bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cannabis and driving: A new perspective
Authors: O'Kane Carl J , Tutt Douglas C , Bauer Lyndon A 
Published: December 2004

AbstractCannabis and driving is an emerging injury‐prevention concern. The incidence of driving while affected by cannabis is rising in parallel with increased cannabis use in the community. Younger drivers are at particular risk. Improvements in research methodology, technology and laboratory testing methods have occurred in the last 10 years. These cast doubt on earlier results and conclusions. Studies now show that cannabis has a significant impairing effect on driving when used alone and that this effect is exaggerated when combined with alcohol. Of particular concern is the presence of cannabis as the sole psychoactive drug in an increasing number of road fatalities and the lack of any structural response to this problem. A review of testing methods, laboratory and real driving studies, and recent epidemiological studies is presented. Suggestions for methods of further data collection and future public policy are made.
Enhancing cognitive performance with repetitive transcranial magnetic stimulation at human individual alpha frequency
Authors: Klimesch Wolfgang , Sauseng Paul , Gerloff Christian 
Published: December 2004

AbstractWe applied rapid‐rate repetitive transcranial magnetic stimulation (rTMS) at individual alpha frequency (IAF) to improve cognitive performance by influencing the dynamics of alpha desynchronization. Previous research indicates that a large upper alpha power in a reference interval preceding a task is related to both large suppression of upper alpha power during the task and good performance. Here, we tested the hypothesis that rTMS at individual upper alpha frequency (IAF + 1 Hz) can enhance alpha power in the reference interval, and can thus improve task performance. Repetitive TMS was delivered to the mesial frontal (Fz) and right parietal (P6) cortex, and as sham condition with 90°‐tilted coil (P6 position). The behavioural effect was assessed in a mental rotation task. Further control conditions were rTMS at a lower IAF (IAF − 3 Hz) and at 20 Hz. The results indicate that rTMS at IAF + 1 Hz can enhance task performance and, concomitantly, the extent of task‐related alpha desynchronization. This provides further evidence for the functional relevance of oscillatory neuronal activity in the alpha band for the implementation of cognitive performance.
Rhinal–hippocampal theta coherence during declarative memory formation: interaction with gamma synchronization?
Authors: Fell Juergen , Klaver Peter , Elfadil Hakim , Schaller Carlo , Elger Christian E. , Fernández Guillén 
Published: December 2004

AbstractThe hippocampus and the rhinal cortex, two substructures of the medial temporal lobe, together play a crucial role in human declarative memory formation. To investigate in detail the mechanism connecting these two structures transiently during memory formation we recorded depth EEG in epilepsy patients from within the hippocampus and the rhinal cortex. During this recording, patients performed a single‐trial word list‐learning paradigm with a free recall memory test following a distraction task. Rhinal–hippocampal EEG coherence and spectral power at both locations in the time interval up to 2 s after onset of word presentation were analysed in the frequency range 1–19 Hz. Successful as opposed to unsuccessful memory formation was associated with a general rhinal–hippocampal coherence enhancement, but without alterations in spectral power. Coherence increases in the theta range were correlated with the previously reported memory‐related changes in rhinal–hippocampal gamma phase synchronization. This correlation may suggest an interaction of the two mechanisms during declarative memory formation. While theta coherence might be associated with slowly modulated coupling related to an encoding state, rhinal–hippocampal gamma synchronization may be more closely related to actual memory processes by enabling fast coupling and decoupling of the two structures.
Working memory controls involuntary attention switching: evidence from an auditory distraction paradigm
Authors: Berti Stefan , Schröger Erich 
Published: December 2004

AbstractOne function of working memory is to protect current mental processes against interference. In contrast, to be able to react flexibly on unpredictable environmental changes working memory should not totally be encapsulated from processing task unrelated information; that is, it should remain distractible. By manipulating the task load of the primary task in an auditory distraction paradigm we investigated how these opposing functions are coordinated by working memory. The behavioural results show that distraction effects were still present but reduced markedly with higher task demands. This suggests that working memory exerts some control over involuntary attention. In addition, event‐related brain potentials related to the different processing stages reveal that the preattentive change detection system underlying distraction was not modulated by task demand whereas distraction per se was. The present data suggest that working memory is able to coordinate the maintenance of distractibility and the focus on the task at hand.
The expression of genes encoding visual components is regulated by a circadian clock, light environment and age in the honeybee (Apis mellifera)
Authors: Sasagawa Hiromi , Narita Ryo , Kitagawa Yasuo , Kadowaki Tatsuhiko 
Published: December 2004

