Tourette syndrome (TS) is a continuous lifelong condition that is highly prevalent and socially embarrassing. Although motor and vocal tics usually wane by the late teenage years, some individuals require medical or behavioral interventions. However, th...

We examined heterozygous transgenic (Tg) mice that overexpress V717F amyloid precursor protein (APP) for behavioral learning with eyeblink conditioning, and for hippocampal volume with magnetic resonance imaging (MRI). Mice (6 or 10m of age) were conditioned to blink by pairing a 350 ms flash of light with a 100 ms coterminating periorbital shock. A significant increase in eyelid EMG activity prior to the shock defined a conditioned response (CR). Mice that exhibited 7 CRs within any block of 10 consecutive trials were considered learners. Our results indicate that a significant proportion of transgenic mice were impaired relative to age-matched wild type (WT) controls. While 75% of WT mice learned by day 6 (90% by day 12), only 20% of Tg mice learned by day 6 (30% by day 12). The same mice were examined with MRI 4 months after behavioral training. T2-weighted spin echo images (62.5 x 125 x 500 µm) were taken from anesthetized mice using a 9.4T vertical bore magnet. The number of pixels comprising the hipp...

Background and Purpose: Severe perinatal aphyxia is an important cause of brain injury in the newborn infant. We examined if the early events after hypoxic ischemia (HI) in the 7-day-old mouse brain detected by magnetic resonance imaging (MRI) were related to and the long-term functional effects assessed in the same animals at 4 weeks of age. Methods: Hypoxic ischemia was induced in 7-day-old CD1 mice by exposure to 8% oxygen for 30 minutes after occlusion of the left common carotid artery. The resulting unilateral focal lesion was evaluated in vivo by MRI (T2 maps, ADC maps) at 3, 6, 24 hours and 5 days after hypoxia. Locomotion and sensorimotor function were analysed after 3 weeks. After 4 weeks morphological evaluation was performed on cresyl violet stained brain slices. Results: A decrease in ADC-values in cortex on the affected side was found at 3 hours after reperfusion. A significant increase in T2-values was seen after 6h to 5 days. Maximal size of the lesion was attained at 3-6 hours after reperfu...

The rhesus monkey brain undergoes age-related changes after 25 years of age, such as the appearance of amyloid plaques. However, the effect of age on brain volume is more controversial, especially in light of reports of stability of brain weight and neuron number. To address this issue 27 animals (7-37 years old) were examined by magnetic resonance imaging (MRI) between the Oregon and Wisconsin Regional Primate Research Centers. With numerical emphasis on older animals (18 of the 27 were 25 years of age or older), brains were imaged using multi-echo and 3D-SPGR protocols on 1.5 Tesla Signa scanners. Image analysis revealed a progressive age-related increase in cerebrospinal fluid, with a concomitant decrease in brain volume in monkeys after 25 years of age. This was visualized as a dilation of ventricular space throughout the brains and measured in a subset of animals. In addition, T2-weighed MRI scans revealed a progressive decrease in signal intensity over a larger volume in the globus pallidus and subst...

Correction: In the “Table of Contents” of the September 9, 2009 issue, there was an error in the “cover legend.” The first three sentences should read: “Reconstruction of human cortical surface in the FreeSurfer software. The reconstruction is based on magnetic resonance imaging anatomical

The purpose of this study was to investigate the volumetric development of medial temporal lobe structures in rhesus macaques using non-invasive magnetic resonance imaging (MRI) techniques. Four infant macaques (2 males, 2 females) were scanned in the coronal plane using a Fast Spin Echo Inversion Recovery protocol at 3-4 and 6 months of age. Three adult males (3 years old) were also scanned using identical procedures. We began our analysis by measuring the volume of the hippocampal formation (HF) using the Image J software. Surface area of the left and right HF were obtained from each image where the HF could be seen and were ultimately combined with image thickness (1.5 mm) to calculate the total HF volume for each subject. Data were analyzed using repeated measures ANCOVAs to adjust for total cerebral volume (3-4 months vs. 6 months comparison) or one-way ANOVAs (6 months vs. 3 years). The left and right HF volume did not differ at any age studied. However, the HF volume increased between 3-4 months and...

Amnestic Alzheimer's disease (aAD) is defined by early atrophy of the medial temporal lobes (MTL) before spreading to neocortex. Following early memory difficulty, patients show impairments in other cognitive domains. In contrast, atypical Alzheimer's d...

Reversible inactivations using GABA agonists like muscimol are an effective tool in causally exploring the functional roles of particular brain regions in complex behavioral tasks. However, targeting deep brain structures in the primate brain for inacti...

Functional magnetic resonance imaging (fMRI) combined with population receptive field (pRF) mapping allows for associating positions on the visual cortex to areas on the visual field. Apart from applications in healthy subjects, this method can also be used to examine dysfunctions in patients suffering from partial visual field losses. While such objective measurement of visual deficits (scotoma) is of great importance for, e.g., longitudinal studies addressing treatment effects, it requires a thorough assessment of accuracy and reproducibility of the results obtained. In this study, we quantified the reproducibility of pRF mapping results within and across sessions in case of central visual field loss in a group of 15 human subjects. We simulated scotoma by masking a central area of 2° radius from stimulation to establish ground-truth conditions. This study was performed on a 7 T ultra-high field MRI scanner for increased sensitivity. We found excellent intra- and intersession reproducibility for the pRF ...

Sex differences in the progression of Alzheimer’s disease (AD) in APOE4 carriers is eminent in the early stages. Early changes in white matter microstructure and alteration in regional brain volumes can be indicative of neurodegeneration during disease ...