Injection of manganese, a calcium analogue and paramagnetic tract-tracing agent, into the high vocal center (HVc) of starlings labeled within a few hours the nucleus robustus archistriatalis (RA) and area X as observed by in vivo magnetic resonance imaging (MRI). Structures highlighted by manganese accumulation assumed the expected tri-dimensional shape of RA and area X as identified by classical histological or neurochemical methods. The volume of these nuclei could be accurately calculated by segmentation of the areas highlighted by manganese. Besides confirming previously established volumetric sex differences, manganese uptake into these nuclei revealed new functional sex differences affecting manganese transport. A faster transport was observed in males than in females and different relative amounts of Mn2+ were transported to RA and area X in males as compared to females. In males, similar amounts of Mn2+ were transported from HVc to these two nuclei despite their different size but in females, twice...

The present study examined the effects of a selective inducible nitric oxide synthase (iNOS) inhibitor on neuronal cell survival and post-traumatic recovery in rats following a lateral fluid percussion injury. Aminoguanidine at the dosage of 100 mg/kg or normal saline was injected intraperitoneally into rats 2 hours before or 30 minutes after the head injury. Animals were sacrificed at 4h, 1, 3 and 7 days post-injury. Treatment with iNOS inhibitor aminoguanidine significantly reduced lesion volumes in rats after fluid percussion, as evaluated by high-resolution magnetic resonance imaging (MRI). Immunohistochemical analysis showed a marked induction of iNOS expression in macrophages in the subarachnoid space and cerebral ventricles ipsilateral to the injury in rats killed at 1-day. In parallel with the appearance of iNOS positive macrophages, apoptotic neurons were observed in the ipsilateral cerebral cortex by in situ terminal transferase d-UTP nick-end labelling (TUNEL). In rats receiving prophylactic or ...

Successful learning is often contingent on feedback. In instrumental conditioning, an animal or human learns to perform specific responses to obtain reward. Instrumental conditioning is often used by behavioral psychologists to train an animal (or human) to produce a desired behavior. Shaping involves reinforcing those behaviors, which in a stepwise manner are successively closer to the desired behavior until the desired behavior is reached. Here, we aimed to extend this traditional approach to directly shape neural activity instead of overt behavior. To achieve this, we scanned 22 human subjects with functional magnetic resonance imaging and performed image processing in parallel with acquisition. We delineated regions of interest (ROIs) in finger and toe motor/somatosensory regions and used an instrumental shaping procedure to induce a regionally specific increase in activity by providing an explicit monetary reward to reinforce neural activity in the target areas. After training, we found a significant ...

The diversity of the diprotodontids provides an excellent opportunity to study how a basic marsupial cortical plan has been modified for the needs of the mammals living in the different habitats. Very little is known about the connections of the cerebra...

Although neurodevelopmental in origin, autism spectrum disorders are not currently diagnosed by neuroanatomical metrics but rather by behavioral observation. Autistic people differ from other people in their social interactions, communication, movement, and the level to which they focus on interests

Goal-directed navigation is a complex behavioral capacity (Chersi & Burgess, 2015) and requires both a neural representation of the associative cue-location-memory as well as readout mechanisms of the representation during retrieval. Whereas representat...

Restricted, repetitive behavior is a prominent feature of a number of neurodevelopmental disorders and diagnostic for autism spectrum disorder (ASD). Our lab utilizes an inbred mouse strain (C58) that demonstrates robust repetitive motor behavior phenot...

The human brain is extraordinarily complex, and yet its origin is a simple tubular structure. Characterizing its anatomy at different stages of human fetal brain development not only aids in understanding this highly ordered process but also provides clues to detecting abnormalities caused by genetic or environmental factors. During the second trimester of human fetal development, neural structures in the brain undergo significant morphological changes. Diffusion tensor imaging (DTI), a novel method of magnetic resonance imaging, is capable of delineating anatomical components with high contrast and revealing structures at the microscopic level. In this study, high-resolution and high-signal-to-noise-ratio DTI data of fixed tissues of second-trimester human fetal brains were acquired and analyzed. DTI color maps and tractography revealed that important white matter tracts, such as the corpus callosum and uncinate and inferior longitudinal fasciculi, become apparent during this period. Three-dimensional rec...

Research in recent decades has suggested the existence of a dedicated brain network devoted to the organization and execution of grasping, one of the most important and skilled movements of primates. Grasping an object requires the transformation of intrinsic object properties such as size, orientation, and shape into an appropriate motor scheme shaping the hand. Although electrophysiological recordings in the monkey model have proven invaluable for gaining insights into the neuronal substrate underlying this complex behavior, knowledge concerning the existence and organization of a similar system in the human brain is derived mainly from imaging studies. Here, we present for the first time functional magnetic resonance imaging (fMRI) of brain activity while macaque monkeys performed reaching and grasping movements in a 3 tesla MR scanner. Grasping in the dark (compared with reaching) yielded significant activations in anterior intraparietal area and ventral premotor area F5, in addition to area PFG in the...

Previous studies using the serial prediction task (SPT) have shown that attending to the locations of objects activates the dorsal part of premotor cortex more than attending to the sizes of objects. The opposite holds for the ventral part of the premotor cortex. The present study used functional magnetic resonance imaging to investigate whether the learning of arbitrary stimulus-response mappings influences this functional dissociation. One experimental group learned to assign stimuli to response buttons based on stimulus size; another group did so based on stimulus location. More specifically, one-half of the participants in both experimental groups learned to assign stimuli to finger movements of their right hand, whereas the other half assigned stimuli to finger movements of their left hand. During scanning, all participants performed both size SPT and location SPT. Thus, we investigated the effects of the attended stimulus property (size or location), the motor effector assigned to it (fingers of left...