AbstractThe honeybee, Apis mellifera, has been used as a model to study the development of the visual system and adult bee behaviour. However, the regulation of the levels of visual component genes has never been addressed in this organism. We isolated honeybee cDNAs encoding green‐sensitive opsin and visual arrestin and then measured their mRNA levels in honeybee workers. Both mRNAs fluctuate on a daily cycle that depends on a pacemaker that functions separately from the pacemaker which controls rhythmic locomotor activity. The cycling‐patterns of opsin and arrestin mRNAs are different from each other and are modified by light. Furthermore, light exposure can increase the absolute levels of both mRNAs and the arrestin mRNA level is also dependent on age. Consistent with these results, both mRNA levels are higher in foragers than in in‐hive bees under natural conditions. This study thus shows that the expression of genes encoding visual components is regulated by multiple factors and is adjusted to the honeybees' need for vision during the day, and throughout their lives. Comparison of data obtained with honeybees and other organisms indicates that there is a link between the regulation of phototransduction components and vision‐related animal behaviour.
The essential role of Broca's area in imitation
Authors: Heiser Marc , Iacoboni Marco , Maeda Fumiko , Marcus Jake , Mazziotta John C. 
Published: December 2004

AbstractThe posterior sector of Broca's area (Brodmann area 44), a brain region critical for language, may have evolved from neurons active during observation and execution of manual movements. Imaging studies showing increased Broca's activity during execution, imagination, imitation and observation of hand movements support this hypothesis. Increased Broca's activity in motor task, however, may simply be due to inner speech. To test whether Broca's area is essential to imitation, we used repetitive transcranial magnetic stimulation (rTMS), which is known to transiently disrupt functions in stimulated areas. Subjects imitated finger key presses (imitation) or executed finger key presses in response to spatial cues (control task). While performing the tasks, subjects received rTMS over the left and right pars opercularis of the inferior frontal gyrus (where Brodmann area 44 is probabilistically located) and over the occipital cortex. There was significant impairment in imitation, but not in the control task, during rTMS over left and right pars opercularis compared to rTMS over the occipital cortex. This suggests that Broca's area is a premotor region essential to finger movement imitation.
Auditory sensory memory disorder in dyslexic adults as indexed by the mismatch negativity
Authors: Kujala T. , Belitz S. , Tervaniemi M. , Näätänen R. 
Published: December 2004

AbstractDeficient temporal discrimination and vulnerability to masking effects caused by rapidly succeeding or simultaneous sounds might be one factor underlying the phonological difficulties in dyslexia. We evaluated cortical auditory discrimination in dyslexia by recording the mismatch negativity (MMN) for a simple pitch change, for an order reversal of tone pairs, and for tone‐pair order reversals, with a third tone either preceding or following the tone pairs. It was found that when an additional tone followed the pairs the MMN amplitude was attenuated, suggesting elevated backward‐masking effects in the auditory cortex of dyslexic individuals. In addition, the MMN elicited by pitch change was diminished over the left hemisphere of the dyslexic individuals suggesting left hemisphere auditory dysfunction. These results suggest impaired cortical discrimination of sounds and lowered tolerance for the masking effects of rapidly following sounds in dyslexia.
The ERK/MAP kinase pathway couples light to immediate‐early gene expression in the suprachiasmatic nucleus
Authors: Dziema Heather , Oatis Ben , Butcher Greg Q. , Yates Robert , Hoyt Kari R. , Obrietan Karl 
Published: December 2004

