Primate spinal interneurons show pre-movement instructed delay activity

Prut, Yifat; Fetz, Eberhard E.

doi:10.1038/44145

Cited by 226 publications

(194 citation statements)

References 27 publications

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“…Conversely, when the information about the imperative stimulus is suYcient to specify the response in advance, preparatory activity is present in the most caudal parts of PMd, which have access to the primary motor cortex and the spinal cord (Mars et al 2005). Consistent with this Wnding, modulation of activity of spinal neurons during movement preparation has been observed in monkeys (Prut and Fetz 1999).…”

Section: Introductionsupporting

confidence: 80%

Effects of motor preparation and spatial attention on corticospinal excitability in a delayed-response paradigm

et al. 2007

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The preparation of motor responses during the delay period of an instructed delay task is associated with sustained neural Wring in the primate premotor cortex. It remains unclear how and when such preparation-related premotor activity inXuences the motor output system. In this study, we tested modulation of corticospinal excitability using single-pulse transcranial magnetic stimulation (TMS) during a delayed-response task. At the beginning of the delay interval participants were either provided with no information, spatial attentional information concerning location but not identity of an upcoming imperative stimulus, or information regarding the upcoming response. Behavioral data indicate that participants used all information available to them. Only when information concerning the upcoming response was provided did corticospinal excitability show diVerential modulation for the eVector muscle compared to other task-unrelated muscles. We conclude that modulation of corticospinal excitability reXects speciWc response preparation, rather than non-speciWc event preparation.

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Section: Introductionsupporting

confidence: 80%

Effects of motor preparation and spatial attention on corticospinal excitability in a delayed-response paradigm

et al. 2007

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“…In this view, the processes that give rise to intentions and expec- tations are somehow different from those that generate behavior. However, recent indirect evidence suggests that intentions and expectations may arise in behavior-generating networks themselves even in primates (28)(29)(30). In that case, interestingly, the intentions and expectations inferred from behavioral observations are not always identical to the intentions and expectations that are consciously accessible.…”

Section: Discussionmentioning

confidence: 95%

Dynamical basis of intentions and expectations in a simple neuronal network

Proekt

Březina

Weiss

2004

Proc. Natl. Acad. Sci. U.S.A.

166

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Selection of behavioral responses to external stimuli is strongly influenced by internal states, such as intentions and expectations. These internal states are often attributed to higher-order brain functions. Yet here we show that even in the simple feeding network of Aplysia, external stimuli do not directly specify which motor output is expressed; instead, the motor output is specified by the state of the network at the moment of stimulation. The history-dependence of this network state manifests itself in the same way as do intentions and expectations in the behavior of higher animals. Remarkably, we find that activity-dependent plasticity of a synapse within the network itself, rather than some higher-order network, mediates one important aspect of the change in the network state. Through this mechanism, changes in the network state become an automatic consequence of the generation of behavior. Altogether, our findings suggest that intentions and expectations may emerge within behavior-generating networks themselves from the plasticity of the very processes that generate the behavior.A nimal behavior is not merely a passive response to external stimuli; rather, it expresses also the internal state of the animal. This internal state is presumably somehow embodied in the state of the nervous system. Here we study the manifestations and the neurophysiological basis of the internal state in the experimentally advantageous feeding network of the mollusk Aplysia.State-dependence of network function is not a new concept. In the neurophysiological literature, state-dependence is typically discussed as the ability of contextual cues to modify the response to a stimulus. This type of state-dependence has been demonstrated, for example, for locomotion by using stimulation of the mesencephalic locomotor region to elicit walking in the decerebrate cat. The speed of locomotion is determined by the speed of the treadmill on which the cat is placed (1). In another compelling example, stimulation of a command-like neuron in a leech immersed in water elicits swimming, whereas stimulation of the same neuron when the leech is placed on solid substrate elicits crawling (2). Similarly, stimulation of a command-like neuron in a cricket suspended in air elicits avoidance responses but it fails to do so when the cricket is placed on the ground (3). State-dependence of this type is also seen with neuromodulation. For instance, the ability of sensory stimulation to elicit stridulation in the grasshopper is critically dependent on the presence of a muscarinic agonist (4). The setting of network state by application of neuromodulators is a common phenomenon that has been well characterized in simple neuronal networks, such as the stomatogastric system of crustaceans (5-9).This type of state-dependence fails, however, to account for a fundamental feature of the state-dependence that is observed in animal behavior and human psychology. In the type of statedependence just discussed, the behavior is still unambiguously specified by the ext...

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“…In fact, using experimental procedures that involve an instructed delay period between a cue and the triggered movement, many papers have documented the effects of this motor preparation activity. This kind of activity has been shown to occur in many motor centers: the motor cortex (37)(38)(39) , the basal ganglia (40)(41)(42) and also at spinal interneurons (43) . It seems obvious that for the development of this preparatory activity subjects must be able to predict the timing of target occurrence -temporal expectancy.…”

Section: Discussionmentioning

confidence: 99%