Objective: Evidence suggests that inflammatory processes may cause neurodegeneration in Alzheimer's disease (AD). This project assessed a new diffusion-weighted magnetic resonance imaging method, DIFRAD-FSE, in identifying early markers of AD in individuals at risk. DIFRAD can be used to evaluate inflammation and is useful for assessing white matter (WM) integrity. Methods: Subjects were 32 adults (66-87 yrs): 16 with risk for AD and 16 without. Risk was defined as presence of the APOE e4 allele, and/or by presence of a 1st order relative with probable AD. A neuropsychological test battery yielded 2 composite scores for memory and executive function. Using a 3T scanner, 14 coronal sections were acquired from the medial temporal lobe (MTL). Fractional Anisotropy (FA) and Average Diffusion Coefficients (ADC) were determined for: splenium of the corpus callosum, WM of the temporal stem (TStem), and hippocampus (HC). We predicted a drop in brain integrity (increased ADC and decreased FA) in subjects with risk....

In recent years, functional neuroimaging has disclosed a network of cortical areas in the basal temporal lobe that selectively respond to visual scenes, including the parahippocampal place area (PPA). Beyond the observation that lesions involving the PPA cause topographic disorientation, there is little causal evidence linking neural activity in that area to the perception of places. Here, we combined functional magnetic resonance imaging (fMRI) and intracranial EEG (iEEG) recordings to delineate place-selective cortex in a patient implanted with stereo-EEG electrodes for presurgical evaluation of drug-resistant epilepsy. Bipolar direct electrical stimulation of a cortical area in the collateral sulcus and medial fusiform gyrus, which was place-selective according to both fMRI and iEEG, induced a topographic visual hallucination: the patient described seeing indoor and outdoor scenes that included views of the neighborhood he lives in. By contrast, stimulating the more lateral aspect of the basal temporal ...

For a more accurate determination of a thalamic lesion or target for neurosurgical intervention as well as for a better interpretation of functional MRIs and PET studies, we are currently preparing a 3-D atlas of the human thalamus. For the present study, 5 brains have been used from human subjects without known neurological or psychiatric deficits. Postmortem MRIs were taken before brains were paraffin embedded, cut in the frontal plane at a thickness of 20 μm and stained with Gallyas modification for neuronal cell bodies. Cytoarchitectonic criteria, in particular cell density, cell size and shape, as well as arrangement of cells, were used to delineate the various thalamic nuclei in sections taken at an interval of about 1 mm. The mammillary bodies, mammillothalamic tract, habenula, subthalamic nucleus, and nucleus ruber were included in the 3-D atlas as additional landmarks. The Gallyas-stained sections with the delineated cell masses were superimposed on the postmortem 3-D MRIs after local affine trans...

Human episodic memory is supported by networks of white matter tracts that connect frontal, temporal, and parietal regions. Degradation of white matter microstructure is increasingly recognized as a general mechanism of cognitive deterioration with aging. However, atrophy of gray matter regions also occurs and, to date, the potential role of specific white matter connections has been largely ignored. Changes to frontotemporal tracts may be important for the decline of episodic memory; while frontotemporal cooperation is known to be critical, the precise pathways of interaction are unknown. Diffusion-weighted MRI tractography was used to reconstruct three candidate fasciculi known to link components of memory networks: the fornix, the parahippocampal cingulum, and the uncinate fasciculus. Age-related changes in the microstructure of these tracts were investigated in 40 healthy older adults between the ages of 53 and 93 years. The relationships between aging, microstructure, and episodic memory were assessed...

The subjective experience of one's environment is constructed by interactions among sensory, cognitive, and affective processes. For centuries, meditation has been thought to influence such processes by enabling a nonevaluative representation of sensory events. To better understand how meditation influences the sensory experience, we used arterial spin labeling functional magnetic resonance imaging to assess the neural mechanisms by which mindfulness meditation influences pain in healthy human participants. After 4 d of mindfulness meditation training, meditating in the presence of noxious stimulation significantly reduced pain unpleasantness by 57% and pain intensity ratings by 40% when compared to rest. A two-factor repeated-measures ANOVA was used to identify interactions between meditation and pain-related brain activation. Meditation reduced pain-related activation of the contralateral primary somatosensory cortex. Multiple regression analysis was used to identify brain regions associated with individ...

Methamphetamine is a popular addictive drug whose use is associated with multiple neuropsychiatric adverse events and toxic to the dopaminergic and serotonergic systems of the brain. Methamphetamine-induced neuropathology is associated with increased expression of microglial cells that are thought to participate in either pro-toxic or protective mechanisms in the brain. Although reactive microgliosis has been observed in animal models of methamphetamine neurotoxicity, no study has reported on the status of microglial activation in human methamphetamine abusers. The present study reports on 12 abstinent methamphetamine abusers and 12 age-, gender-, and education-matched control subjects who underwent positron emission tomography using a radiotracer for activated microglia, [11C]( R )-(1-[2-chlorophenyl]- N -methyl -N- [1-methylpropyl]-3-isoquinoline carboxamide) ([11C]( R )-PK11195). Compartment analysis was used to estimate quantitative levels of binding potentials of [11C]( R )-PK11195 in brain regions wi...

Well established unilateral 6-hydroxy dopamine (6-OHDA) lesion in nigrostriatal pathway is widely used rodent model for Parkinson’s Disease (PD). The destruction of dopaminergic cells accounts for robust and permanent changes in behavioral and biomarker...

Moll, J., Weingartner, J. H., Bado, P., Basilio, R., Sato, J. R., Melo, B. R., et al. (2014). Voluntary enhancement of neural signatures of affiliative emotion using fMRI neurofeedback. PLoS ONE 9:e97343. doi: 10.1371/journal.pone.0097343

Understanding the anatomy of the human olfactory tracts is important to understanding their function in health and disease. This is especially important in cases of neurodegenerative disease, such as Alzheimer’s and Parkinson’s diseases, where olfactory...

Traumatic brain injury (TBI) produces life-long disabilities including anxiety, balance and cognitive impairments. Our objective was to perform longitudinal (acute to chronic) in-vivo evaluation of TBI-induced diffuse axonal injury (DAI), microbleeds, a...