AbstractSignalling via the p42/44 mitogen‐activated protein kinase (MAPK) pathway has been identified as an intermediate event coupling light to entrainment of the mammalian circadian clock located in the suprachiasmatic nucleus (SCN). Given this observation, it was of interest to determine where within the entrainment process the MAPK pathway was functioning. In this study, we examined the role of the MAPK pathway as a regulator of light‐induced gene expression in the SCN. Towards this end, we characterized the effect pharmacological disruption of the MAPK cascade has on the expression of the immediate‐early genes c‐Fos, JunB and EGR‐1. We report that uncoupling light from MAPK pathway activation attenuated the expression of all three gene products. In the absence of photic stimulation, inhibition of the MAPK pathway did not alter basal gene product expression levels. Light‐induced activation of cAMP response element (CRE)‐dependent transcription, as assessed using a CRE‐LacZ transgenic mouse strain, was also disrupted by blocking MAPK pathway activation. These results reveal that the MAPK cascade functions as one of the first transduction steps leading from light to rapid transcriptional activation, an essential event in the entrainment process. MAPK pathway‐dependent gene expression in the SCN may result, in part, from stimulation of CRE‐dependent transcription.
A damage to locus coeruleus neurons converts sporadic seizures into self‐sustaining limbic status epilepticus
Authors: Giorgi Filippo S. , Ferrucci Michela , Lazzeri Gloria , Pizzanelli Chiara , Lenzi Paola , AlessandrÏ Maria G. , Murri Luigi , Fornai Francesco 
Published: December 2004

AbstractVarious studies demonstrated that the neurotransmitter norepinephrine (NE) plays a relevant role in modulating seizures; in particular, a powerful effect consists in delaying the kindling of limbic areas such as the amygdala and hippocampus. Given the rich NE innervation of limbic regions, we selected a sensitive trigger area, the anterior piriform cortex, to test whether previous loss of noradrenergic terminals modifies sporadic seizures in rats. The damage to locus coeruleus terminals was produced by using the selective neurotoxin N‐(‐2‐chloroethyl)‐N‐ethyl‐2‐bromobenzylamine (DSP‐4, 60 mg/kg i.p.). In intact rats, bicuculline (a GABA‐A antagonist, 118 pmol) microinfused into this area produced sporadic seizures, while in rats previously injected with DSP‐4, bicuculline determined long‐lasting self‐sustaining status epilepticus. In intact rats, sporadic seizures were accompanied by a marked increase in norepinephrine release in the contralateral piriform cortex, while in locus coeruleus‐lesioned rats this phenomenon was attenuated. While bicuculline‐induced sporadic seizures were prevented by the focal infusion of amino‐7‐phosphonoheptanoic acid (AP‐7, a selective NMDA antagonist), or 1,2,3,4‐tetrahydro‐6‐nitro‐2,3‐dioxo‐benzo[f]quinoxaline‐7‐sulphonamide (NBQX, a selective non‐NMDA antagonist), status epilepticus obtained in norepinephrine‐lesioned rats was insensitive to AP‐7 but was still inhibited by NBQX. By using fluorescent staining for damaged (Fluoro‐Jade B) and intact (DAPI) neurons, as well as cresyl violet, we found that rats undergoing status epilepticus developed neuronal loss in various limbic regions. This study demonstrates a powerful effect of noradrenergic terminals in regulating the onset of limbic status epilepticus and its sensitivity to specific glutamate antagonists.
Production and perception of grip force without proprioception: is there a sense of effort in deafferented subjects?
Authors: Lafargue Gilles , Paillard Jacques , Lamarre Yves , Sirigu Angela 
Published: December 2004

AbstractWe assessed the ability of healthy subjects (n = 7) and a patient deprived of proprioception (GL) to produce and assess different levels of isometric forces. They first produced a target force with one hand (the reference control hand) and then, after a delay of 3 s, they attempted to match it with the other hand (the experimental matching hand). Despite abnormal variations in motor outputs, we found that GL could, as could the control subjects, maintain a constant relationship between the force exerted by the control hand and the force exerted by the experimental hand. As GL was deprived of proprioceptive cues, these results suggest that she indirectly perceived muscular force through central effort. Interestingly, when carrying out the task the patient reported neither feelings of fatigue nor awareness of how hard she tried to perform the matches. Hence, under certain circumstances (such as in our motor task), it seems possible to assess and scale muscular force on the basis of endogenous signals only. However, internally generated signals related to the size of the motor command may need to interact with afferent input to gain full access to consciousness.
Anandamide regulates neuropeptide release from capsaicin‐sensitive primary sensory neurons by activating both the cannabinoid 1 receptor and the vanilloid receptor 1 in vitro
Authors: Ahluwalia Jatinder , Urban Laszlo , Bevan Stuart , Nagy Istvan 
Published: December 2004

