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Naranjargal Dashdorj¹, Alexakis Charilaos¹, Jaroslav Hlinka¹, Rob Mason¹, Quazi Siddiqui¹, Dorothee Auer¹

¹University of Nottingham, Nottingham, UK

Functional neuroimaging modalities are increasingly applied to study functional connectivity (fc)  defined as synchronisation of spatially remote neurophysiological events. Spontaneous low frequency fluctuations of the BOLD fMRI signal have been successfully used to study fc in the brain ‘at rest'. Advanced processing for spurious correlations allowed in recent years to characterise disease-specific alterations including the dysregulation of cortical-limbic circuitry in major depression. Moreover, cortico-limbic dysregulation as assessed by fc BOLD fMRI were found to be reversible after chronic antidepressant treatment.However, it remains unclear if and how acute pharmacological manipulations affect the functional connectivity between cortical-limbic networks. To our best knowledge, this is the first study investigating the effects of anxiolytic and sedative drug midazolam on fc in the cortico-limbic circuit in healthy volunteers.

David C. Zhu¹, Rose T. Zacks¹, Jill M. Slade¹

¹Michigan State University, East Lansing, Michigan, USA

The frontal-striatal neural circuit is thought to be associated with attention and executive function. To understand the modification of this neural circuit with aging, a rapid-event related fMRI flanker paradigm was applied to study the difference between the young (age 20 ± 3 yrs) and older (age 74 ± 6 yrs) populations. This study found that various anatomical regions associated this circuit were modified with aging as reflected by either the amplitude or latency of the BOLD response.

George Andrew James¹, Scott J. Peltier², Richard Cameron Craddock³, Stephen M. LaConte⁴, Helen S. Mayberg³, Xiaoping P. Hu¹

¹Emory University and Georgia Tech, Atlanta, USA; ²University of Michigan, Ann Arbor, USA; ³Emory University, Atlanta, USA; ⁴Baylor College of Medicine, Houston, USA

Exploratory SEM evaluated the neural network mediating emotion for fMRI resting-state data with healthy (n=28) and depressed (n=5) samples.  Jackknife and split-sample reliability testing assessed SEM validity.  The winning model for controls consistently beat its closest rivals despite exclusion of 1-5 subjects.  This model showed moderately negative influence of thalamus upon cingulate and reciprocal feedback loops within cingulate and within prefrontal cortices.  Randomly splitting the sample into halves or quarters and repeating the analysis yielded qualitatively similar models.  Yet depressed and control samples differed dramatically, thus demonstrating the feasibility of exploratory SEM for detecting functional differences despite small samples.

Ali-Mohammad Golestani¹, Andrew Demchuk¹, Bradley G. Goodyear¹

¹University of Calgary, Calgary, Canada

fMRI has not emerged as a tool to assess acute stroke, due to difficulties associated with patients performing tasks. We propose the strength of resting-state connections (connectivity) as an index of function that does not require tasks. Twelve stroke patients with a sensory-motor deficit underwent two MRI sessions (<24 hours and 90 days post-stroke). Eight fully recovered by day 90. Twelve healthy volunteers are also recruited. Connectivity in all patients at day0 was less than healthy controls. Recovered patients regained connectivity by day 90, whereas non-recovered patients did not. Connectivity may potentially link stroke injury with brain function and communication.

Paola Valsasina¹, Maria A. Rocca¹, Martina Absinta¹, Antonia Ceccarelli¹, Andrea Falini¹, Giuseppe Scotti¹, Giancarlo Comi¹, Massimo Filippi¹

¹Scientific Institute and University Ospedale San Raffaele, Milan, Italy

Aim of this study was to investigate the influence of normal aging on resting state networks (RSN) using independent component analysis in a group of 49 healthy subjects, with age ranging from 20 to 69 years. Ten relevant RSN were detected: two visual RSN; two sensorimotor RSN; five fronto-parietal-temporal RSN -three bilateral and two lateralized to left and right, respectively, and one parietal RSN, that included the precuneus and the posterior cingulum. Correlations with age were found only for one visual and one sensorimotor RSN, suggesting that the different RSN of the healthy brain might respond differently to aging.

