The neural systems controlling head movements are not well delineated in humans. It is not clear whether the ipsilateral or contralateral primary motor cortex is involved in turning the head right or left. Furthermore, the exact location of the neck motor area in the somatotopic organization of the motor homunculus is still debated and evidence for contributions from other brain regions in humans is scarce. Because currently available neuroimaging methods are not generally suitable for mapping brain activation patterns during head movements, we conducted fMRI scans during isometric tasks of the head. During isometric tasks, muscle contractions occur without an actual movement and they have been used to delineate patterns of brain activity related to movements of other body parts such as the hands. Healthy individuals were scanned during isometric head rotation or wrist extension. Isometric wrist extension was examined as a positive control and to establish the relative locations of head and hand regions in...

Memories vary in their durability even when encoding conditions apparently remain constant. We investigated whether, under these circumstances, memory durability is nonetheless associated with variation in the neural activity elicited during encoding. Event-related functional magnetic resonance imaging data were acquired while volunteers semantically classified visually presented words. Using the “remember/know” procedure, memory for one-half of the words was tested after 30 min and for the remaining half after 48 h. In several regions, including left hippocampus and left dorsal inferior frontal gyrus (IFG), activity at encoding differed depending on whether items were later recollected regardless of study-test delay. Delay-selective effects were also evident, however. Recollection after 48 h was associated with enhanced activity in bilateral ventral IFG, whereas recollection after 30 min was associated with greater fusiform activity. Thus, there is a relationship between the neural activity elicited by an...

Joseph Coyle is the chair of psychiatry and neuroscience at Harvard Medical School. In addition to his clinical research and patient care, he has extensive experience with rodent models of neuropsychiatric disorders to develop more effective treatments. During his junior year of college, he worked as an orderly in a psychiatric ward. When a friend's brother was admitted with schizophrenia, he became interested in studying psychiatry. He wanted to know more about how drugs affect the brain, so after receiving his degree from Johns Hopkins School of Medicine in 1969, he started doing scientific research in that area. Coyle joined Harvard as a faculty member in 1975. He continues to run a research lab alongside his medical practice.

The cerebral deposition of amyloid β-peptide, a central event in Alzheimer's disease (AD) pathogenesis, begins several years before the onset of clinical symptoms. Non-invasive detection of AD pathology at this initial stage would facilitate intervention and enhance treatment success. Here, we demonstrate the ability of high field strength MRI to detect regional brain volume reductions and ventricular enlargement in the PS-APP transgenic mouse model of AD more sensitively than histopathologic analysis by unbiased stereology. Moreover, the transverse relaxation time T2, an intrinsic MR parameter thought to reflect impaired cell physiology, was altered substantially in cortical regions containing β-amyloid but only slightly in cerebellum, which contains little β-amyloid. MR measures were also minimally altered in mice expressing mutant presenilin-1, which do not deposit β-amyloid, supporting the view that the MR abnormalities in PS-APP mice are partly related to amyloid β-peptide deposition. These results se...

Oxytocin is released in the maternal brain during breastfeeding and may help strengthen the mother–infant relationship. Here, we used functional magnetic resonance imaging to determine whether oxytocin modulates brain activity in postpartum day 4–8 dams receiving suckling stimulation. During imaging sessions, dams were exposed to pup suckling before and after administration of an oxytocin receptor antagonist. Another group of dams received oxytocin alone. Changes in brain activation in response to suckling closely matched that elicited by oxytocin administration. The overlapping brain areas included the olfactory system, nucleus accumbens, insular cortex, prefrontal cortex, ventral tegmental area, cortical amygdala, and several cortical and hypothalamic nuclei. Blockade of oxytocin receptors largely attenuated activation in these regions. The data suggest that oxytocin may strengthen mother–infant bond formation partly by acting through brain areas involved in regulating olfactory discrimination, emotions,...

Subjects were trained on a pursuit task in which the target trajectory was predictable only on the horizontal axis. Half of them were sleep deprived on the first post-training night ( n = 13). Three days later, functional magnetic resonance imaging revealed task-related increases in brain responses to the learned trajectory, as compared with a new trajectory. In the sleeping group ( n = 12) as compared with the sleep-deprived group, subjects' performance was improved, and their brain activity was greater in the superior temporal sulcus (STS). Increased functional connectivity was observed between the STS and the cerebellum and between the supplementary eye field and the frontal eye field. These differences indicate sleep-related plastic changes during motor skill learning in areas involved in smooth pursuit eye movements.

Intramedullary hemorrhage following traumatic spinal cord injury is consistently identified as an MRI feature associated with poorer neurological outcomes. The presence of hemorrhage is predictive of complete lesion, and it is associated with the most s...

Introduction: Magnetic resonance diffusion tensor imaging (DTI) is a widely accepted tool to study microstructural changes of white matter (WM) based on diffusion properties of the WM regions [1]. Previously, several groups have reported age-related WM ...

The aim of our study is to develop non invasive approaches to follow the fate, viability and migratory potential of progenitor cells following transplantation using super high resolution positron emission tomography (PET) and magnetic resonance imaging (MRI). We labeled rat subventricular zone (SVZ) progenitor cells and control cell line (PC12, pheochromocytoma cells) using 18F-fluorodeoxyglucose for PET studies and dendrimer-encapsulated super paramagnetic particles (Feredex) for MRI. These labeled cells were transplanted into the striatum or rostral migratory stream (RMS) of normal and 6-OHDA lesioned rats. During a period of 2 months, transplanted progenitor cells were easily identifiable with MRI. SVZ cells implanted into the RMS migrated after one week retention time toward olfactory bulb as seen with MRI. Slow migration of the cells implanted into the striatum was observed after 3 weeks. Histological analyses using Nissl, Iron stain, H&E and Fluoro-Jade, allowed delineation of the transplantation sit...

Schwann cell (SC) and olfactory ensheathing cell (OEC) transplantation has been shown experimentally to promote CNS axonal regeneration and remyelination. To advance this technique into a clinical setting it is important to be able to follow the fates of transplanted cells by noninvasive imaging. Previous studies, using complex modification processes to enable uptake of contrast agents, have shown that cells labeled in vitro with paramagnetic contrast agents transplanted into rodent CNS can be visualized using magnetic resonance imaging (MRI). Here we show that SCs and OECs efficiently internalize dextran-coated superparamagnetic iron oxide (SPIO) from the culture medium by fluid phase pinocytosis. After transplantation into focal areas of demyelination in adult rat spinal cord both transplanted SPIO-labeled SCs and OECs produce a signal reduction using T2-weighted MRI in anesthetized rats that persists for up to 4 weeks. Although signal reduction was discernable after transplantation of unlabelled cells, ...