Comparison of thigh muscle activations in single leg exercises: bench squat, step-up, airborne lunge

Background and Study Aim. Single leg exercises have some advantages in terms of time, practice and energy costs. However, the activation values that occur in different single leg exercises can be used for training planning. The aim of this research was to examine the thigh muscle activation values during three different single leg exercises. Materials and Methods. Ten healthy male volunteers who were students of the faculty of sports sciences participated in the study. In the study, the EMG ampilitude values of the vastus medialis (VM), vastus lateralis (VL), semitendinosus (SEM) and biceps femoris (BF) muscles were examined during Step-up, Bench Squat and Airborne Lunge exercises. At the same time, Quadriceps (VM+VL): Hamstring (SEM+BF) ratios were determined. Results. Significant differences were detected in all thigh muscles in the ascent and descent phases (p<0.05). While the greatest activation for the quadriceps group was seen in the airborne lunge, the greatest activation for the hamstring group was detected in the bench squat. A statistically significant difference was found in terms of exercise practices in the quadriceps: hamstring (Q:H) ratio (F(2,18)=12.282, p=.003). It was seen that the most balanced exercise was bench squat (Q:H=2.55), and the most unbalanced exercise (agonist dominant) was airborne lunge (Q:H=5.51). Conclusions. The findings show that the exercises examined can be selected depending on the purpose of the training. While bench squats can be preferred for more balanced co-activation the airborne lunge can be preferred for dominant knee extensors.

Interactions within the social brain: Co-activation and connectivity among networks enabling empathy and Theory of Mind

While empathy and Theory of Mind (ToM) have classically been studied as separate social functions, recent advances demonstrate the need to investigate the two in interaction: Naturalistic settings often blur the distinction of affect and cognition and demand the simultaneous processing of such different stimulus dimensions. Here, we investigate how empathy and ToM related brain networks interact in contexts wherein multiple cognitive and affective demands must be processed simultaneously. Building on the findings of a recent meta-analysis and hierarchical clustering analysis, we perform meta-analytic connectivity modeling to determine patterns of task-context specific network changes. We analyze 140 studies including classical empathy and ToM tasks, as well as complex social tasks. For studies at the intersection of empathy and ToM, neural co-activation patterns included areas typically associated with both empathy and ToM. Network integration is discussed as a means of combining mechanisms across unique behavioral domains. Such integration may enable adaptive behavior in complex, naturalistic social settings that require simultaneous processing of a multitude of different affective and cognitive information.

Brain-wide neural co-activations in resting human

Spontaneous neural activity in human as assessed with resting-state functional magnetic resonance imaging (fMRI) exhibits brain-wide coordinated patterns in the frequency of <0.1Hz. However, fast brain-wide networks at the timescales of neuronal events (milliseconds to sub-seconds) and their spatial, spectral, and propagational characteristics remain unclear due to the temporal constraints of hemodynamic signals. With milli-second resolution and whole-head coverage, scalp-based electroencephalography (EEG) provides a unique window into brain-wide networks with neuronal-timescale dynamics, shedding light on the organizing principles of brain function. Using state-of-the-art signal processing techniques, we reconstructed cortical neural tomography from resting-state EEG and extracted component-based co-activation patterns (cCAPs). These cCAPs revealed brain-wide intrinsic networks and their dynamics, indicating the configuration/reconfiguration of resting human brains into recurring and propagating functional states, which are featured with the prominent spatial phenomena of global patterns and anti-state pairs of co-(de)activations. Rich oscillational structures across a wide frequency band (i.e., 0.6Hz, 5Hz, and 10Hz) were embedded in the dynamics of these functional states. We further identified a superstructure that regulated between-state propagations and governed a significant aspect of brain-wide network dynamics. These findings demonstrated how resting-state EEG data can be functionally decomposed using cCAPs to reveal rich structures of brain-wide human neural activations.

