Previous functional neuroimaging studies have not determined cortical areas of selective somatosensory processing of stimulus attributes or location. To address this, we studied 20 subjects trained in two tactile tasks. For both tasks, a set of domes with gratings was used. Gratings were delivered to the immobilized finger. For each trial, a grating was first applied distally with the bars/grooves parallel to the long axis of the finger. Subjects were either required to judge if the grating orientation (GOT) or stimulation site (location task (LOT) changed during a 2nd presentation. Subjects attended to either orientation or location while activations were measured using block design fMRI at 3T. Group performance was very similar for the GOT (74% correct responses) and LOT (74%). Similar activations for both tasks were seen in the primary and secondary somatosensory cortices. The intraparietal sulcus (IPS) was preferentially activated bilaterally in most subjects during the GOT. However, there were signifi...

The capacity to attend to task demands while viewing nontask-related emotional stimuli undergoes profound development during adolescence. However, researchers are only beginning to explore neurobiological correlates of this cognitive process. In the present investigation, 17 adolescents (9-17 years of age) and 17 adults (25-36 years of age) were scanned using event-related fMRI at 3T. Subjects viewed neutral and emotional faces (angry, fearful and happy) passively and also while attending to emotional and physical features. In the initial analysis, three main results emerged. (1) Adolescents showed greater amygdala and prefrontal cortex activation than adults during passive viewing of angry vs. neutral faces. (2) Both adults and adolescents engaged ventral lateral and dorsal prefrontal regions while attending to internal fear state during angry vs neutral face viewing. (3) Greater discriminant activation emerged in adults vs. adolescents within the contrast of internal fear rating to angry faces vs. physic...

A comprehensive characterization of sex differences in the brain is critical for improving our understanding of sex effects in health and disease. However, we still lack a complete understanding of such differences in developmental populations. Here we ...

The anterior limb of the internal capsule (ALIC) carries thalamic and brainstem fibers from prefrontal cortical regions that are associated with different aspects of emotion, motivation, cognition processing, and decision-making. This large fiber bundle is abnormal in several psychiatric illnesses and a major target for deep brain stimulation. Yet, we have very little information about where specific prefrontal fibers travel within the bundle. Using a combination of tracing studies and diffusion MRI in male nonhuman primates, as well as diffusion MRI in male and female human subjects, we segmented the human ALIC into five regions based on the positions of axons from different cortical regions within the capsule. Fractional anisotropy (FA) abnormalities in patients with bipolar disorder were detected when FA was averaged in the ALIC segment that carries ventrolateral prefrontal cortical connections. Together, the results set the stage for linking abnormalities within the ALIC to specific connections and dem...

Although gyral and sulcal patterns are highly heritable, and emerge in a tightly controlled sequence during development, very little is known about specific genetic contributions to abnormal gyrification or the resulting functional consequences. Williams syndrome (WS), a genetic disorder caused by hemizygous microdeletion on chromosome 7q11.23 and characterized by abnormal brain structure and striking cognitive (impairment in visuospatial construction) and behavioral (hypersocial/anxious) phenotypes, offers a unique opportunity to study these issues. We performed a detailed analysis of sulcal depth based on geometric cortical surface representations constructed from high-resolution magnetic resonance imaging scans acquired from participants with WS and from healthy controls who were matched for age, sex, and intelligence quotient, and compared between-group differences with those obtained from a voxel-based morphometry analysis. We found bilateral reductions in sulcal depth in the intraparietal/occipitopar...

Whether conventional gradient-echo (GE) blood oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) is able to map submillimeter-scale functional columns remains debatable mainly because of the spatially nonspecific large vessel contribution, poor sensitivity and reproducibility, and lack of independent evaluation. Furthermore, if the results from optical imaging of intrinsic signals are directly applicable, regions with the highest BOLD signals may indicate neurally inactive domains rather than active columns when multiple columns are activated. To examine these issues, we performed BOLD fMRI at a magnetic field of 9.4 tesla to map orientation-selective columns of isoflurane-anesthetized cats. We could not convincingly map orientation columns using conventional block-design stimulation and differential analysis method because of large fluctuations of signals. However, we successfully obtained GE BOLD iso-orientation maps with high reproducibility ( r = 0.74) using temporally enco...

It is currently estimated that over 35 million people worldwide have dementia, and with demographic trends of an aging global population this figure is expected to triple by 2050 ([Prince and Jackson, 2009][1]). As the leading cause of dementia, Alzheimer's disease (AD) is the source of much

Spinal cord injury (SCI) severity and recovery are influenced by complex pathological mechanisms, including demyelination/remyelination, glutamate excitotoxicity, scar formation, and inflammatory responses. The overall goal of this study is to develop a...

Working memory (WM) entails maintenance and manipulation of information in the absence of sensory input. This study investigated the trajectories and neural basis of these component processes of WM functions in aging. Longitudinal human functional magnetic resonance imaging (fMRI) data are presented from 136 older individuals (55–80 years) who were scanned at baseline and again 4 years later. We obtained evidence that age-related changes in parietal and frontal components of the WM core network are dissociable in terms of their role in maintenance of perceptual representations and further manipulation of this information, respectively. Individual difference analyses in performance subgroups showed that only prefrontal changes in fMRI activation were accompanied by changes in performance, but parietal brain activity was related to study dropout. We discuss the results in terms of possible neurobiological causes underlying separable aging-related declines in inferior parietal cortex and lateral prefrontal co...

In 1991, Milner et al. described a neurological patient, D.F., who was able to calibrate precise movements toward objects but unable to perceive their visual forms. Despite being able to discriminate basic visual properties (e.g., color, intensity), she was impaired in perceiving geometric shape