Directing attention to some acoustic features of a sound has been shown repeatedly to modulate the stimulus-induced neural responses. On the contrary, little is known about the neurophysiological impact of auditory attention when the auditory scene remains empty. We performed an experiment in which subjects had to detect a sound emerging from silence (the sound was detectable after different durations of silence). Two frontal activations (right dorsolateral prefrontal and inferior frontal) were found, regardless of the side where sound was searched for, consistent with the well established role of these regions in attentional control. The main result was that the superior temporal cortex showed activations contralateral to the side where sound was expected to be present. The area extended from the vicinity of Heschl's gyrus to the surrounding areas (planum temporale/anterior lateral areas). The effect consisted of both an increase in the response to a sound delivered after attention was directed to detect ...

Regional brain volume deficits are accompanied by a commensurate increase in the local volume of CSF. Thus, CSF may be considered an endogenous tracer for detecting regional brain volume deficits using MRI. In diffusion tensor imaging (DTI), affected brain areas show greater CSF partial volume effects and increased apparent diffusion coefficient (ADC). We propose a new method, ADC-based morphometry (ABM), for assessment of regional brain volume deficits using voxelwise analysis of ADC maps computed from DTI. We demonstrate this approach by its application to 15 patients with schizophrenia and 15 healthy controls. DTI and structural MRI were performed on all subjects. All 30 ADC maps were registered to a template in Talairach space by applying a nonlinear registration to their corresponding structural MRI volume. Following inter-subject registration of the ADC maps, a two-tailed independent samples t-test was applied at each voxel to determine the voxels at which the ADC values significantly differed betwee...

Isolated rapid eye movement (REM) sleep behavior disorder (iRBD) is a prodromal stage of Parkinsonism characterized by abnormal behaviors and loss of normal muscle atonia during REM sleep. Most iRBD subjects develop Parkinson’s disease (PD) or dementia ...

The cortical organization of language in bilinguals remains disputed. We studied 24 right-handed fluent bilinguals: 15 exposed to both Mandarin and English before the age of 6 years; and nine exposed to Mandarin in early childhood but English only after the age of 12 years. Blood oxygen level-dependent contrast functional magnetic resonance imaging was performed while subjects performed cued word generation in each language. Fixation was the control task. In both languages, activations were present in the prefrontal, temporal, and parietal regions, and the supplementary motor area. Activations in the prefrontal region were compared by (1) locating peak activations and (2) counting the number of voxels that exceeded a statistical threshold. Although there were differences in the magnitude of activation between the pair of languages, no subject showed significant differences in peak-location or hemispheric asymmetry of activations in the prefrontal language areas. Early and late bilinguals showed a similar p...

We are using manganese-enhanced Magnetic Resonance Imaging (ME-MRI) to visualize the brains of crayfish. Manganese, a paramagnetic contrast agent and calcium analog, can highlight specific brain areas that are active. Several vertebrate studies show that ME-MRI is directly sensitive to calcium-dependent neuronal activity and can also be used to trace neuronal connections within the brain. Moreover, due to the slow clearing rate of manganese from the stimulated region of the brain, ME-MRI allows the application of the contrast agent and the sensory stimulation to take place outside the magnet before the animal is imaged. Vertebrate studies using ME-MRI are complicated by the fact that manganese does not easily pass through the blood-brain barrier, which requires intravenous infusion of the contrast agent over a long period of time in combination with injection of a hyperosmolar agent. Furthermore, vertebrates are usually anesthetized during ME-MRI studies, which reduces brain activity and makes manganese a ...

The functional network within the brain has been investigated with resting state (rs-) connectivity analysis in human participants. Changes in network connectivity in the brain have been reported in patients with neuropsychiatric disorders such as demen...

The definitive diagnosis of Alzheimer's disease (AD) currently requires post-mortem examination. We present a novel method for the detection of amyloid β (Aβ) plaques by magnetic resonance micro-imaging (μMRI) using transgenic mouse models of AD. This method utilizes Aβ1-40 peptides, which are labeled with either gadolinium (Gd) or monocrystalline iron oxide nanoparticles (MION). When either of these ligands is injected in vivo systemically with mannitol to transiently open the blood-brain-barrier, we are able to image both ex vivo and in vivo the majority of Aβ plaques. No lesions are detected in the non-Tg mice injected with these ligands. Tg mice injected with Aβ not coupled to Gd or MION also showed no lesions. This μMRI approach can be used to monitor potential therapeutic amyloid clearance in AD model mice in vivo and with further development could be the basis for plaque detection in AD patients.

The Society for Neuroscience (SfN) will present four awards to leading researchers who have made significant contributions to the advancement of women in neuroscience and early-career researchers who have demonstrated great originality and creativity in their work.

Person identification is believed to be achieved through hierarchical processes, from the sensory processing of stimuli (e.g., faces and names) to the access of multimodal representations. From recent functional imaging studies it has been suggested tha...

Event-related functional magnetic resonance imaging was used to measure blood oxygenation level-dependent responses in 13 young healthy human volunteers during performance of a probabilistic reversal-learning task. The task allowed the separate investigation of the relearning of stimulus–reward associations and the reception of negative feedback. Significant signal change in the right ventrolateral prefrontal cortex was demonstrated on trials when subjects stopped responding to the previously relevant stimulus and shifted responding to the newly relevant stimulus. Significant signal change in the region of the ventral striatum was also observed on such reversal errors, from a region of interest analysis. The ventrolateral prefrontal cortex and ventral striatum were not significantly activated by the other, preceding reversal errors, or when subjects received negative feedback for correct responses. Moreover, the response on the final reversal error, before shifting, was not modulated by the number of prece...