40 research outputs found
Imagined gait modulates neuronal network dynamics in the human pedunculopontine nucleus
The pedunculopontine nucleus (PPN) is a part of the mesencephalic locomotor region and is thought to be important for the initiation and maintenance of gait. Lesions of the PPN induce gait deficits, and the PPN has therefore emerged as a target for deep brain stimulation for the control of gait and postural disability. However, the role of the PPN in gait control is not understood. Using extracellular single-unit recordings in awake patients, we found that neurons in the PPN discharged as synchronous functional networks whose activity was phase locked to alpha oscillations. Neurons in the PPN responded to limb movement and imagined gait by dynamically changing network activity and decreasing alpha phase locking. Our results indicate that different synchronous networks are activated during initial motor planning and actual motion, and suggest that changes in gait initiation in Parkinson's disease may result from disrupted network activity in the PPN
Questionnaire study of the possible occurrence of ASD syndrome in family dogs
Arra a kĂ©rdĂ©sre szerettĂĽnk volna választ kapni, hogy vajon kimutathatĂł-e a magyar családi kutya populáciĂłban egy emberi autizmus spektrumzavarhoz hasonlĂł szindrĂłma. A rĂ©sztvevĹ‘k kĂ©rdĹ‘Ăvben elĹ‘zetesen adott válaszait hasonlĂtottuk össze a kĂsĂ©rlet alatt tanĂşsĂtott viselkedĂ©ssel. A teszthelyzet alatti viselkedĂ©s Ă©s a kĂ©rdĹ‘Ăv eredmĂ©nyeibĹ‘l számolt faktorokon elĂ©rt pontszámok között egyetlen korreláciĂłt sikerĂĽlt kimutatni
Quantification of Clustering in Joint Interspike Interval Scattergrams of Spike Trains
Joint interval scattergrams are usually employed in determining serial correlations between events of spike trains. However, any inherent structures in such scattergrams that are often seen in experimental records are not quantifiable by serial correlation coefficients. Here, we develop a method to quantify clustered structures in any two-dimensional scattergram of pairs of interspike intervals. The method gives a cluster coefficient as well as clustering density function that could be used to quantify clustering in scattergrams obtained from first- or higher-order interval return maps of single spike trains, or interspike interval pairs drawn from simultaneously recorded spike trains. The method is illustrated using numerical spike trains as well as in vitro pairwise recordings of rat striatal tonically active neurons
Whistler waves with angular momentum in space and laboratory plasmas and their counterparts in free space
Electromagnetic waves with helical phase surfaces arise in different fields of physics such as space plasmas, laboratory plasmas, solid-state physics, atomic, molecular and optical sciences. Their common features are the wave orbital angular momentum associated with the circular wave propagation around the axis of wave propagation. In plasmas these waves are called helicons. When particles or waves change the field momentum they experience a pressure and a torque which can lead to useful applications. In plasmas electrons can damp or excite rotating whistlers, depending on the electron distribution function in velocity space. A magnetized plasma is an anisotropic medium in which electromagnetic waves propagate differently than in space. Phase and group velocities are different such that wave focusing and wave reflections are different from those in free space. Electrons experience Doppler shifts and cyclotron resonance which creates wave damping and growth. All media exhibit nonlinear effects which do not occur in free space. Common and different features of vortex waves in different fields will be reviewed. However, a comprehensive review of this vast field is not possible and further readings are referred to the cited literature