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.

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.

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.

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.

Emigration of neutrophils in the central nervous system

1983 ◽  
Vol 41 ◽  
pp. 788-789
Author(s):  
John L.Beggs ◽  
John D. Waggener ◽  
Wanda Miller ◽  
Jane Watkins
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Osmium Tetroxide ◽  
White Blood Cells ◽  
Arterial Perfusion ◽  
E Coli ◽  
Intracisternal Injection ◽  
The Central Nervous System ◽  
Brain And Spinal Cord ◽  
Interendothelial Junctions

Studies using mesenteric and ear chamber preparations have shown that interendothelial junctions provide the route for neutrophil emigration during inflammation. The term emigration refers to the passage of white blood cells across the endothelium from the vascular lumen. Although the precise pathway of transendo- thelial emigration in the central nervous system (CNS) has not been resolved, the presence of different physiological and morphological (tight junctions) properties of CNS endothelium may dictate alternate emigration pathways.To study neutrophil emigration in the CNS, we induced meningitis in guinea pigs by intracisternal injection of E. coli bacteria.In this model, leptomeningeal inflammation is well developed by 3 hr. After 3 1/2 hr, animals were sacrificed by arterial perfusion with 3% phosphate buffered glutaraldehyde. Tissues from brain and spinal cord were post-fixed in 1% osmium tetroxide, dehydrated in alcohols and propylene oxide, and embedded in Epon. Thin serial sections were cut with diamond knives and examined in a Philips 300 electron microscope.

Mammalian Bone Marrow Acetylcholinesterase

1982 ◽  
Vol 40 ◽  
pp. 44-45
Author(s):  
Ezzatollah Keyhani
Keyword(s):  
Central Nervous System ◽  
Bone Marrow ◽  
Nervous System ◽  
Common Property ◽  
Extracellular Medium ◽  
The Central Nervous System ◽  
The Common ◽  
Mammalian Bone

Acetylcholinesterase (EC 3.1.1.7) (ACHE) has been localized at cholinergic junctions both in the central nervous system and at the periphery and it functions in neurotransmission. ACHE was also found in other tissues without involvement in neurotransmission, but exhibiting the common property of transporting water and ions. This communication describes intracellular ACHE in mammalian bone marrow and its secretion into the extracellular medium.

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