GABA levels were non-invasively measured with 1H MRS. Rate of response saturation was inversely related to GABA concentration such that participants with higher GABA levels had faster BOLD response saturation to contrast. GABA concentration is associated with individual differences in haemodynamic contrast tuning and may be a mediator of the dynamic range of BOLD/CBF responses.