Barrels in somatic sensory neocortex of the marsupialTrichosurus vulpecula (brush-tailed possum)

Weller, W. Lee

doi:10.1016/0006-8993(72)90271-5

Cited by 60 publications

(38 citation statements)

References 14 publications

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“…The whole sensorimotor region can be divided cytoarchitectonically into agranular motor cortex, a body region of somatosensory cortex (SSb) which partly overlaps functional motor cortex, a head region of somatosensory cortex (SSh) characterized by 'barrels' in layer four, plus secondary somatosen sory cortex [Weller, 1972;Weller and Haight, 1973;Neylon and Haight, 1983]. In this study we have ana lyzed neurogenesis in both body (SSb) and head (SSh) regions of sensorimotor cortex.…”

Section: Sensorimotor Cortexmentioning

confidence: 99%

“…Subcortical levels of the somatosensory system of both mice and rats also have a vibrissa-related struc tural organization [Van der Loos, 1976;Belford and Killackey, 1979;Ma and Woolsey, 1984] which can be similarly altered by postnatal damage to vibrissal fol licles [Woolsey et al, 1979;Bates et al, 1982;Durham and Woolsey, 1984], While the period during which the organization of the cortical barrel field may be al tered by vibrissal damage lasts until the 4th or 5th postnatal day, the corresponding periods for thalamic and medullary somatosensory nuclei last only until about the 3rd postnatal day [Durham and Woolsey, 1984;Bates etal., 1982], Weller [1972] reported the presence of cortical bar rels in brush-tailed possums. Some of these barrels re ceive sensory input from single facial vibrissae .…”

Section: Neurogenesis and Plasticitymentioning

confidence: 99%

“…We have examined neurogenesis in sensorimotor thalamus, sensorimotor cortex, basal ganglia, and cerebellum, since forma tion of these regions occurs during postnatal life. Sen sorimotor thalamus and cortex have been character ized by anatomical and physiological studies [Goldby, 1939;Abbie, 1940;Adey and Kerr, 1954;Rees and Hore, 1970;Weller, 1972;Haight and Weller, 1973;Weller and Haight, 1973;Neylon, 1978a, b, 1979;Joschko and Sanderson, 1987] which permit identification of functional areas within thalamus and cortex. Specific questions that we have been able to address involve the relative timing of neurogenesis in different parts of the sensor imotor system, what sorts of cytogenetic gradients oc cur, and how timing of neurogenesis relates to the plasticity of the vibrissal barrel field in sensorimotor cortex [Weller, 1979].…”

Section: Introductionmentioning

confidence: 99%

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Neurogenesis in a Marsupial: The Brush-Tailed Possum (Trichosurus vulpecula)

Sanderson

Weller

1990

Brain Behav Evol

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The times of origin of neurons in sensorimotor pathways of the marsupial brush-tailed possum were determined with ³H-thymidine autoradiography. A series of 20 possums were injected with ³H-thymidine from postnatal days 5–95 and were normally allowed to survive until the brain cytoarchitecture was mature. Brain stem and spinal sensorimotor regions were not labelled in our study and presumably form before birth in order to enable the newborn young to make the journey from the birth canal to the pouch on its own. Neurogenesis in thalamic sensorimotor nuclei probably begins about the time of birth and continues into the 2nd week of postnatal life. Formation of neurons in the sensorimotor cortex and the basal ganglia occurs during the first 2 months of postnatal life and in the cerebellum during the first 3 months. This protracted postnatal development of telencephalic and cerebellar sensorimotor regions offers great advantages for developmental studies.

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Section: Sensorimotor Cortexmentioning

confidence: 99%

Section: Neurogenesis and Plasticitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Neurogenesis in a Marsupial: The Brush-Tailed Possum (Trichosurus vulpecula)

Sanderson

Weller

1990

Brain Behav Evol

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“…Besides the wallaby, several marsupial species are known to have cortical barrels, including gliders and possums (Weller, 1972). The barrel field is situated just in front of the parietal sulcus, in the region corresponding to the muzzle and upper lip (Lende, 1963).…”

