The interpretation of changes in the soleus H reflex is problematic in the face of reflex gain changes, a nonlinear input/output relationship for the motoneuron pool, and a nonhomogeneous response of different motoneurons to afferent inputs. By altering the stimulus intensity to maintain a constant reflex output, threshold tracking allows a relatively constant population of alpha-motoneurons to...

Voltage-dependent persistent inward currents (PICs) make an important contribution to the input-output properties of alpha motoneurons. PICs are thought to be mediated by membrane channels located primarily on the dendrites as evidenced by prolonged tail currents following the termination of a voltage step and by a clockwise hysteresis in the whole cell inward currents recorded in response to d...

Background: The Jendrassik maneuver (JM) is a remote facilitation muscular contraction shown to affect amplitude and temporal components of the human stretch reflex. Conflicting theoretical models exist regarding the neurological mechanism related to its ability to reinforce reflex parameters. One mechanism involves the gamma motoneurons of the fusimotor system, which are subject to both physic...

The thyroid hormones have profound effects on the development of neuromuscular system. These hormones exert their influence on both muscle fibers and related motoneurons during development. Masseter is one of the most important muscles for mastication in mammals. Thyroid hormone deficiency 3 weeks after birth, the period in which an alteration from sucking to biting occurs, could influence the ...

Background & Aims: Since apoptotic cell death plays a crucial role in many neurodegenerative diseases, control of apoptosis can be taken into account as a putative neuroprotective strategy. Due to the reported neuroprotective effect of the herbal medicine Nepeta Menthoides (Ostokhodus) on the axotomy-induced apoptosis in the spinal motoneurons, in the present study we have investigated its prop...

In amyotrophic lateral sclerosis (ALS) the large motoneurons that innervate the fast-contracting muscle fibers (F-type motoneurons) are vulnerable and degenerate in adulthood. In contrast, the small motoneurons that innervate the slow-contracting fibers (S-type motoneurons) are resistant and do not degenerate. Intrinsic hyperexcitability of F-type motoneurons during early postnatal development ...

These are the neurons that actually drive the muscle cells. There are five classes, designated as alpha ( -MNs), static beta ( s-MNs), dynamic beta ( d-MNs), static gamma ( s-MNs), and dynamic gamma ( d-MNs). The -MNs are the main drive neurons for the extrafusal muscle fibers, and hence are known as slow (S), fast-resistant to fatigue (FR), and fast-fatiguing (FF) skeleto-motoneurons. The -MNs...

Mesopontine cholinergic (ACh) neurons have increased discharge during wakefulness, rapid eye movement (REM) sleep, or both. Hypoglossal (12) motoneurons, which play an important role in the control of upper airway patency, are postsynaptically excited by stimulation of nicotinic receptors, whereas muscarinic receptors presynaptically inhibit inputs to 12 motoneurons. These data suggest that ACh...

Multifunctional motoneurons and muscles, which are active during forward and backward locomotion are ubiquitous in animal models. However, studies in the nematode Caenorhabditis elegans suggest that some locomotor motoneurons are necessary only for forward locomotion (dorsal B-motoneurons, DB), while others (dorsal A-motoneurons, DA) are necessary only for backward locomotion. We tested this hy...