Elimination of glutamatergic transmission from Hb9 interneurons does not impact treadmill locomotion

The spinal cord contains neural circuits that can produce the rhythm and pattern of locomotor activity. It has previously been postulated that a population of glutamatergic neurons, termed Hb9 interneurons, contributes to locomotor rhythmogenesis. These neurons were identified by their expression of the homeobox gene, Hb9, which is also expressed in motor neurons. We developed a mouse line in which Cre recombinase activity is inducible in neurons expressing Hb9. We then used this line to eliminate vesicular glutamate transporter 2 from Hb9 interneurons, and found that there were no deficits in treadmill locomotion. We conclude that glutamatergic neurotransmission by Hb9 interneurons is not required for locomotor behaviour. The role of these neurons in neural circuits remains elusive.

Elimination of Glutamatergic Transmission From Hb9 Interneurons Does Not Impact Treadmill Locomotion

The spinal cord contains neural circuits that can produce the rhythm and pattern of locomotor activity. It has previously been postulated that a rhythmogenic population of glutamatergic neurons, termed Hb9 interneurons, contributes to this rhythmogenesis. The homeobox gene, Hb9, is expressed in these interneurons as well as motor neurons. We developed a mouse line in which cre recombinase activity is inducible in neurons expressing Hb9. We then used this line to eliminate vesicular glutamate transporter 2 from Hb9 interneurons, and found that there were no deficits in treadmill locomotion. We conclude that glutamatergic neurotransmission by Hb9 interneurons is not required for locomotor rhythmogenesis. The role of these neurons in neural circuits remains elusive.

Elimination of glutamatergic transmission from Hb9 interneurons does not impact treadmill locomotion

ABSTRACTThe spinal cord contains neural circuits that can produce the rhythm and pattern of locomotor activity. It has previously been postulated that a rhythmogenic population of glutamatergic neurons, termed Hb9 interneurons, contributes to this rhythmogenesis. The homeobox gene, Hb9, is expressed in these interneurons as well as motor neurons. We developed a mouse line in which cre recombinase activity is inducible in neurons expressing Hb9. We then used this line to eliminate vesicular glutamate transporter 2 from Hb9 interneurons, and found that there were no deficits in treadmill locomotion. We conclude that glutamatergic neurotransmission by Hb9 interneurons is not required for locomotor rhythmogenesis. The role of these neurons in neural circuits remains elusive.

Horse Behavior, Physiology and Emotions during Habituation to a Treadmill

A treadmill is an important tool in the equine analysis of gait, lameness, and hoof balance, as well as for the evaluation of horse rehabilitation or poor performance including dynamic endoscopy. Before all of these uses, horses have to be habituated to a treadmill locomotion. We used principal component analysis to evaluate the relationship between aspects of the horse’s temperament and emotional response, and progress in the behavioral habituation to a treadmill. Fourteen horses were tested, by the same familiar handler, using the novel object test, the handling test, and both positive and negative emotional response tests. Then, four stages of gradual habituation of the first work on a treadmill were conducted. Each time, the horse’s behavior was filmed. Data obtained from ethograms and heart rate measurements were tested. Four principal components were identified in examined horses: “Flightiness”, “Freeziness”, “Curiosity”, and “Timidity”. Flightiness was connected with nervousness, agitation by new objects, and easy excitability, and gradually decreased of features during habituation. Timidity was associated with a lack of courage and stress in new situations, and those features strongly increased when the treadmill was introduced. Freeziness and Curiosity features showed strong stability throughout the whole habituation. The results of this study provide evidence for a connection between temperament, emotional response, and habituation process in a horse.

Recovery of locomotion in cats after severe contusion of the low thoracic spinal cord

The recovery of quadrupedal treadmill locomotion after a large bilateral contusion at the low thoracic T10 spinal level and the ability to negotiate obstacles were studied for 5 wk in 16 cats. Ten cats were further completely spinalized at T13 and were found to walk with the hindlimbs within 24–72 h. We conclude that the extent of locomotor recovery after large spinal contusions hinges both on remnant supraspinal pathways and on a spinal pattern generator.