Neuroscience
-
The gene associated with retinoid-interferon-induced mortality-19 (GRIM-19) plays several significant roles in cellular processes, including ATP synthesis, reactive oxygen species formation, and the regulation of glycolytic enzyme activity, which are closely related to the pathophysiological mechanisms of epilepsy. Therefore, we investigated the expression pattern of GRIM-19 in the CA1 area of the hippocampus in 8-week-old male C57BL/6 mice following pilocarpine-induced status epilepticus (SE). Neuronal death in the hippocampal CA1 area was prominently observed at 4 and 7 days after SE, and astrocytes and microglia became progressively activated beginning at 1 day after SE. ⋯ Moreover, we observed that both GRIM-19 and pyruvate kinase isozyme M2, a glycolytic enzyme, were highly expressed in reactive astrocytes after SE. These results indicate that expression of GRIM-19 in the hippocampus is mainly observed in neurons under normal conditions but is altered in the SE mouse model as evidenced by its increased expression in reactive astrocytes. The possible role of GRIM-19 in the glycolytic activity of reactive astrocytes is also discussed.
-
High gamma activity (HGA) of verbal-memory encoding using invasive-electroencephalogram has laid the foundation for numerous studies testing the integrity of memory in diseased populations. Yet, the functional connectivity characteristics of networks subserving these memory linkages remains uncertain. ⋯ The HGA-memory network comprised regions from both the cognitive control and primary processing networks, validating that effective verbal-memory encoding requires integrating brain functions, and is not dominated by a central cognitive core. Our results demonstrate a tonic intrinsic set of functional connectivity, which provides the necessary conditions for effective, phasic, task-dependent memory encoding.
-
This study examines binaural response properties and sensitivity to interaural level difference of single neurons in the primary auditory cortex (AC) of the big brown bat, Eptesicus fuscus under earphone stimulation conditions. Contralateral sound stimulation always evoked response from all 306 AC neurons recorded but ipsilateral sound stimulation either excited, inhibited or did not affect their responses. High best frequency (BF) neurons typically had high minimum threshold (MT) and low BF neurons had low MT. ⋯ Neurons sequentially isolated within an orthogonal electrode puncture shared similar BF, MT, binaurality and ILD curves. However, the response latency of these AC neurons progressively shortened with recording depth. Species-specific difference among this bat, the mustached bat and the pallid bat is discussed in terms of frequency and binaurality representation in the AC.
-
Electroencephalography (EEG) as a biomarker of neuromodulation by High Definition transcranial Direct Current Stimulation (HD-tDCS) offers promise as both techniques are deployable and can be integrated into a single head-gear. The present research addresses experimental design for separating focal EEG effect of HD-tDCS in the '4-cathods × 1-anode' (4 × 1) montage over the left motor area (C3). We assessed change in offline EEG at the homologous central (C3, C4), and occipital (O1, O2) locations. ⋯ For the active arm, similar but less pronounced changes occurred in the alpha band. In contrast, responses to IPS developed similar asymmetric amplitude increase at four harmonics of the IPS of 3 Hz only in the active arm, against a background of a brain-wide symmetric increase in both active and sham arms. Our protocols and analyses suggest methodological caveats for how EEG of tDCS studies could be conducted to isolate putative brain polarization outcomes.