Wen-Ching Liu

Objective evidence of cognitive complaints in Chronic Fatigue Syndrome: A BOLD fMRI study of verbal working memory

Individuals with Chronic Fatigue Syndrome (CFS) often have difficulties with complex auditory information processing. In a series of two Blood Oxygen Level Dependent (BOLD) functional Magnetic Resonance Imaging (fMRI) studies, we compared BOLD signal changes between Controls and individuals with CFS who had documented difficulties in complex auditory information processing (Study 1) and those who did not (Study 2) in response to performance on a simple auditory monitoring and a complex auditory information processing task (mPASAT). We hypothesized that under conditions of cognitive challenge: (1) individuals with CFS who have auditory information processing difficulties will utilize frontal and parietal brain regions to a greater extent than Controls and (2) these differences will be maintained even when objective difficulties in this domain are controlled for. Using blocked design fMRI paradigms in both studies, we first presented the auditory monitoring task followed by the mPASAT. Within and between regions of interest (ROI), group analyses were performed for both studies with statistical parametric mapping (SPM99). Findings showed that individuals with CFS are able to process challenging auditory information as accurately as Controls but utilize more extensive regions of the network associated with the verbal WM system. Individuals with CFS appear to have to exert greater effort to process auditory information as effectively as demographically similar healthy adults. Our findings provide objective evidence for the subjective experience of cognitive difficulties in individuals with CFS.

Women's clitoris, vagina, and cervix mapped on the sensory cortex: fMRI evidence.

INTRODUCTION The projection of vagina, uterine cervix, and nipple to the sensory cortex in humans has not been reported. AIMS The aim of this study was to map the sensory cortical fields of the clitoris, vagina, cervix, and nipple, toward an elucidation of the neural systems underlying sexual response. METHODS Using functional magnetic resonance imaging (fMRI), we mapped sensory cortical responses to clitoral, vaginal, cervical, and nipple self-stimulation. For points of reference on the homunculus, we also mapped responses to the thumb and great toe (hallux) stimulation. MAIN OUTCOME MEASURES The main outcome measures used for this study were the fMRI of brain regions activated by the various sensory stimuli. RESULTS Clitoral, vaginal, and cervical self-stimulation activated differentiable sensory cortical regions, all clustered in the medial cortex (medial paracentral lobule). Nipple self-stimulation activated the genital sensory cortex (as well as the thoracic) region of the homuncular map. CONCLUSION The genital sensory cortex, identified in the classical Penfield homunculus based on electrical stimulation of the brain only in men, was confirmed for the first time in the literature by the present study in women applying clitoral, vaginal, and cervical self-stimulation, and observing their regional brain responses using fMRI. Vaginal, clitoral, and cervical regions of activation were differentiable, consistent with innervation by different afferent nerves and different behavioral correlates. Activation of the genital sensory cortex by nipple self-stimulation was unexpected, but suggests a neurological basis for womens reports of its erotogenic quality.

Cerebral activation patterns during working memory performance in multiple sclerosis using FMRI.

Working memory deficits are common in Multiple Sclerosis (MS) and have been identified behaviorally in numerous studies. Despite recent advance in functional magnetic resonance imaging (fMRI), few published studies have examined cerebral activations associated with working memory dysfunction in MS. The present study examines brain activation patterns during performance of a working memory task in individuals with clinically definite MS, compared to healthy controls (HC). fMRI was performed using a 1.5 Tesla GE scanner during a modified Paced Auditory Serial Addition Test (mPASAT). Participants were 6 individuals with MS with working memory impairment as evidenced on neuropsychological testing, 5 individuals with MS without working memory impairment, and 5 HC. Groups were demographically equivalent. Data were analyzed using Statistical Parametric Mapping (SPM99) software, with a stringent significance level (alpha < .005, voxel extent ≥ 8). Both MS groups and the HC group were able to perform the task, with comparable performance in terms of numbers of correct responses. Activation patterns within the HC and MS not-impaired groups were noted in similar brain regions, consistent with published observations in healthy samples. That is, activations were lateralized to the left hemisphere, involving predominantly frontal regions. In contrast, the MS impaired group showed greater right frontal and right parietal lobe activation, when compared with the HC group. Thus, it appears that working memory dysfunction in MS is associated with altered patterns of cerebral activation that are related to the presence of cognitive impairment, and not solely a function of MS. This research was supported by the Henry H. Kessler Foundation, the Hyde and Watson Foundation and the Kirby Foundation. The authors wish to thank Rinki Jajoo for her help with data management, as well as Dr. Scott Millis and Dr. Dane Cook for their statistical advice. Dr. Christopher Christodoulou is now in the Department of Neurology, State University of New York at Stony Brook. Dr. Joseph Ricker is now in the Department of Physical Medicine and Rehabilitation, University of Pittsburgh.

fMRI study of acupuncture-induced periaqueductal gray activity in humans

BOLD fMRI was used to study acupuncture-induced activation (increase in the BOLD signal from undetectable) of the periaqueductal gray (PAG) and two somatosensory cortical areas in seven healthy human subjects. Mechanical stimulation (push-pull) was given to the LI4 (Hoku) acupoint or to a non-acupoint. The stimulation paradigm consisted of 5 runs, each consisting of four 30 s On/30 s OFF periods over 30 min. The scan for each ON period was analyzed individually. The PAG and cortical areas showed different activity patterns. PAG activity was episodic and reliably demonstrated after 20–25 min of stimulation; both cortical areas, however, were active >90% of the time. Stimulation of a non-acupoint (leg) resulted in reduced levels of PAG and cortical activity.