Cholinergic control of striatal GABAergic microcircuits

Cholinergic interneurons (CINs) are essential elements of striatal circuits and behaviors. While acetylcholine signaling via muscarinic receptors (mAChRs) have been well studied, more recent data indicate that postsynaptic nicotinic receptors (nAChRs) located on GABAergic interneurons (GINs) are equally critical. One demonstration is that CINs stimulation induces large disynaptic inhibition of SPNs mediated by nAChR activation of striatal GINs. While these circuits are ideally positioned to modulate striatal output activity, the neurons involved are not definitively identified due largely to an incomplete mapping of CINs-GINs interconnections. Here, we show that CINs optogenetic activation evokes an intricate dual mechanism involving co-activation of pre- and postsynaptic mAChRs and nAChRs on four GINs populations. Using multi-optogenetics, we demonstrate the participation of tyrosine hydroxylase-expressing GINs in the disynaptic inhibition of SPNs likely via heterotypic electrical coupling with neurogliaform interneurons. Altogether, our results highlight the importance of CINs in regulating GINs microcircuits via complex synaptic/heterosynaptic mechanisms.

I. Synthesis and Reactivity of Novel β-Diketiminato-cadmium Complexes, II. Synthesis of Lead Selenide Nanoparticles for Use in Solar Cells

<p>Rising levels of carbon dioxide (CO₂) in the atmosphere has led to metal amide and alkoxide complexes being explored as potential CO₂ activators. A wide variety of M–O and M–N bonds have been shown to activate CO₂, however to date there are no examples with cadmium. A range of novel cadmium amide and alkoxide complexes have been synthesised, using the β-diketiminato ligand (BDI) as an ancilliary ligand. Initial reactivity studies have suggested CO₂ activation may be possible, although no products were isolated. Homonuclear metallic bonding (M–M) has been explored since the 1950’s and complexes containing M–M bonds are known for almost all transition and main group metals. There are only two reported Cd–Cd bonds, both using sterically bulky monoanionic ligands, like the β-diketiminato ligand. A novel β-diketiminato-cadmium chloride complex was synthesised and treated with a range of different reducing agents to generate a Cd–Cd bond. Different reactivities were observed for the reducing agents, however evidence of a Cd–Cd bond was not obtained. Group 14-16 materials, such as lead selenide, are p-type semi-conductors and have the potential to replacing silicon as a photon acceptor in solar cells. Lead selenide nanoparticles display quantum confinement effects, which allows one to tailor the band gap energies to maximise their absorbance of solar energy. The synthesis of PbSe nanoparticles is described in this study from the reaction between selenium and the lead complex [(BDIph)₂Pb], as well as from the decomposition of [(BDIdipp)PbSeP{Se}Cy₂]. Differences in the size and shapes of the nanoparticles was observed, highlighting the need for controlled nucleation and growth conditions.</p>

I. Synthesis and Reactivity of Novel β-Diketiminato-cadmium Complexes, II. Synthesis of Lead Selenide Nanoparticles for Use in Solar Cells

<p>Rising levels of carbon dioxide (CO₂) in the atmosphere has led to metal amide and alkoxide complexes being explored as potential CO₂ activators. A wide variety of M–O and M–N bonds have been shown to activate CO₂, however to date there are no examples with cadmium. A range of novel cadmium amide and alkoxide complexes have been synthesised, using the β-diketiminato ligand (BDI) as an ancilliary ligand. Initial reactivity studies have suggested CO₂ activation may be possible, although no products were isolated. Homonuclear metallic bonding (M–M) has been explored since the 1950’s and complexes containing M–M bonds are known for almost all transition and main group metals. There are only two reported Cd–Cd bonds, both using sterically bulky monoanionic ligands, like the β-diketiminato ligand. A novel β-diketiminato-cadmium chloride complex was synthesised and treated with a range of different reducing agents to generate a Cd–Cd bond. Different reactivities were observed for the reducing agents, however evidence of a Cd–Cd bond was not obtained. Group 14-16 materials, such as lead selenide, are p-type semi-conductors and have the potential to replacing silicon as a photon acceptor in solar cells. Lead selenide nanoparticles display quantum confinement effects, which allows one to tailor the band gap energies to maximise their absorbance of solar energy. The synthesis of PbSe nanoparticles is described in this study from the reaction between selenium and the lead complex [(BDIph)₂Pb], as well as from the decomposition of [(BDIdipp)PbSeP{Se}Cy₂]. Differences in the size and shapes of the nanoparticles was observed, highlighting the need for controlled nucleation and growth conditions.</p>