Neuroscience
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N-methyl-d-aspartate receptors (NMDARs) at layer (L)1/primary whisker motor cortex synaptic inputs are distinct from thalamic/striatal (Str) synaptic inputs onto L5 pyramidal neurons in the rat somatosensory cortex. However, the consequences of differential expression of putative GluN3A-containing triheteromeric NMDARs at L1 inputs and GluN2A-containing diheteromeric NMDARs at Str inputs on plasticity of the underlying synapses at the respective inputs remain unknown. Here we demonstrate that L1, but not Str, synapses are potentiated following delta burst stimulation (dBS). ⋯ Our data suggest distinct potentiating paradigms for the two convergent inputs onto pyramidal neurons in the somatosensory cortex and co-dependence of synaptic potentiation on brain wave-tuned frequencies of burst stimulation and subunit composition of underlying NMDARs. A model for predicting the likelihood of enhancing synaptic efficacy is proposed based on Ca(2+) influx through these receptors and integration of EPSPs at these inputs. Together, these findings raise the possibility of input-specific enhancements of synaptic efficacy in neurons as a function of the animal's behavioral state and/or arousal in vivo.
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Mindfulness is the state of being attentive to and aware of what is taking place in the present, which is beneficial for reducing stress-related symptoms and improving mental and physical health. Previous studies have demonstrated that meditation practice can improve individuals' mindfulness through modifying functions and structures of multiple brain regions, including the anterior cingulate cortex (ACC), insula, fronto-limbic network, posterior cingulate cortex (PCC), and temporal-parietal junction. ⋯ We found that individuals who were more mindful of the present had greater GM volume in the right hippocampus/amygdala and bilateral ACC, but less GM volume in bilateral PCC and the left orbitofrontal cortex. These results suggest that trait mindfulness is associated with brain regions involved in executive attention, emotion regulation, and self-referential processing, through which mindfulness may exert its beneficial effects on psychological and physical well-being.
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Paced Auditory Serial-Addition Task (PASAT) is a complex task commonly used to examine patients with diffuse brain damage. A visual version of the neuropsychological test (Paced Visual Serial-Addition Task, PVSAT) has also been introduced to clinical practice, and both versions were adapted to be used in neuroimaging, namely functional magnetic resonance imaging (fMRI). The aim of our work was direct comparison of auditory and visual versions of the paced serial addition test (PASAT/PVSAT) in a within-subject and within-session study and description of the commonalities and differences in both activated and deactivated brain regions. ⋯ Activation in one task and deactivation in the other jointly contributed to significant differences in all occipital and occipitotemporal regions. Both tasks activated right FEF, but activation during PASAT was significantly stronger than during PVSAT. Between-modality differences should be considered when preparing and interpreting neuroimaging experiments.
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Glutamate transporter type 3 (EAAT3) may play a role in cognition. Isoflurane enhances EAAT3 trafficking to the plasma membrane. Thus, we used isoflurane to determine how EAAT3 might regulate learning and memory and the trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors, such as GluR1, to the plasma membrane, a fundamental biochemical process for learning and memory. ⋯ Finally, isoflurane inhibited context-related fear conditioning in EAAT3(-/-) mice but not in wild-type mice. Thus, isoflurane may increase GluR1 trafficking to the plasma membrane via EAAT3 and inhibit GluR1 trafficking via protein phosphatase. Lack of EAAT3 effects leads to decreased GluR1 trafficking and impaired cognition after isoflurane exposure in EAAT3(-/-) mice.
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Type A behavior pattern (TABP) is characterized by competitiveness and hostility, time urgency and impatience. These traits can have a significant impact on physical and mental health. We have not found studies focusing on brain structure or functional connectivity correlates associated with individual differences in TABP. ⋯ In addition, TABP was positively correlated with the strength of rsFC between the left ventral striatum and areas in the left ventromedial prefrontal cortex (vmPFC) and the right rostral anterior cingulate cortex (rACC). These regions are associated with achievement striving related to impatience, aggressiveness, and worry under time pressure. In summary, the combination of morphometric results (increased rGMV of the left sgACC) and functional connectivity findings (increased rsFC between the left ventral caudate and the left vmPFC/right rACC in the fronto-striatal network) may provide a valuable basis for a comprehensive understanding of the neural circuitry underlying individual differences in TABP.