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GEORGE SZÉKELY
specificity) require a different interpretation. In an effort to categorize
the foregoing surmises, an attempt may be made here to group the
conclusions in the following four propositions:
a. The neural mechanisms investigated are performed by "networklike" systems.
b. Only an approximate preference for selective neural connectivity
can be attained in network-like systems.
c. The cell pattern of the nervous centers is determined in early embryonic life.
d. Cell groups with similar components may have similar functions.
a. In the course of discussion of the experiments presented, several
references have been made to diffuse, network-like systems. By this is
meant the distinction between two great systems lying parallel in the
brain and the cord. One is the set of ascending and descending pathways
that transmits information by all-or-nothing electrical events of the
participating elements. A remarkable point-to-point localization is found
from receptors right through to effectors, including synaptic relays, classical tracts, and projection areas. The other is a newly appreciated, network-like system clarified only partially in its physiological (Bishop,
1956; Bullock, 1959; Mclntire, 1957; Melzack and Wall, 1962) and
morphological (Scheibel and Scheibel, 1958; Szentâgothai, 1964) aspects.
It is a core of cells or distinct assemblies of cells, in contact mainly with
diffuse-type synapses that pour in impulses from many afferent pathways. The predominance of axodendritic synapses and the immense
wealth of branching cell processes create the anatomical basis of a structure in which the graded, décrémentai activity of the participating
elements, evoked by a large number of presynaptic fibers commonly impinging on postsynaptic neurons, plays an essential role in the information transfer. A sort of integration of afferent inputs may occur at
synaptic level by combining and sorting the impulses so that their
summed effect will determine the activity of the postsynaptic neuron and
thus exert a general influence, either facilitatory or inhibitory, on reflexes.
It is always hazardous to make rigid distinctions in the nervous system,
and, of course, the above two structures only represent the two extremes in a rich variety of different transition forms. Although the
neurophysiological side of the discussed reflexes and behavioral responses
is only very scantily explored, one is inclined to regard them as belonging
to structures lying closer to the second system in their anatomical and
physiological features. The important role of alterations in the type of
sensory terminals (viz., corneal reflex), or the extent of receptive area
(limb reflexes, ganglion transplantation), is immediately obvious in the
function of these structures. It is also obvious, on the other hand, that
GEORGE SZÉKELY
specificity) require a different interpretation. In an effort to categorize
the foregoing surmises, an attempt may be made here to group the
conclusions in the following four propositions:
a. The neural mechanisms investigated are performed by "networklike" systems.
b. Only an approximate preference for selective neural connectivity
can be attained in network-like systems.
c. The cell pattern of the nervous centers is determined in early embryonic life.
d. Cell groups with similar components may have similar functions.
a. In the course of discussion of the experiments presented, several
references have been made to diffuse, network-like systems. By this is
meant the distinction between two great systems lying parallel in the
brain and the cord. One is the set of ascending and descending pathways
that transmits information by all-or-nothing electrical events of the
participating elements. A remarkable point-to-point localization is found
from receptors right through to effectors, including synaptic relays, classical tracts, and projection areas. The other is a newly appreciated, network-like system clarified only partially in its physiological (Bishop,
1956; Bullock, 1959; Mclntire, 1957; Melzack and Wall, 1962) and
morphological (Scheibel and Scheibel, 1958; Szentâgothai, 1964) aspects.
It is a core of cells or distinct assemblies of cells, in contact mainly with
diffuse-type synapses that pour in impulses from many afferent pathways. The predominance of axodendritic synapses and the immense
wealth of branching cell processes create the anatomical basis of a structure in which the graded, décrémentai activity of the participating
elements, evoked by a large number of presynaptic fibers commonly impinging on postsynaptic neurons, plays an essential role in the information transfer. A sort of integration of afferent inputs may occur at
synaptic level by combining and sorting the impulses so that their
summed effect will determine the activity of the postsynaptic neuron and
thus exert a general influence, either facilitatory or inhibitory, on reflexes.
It is always hazardous to make rigid distinctions in the nervous system,
and, of course, the above two structures only represent the two extremes in a rich variety of different transition forms. Although the
neurophysiological side of the discussed reflexes and behavioral responses
is only very scantily explored, one is inclined to regard them as belonging
to structures lying closer to the second system in their anatomical and
physiological features. The important role of alterations in the type of
sensory terminals (viz., corneal reflex), or the extent of receptive area
(limb reflexes, ganglion transplantation), is immediately obvious in the
function of these structures. It is also obvious, on the other hand, that