Neurodevelopmental disorders, such as ASD and ADHD, affect males about 3-4 times more often than females. 16p11.2 hemideletion is a copy number variation that is highly associated with neurodevelopmental disorders. Previous work from our lab has shown t...

Athletic performances require quick and accurate perception and cognition of visual information. High-level athletes perform well in three-dimensional multiple object tracking (3D-MOT), which requires dynamic visual information processing, analogous to ...

Objective. Recent fMRI studies suggest that functional sequence variation of the COMT Val158Met and 5-HTTLPR polymorphisms are associated with responsiveness and resiliency to emotional unpleasant stimuli in healthy subjects. These polymorphisms are ass...

Although the spinal cord is the output station of the central motor system, little is known about the relationships between its functional activity and willed movement parameters in humans. We investigated here blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) signal changes in the cervical spinal cord during a simple finger-to-thumb opposition task in 13 right-handed volunteers, using a dedicated array of 16 receive-only surface coils on a 3 Tesla MRI system. In a first experiment, we found significant fMRI signal increases on both sides of the lower cervical spinal cord while subjects performed the motor task at a comfortable pace (∼0.5 Hz) using either hand. Both the spatial extent of movement-related clusters and peak signal increases were significantly higher on the side of the cord ipsilateral to the moving hand than on the contralateral side. Movement-related activity was consistently larger than signal fluctuations during rest. In a second experiment, we recorded spinal...

DOMS is a common physiological pain state following a bout of eccentric muscle contractions. We used magnetic resonance imaging (MRI) to study its cortical activation pattern. Eight healthy volunteers were subjected to a series of eccentric contractions in their right quadriceps muscle group. The left leg served as control. 48 hours later, subjects were psychophysically evaluated and found to experience intense soreness in the vastus lateralis, medialis and the iliotibial tract. The stimulus paradigm involved 5 cycles of alternate repeated voluntary contractions of the right sore and the left sound quadriceps muscle group (24 seconds each) with eleven interleaved resting conditions (18 seconds each). A light signal indicated the sequence of the protocol. A contrast analysis of the painful versus the non-painful stimulus disclosed the pain matrix as similar to that for cutaneous pain, however in addition with strong activations spanning large areas of the cingulate cortex from posterior anterior to posterio...

It has been shown that the frontal lobe undergoes marked structural and functional changes during adolescence. Previously, adolescents family history positive for substance abuse have been reported to show poorer performance on neuropsychological tests of frontal lobe function relative to family history negative counterparts. The objective of this study was to use functional magnetic resonance imaging (fMRI) to examine activation of the prefrontal cortex in adolescents at risk for substance abuse. Twenty-four adolescents underwent fMRI while completing the Stroop test. Functional images were acquired for the whole brain on a 1.5 Tesla GE MRI scanner. Preprocessing and statistical analyses were conducted in SPM99. Subjects were stratified into low (family history negative (FH-), n=10) or high risk (FH+, n=14) for substance abuse, based on family history data. To test whether family history status was associated with distinct patterns of frontal activation, the FH- and FH+ groups were subjected to two contra...

Acute treatment with minocycline (MINO) reduces infarct size in focal cerebral ischemia. However, long term effects of MINO on ischemic brain damage and behavioral outcome have not been previously reported. The objective of this study was to explore the effects of acute MINO treatment on motor performance and cognitive functions during a 2-month follow-up after focal cerebral ischemia in male Sprague-Dawley rats. Rats were subjected to 90 min middle cerebral artery occlusion (tMCAO) and treated with vehicle (Veh) or MINO starting 45 min after the occlusion and continued for 3 days. Total infarct volume was evaluated 14 days after tMCAO with T2- weighed magnetic resonance imaging (T2wt-MRI). Sensory-motor behavior and activity [neuroscore (NS), cylinder test (CT), Montoya’s staircase test (MT), beam traversing test (BT), open field (OF)] as well as cognitive functions [object recognition (OR), passive avoidance (PA)] were evaluated at different time points. Significant post-ischemic functional deficits in N...

Individual differences in amygdala activation have been related to individual differences in personality. This study evaluated the association between individual differences in the structure of the amygdala and the personality traits of extraversion (E) and neuroticism (N), using high-resolution magnetic resonance imaging (MRI). Forty-one healthy subjects completed personality questionnaires (NEO-PI) and were scanned on a 3T siemens Trio scanner with a sagittal 3 D MPRAGE sequence (T1 = 1100, TR = 2530, TE = 3.66, Flip Angle = 7 degrees, matrix = 256 x 256). Strucutral data were then examined for gray matter volume and density in the amygdala using voxel-based morphometry (VBM) analysis, using an optimized VBM protocol. A study-specific T1 brain template, and gray matter, white matter, and cerebrospinal fluid images were used for this procedure. The spatially normalized segments of the each subject’s gray matter images were modulated for volume analysis. The unmodulated images were used for density analysi...

Rehabilitation is the most effective to improve neurological deficits in stroke patients. To investigate physiology of rehabilitation, we developed a monkey model of chronic stroke, and then examined the effects of rehabilitation. Male rhesus monkeys were subjected, and right middle cerebral artery was occluded for 4 hr with an embolization coil inserted from the femoral artery to the MCA using endovascular technique, and then the MCA occlusion was reopened by removing the coil. Infarct volume was determined using magnetic resonance imaging (MRI) at 7 and 90 days after the MCA occlusion and by pathohistological observation at 90 days after. Neurological deficits (consciousness level, motor system, muscle coordination, and sensory system) were observed 1, 3, 5, 7, 14, 21, 30, 60, and 90 days after the MCA occlusion. One group (n=6) treated with rehabilitation started from 7 days, and then continued until 90 days after the MCA occlusion, and the other (n=5) was treated without rehabilitation. In rehabilitati...

O. Khan, M.R. Del Bigio* Department of Pathology, University of Manitoba Hydrocephalus is a common neurological condition characterized by obstruction of cerebrospinal fluid (CSF) flow leading to enlargement of CSF-containing ventricular cavities in the brain. The use of pharmacological drugs to reduce brain damage in immature (5 – 7 weeks) hydrocephalic rats have been investigated in our lab with various outcomes (Del Bigio 2002). Magnesium sulphate and nimodipine have shown promising results with improvements in behavioral outcomes and reduced damage in the white matter (Del Bigio 2001, Khan 2003). However, shunting delay is more likely to be a clinical problem in very premature infants. Hence our desire to study the effects of these agents in neonatal rats with brains more comparable to those of 24-26 week humans. Rats were injected with kaolin on postnatal day 1 and magnetic resonance imaging (MRI) was performed on day 7 to assess ventricle size. On postnatal day 7 osmotic mini pumps with MgSO4, MgCl2 ...