Grasp stability during manipulative actions

1994 ◽  
Vol 72 (5) ◽  
pp. 511-524 ◽  
Author(s):  
Roland S. Johansson ◽  
Kelly J. Cole
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Precision Grip ◽  
Sensory Information ◽  
Parameter Control ◽  
Control Mechanisms ◽  
Control Processes ◽  
Grasp Stability ◽  
The Central Nervous System ◽  
Fingertip Forces

The control of adequate contact forces between the skin and an object (grasp stability) is examined for two classes of prehensile actions that employ a precision grip: lifting objects that are "passive" (subject only to inertial forces and gravity) and preventing "active" objects from moving. For manipulating either passive or active objects the relevant fingertip forces are determined by at least two control processes. "Anticipatory parameter control" is a feedforward controller that specifies the values for motor command parameters on the basis of predictions of critical characteristics, such as object weight and skin–object friction, and initial condition information. Through vision, for instance, common objects can be identified in terms of the fingertip forces necessary for a successful lift according to previous experiences. After contact with the object, sensory information representing discrete mechanical events at the fingertips can (i) automatically modify the motor commands, (ii) update sensorimotor memories supporting the anticipatory parameter control policy, (iii) inform the central nervous system about completion of the goal for each action phase, and (iv) trigger commands for the task's sequential phases. Hence, the central nervous system monitors specific, more or less expected peripheral sensory events to produce control signals that are appropriate for the task at its current phase. The control is based on neural modelling of the entire dynamics of the control process that predicts the appropriate output for several steps ahead. This "discrete-event, sensor-driven control" is distinguished from feedback or other continuous regulation. Using these two control processes, slips are avoided at each digit by independent control mechanisms that specify commands and process sensory information on a local, digit-specific basis. This scheme obviates explicit coordination of the digits and is employed when independent nervous systems lift objects. The force coordination across digits is an emergent property of the local control mechanisms operating over the same time span.Key words: precision grip, hand, grasp stability, grasp force, tactile afferents.

Mechanisms for generating temporal filters in the electrosensory system

1999 ◽  
Vol 202 (10) ◽  
pp. 1281-1289 ◽  
Author(s):  
G.J. Rose ◽  
E.S. Fortune
Keyword(s):  
Nervous System ◽  
Discharge Rate ◽  
Temporal Structure ◽  
Sensory Information ◽  
Gain Control ◽  
Membrane Properties ◽  
Control Mechanisms ◽  
Temporal Features ◽  
Level Of Activity ◽  
The Central Nervous System

Temporal patterns of sensory information are important cues in behaviors ranging from spatial analyses to communication. Neural representations of the temporal structure of sensory signals include fluctuations in the discharge rate of neurons over time (peripheral nervous system) and the differential level of activity in neurons tuned to particular temporal features (temporal filters in the central nervous system). This paper presents our current understanding of the mechanisms responsible for the transformations between these representations in electric fish of the genus Eigenmannia. The roles of passive and active membrane properties of neurons, and frequency-dependent gain-control mechanisms are discussed.

Are There Parallel Channels in the Vestibular Nerve?

Physiology ◽  
1998 ◽  
Vol 13 (4) ◽  
pp. 194-201 ◽  
Author(s):  
Ellengene H. Peterson
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Information ◽  
Primary Afferents ◽  
Vestibular Nerve ◽  
Functional Roles ◽  
The Central Nervous System ◽  
Parallel Channels

A popular concept in neurobiology is that sensory information is transmitted to the central nervous system over parallel channels of neurons that play different functional roles. But alternative organizing schemes are possible, and it is useful to ask whether some other framework might better account for the diversity of vestibular primary afferents.

scholarly journals Adaptive Encoding of Coordinating Information in the Crayfish Central Nervous System

2018 ◽  
Author(s):  
Anna C. Schneider ◽  
Felix Blumenthal ◽  
Carmen R. Smarandache-Wellmann
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Information ◽  
Excitation Level ◽  
Electrophysiological Properties ◽  
Body Segments ◽  
Adaptive Encoding ◽  
The Central Nervous System ◽  
Activity State ◽  
A Chain