AbstractThe effect of anandamide, which activates both the cannabinoid 1 (CB1) receptor and the vanilloid receptor 1 (VR1), was studied on calcitonin gene‐related peptide (CGRP) release from cultured primary sensory neurons, the majority of which coexpress the CB1 receptor and VR1. Concentrations of anandamide < 1 µm produced a small but significant CB1 receptor‐mediated inhibition of basal CGRP release while higher concentrations induced VR1‐mediated CGRP release. The excitatory effect of anandamide was potentiated by the CB1 receptor antagonist SR141716A. In the presence of SR141716A at concentrations < 100 nm, anandamide was equipotent with capsaicin in stimulating CGRP release. However, at higher concentrations anandamide produced more CGRP release than equimolar concentrations of capsaicin. Three and ten nanomolar anandamide inhibited the capsaicin‐evoked CGRP release. In the presence of SR141716A, treatments which activated protein kinase A, protein kinase C and phospholipase C significantly potentiated the anandamide‐evoked CGRP release at all anandamide concentrations. Although this potentiation was reduced when the CB1 receptor antagonist was omitted from the buffer, the CGRP release evoked by 300 nm and 1 µm anandamide was still significantly larger than that seen with nonpotentiated cells. These data indicate that anandamide may regulate CGRP release from capsaicin‐sensitive primary sensory neurons in vivo, and that the net effect of anandamide on transmitter release from capsaicin‐sensitive primary sensory neurons depends on the concentration of anandamide and the state of the CB1 receptor and VR1. These findings also suggest that anandamide could be one of the molecules responsible for the development of inflammatory heat hyperalgesia.
Bursts of high‐frequency stimulation trigger rapid delivery of pre‐existing α‐CaMKII mRNA to synapses: a mechanism in dendritic protein synthesis during long‐term potentiation in adult awake rats
Authors: Håvik Bjarte , Røkke Håvard , Bårdsen Kjetil , Davanger Svend , Bramham Clive R. 
Published: December 2004

AbstractMessenger ribonucleic acid encoding the alpha‐subunit of calcium/calmodulin‐dependent protein kinase II (camkII) is abundantly and constitutively expressed in dendrites of pyramidal and granule cell neurons of the adult hippocampus. Recent evidence suggests that camkII messenger ribonucleic acid is stored in a translationally dormant state within ribonucleic acid storage granules. Delivery of camkII messenger ribonucleic acid from sites of storage to sites of translation may therefore be a key step in activity‐driven dendritic protein synthesis and synaptic plasticity. Here we explored possible camkII trafficking in the context of long‐term potentiation in the dentate gyrus of awake, adult rats. Long‐term potentiation was induced by patterned high‐frequency stimulation, synaptodendrosomes containing pinched‐off dendritic spines were obtained from microdissected dentate gyrus, and messenger ribonucleic acid levels were determined by real‐time polymerase chain reaction. High‐frequency stimulation triggered a rapid 2.5‐fold increase in camkII messenger ribonucleic acid levels in the synaptodendrosome fraction. This increase occurred in the absence of camkII upregulation in the homogenate fraction, indicating trafficking of pre‐existing messenger ribonucleic acid to synaptodendrosomes. The elevation in camkII messenger ribonucleic acid was paralleled by an increase in protein expression specific to the synaptodendrosome fraction, and followed by depletion of camkII message. Activity‐dependent regulation of camkII messenger ribonucleic acid and protein did not require N‐methyl‐d‐aspartate receptor activation. In contrast, N‐methyl‐d‐aspartate receptor activation was required for induction of the immediate early genes zif268 and activity‐regulated cytoskeleton‐associated protein in dentate gyrus homogenates. The results support a model in which locally stored camkII messenger ribonucleic acid is rapidly transported to dendritic spines and translated during long‐term potentiation in behaving rats.
Suppressed proliferation and apoptotic changes in the rat dentate gyrus after acute and chronic stress are reversible
Authors: Heine Vivi M. , Maslam Suharti , Zareno Jessica , Joëls Marian , Lucassen Paul J. 
Published: December 2004

