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.

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.

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.

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.

scholarly journals Role of L-glutamate in aggression

2016 ◽  
Vol 72 (12) ◽  
pp. 740-744
Author(s):  
Bogdan Feliks Kania ◽  
Danuta Wrońska
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Steroid Receptors ◽  
Cation Channels ◽  
Metabotropic Receptor ◽  
Ionotropic Receptors ◽  
The Central Nervous System ◽  
G Protein Coupled ◽  
Stimulation Of

L-glutamate is one of major excitatory transmitters (along with aspartic, kainate acids and glycine) in the central nervous system and/or the peripheral nervous system. It mediates interaction through the stimulation of various ionotropic receptors families (ligand gated cation channels) and metabotropic receptor families (G-protein coupled). In this review, we describe the molecular composition of these glutamatergic receptors and discuss their neuropharmacology, particularly with respect to their roles in animal social behaviors and, particularly, in aggression. It is also known, that during aggression different interactions occur in the nervous system among glutamate, serotonin, vasopressin, oxytocin, dopamine, GABA and steroid receptors.

scholarly journals ON THE ROLE OF THE SPINAL AFFERENT NEURON AS A GENERATOR OF EXTRACELLULAR CURRENT

1954 ◽  
Vol 37 (6) ◽  
pp. 795-812 ◽  
Author(s):  
Donald O. Rudin ◽  
George Eisenman
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Dorsal Root ◽  
Evoked Potential ◽  
Dorsal Column ◽  
Membrane Properties ◽  
Afferent Neuron ◽  
The Central Nervous System ◽  
Experimental Findings

The prediction that a system of currents flows between the dorsal column and the dorsal root due to differences in their after-potentials was found to be consistent with the experimental findings. The form, magnitude, duration, and sign of the electrotonic component DRα fulfill the requirements of the postulated system. A contribution of tract after-potentials to the evoked potential of intramedullary structures is indicated. It is a conclusion of this and previous studies that profound changes occur in certain membrane properties of myelinated primary afferent axons as they penetrate the central nervous system. The working concept of abrupt intraaxonal junctional regions is therefore justifiable.

Effects of Hyperoxia on Lung Utrastructure

1970 ◽  
Vol 28 ◽  
pp. 26-27
Author(s):  
Gladys Harrison
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Light Microscopy ◽  
Oxygen Effects ◽  
Age Dependent ◽  
The Central Nervous System ◽  
The Subject ◽  
Space Age ◽  
Alveolar Septa ◽  
Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

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