Brain research
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Secondary brain damage plays a critical role in the outcome of patients with traumatic brain injury (TBI). The multiple mechanisms underlying secondary brain damage, including posttraumatic cerebral ischemia, glutamate excitotoxicity, oxidative stress, calcium overload and inflammation, are associated with increased mortality and morbidity after head injury. TBI is documented to have detrimental effects on mitochondria, such as alterations in glucose utilization and the depression of mitochondrial oxidative phosphorylation. ⋯ The differences may indicate the degree of metabolic and physiologic dysfunction. Our results will better define the roles of gene expression and metabolic function in long-term prognosis and outcome after TBI. With a considerable understanding of post-injury mitochondrial dysfunction, therapeutic interventions targeted to the mitochondria may prevent secondary brain damage that leads to long-term cell death and neurobehavioral disability.
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This neuroimaging study investigated the neural mechanisms of the effect of conversation on visual event detection during a driving-like scenario. The static load paradigm, established as predictive of visual reaction time in on-road driving, measured reaction times to visual events while subjects watched a real-world driving video. Behavioral testing with twenty-eight healthy volunteers determined the reaction time effects from overt and covert conversation tasks in this paradigm. ⋯ We identified a frontal-parietal network that maintained event detection performance during the conversation task while watching the driving video. Increased brain activations for conversation vs. no conversation during such simulated driving was found not only in language regions (Broca's and Wernicke's areas), but also specific regions in bilateral inferior frontal gyrus, bilateral anterior insula and orbitofrontal cortex, bilateral lateral prefrontal cortex (right middle frontal gyrus and left frontal eye field), supplementary motor cortex, anterior and posterior cingulate gyrus, right superior parietal lobe, right intraparietal sulcus, right precuneus, and right cuneus. We propose an Asynchrony Model in which the frontal regions have a top-down influence on the synchrony of neural processes within the superior parietal lobe and extrastriate visual cortex that in turn modulate the reaction time to visual events during conversation while driving.
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Rehabilitation improves recovery after intracerebral hemorrhage (ICH) in rats. In some cases, brain damage is attenuated. In this study, we tested whether environmental enrichment (EE) combined with skilled reach training improves recovery and lessens brain injury after ICH in rats. ⋯ Unexpectedly, REHAB treatment lessened spontaneous use of the contralateral-to-ICH limb at 4 (p=0.045) and 6 weeks (p=0.041). In summary, the combination of EE and reach training significantly attenuates lesion volume (striatal injury) while improving skilled reaching and walking ability. These findings encourage the use of early rehabilitation therapies in patients suffering from basal ganglia hemorrhaging.
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A subset of German function verbs can be used either in a full, concrete, 'heavy' ("take a computer") or in a more metaphorical, abstract or 'light' meaning ("take a shower", no actual 'taking' involved). The present magnetoencephalographic (MEG) study explored whether this subset of 'light' verbs is represented in distinct cortical processes. A random sequence of German 'heavy', 'light', and pseudo verbs was visually presented in three runs to 22 native German speakers, who performed lexical decision task on real versus pseudo verbs. ⋯ Thus, 'heavy' versus 'light readings' of verbs already modulate early posterior visual evoked response even when verbs are presented in isolation. This response becomes clearer in the disambiguating contextual condition. This type of study shows for the first time that language processing is sensitive to representational differences between two readings of one and the same verb stem.
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Perinatal development of the mammillothalamic tract and innervation of the anterior thalamic nuclei.
Axonal projections originating from the mammillary bodies represent important pathways that are essential for spatial information processing. Mammillothalamic tract is one of the main efferent projection systems of the mammillary body belonging to the limbic "Papez circuit". This study was aimed to describe the schedule of the mammillothalamic tract development in the rat using carbocyanine dye tracing. ⋯ Ipsilateral projections from the medial mammillary nucleus to the anteromedial and anteroventral thalamic nuclei develop from E20 to P6. Bilateral projections from the lateral mammillary nucleus to the anterodorsal thalamic nuclei develop later, on P3-P6, after the formation of the thalamic decussation of the mammillary body axons. Unique spatial and temporal pattern of the perinatal development of ascending mammillary body projections to the anterior thalamic nuclei may reflect the importance of these connections within the limbic circuitry.