Natalie Laura Voets¹, Steve M. Smith², Jane E. Adcock, Richard Stacey³, Yvonne Hart, Katherine Carpenter, Paul M. Matthews¹, Christian F. Beckmann

¹GSK, London, UK; ²Oxford University, FMRIB Centre, Oxford, UK; ³John Radcliffe Hospital, Oxford, UK

Memory reorganisation in temporal lobe epilepsy remains central to predicting surgical outcome.  Recurrent seizures may arise as a result of aberrant connectivity within the mesial temporal lobes, resulting in altered structural coherence between regions of the memory network rather than hemispheric reorganisation per se.   This study used TICA and voxel-wise diffusion analyses to identify altered structural coherence within the memory network in left temporal lobe epilepsy patients relative to healthy volunteers.  These functional changes were related to white matter integrity along the contralesional uncinate fasciculus.

Jianli Wang¹, Helena F. Wrzos, Christopher M. Collins¹, Jelena Zinnanti, Wanzhan Liu, Qing Li, Paul J. Eslinger, Qing X. Yang¹, Michael B. Smith¹, Ann Ouyang

¹Penn State College of Medicine, Hershey, Pennsylvania, USA

The effect of menstrual cycle on the brain response to the visceral pain stimulation was studied on eleven healthy women using fMRI. Although there was no significant subjective perception difference of the same level of visceral stimulation between the two menstrual phases, during the luteal phase there was a significant increase of brain activation responding to the visceral pain stimulation than during the follicular phase. This finding supports the notion that the visceral pain perception may be augmented during the luteal phase at the central nervous system level.

Anthony Peter Goldstone¹, Christina Prechtl de Hernandez¹, Kinan Muhammed¹, Gabriel Bell¹, Giuliana Durighel¹, Emer Hughes¹, Adam D. Waldman, ¹², Jimmy D. Bell¹

¹Hammersmith Hospital, Imperial College, London, UK; ²Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, UK

We examined how regional brain activity measured by fMRI varies with nutritional state (fasted vs. fed) when viewing food pictures. 18 non-obese healthy volunteers (age 19-36y) were scanned on 2 separate mornings after an overnight fast or 1hr after breakfast. There was significant activation of the ventral striatum, insula and amygdala when viewing high-calorie vs. object or high- vs. low-calorie pictures when fasted, but not when fed, which mirrored how appealing the pictures were rated. Increased hunger and desire for food when fasted vs. fed is associated with increased activation in brain regions involved in reward, cue-elicited craving and emotion.

Eric Murphy¹, Matcheri S. Keshavan¹, ², Vaibhav A. Diwadkar¹, ²

¹Wayne State University SOM, Detroit, Michigan, USA; ²University of Pittsburgh SOM, Pittsburgh, Pennsylvania, USA

The hippocampus and prefrontal cortex are critical regions in the encoding-retrieval memory circuit.  Both regions are impaired in schizophrenia, yet few studies have assessed their functional connectivity in the illness specifically during tasks of memory encoding.  In our fMRI study, patients and controls participated in an associative memory task during which they iteratively learned the associations between objects and locations in space.  Functional connectivity was assessed with seed voxels drawn in each subject from the cornu ammonis region in the right hippocampus.  Contrast analyses showed reduced fronto-hippocampal connectivity in patients relative to controls during memory encoding.

Vijay K Venkatraman¹, Howard J. Aizenstein, Jack Guralnik, Jeff D. Williamson, Marco Pahor, Lenore Launer, Anne B. Newman, Stephanie Studenski, Nancy Glynn, Caterina Rosano

¹University of Pittsburgh, Pittsburgh, Pennsylvania, USA

Several previous functional MRI studies in the elderly have identified age-related increased prefrontal activation in association with working memory performance. The primary hypotheses accounting for the increased activation include compensation or dedifferentiation. This current study tests these competing models using the digit symbol substitution task, a task involving working memory and processing speed, which is particularly sensitive to cognitive changes associated with aging. The findings suggest that older adults engage distinct overlapping networks of fronto-parietal regions to perform the DSST with greater accuracy and shorter reaction times.