Progress in brain research
-
Obstructive sleep apnea-hypopnea syndrome (OSAHS) is a common sleep disorder that is characterized by repeated episodes of complete or partial cessation of breathing while sleeping. These recurrent breathing events result in fragmented sleep and recurrent hypoxemia. Distressing daytime sequelae reported by OSAHS patients include excessive daytime sleepiness, self-reported changes in mood, and cognitive problems. ⋯ Current studies examining cognitive recovery with positive airway pressure treatment are presented. It appears that the cognitive dysfunction of OSAHS is not likely to be due to a single mediating mechanism, nor is it pervasive across all patients. Future research should attempt to identify these moderators for cognitive dysfunction in OSAHS and to highlight the mechanisms of dysfunction by cognitive domain.
-
It is well established that a spinal circuitry can generate locomotor movements of the hindlimbs in absence of descending supraspinal inputs. This is based, among others, on the observation that after a complete spinalization, cats can walk with the hindlimbs on a treadmill. ⋯ This review focuses mainly on the capacity of the spinal and supraspinal structures to reorganize spontaneously after incomplete SCI in animals (rats and cats). BMI approaches to foster recovery of functions after various types of SCI should take into account these changes at the various levels of the CNS.
-
Resting state networks (RSNs), as imaged by functional MRI, are distributed maps of areas believed to be involved in the function of the "resting" brain, which appear in both resting and task data. The current dominant view is that such networks are associated with slow (∼0.015Hz), spontaneous fluctuations in the BOLD signal. ⋯ In addition, we show that RSNs exhibit different levels of phase synchrony at different frequencies. These findings challenge the notion that FMRI resting signals are simple "low frequency" spontaneous signal fluctuations.
-
Levodopa therapy represents a major breakthrough in the treatment of Parkinson's disease (PD). As time and disease severity progresses, however, the shortcomings and adverse effects of this neurotransmitter replacement strategy become apparent and patients develop disabilities despite best medical therapy. The heightened awareness of these difficulties has given birth to a re-examination of functional neurosurgery for advanced PD. ⋯ Other problems are less or non-responsive. Further, despite the widespread use of this technology, the mechanism through which DBS alleviates symptoms is not fully understood. This review will discuss the patient population most likely to benefit from surgery, what aspects of the disease are most responsive, the current limitations of DBS, and new therapeutic targets that are being examined to address these limitations.
-
Review
Sexual differentiation of the human brain in relation to gender identity and sexual orientation.
It is believed that during the intrauterine period the fetal brain develops in the male direction through a direct action of testosterone on the developing nerve cells, or in the female direction through the absence of this hormone surge. According to this concept, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation should be programmed into our brain structures when we are still in the womb. However, since sexual differentiation of the genitals takes place in the first two months of pregnancy and sexual differentiation of the brain starts in the second half of pregnancy, these two processes can be influenced independently, which may result in transsexuality. ⋯ To what extent fetal programming may determine sexual orientation is also a matter of discussion. A number of studies show patterns of sex atypical cerebral dimorphism in homosexual subjects. Although the crucial question, namely how such complex functions as sexual orientation and identity are processed in the brain remains unanswered, emerging data point at a key role of specific neuronal circuits involving the hypothalamus.