AbstractLocomotion is essential for an animal’s survival. This behavior can range from directional changes to adapting the motor force to the conditions of its surroundings. Even if speed and force of movement are changing, the relative coordination between the limbs or body segments has to stay stable in order to provide the necessary thrust. The coordinating information necessary for this task is not always conveyed by sensory pathways. Adaptation is well studied in sensory neurons, but only few studies have addressed if and how coordinating information changes in cases where a local circuit within the central nervous system is responsible for the coordination between body segments at different locomotor activity states.One system that does not depend on sensory information to coordinate a chain of coupled oscillators is the swimmeret system of crayfish. Here, the coordination of four coupled CPGs is controlled by central Coordinating Neurons. Cycle by cycle, the Coordinating Neurons encode information about the activity state of their home ganglion as burst of spikes, and send it as corollary discharge to the neighboring ganglia. Activity states, or excitation levels, are variable in both the living animal and isolated nervous system; yet the amount of coordinating spikes per burst is limited.Here, we demonstrate that the system’s excitation level tunes the encoding properties of the Coordinating Neurons. Their ability to adapt to excitation level, and thus encode relative changes in their home ganglion’s activity states, is mediated by a balancing mechanism. Manipulation of cholinergic pathways directly affected the coordinating neurons’ electrophysiological properties. Yet, these changes were counteracted by the network’s influence. This balancing may be one feature to adapt the limited spike range to the system’s current activity state.

The antinociceptive system. Endogenous mechanisms of pain control

2019 ◽  
pp. 130-136
Author(s):  
В.Г. Овсянников ◽  
А.Е. Бойченко ◽  
В.В. Алексеев ◽  
А.В. Каплиев ◽  
А.Е. Шумарин ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Pain Control ◽  
Current Data ◽  
System Control ◽  
Control Mechanisms ◽  
Spinal Level ◽  
Inhibitory System ◽  
Antinociceptive System ◽  
The Central Nervous System

Представлен обзор современных данных по изучению антиноцицептивной системы и эндогенных механизмов обезболивания. Контроль болевой чувствительности осуществляется многими структурами ЦНС, каждая из которых функционирует как самостоятельное образование. В комплексе все они входят в состав сложной системы антиноцицепции, аналогично тому, как ощущение боли является результатом интегративной функции ЦНС. Данное сообщение посвящено анализу роли информации, поступающей по толстым миелиновым волокнам в задние рога спинного мозга и нисходящих тормозных влияний на уровне задних рогов спинного мозга. Охарактеризованы структуры, влияющие на антиноцицепцию. На уровне спинного мозга обнаружены два механизма подавления боли - это сегментарный контроль и система нисходящего тормозного контроля. По современным данным обезболивающие эффекты объясняются не только сегментарным контролем, но и включением надсегментарных механизмов контроля, в т.ч. и гуморальных. Центральные структуры головного мозга оказывают не только нисходящее влияние на спинальном уровне, но и модифицируют болевые сигналы в местах их переключения в различных структурах головного мозга. Нисходящая ингибиторная система тесно взаимосвязана с тремя нейротрансмиттерными системами: опиатной, норадренергической и серотонинергической. Возникновение боли зависит не только от интенсивности ноцицептивного повреждения, но и от состояния различных звеньев антиноцицептивной системы. На основании знаний о патогенезе острой боли, структуре и функции антиноцицептивной системы дается определение понятия «боль». This review focused on the antinociceptive system and endogenous mechanisms of pain control. Multiple structures of the central nervous system control the pain sensitivity, and each of them functions as an independent entity. Together they constitute a complex system of antinociception consistent with that the sensation of pain is provided by integrative functioning of the central nervous system. This review analyzed the role of information delivered through thick myelin fibers to posterior horns and descending inhibitory effects at the level of the posterior horns. Two pain relief mechanisms were found at the spinal level, the segmental control and the descending inhibitory control system. According to current data anesthetic effects are explained not only by the segmental control but also by involvement of suprasegmental control mechanisms, including humoral ones. Central structures both exert downstream effects at the spinal level and modify pain signals at the locations where they switch over in various cerebral structures. The descending inhibitory system is closely interrelated with three neurotransmitter systems, the opiate, noradrenergic and serotonergic ones. Emergence of pain depends on both the intensity of nociceptive damage and on the condition of multiple parts of the antinociceptive system.Based on studying the pathogenesis of acute pain and the structure and function of antinociceptive system the authors provided a definition for the term of pain.

Afferent System Overview

2021 ◽  
pp. 21-28
Author(s):  
Stephen W. English ◽  
Eduardo E. Benarroch
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Sensory Information ◽  
Dorsal Column ◽  
Sensory Transduction ◽  
Cation Channels ◽  
Electric Signal ◽  
Visceral Sensation ◽  
The Central Nervous System ◽  
Lemniscal System

The afferent, or sensory, systems include visual, auditory, somatosensory, and interoceptive (ie, pain, temperature, and visceral sensation) inputs to the central nervous system. This chapter briefly reviews principles of transduction, relay, and processing of sensory information. The dorsal column–medial lemniscal system is reviewed in more detail. However, pain, vision, olfaction, and hearing are reviewed in subsequent chapters. Sensory transduction refers to the transformation of a stimulus into an electric signal. This process involves several distinct families of cation channels and associated receptor types.

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