Combined Positive and Negative Feedback Allows Modulation of Neuronal Oscillation Frequency during Sensory Processing

Both negative feedback, resistance reflexes and positive feedback, assistance reflexes are mediated by the thoracocoxal muscle receptor organ (TCMRO) in the crayfish, depending on the central excitability of the preparation. In this paper we present evidence that the velocity-sensitive afferent T fiber of the TCMRO may elicit either resistance or assistance reflexes in different preparations. In preparations displaying assistance reflexes, the S and T fibers of the TCMRO exert reciprocal effects on leg motor neurons (MNs). The S fiber excites promotor MNs (negative feedback) and inhibits remotor MNs, the T fiber excites remotor MNs (positive feedback) and inhibits promotor MNs. During reciprocal motor output of promotor and remotor MNs, reflexes mediated by the TCMRO are modulated in a phase-dependent manner. The TCMRO excites promotor MNs during their active phases (negative feedback) but inhibits them during their reciprocal phases. Remotor MNs are excited by the TCMRO during their active phases (positive feedback). It is proposed that depolarizing central inputs that occur in the S and T fibers at opposite phases of the motor output cycle (21) facilitate the output effects of each afferent in alternation, effectively mediating a phase-dependent shift between the effects of one afferent and the other. The implications of central modulation of reflex pathways and the possible functions of positive and negative feedback reflexes during locomotion are discussed.

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Oxytocin-induced facilitation of learning in a probabilistic task is associated with reduced feedback- and error-related negativity potentials

Journal of Psychopharmacology ◽

10.1177/0269881120972347 ◽

2020 ◽

Vol 35 (1) ◽

pp. 40-49

Author(s):

Qian Zhuang ◽

Siyu Zhu ◽

Xue Yang ◽

Xinqi Zhou ◽

Xiaolei Xu ◽

...

Keyword(s):

Negative Feedback ◽

Early Stage ◽

Conflict Detection ◽

Social Feedback ◽

Double Blind ◽

Subsequent Performance ◽

Error Awareness ◽

Error Related Negativity ◽

Positive And Negative Feedback ◽

The Impact

Background: Feedback evaluation of actions and error response detection are critical for optimizing behavioral adaptation. Oxytocin can facilitate learning following social feedback but whether its effects vary as a function of feedback valence remains unclear. Aims: The present study aimed to investigate whether oxytocin would influence responses to positive and negative feedback differentially or equivalently. Methods: The present study employed a randomized, double-blind, placebo controlled within-subject design to investigate whether intranasal oxytocin (24 IU) influenced behavioral and evoked electrophysiological potential responses to positive or negative feedback in a probabilistic learning task. Results: Results showed that oxytocin facilitated learning and this effect was maintained in the absence of feedback. Using novel stimulus pairings, we found that oxytocin abolished bias towards learning more from negative feedback under placebo by increasing accuracy for positively reinforced stimuli. Oxytocin also decreased the feedback-related negativity difference (negative minus positive feedback) during learning, further suggesting that it rendered the evaluation of positive and negative feedback more equivalent. Additionally, post-learning oxytocin attenuated error-related negativity amplitudes but increased the late error positivity, suggesting that it may lower conflict detection between actual errors and expected correct responses at an early stage of processing but at a later stage increase error awareness and motivation for avoiding them. Conclusions: Oxytocin facilitates learning and subsequent performance by rendering the impact of positive relative to negative feedback more equivalent and also by reducing conflict detection and increasing error awareness, which may be beneficial for behavioral adaption.

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