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  • Autumn 2011 - Issue Number 84
  • Autumn 2011 - Issue Number 84
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Research at high altitude

The factors that regulate brain blood flow at high altitude are unclear. Our recent findings show that the balance of oxygen (O2) and carbon dioxide (CO2) pressures in arterial blood explains 40% of the change in brain blood flow upon arrival to high altitude (5050 m). We have also shown that blood vessels in the brain respond to changes in CO2 differently at high altitude compared to sea level – a factor that can influence breathing responses as well.
  • Features

Transmission of cortical oscillations to motoneuron output for force control

The precise control of muscles for movement execution requires reliable transmission of information in the central nervous system. At the spinal motoneurons, information transmission is partly linear because the input is common to a large number of neurons. This generates coherence between the EEG and EMG signals, a measure whose validity is, however, debated.
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The trouble with CO2

We breathe for two reasons: to take in O2 and to regulate the amount of dissolved CO2 in the blood. This latter function is fundamental to the control of the pH of blood and hence is a vital homeostatic function. For many years the quest to understand the regulation of breathing by CO2 has concentrated on how the brain measures the pH of blood. New evidence now suggests that the brain also directly measures the level of dissolved CO2.
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Tissue biomechanics as a modulator of lymphatic function

The lymphatic network represents a good example of how biological structures maximise their efficiency by exploiting the anatomical and biomechanical properties of their microenvironment. Indeed, the stiffness of the extracellular matrix may directly affect the absorptive and/or propulsive nature of a lymphatic vessel, thus exerting an important modulatory role in lymphatic function.

  • Features

How does the visual brain code contours?

Neurones in the primary visual cortex of mammals show a remarkable selectivity for the orientation of contours in the visual scene. The neuronal basis of this property has been the subject of intense debate for nearly half a century. Our recent work throws new light on this problem.
  • Features

Pulsed infrared radiation: a potential tool to reveal cellular secrets

Pulsed infrared radiation (IR) has been shown to stimulate excitable cells through activating key intracellular signalling events. Data suggest the presence of fundamental IR-sensitive mechanisms that generalize across cell types. Our recent results demonstrate the importance of IR-modulated intracellular Ca2+ signalling in cardiomyocytes and inner-ear hair cells. Application of pulsed IR to modulate intracellular Ca2+ may be particularly useful to study events controlling synaptic transmission and excitation–contraction coupling.
  • Features

The physiology of ‘ooh’ and ‘aagh’

(Muscle cramp: circumstances, cures and causes)
  • Features

Mitochondrial responses to hypoxia and physiological stimulation of harbouring cells measured optically in situ

Understanding the involvement of mitochondria in cellular regulatory processes in living cells and tissues is the hallmark of the current interest in mitochondria. One way to monitor these organelles in live tissue is the newly developed, high-precision, spectral absorption-based method for measuring respiratory pigments’ redox state changes. With it we monitored responses of mitochondria, inside the eyes of live insects, to large perturbations like hypoxia, as well as to more physiological ones such as light stimulation.
  • Features

The orderly recruitment of postganglionic sympathetic neurons

Investigations into discharge patterns of the multi-unit postganglionic sympathetic neural population in humans have been hampered by the poor signal-to-noise aspect of this signal. New signal processing and denoising approaches have now been used to expose such action potential patterns. Such approaches have revealed that variations exist in the conduction velocity of action potentials observed in this neurogram and that a subpopulation of fast-conducting neurons exists for probable recruitment during high stress scenarios.
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