Section: Whisker Patterns In Marsupialsmentioning

confidence: 99%

Whisker maps in marsupials: Nerve lesions and critical periods

et al. 2006

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In the wallaby, whisker-related patterns develop over a protracted period of postnatal maturation in the pouch. Afferents arrive simultaneously in the thalamus and cortex from postnatal day (P) 15. Whiskerrelated patterns are first seen in the thalamus at P50 and are well formed by P73, before cortical patterns first appear (P75) or are well developed (P85). This study used the slow developmental sequence and accessibility of the pouch young to investigate the effect of nerve lesions before afferent arrival, or at times when thalamic patterns are obvious but cortical patterns not yet formed. The left infraorbital nerve supplying the whiskers was cut at P0 -93 and animals were perfused at P112-123. Sections through the thalamus (horizontal plane) and cortex (tangential) were reacted for cytochrome oxidase to visualize whisker-related patterns. Lesions of the nerve at P2-5, before innervation of the thalamus or cortex, resulted in an absence of patterns at both levels. Lesions from P66 -77 also disrupted thalamic and cortical patterns, despite the fact that thalamic patterns are normally well established by P73. Lesions from P82-93 resulted in normal thalamic and cortical patterns. Thus, despite the wallaby having clearly separated times for the development of patterns at different levels of the pathway, these results suggest a single critical period for the thalamus and cortex, coincident with the maturation of the cortical pattern. Possible mechanisms underpinning this critical period could include dependence of the thalamic pattern on corticothalamic activity or peripheral signals to allow consolidation of thalamic barreloids. © 2006 Wiley-Liss, Inc. Key words: trigeminal pathway; vibrissa; barrel; somatosensory development; whisker folliclesThe rodent whisker-barrel pathway has provided a model system par excellence for studies of normal somatosensory development and function as well as plasticity after lesioning (Miller et al., 2001;Waite, 2004). The pattern of whiskers on the muzzle is replicated in visible and quantifiable patterns at each level of the neuraxis from brainstem to cortex. Moreover, the patterns develop in a temporal sequence from periphery to somatosensory cortex. The whiskers on the muzzle are visible from embryonic day (E) 14 in the rat, with whisker-related patterns appearing first in the brainstem [E20 to postnatal day (P) 0 -1], then the thalamus (P2-3) and cortex (P3-5) (Killackey, 1985). During this developmental period, pattern development is vulnerable to peripheral lesions, such as removal of the whisker follicles or section of their sensory nerve, the infraorbital. Peripheral lesions in the perinatal period cause death of many trigeminal ganglion cells and permanent loss of patterns in the brainstem nuclei.

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“…nolds et al, 1985;Dunlop et al, 1987;Beazley, 1987-1989;Reynolds and Saunders, 1988;. Australian species, occuring as they do in greater number and diversity than their American cousins, present a wider and more interest ing variety of specializations of life-style, behaviour, and neuroanatomy [Johnson, 1977;Kirsch, 1977], Brush-tailed possums are not the least interesting in these regards [Hayhow, 1967;Weller, 1972;Haight et al, 1980;Gates and Aitkin, 1984], Tables 2 and 3 summarize data for time of origin of neurons in visual and auditory centres in the brush tailed possum and in other marsupials and placenta! mammals that have been studied.…”

Section: Discussionmentioning

confidence: 99%

Neurogenesis in a Marsupial: The Brush-Tailed Possum (Trichosurus vulpecula)

Sanderson

Aitkin²

1990

Brain Behav Evol

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The times of origin of neurons in the visual and auditory systems were studied in a marsupial, the brush-tailed possum, using tritiated thymidine autoradiography. Within the subcortical visual pathways, most neurons are generated between postnatal days 5 and 21, and the neurons of the primary visual cortex up to postnatal day 68. In the subcortical auditory pathways, most neurons are generated between postnatal days 5 and 28, and all auditory cortex neurons have appeared by postnatal day 46. Neurons in a single layer of cerebral cortex are generated during a period of about 2 weeks. Thus cortical neurogenesis in marsupials extends over a period similar to that seen in primates

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Barrels in somatic sensory neocortex of the marsupialTrichosurus vulpecula (brush-tailed possum)

Cited by 60 publications

References 14 publications

Neurogenesis in a Marsupial: The Brush-Tailed Possum <i>(Trichosurus vulpecula)</i>

Neurogenesis in a Marsupial: The Brush-Tailed Possum <i>(Trichosurus vulpecula)</i>

Whisker maps in marsupials: Nerve lesions and critical periods

Neurogenesis in a Marsupial: The Brush-Tailed Possum <i>(Trichosurus vulpecula)</i>

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