Transcranial direct current stimulation (tDCS) is a promising novel intervention for major depression (MD). Yet neurobiological determinants of tDCS response are still to be investigated. In The Escitalopram versus Electric Current Therapy for Treating ...

Functional magnetic resonance imaging (fMRI) is among the foremost methods for mapping human brain function but provides only an indirect measure of underlying neural activity. Recent findings suggest that the neurophysiological correlates of the fMRI blood oxygenation level-dependent (BOLD) signal might be regionally specific. We examined the neurophysiological correlates of the fMRI BOLD signal in the hippocampus and neocortex, where differences in neural architecture might result in a different relationship between the respective signals. Fifteen human neurosurgical patients (10 female, 5 male) implanted with depth electrodes performed a verbal free recall task while electrophysiological activity was recorded simultaneously from hippocampal and neocortical sites. The same patients subsequently performed a similar version of the task during a later fMRI session. Subsequent memory effects (SMEs) were computed for both imaging modalities as patterns of encoding-related brain activity predictive of later fr...

Syncopation (movement antiphase to a pacing stimulus) has proven to engage a more distributed network of cortical and subcortical structures than does synchronization (movement in-phase with the same stimulus). In addition, the networks recruited may be modality specific. For example, left superior temporal gyrus (STG) activity occurs during auditory-motor, but not visuomotor synchronization. The present study used FMRI and behavioral measures to assess whether aspects of the neural networks for synchronization and syncopation are modality specific. A standard block design allowed us to measure levels of the BOLD response from six subjects while they syncopated or synchronized (right hand) with an auditory or visual pacer at 1.33 Hz. Behavioral results confirmed that syncopation is more variable than synchronization. FMRI revealed modality specific activation that nevertheless indexed the coordination pattern: activity in occipital cortex was greater during visuomotor syncopation than synchronization. The ...

It is believed that the olfactory bulb (OB) codes the olfactory information from the periphery into a spatial activity pattern in the glomerular layer. Here we used high-resolution fMRI to examine how the structural features of odorants are represented spatially in the entire rat OB. The whole OB mapping results showed that the areas activated by the three structurally related odorants, iso-amyl acetate, ethyl acetate, and benzyl acetate distributed broadly across the entire OB. Many of the activated regions are shared by all three odorants. The patterns are more similar between the two aliphatic acetates than between the aliphatic and aromatic acetates. Statistical analysis showed that the similarity between the patterns of iso-amyl acetate in different exposures is significantly higher than between the patterns of iso-amyl acetate and ethyl acetate. One major cluster, covering nearly 60 glomeruli (thresholded at p < 0.01) at the latero-ventral region in the anterior end of the OB, was activated by the al...

The human cerebellum contains approximately half of all the neurons within the cerebrum, yet most experimental work in human neuroscience over the last century has focused exclusively on the structure and functions of the forebrain. The cerebellum has an undisputed role in a range of motor functions ([Thach et al., 1992][1]), but its potential contributions to sensory and cognitive processes are widely debated ([Stoodley and Schmahmann, 2009][2]). Here we used functional magnetic resonance imaging to test the hypothesis that the human cerebellum is involved in the acquisition of auditory and visual sensory data. We monitored neural activity within the cerebellum while participants engaged in a task that required them to discriminate the direction of a visual or auditory motion signal in noise. We identified a distinct set of cerebellar regions that were differentially activated for visual stimuli (vermal lobule VI and right-hemispheric lobule X) and auditory stimuli (right-hemispheric lobules VIIIA and VII...

The ability to learn novel skills throughout our lifetime is known to be mediated by structural changes in the brain. However, the nature of the structural changes, and the spatiotemporal dynamics of such changes during the course of learning are unclea...

We tested for cortical shape abnormalities using surface-based morphometry across a range of autism spectrum disorders (7.5–18 years of age). We generated sulcal depth maps from structural magnetic resonance imaging data and compared typically developing controls to three autism spectrum disorder subgroups: low-functioning autism, high-functioning autism, and Asperger's syndrome. The low-functioning autism group had a prominent shape abnormality centered on the pars opercularis of the inferior frontal gyrus that was associated with a sulcal depth difference in the anterior insula and frontal operculum. The high-functioning autism group had bilateral shape abnormalities similar to the low-functioning group, but smaller in size and centered more posteriorly, in and near the parietal operculum and ventral postcentral gyrus. Individuals with Asperger's syndrome had bilateral abnormalities in the intraparietal sulcus that correlated with age, intelligence quotient, and Autism Diagnostic Interview-Revised social...

Neuropsychological investigations of patients with Parkinson's disease, schizophrenia, or attention deficit disorder converge with psychopharmacological studies in animals and healthy volunteers to implicate dopamine (DA) pathways in timing. In parallel, single-cell recording and functional neuroimaging studies have highlighted the importance of basal ganglia, prefrontal cortex, and supplementary motor area (SMA) for timing. In a placebo-controlled, within-subject design, we combined event-related functional magnetic resonance imaging with a DA manipulation (acute phenylalanine/tyrosine depletion; APTD) in healthy volunteers to pinpoint the neuroanatomical and functional substrates of the DA modulation of timing. Behaviorally, APTD selectively impaired accuracy of perceptual timing, with no effect on performance of a color-control task matched for difficulty, working memory (WM), and attentional demands. Neurally, APTD attenuated timing-specific activity in the putamen and SMA. Notably, APTD-induced decrea...

In the past years, claims of cognitive and attentional function of the cerebellum have first been raised but were later refuted. One reason for this controversy might be that attentional deficits only occur when specific cerebellar structures are affected. To further elucidate this matter and to determine which cerebellar regions might be involved in deficits of covert visual attention, we used new brain imaging tools of lesion mapping that allow a direct comparison with control patients. A total of 26 patients with unilateral right-sided cerebellar infarcts were tested on a covert visual attention task. Eight (31%) patients showed markedly slowed responses, especially in trials in which an invalid cue necessitated reorienting of the focus of attention for target detection. Compared with the 18 patients who performed within the range of healthy control subjects, only the impaired patients had lesions of cerebellar vermal structures such as the pyramid. We suggest that these midcerebellar regions are indire...

Young healthy participants spontaneously use different strategies in a virtual radial maze, an adaptation of a task typically used with rodents. Functional magnetic resonance imaging confirmed previously that people who used spatial memory strategies showed increased activity in the hippocampus, whereas response strategies were associated with activity in the caudate nucleus. Here, voxel based morphometry was used to identify brain regions covarying with the navigational strategies used by individuals. Results showed that spatial learners had significantly more gray matter in the hippocampus and less gray matter in the caudate nucleus compared with response learners. Furthermore, the gray matter in the hippocampus was negatively correlated to the gray matter in the caudate nucleus, suggesting a competitive interaction between these two brain areas. In a second analysis, the gray matter of regions known to be anatomically connected to the hippocampus, such as the amygdala, parahippocampal, perirhinal, entor...