Erich von Holst
Encyclopedia
Erich von Holst was a German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 behavioral physiologist who was a native of Riga
Riga
Riga is the capital and largest city of Latvia. With 702,891 inhabitants Riga is the largest city of the Baltic states, one of the largest cities in Northern Europe and home to more than one third of Latvia's population. The city is an important seaport and a major industrial, commercial,...

, and was related to historian
Historian
A historian is a person who studies and writes about the past and is regarded as an authority on it. Historians are concerned with the continuous, methodical narrative and research of past events as relating to the human race; as well as the study of all history in time. If the individual is...

 Hermann Eduard von Holst
Hermann Eduard von Holst
Hermann Eduard von Holst was a German-American historian.-Biography:Holst was a Baltic German born at Fellin in Russian Livonia. He was the seventh of ten children of a Lutheran minister...

 (1841–1904). In the 1950s he founded the Max Planck Institute for Behavioral Physiology
Max Planck Institute for Behavioral Physiology
The former Max Planck Institute for Behavioral Physiology was located in Seewiesen, Bavaria, Germany. It was one of 80 institutes in the Max Planck Society ....

 at Seewiesen, Bavaria
Bavaria
Bavaria, formally the Free State of Bavaria is a state of Germany, located in the southeast of Germany. With an area of , it is the largest state by area, forming almost 20% of the total land area of Germany...

.

Holst is remembered for his work with zoologist Konrad Lorenz
Konrad Lorenz
Konrad Zacharias Lorenz was an Austrian zoologist, ethologist, and ornithologist. He shared the 1973 Nobel Prize with Nikolaas Tinbergen and Karl von Frisch...

 (1903–1989) concerning the processes of endogenous
Endogenous
Endogenous substances are those that originate from within an organism, tissue, or cell. Endogenous retroviruses are caused by ancient infections of germ cells in humans, mammals and other vertebrates...

 generation of stimuli and of central coordination as a basis of behavior
Behavior
Behavior or behaviour refers to the actions and mannerisms made by organisms, systems, or artificial entities in conjunction with its environment, which includes the other systems or organisms around as well as the physical environment...

al physiology. This idea refuted the existing "reflex theory" which stated that this behavior was based on a chain of reflexes.

Holst postulated that the basic central nervous
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

 configuration consisted of a "cell" permanently producing endogenous stimulation, but prevented from activating its effector
Effector
Effector may refer to:*An actuator, in robotics*Effector , a music album by the Experimental Techno group Download*Effector cell, a type of lymphocyte in immunology...

 by another "cell" that also produced endogenous stimulation which contained an inhibition effect. This inhibiting "second cell" was influenced by the receptor
Receptor (biochemistry)
In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

, and stopped its inhibitory functionality precisely at the biologically
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

 right moment. In this fashion normal physiological stability was achieved.

From his studies of fish that use rhythmic, synchronized fin motions while maintaining an immobile body, he developed two fundamental principles to describe the coordinative properties of "neural oscillators":
  • Beharrungstendenz: a tendency of an oscillator to maintain a steady rhythm. This would include movements such as breathing, chewing and running, which Holst called states of absolute coordination
    Coordination
    Coordination is the act of coordinating, making different people or things work together for a goal or effect to fulfill desired goals in an organization.Coordination is a managerial function in which different activities of the business are properly adjusted and interlinked.Coordination may also...

    .
  • Magneteffekt: described as an effect that one oscillator exercises over another oscillator of a different frequency
    Frequency
    Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...

     so that it appears "magnetically" to draw and couple it to its own frequency.

The result of the interaction and struggle between Beharrungstendenz and Magneteffekt create an infinite number of variable couplings, and in essence form a state of relative coordination.

In 1950, with Horst Mittelstaedt, Holst demonstrated the "Reafference Principle" (Das Reafferenzprinzip) concerning how an organism is able to separate reafferent
Afferent nerve
In the nervous system, afferent neurons , carry nerve impulses from receptors or sense organs towards the central nervous system. This term can also be used to describe relative connections between structures. Afferent neurons communicate with specialized interneurons...

 (self-generated) sensory stimuli from exafferent (externally generated) sensory stimuli. This concept largely dealt with interactive processes between the central nervous system and its periphery.

At the University of Göttingen, Holst did extensive research involving the mechanics of winged flight, and constructed numerous life-like replicas of birds and other flying creatures, which included models of pterosaur
Pterosaur
Pterosaurs were flying reptiles of the clade or order Pterosauria. They existed from the late Triassic to the end of the Cretaceous Period . Pterosaurs are the earliest vertebrates known to have evolved powered flight...

s and dragonflies
Dragonfly
A dragonfly is a winged insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder Anisoptera . It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body...

.

With earthworm
Earthworm
Earthworm is the common name for the largest members of Oligochaeta in the phylum Annelida. In classical systems they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, even though the internal male segments are anterior to the female...

s, Holst demonstrated internal, autonomous, rhythmic behavior that is independent of environmental factors. By slicing a worm into separate segments, and attaching each segment to a sensitive voltmeter
Voltmeter
A voltmeter is an instrument used for measuring electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to...

, he noticed distinct, consecutive deflections on the meter which demonstrated a potentional wave moving through the severed parts from the front to the end of the entire cut-up specimen at approximately the speed of a contraction wave of a wriggling earthworm.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK