Influence of globus pallidus on arm movements in monkeys. I. Effects of kainic acid-induced lesions

Abstract

The role of basal ganglia output via the globus pallidus (GP) was examined in monkeys trained to make rapid arm-reaching movements to a visual target in a reaction-time task. When neurons in the globus pallidus were destroyed by injection of kainic acid (KA) during task execution, contralateral arm movement times (MT) were increased significantly, with little or no change in reaction times (RT). The slowed movements were associated with a generalized depression in the amplitude and rate of rise of electromyographic (EMG) activity in all the contralateral muscles studied at the wrist, elbow, shoulder, and back, but there was no change in the sequential activation of these muscles. The most profound and persistent increases in movement time occurred when neurons were destroyed in the ventrolateral and caudal aspects of the internal as well as external pallidal segment. These results suggest a role for globus pallidus output in scaling the magnitude and/or buildup of EMG activity without affecting the initiation or the sequential organization of the programmed motor output.

The complementary brain: unifying brain dynamics and modularity

“…For example, it helps to explain how motor expectations (pattern) interact with volitional speed signals (energy) to generate goaldirected arm movements [89][90][91] , as during the computation of the Desired Velocity Vector in the cortical area 4 circuit of Figure 6. As noted in the discussion of 'where' and 'how' processing, a motor expectation represents where we want to move, such as to the position where our hand can grasp a desired object.…”

“…Such a motor representation, or Target Position Vector (TPV), can prime a movement, or get us ready to make a movement, but by itself, it cannot release the movement 55,89 . First the TPV needs to be converted into a Difference Vector (DV), which triggers an overt action only when a volitional signal 90 that multiplicatively gates action read-out. The volitional signal for controlling movement speed is called a GO signal, as in Figure 6.…”

“…As noted in Figure 6, some motor expectations seem to be computed in the parietal and motor cortex. Volitional signals seem to be computed within the basal ganglia 90 .…”

Force development during target-directed isometric force production in Parkinson's disease

“…Earlier studies have reported that PD patients have an inherent limitation in the rate at which they can develop force during rapid and discrete isometric contractions [25,29]. Damage to basal ganglia structures has been shown to produce abnormalities in force recruitment [17,18] and such abnormities are often compensated for by lengthening impulse duration to augment force output [1,16]. Recent studies using neuroimaging techniques in human have demonstrated that the internal segment of the globus pallidus and subthalamic nucleus in basal ganglia nuclei are directly related to the force development speed during isometric force production [28].…”

Attentive Learning of Sequential Handwriting Movements: A Neural Network Model

“…The DV is multiplied by a gradually increasing GO signal, that is under volitional control, whose growth rate can be changed to alter movement speed while preserving movement direction and length ( Figure 1). The "GO" signal seems to be generated with in the basal ganglia (Hallett & Khoshbin, 1980;Georgopoulos et a!., 1983;Horak & Anderson, 1984a, 1984bBcrardclli eta!., 1996;Turner & Anderson, 1997;Turner ct a!., 1998). The DV times the GO signal is an outflow representation of movement velocity that is integrated at the PPV until the present position of the hand reaches the target.…”