Diameters of callosal fibers interconnecting cat sensorimotor cortex

Naito, Haruhiko; Miyakawa, Fumio; Ito, Noboru

doi:10.1016/0006-8993(71)90263-0

Cited by 16 publications

(7 citation statements)

References 7 publications

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“…When analyzing callosal fibers connecting sensory areas [Naito et al, 1971;Innocenti et al, 1995], the most common (median) fiber diameters have been reported to be somewhat larger than the values obtained when analyzing the whole spectrum of fibers (table 2). This agrees with other findings in primates suggesting that areas 17/18 tend to be connected by relatively large-diameter fibers [La Mantia and Rakic, 1990;Aboitiz et al, 1992].…”

Section: Fibers Connecting Specific Cortical Areasmentioning

confidence: 89%

“…Table 2 summarizes previous studies on callosal fiber composition in different species. In the rat the reported proportions of unmyelinated fibers range from 19% ] to 46.4% [Seggie and Berry, 1972], whereas in the cat these range from zero [Naito et al, 1971] to 85% [Remahl and Hildebrand, 1982]. Note that in one species (cat) even the same group of researchers has documented different proportions of unmyelinated fibers in successive reports: Koppel and Innocenti [1983] reported 43-58% of unmyelinated fibers, whereas Berbel and Innocenti [1988] reported about 74%.…”

Section: Technical Aspectsmentioning

confidence: 91%

“…Animal studies of fiber composition of the corpus callosum have been performed in rodents, rabbits, the cat and macaque [Naito et al, 1971;Swadlow, 1974;Waxman and Swadlow, 1976;Swadlow et al, 1980;Juraska and Kopcic, 1988;La Mantia and Rakic, 1990;Kim et al, 1996;Kim and Juraska, 1997;Schüz and Preissl, 1996;Miller et al, 1999]. Despite the abundance of such intraspecies studies of the corpus callosum (many of them oriented to determine sex differences, hormonal or environmental effects, or simply to give a morphological substrate for neurophysiological experiments), very few studies have addressed callosal fiber diversity across species [Innocenti et al, 1995;Schüz and Preissl, 1996].…”

Section: Introductionmentioning

confidence: 99%

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Species Differences and Similarities in the Fine Structure of the Mammalian Corpus callosum

Olivares

Montiel²,

Aboitiz³

2001

Brain Behav Evol

142

122

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A cross-species ultrastructural study of the corpus callosum was performed in six domestic species: the rat, the rabbit, the cat, the dog, the horse and the cow. The results indicate cross-species conservatism in callosal fiber composition with a good interspecies relation between fiber number and brain size. Across species, increases in both brain size and callosal area indicate more callosal fibers, although less than expected from the estimated increase in cortical cell number. Within each species, the correlation between fiber number and brain weight tends to disappear, although in most cases a larger callosum implies a larger number of callosal fibers. The median fiber diameter was conservative across species (0.11–0.2 µm), indicating the maintenance of conduction velocity of most callosal fibers regardless of interhemispheric distance. Nevertheless, the maximal fiber diameters tended to be higher in species with larger brains. Therefore, there is a population of coarse-diameter fibers that tend to increase their diameter and conduction velocity with increasing brain size. However, allometric calculations suggest that the associated increase in velocity in these large fibers may not be sufficient to maintain a constant interhemispheric transmission time in different species.

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Section: Fibers Connecting Specific Cortical Areasmentioning

confidence: 89%

Section: Technical Aspectsmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Species Differences and Similarities in the Fine Structure of the Mammalian Corpus callosum

Olivares

Montiel²,

Aboitiz³

2001

Brain Behav Evol

142

122

View full text Add to dashboard Cite

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“…8 /Lm, with more than 75 % of the population less than 1 /Lm in diameter, and the smallest 0.3 /Lm in diameter. Naito et al (1971) failed to find unmyelinated axons in the adult cat corpus callosum; the most common diameter for the myelinated fibers there was given as 0.8-1.0 /Lm. Waxman and Swadlow (1976) found in the visual part of the rabbit corpus callosum that 45 % ofaxons were unmyelinated, with calibers of 0.05-0.64 lLffi (median about 0.2 /Lm).…”

Section: Caliber Of Cortico-cortical Axonal Connectionsmentioning

confidence: 93%

“…Ultrastructural studies of cerebral white matter (e. g. , that ofthe corpus callosum) in various species have shown that a significant proportion of the axons therein are either very fine myelinated fibers or unmyelinated ones (Fleischhauer & Wartenberg, 1967;Haug, Kölln, & Rast, 1976;Naito, Miyakawa, & Ito, 1971;Remahl & Hildebrand, 1982;Seggie & Berry, 1972;Swadlow, Waxman, & Geschwind, 1980;Waxman & Swadlow, 1976;Wiggins, BisselI, Durham, & Samorajski, 1983). Fleischhauer and Wartenberg (1967) found that 40% ofaxons in the corpus callosum of the adult cat were unmyelinated; the median diameter of this population ofaxons was about 0.25 /Lm.…”

Section: Caliber Of Cortico-cortical Axonal Connectionsmentioning

confidence: 99%

Representation of brief temporal patterns, Hebbian synapses, and the left-hemisphere dominance for phoneme recognition

Miller

1987

Psychobiology

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There is considerable evidence, including that from single-unit classical conditioning studies, that patterns that are briefly extended in time can be learned. Learning of simultaneous patterns is usually assumed to occur by strengthening of selected synaptic connections converging on single neurons. The present paper extends this principle to the learning of patterns that are slightly extended in time. Evidence is reviewed that cortico-cortical axonal connections impose a range of conduction delays sufficient to permit temporal convergence at the single-neuron level between signals originating up to 100-200 msec apart. By selection of appropriate connections, brief temporal patterns can be represented by converging connections with different conduction delays. The Hebbian postulate for synaptic modification is sufficiently precise in time to permit such selection. FinaIly, this hypothesis is applied to the learning of phoneme recognition in the human forebrain, and a suggestion is made concerning the biological basis of left-hemisphere dominance for phoneme recognition.

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Distribution and properties of commissural and other neurons in cat sensorimotor cortex

Miller

1975

J of Comparative Neurology

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Commissural, cortico-cortical and cortico-caudate neurons have been investigated in the primary sensorimotor cortex of the cat, using antidromic stimulation techniques, and histological identification of recording sites. These neurons are to be found in all cortical laminae except the first; commissural and cortico-cortical neurons were found to be commonest in laminae III and VI, whilst cortico-caudate neurons were most abundant on the border between laminae III and V, in motor areas. In sensory areas topographically identified as representing distal parts of limbs, commissural neurons are very rare, confirming neuroanatomical studies on the origin and termination of callosal fibres. The intracerebral neuronal projections investigated in this study had slow conduction velocities (less than 1 m/sec, up to about 10 m/sec). It was found that projections from area 6, whether commissural, cortico-caudate, or cortico-peduncular have slower conduction velocities than their counterparts from area 4. It is suggested that this is related to the type of motor control in which these two areas are involved (slowly-responding postural movements, as opposed to more rapid distal limb movements). No neurons were found which had both commissural (or cortico-cortical), and cortico-fugal projections.

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Diameters of callosal fibers interconnecting cat sensorimotor cortex

Cited by 16 publications

References 7 publications

Species Differences and Similarities in the Fine Structure of the Mammalian Corpus callosum

Species Differences and Similarities in the Fine Structure of the Mammalian Corpus callosum

Representation of brief temporal patterns, Hebbian synapses, and the left-hemisphere dominance for phoneme recognition

Distribution and properties of commissural and other neurons in cat sensorimotor cortex

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