BMS 777607 was no longer modulated in response to tilts

The PTN was no longer modulated in response to tilts. Figure 8E shows a hindlimb PTN with different responses in passive and active conditions. At rest, this cell was activated during flexion of the knee. BMS 777607 However, in the postural tests the neuron was active in the second half of the tilt cycle, i. e. during extension of the knee. It seems unlikely that, in the postural task, the response in this PTN could be generated on the basis of its receptive field input. The neuronswith similar responses to passive and active limb movements were found among cells whose receptive fields were positioned on different segments of the limbs, they constituted about a half of these PTNs. However, among the forelimb PTNs with distal receptive fields on the palm and digits, only 2 out of 24 neurons exhibited similar responses.
Discussion Possible functions of PTNs in the control of posture When standing, the cat maintains a specific,dorsal side up body orientation in the frontal plane due to the activity of the postural control system. This system SP600125 is driven by sensory feedback signals and generates corrective motor responses when the body orientation in the frontal plane deviates from the desired one. General organization of the postural system in the cat has been characterized in the previous study. It was concluded that the system consists of two subsystems, one for the shoulder girdle and the other for the hip girdle. They compensate for tilts of the anterior and posterior parts of the body, respectively.
Each subsystem includes two controllers, one for the left limb and one for the right limb. Each limb controller contains a reflex mechanism driven by somatosensory J Physiol 586. 1 Origin of cortical responses in postural tasks 259 input from its own limb. These local reflexes partly compensate for tilts. The limb controllers also receive somatosensory input from the contralateral limbs. The motor responses to these crossed influences are added to Figure 8. Role of sensory input from the receptive field in modulation of PTNs A and B, relative number of PTNs in the forelimb population and hindlimb population which had a receptive field with a directional preference, no such preference, or did not have a receptive field. A proportion of group A PTNs with similar responses to passive and active limb movements is shown in grey.
C and D, an example of the hindlimb PTN driven during postural task by afferents of its receptive field. At rest, the PTN was activated with the dorsal flexion of toes. During postural tests, the PTN was also activated during dorsal flexion of toes in the first half of the cycle. When the paw was positioned on the edge of the platform so that during balancing toes did not flex dorsally and the afferents of the receptive field were not activated, the PTN was not modulated. E, an example of a hindlimb PTN not driven by afferents of its receptive field during postural task. At rest, the PTN was activated by knee flexion. In postural tests, the PTN was activated during knee extension. the local reflexes. The forelimb controllers exert influences on the hindlimb controllers promoting coordination of the fore and hindlimbs. Reversed influences are much weaker. 260 A. Karayannidou and others J Phy

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