AbstractAcute stress suppresses new cell birth in the hippocampus in several species. Relatively little is known, however, on how chronic stress affects the turnover, i.e. proliferation and apoptosis, of the rat dentate gyrus (DG) cells, and whether the stress effects are lasting. We investigated how 3 weeks of chronic unpredictable stress would influence the structural dynamic plasticity of the rat DG, and studied newborn cell proliferation, survival, apoptosis, volume and cell number in 10‐week‐old animals. To study lasting effects, another group of animals was allowed to recover for 3 weeks. Based on two independent parameters, bromodeoxyuridine (BrdU) and Ki‐67 immunocytochemistry, our results show that both chronic and acute stress decrease new cell proliferation rate. The reduced proliferation after acute stress normalized within 24 h. Interestingly, chronically stressed animals showed recovery after 3 weeks, albeit with still fewer proliferating cells than controls. Apoptosis, by contrast, increased after acute but decreased after chronic stress. These results demonstrate that, although chronic stress suppresses proliferation and apoptosis, 3 weeks of recovery again normalized most of these alterations. This may have important implications for our understanding of the reversibility of stress‐related hippocampal volume changes, such as occur, for example, in depression.
Synthesis, localization and externalization of galectin‐1 in mature dorsal root ganglion neurons and Schwann cells
Authors: Sango Kazunori , Tokashiki Akiko , Ajiki Kyoko , Horie Masao , Kawano Hitoshi , Watabe Kazuhiko , Horie Hidenori , Kadoya Toshihiko 
Published: December 2004

AbstractWe recently confirmed that oxidized galectin‐1 is a novel factor enhancing axonal growth in peripheral nerves after axotomy, but the process of extracellular release and oxidization of endogenous galectin‐1 in the injured nervous tissue remains unknown. In the present study, we examined the distribution of galectin‐1 in adult rat dorsal root ganglia (DRG) in vivo and in vitro. By RT‐PCR analysis and in situ hybridization histochemistry, galectin‐1 mRNA was detected in both DRG neurons and non‐neuronal cells. Immunohistochemical analyses revealed that galectin‐1 was distributed diffusely throughout the cytoplasm in smaller diameter neurons and Schwann cells in DRG sections. In contrast, the immunoreactivity for galectin‐1 was detected in almost all DRG neurons from an early stage in culture (3 h after seeding) and was restricted to the surface and/or extracellular region of neurons and Schwann cells at later stages in culture. In a manner similar to the primary cultured cells, we also observed the surface and extracellular expression of this molecule in immortalized adult mouse Schwann cells (IMS32). Western blot analysis has revealed that both reduced and oxidized forms of galectin‐1 were detected in culture media of DRG neurons and IMS32. These findings suggest that galectin‐1 is externalized from DRG neurons and Schwann cells upon axonal injury. Some of the molecules in the extracellular milieu may be converted to the oxidized form, which lacks lectin activity but could act on neural tissue as a cytokine.
Indirect facilitation of an anuran invasion by non‐native fishes
Authors: Adams Michael J. , Pearl Christopher A. , Bruce Bury R. 
Published: December 2004

AbstractPositive interactions among non‐native species could greatly exacerbate the problem of invasions, but are poorly studied and our knowledge of their occurrence is mostly limited to plant‐pollinator and dispersal interactions. We found that invasion of bullfrogs is facilitated by the presence of co‐evolved non‐native fish, which increase tadpole survival by reducing predatory macroinvertebrate densities. Native dragonfly nymphs in Oregon, USA caused zero survival of bullfrog tadpoles in a replicated field experiment unless a non‐native sunfish was present to reduce dragonfly density. This pattern was also evident in pond surveys where the best predictors of bullfrog abundance were the presence of non‐native fish and bathymetry. This is the first experimental evidence of facilitation between two non‐native vertebrates and supports the invasional meltdown hypothesis. Such positive interactions among non‐native species have the potential to disrupt ecosystems by amplifying invasions, and our study shows they can occur via indirect mechanisms.