Intraoperative functional MRI using a real-time neurosurgical navigation system.

A 42-year-old-man had focal left hand motor seizures. MR studies demonstrated a right posterior frontal brain tumor. Functional MRI was performed, localizing the motor cortex posterior to the lesion. The functional images were integrated with a neurosurgical navigation computer. A real-time intraoperative display of the anatomic and functional images was produced, registered to a neurosurgical probe. Excellent correlation was demonstrated between the functional maps and invasive electrophysiologic mapping performed at the time of craniotomy.

An Investigation of Working Memory Rehearsal in Multiple Sclerosis Using fMRI

The present study examined patterns of cerebral activation during a working memory (WM) rehearsal task in individuals diagnosed with multiple sclerosis (MS) and in healthy adults. BOLD functional magnetic resonance imaging (fMRI)was performed using a 1.5TGE scanner to assess activation during aWMtask adapted fromthe Sternberg paradigm (Sternberg, 1969). Participants included 8 individuals diagnosed with MS, and 5 healthy controls (HCs) matched for age and education. Task difficulty was manipulated by increasing the length of time that strings of letters were to be rehearsed. Findings revealed increased right prefrontal cortex activation and increased right temporal lobe activation in individuals diagnosed with MS compared to HCs. The potential explanations for increased right hemisphere activation in persons with MS are discussed.

Functional connectivity of the sensorimotor area in naturally sleeping infants

Patterns of cortical functional connectivity in normal infants were examined during natural sleep by observing the time course of very low frequency oscillations. Such oscillations represent fluctuations in blood oxygenation level and cortical blood flow thus allowing computation of neurophysiologic connectivity. Structural and resting-state information were acquired for 11 infants, with a mean age of 12.8 months, using a GE 1.5 T MR scanner. Resting-state data were processed and significant functional connectivity within the sensorimotor area was identified using independent component analysis. Unilateral functional connectivity in the developing sensory-motor cortices was observed. Power spectral analysis showed that slow frequency oscillations dominated the hemodynamic signal at this age, with, on average, a peak frequency for all subjects of 0.02 Hz. Our data suggest that there is more intrahemispheric than interhemispheric connectivity in the sensorimotor area of naturally sleeping infants. This non-invasive imaging technique, developed to allow reliable scanning of normal infants without sedation, enabled computation of neurophysiologic connectivity for the first time in naturally sleeping infants. Such techniques permit elucidation of the role of slow cortical oscillations during early brain development and may reveal critical information regarding the normative development and lateralization of brain networks across time.

Translocation of Broca's area to the contralateral hemisphere as the result of the growth of a left inferior frontal glioma

We report a case of a patient with a left inferior frontal glioma in whom language functional magnetic resonance imaging (fMRI) paradigms produced activation of Brocas area on the right and Wernickes area on the left. We propose that tumor invasion of the left frontal operculum led to cortical reorganization and interhemispheric transfer of Brocas area. This case emphasizes the importance of preoperative fMRI in assessing the location of eloquent cortices adjacent to a tumor and in guiding neurosurgical decision-making.

Functional magnetic resonance imaging aided radiation treatment planning

Functional MRI (magnetic resonance imaging) allows one to noninvasively identify various eloquent cortices in the brain. The integration of cortical activation information into radiosurgical treatment planning may provide an alternative to prevent or minimize radiation damage to eloquent cortex. A novel approach of directly integrating the fMRI (functional magnetic resonance imaging) brain map into treatment planning is proposed. Three brain tumor patients have been studied using this method with motor and/or visual paradigms. Brain activation was demonstrated in eloquent cortex at the precentral gyrus (motor area) and medial occipital lobe (visual area). The activation maps were transferred to a treatment planning workstation, (XKnife), and 3D (three-dimensional) activation maps were generated and co-registered to a 3D CT (computed tomography) anatomical data set, which provided the calibration localizer, for treatment planning. Radiosurgery was designed based on both functional and structural information by the medical team consisting of a radiation oncologist, a neurosurgeon and a physicist. The average maximum dose for the tumor was 2113 cGy. The average maximum dose for tissue surrounding the tumor was 1600 cGy. The average dose with fMRI information to the eloquent cortex was 163.4 cGy over three patients, while without fMRI information it was 240.5 cGy. The average percentage dose reduction over three patients is 32%. The results suggest that using this method can reduce the dose to the eloquent cortex. This approach provides the physician with additional information for treatment planning and may spare the patient unnecessary radiation exposure to adjacent eloquent cortices.

Vagus Nerve Stimulation in patients: a BOLD fMRI study

Wen-Ching LIU1, Kristine MOSIER2, Andrew KALNIN3, David MARKS4 1University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Department of Radiology, Newark, NJ USA; 2University of Medicine and Dentistry of New Jersey, Department of Radiology, Newark, NJ USA; 3University of Medicine and Dentistry of New Jersey, 150 Bergen street, Newark, NJ USA; 4UMDNJ-NJMS, Department of Neurosciences, 150 Bergen street, Newark, NJ USA;