The human brain thalami play essential roles in integrating cognitive, sensory, and motor functions. In multiple sclerosis (MS), quantitative magnetic resonance imaging (qMRI) measurements of the thalami provide important biomarkers of disease progression, but late development and aging confound the interpretation of data collected from patients over a wide age range. Thalamic tissue volume loss due to natural aging and its interplay with lesion-driven pathology has not been investigated previously. In this work, we used standardized thalamic volumetry combined with diffusion tensor imaging, T2 relaxometry, and lesion mapping on large cohorts of controls ( N = 255, age range = 6.2–69.1 years) and MS patients ( N = 109, age range = 20.8–68.5 years) to demonstrate early age- and lesion-independent thalamic neurodegeneration.

We used the combination of functional magnetic resonance imaging and event-related potentials to decompose the processing stages (mental chronometry) of working memory retrieval. Our results reveal an early transient activation of inferotemporal cortex, which was accompanied by the onset of a sustained activation of posterior parietal cortex. We furthermore observed late transient responses in ventrolateral prefrontal cortex and late sustained activity in medial frontal and premotor areas. We propose that these neural signatures reflect the cognitive stages of task processing, perceptual evaluation (inferotemporal cortex), storage buffer operations (posterior parietal cortex), active retrieval (ventrolateral prefrontal cortex), and action selection (medial frontal and premotor cortex). This is also supported by their differential temporal contribution to specific subcomponents of the P300 cognitive potential.

Using functional magnetic resonance imaging, we estimated neural activity in twins to study genetic influences on the cortical response to categories of visual stimuli (faces, places, and pseudowords) that are known to elicit distinct patterns of activity in ventral visual cortex. The neural activity patterns in monozygotic twins were significantly more similar than in dizygotic twins for the face and place stimuli, but there was no effect of zygosity for pseudowords (or chairs, a control category). These results demonstrate that genetics play a significant role in determining the cortical response to faces and places, but play a significantly smaller role (if any) in the response to orthographic stimuli.

Repeated stimulus presentation (priming) is generally associated with a reduction in neuronal firing, macroscopically mirrored by a decrease in oscillatory electrophysiological markers as well as reduced hemodynamic responses. However, these repetition effects seem to be dependent on stimulus familiarity. We investigate the spatiotemporal correlates of repetition priming in cortical word-recognition networks and their modulation by stimulus familiarity (i.e., words vs pseudowords). Event-related functional magnetic resonance imaging results show reduced activation for repeated words in occipitotemporal cortical regions. Electroencephalogram recordings reveal a significant reduction of induced gamma-band responses (GBRs) between 200 and 350 ms after stimulus onset, accompanied by a decrease in phase synchrony between electrode positions. Pseudoword repetition, in contrast, leads to an activation increase in the same areas, to increased GBRs, and to an increased phase coupling. This spatiotemporal repetition...

Brain research in animal models, and specifically in mice, provides powerful techniques for precise molecular and cellular manipulations. In contrast, human brain research, which is usually limited to non-invasive imaging methods, focuses on brain-wide ...

Up to 250,000 veterans of the 1991 Gulf War suffer from illness (GWI) characterized by multiple deficits in cognitive, affective, sensory, motor and pain domains as assessed through self-reported symptoms. In this study, we examined a large group of 60 ...

Several investigators have used motor challenges to study brain function in patients with schizophrenia. We were interested in learning more about the functional brain abnormalities that might underlie the motor difficulties so we performed a meta-analytic review of the functional magnetic imaging (fMRI) literature pertaining to motor tasks. We wanted to answer two questions. First, what is the magnitude of the difference in brain activity between patients and controls in tasks placing demands on primary sensorimotor cortex? Second, is there a reversal of normal primary sensorimotor cortical laterality in patients with schizophrenia? Six studies challenging the motor systems of predominantly right-handed subjects with finger tapping/sequencing tasks provided sufficient fMRI intensity information from which effect sizes (expressed as d-values and interpreted as standard deviation units) could be extracted. From these, we estimated a population effect size for the sensorimotor cortices of each hemisphere by ...

Advances in functional imaging have allowed to investigate neuroanatomical correlates of sexual arousal (SA) in a noninvasive manner. Objective: To identify the neuroanatomical correlates of SA of healthy men presented with sexually stimulating photographs. Methods: in ten healthy men, functional magnetic resonance imaging was used to study brain responses to the presentation of highly arousing and of nonsexually arousing photographs representing women. Immediately after the fMRI run, rating scales were presented to subjects to assess perceived SA. Volumetric penile plethysmography was performed during scans. Results: both rating scales and plethysmography demonstrated SA in response to sexually stimulating photographs. Regions that were more activated in response to the sexually arousing than to the neutral photographs included bilaterally the fusiform gyri, the inferior occipital gyri, the superior and the inferior parietal lobules, the thalami, the right precentral gyrus, the left caudate body, the righ...

Free-floating implantable neural interfaces are an emerging powerful paradigm for mapping and modulation of brain activity. Wirelessly powered microdevices are being miniaturized to improve safety, longevity, and spatial resolution in a wide range of bi...

It has been shown recently that a significant portion of brain electrical field potentials consists of scale-free dynamics. These scale-free brain dynamics contain complex spatiotemporal structures and are modulated by task performance. Here we show that the fMRI signal recorded from the human brain is also scale free; its power-law exponent differentiates between brain networks and correlates with fMRI signal variance and brain glucose metabolism. Importantly, in parallel to brain electrical field potentials, the variance and power-law exponent of the fMRI signal decrease during task activation, suggesting that the signal contains more long-range memory during rest and conversely is more efficient at online information processing during task. Remarkably, similar changes also occurred in task-deactivated brain regions, revealing the presence of an optimal dynamic range in the fMRI signal. The scale-free properties of the fMRI signal and brain electrical field potentials bespeak their respective stationarit...