A histologically visible representation of the fingers and palm in primate area 3b and its immutability following long-term deafferentations

Jain, Neeraj; Catania, Kenneth C.; Kaas, Jon H.

doi:10.1093/cercor/8.3.227

Cited by 110 publications

(138 citation statements)

References 56 publications

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“…Additionally, within 3b, the border between the hand and facial representation (hand/face septum) was clearly identifiable. As reported by other investigators (Jain et al, 1998), we found close correspondence between physiologically and histochemically identified borders (Fig. 4 A).…”

Section: Neurophysiological Mapping Resultssupporting

confidence: 91%

Extensive Cortical Rewiring after Brain Injury

Dancause¹,

Barbay²,

Frost³

et al. 2005

J. Neurosci.

629

476

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Previously, we showed that the ventral premotor cortex (PMv) underwent neurophysiological remodeling after injury to the primary motor cortex (M1). In the present study, we examined cortical connections of PMv after such lesions. The neuroanatomical tract tracer biotinylated dextran amine was injected into the PMv hand area at least 5 months after ischemic injury to the M1 hand area. Comparison of labeling patterns between experimental and control animals demonstrated extensive proliferation of novel PMv terminal fields and the appearance of retrogradely labeled cell bodies within area 1/2 of the primary somatosensory cortex after M1 injury. Furthermore, evidence was found for alterations in the trajectory of PMv intracortical axons near the site of the lesion. The results suggest that M1 injury results in axonal sprouting near the ischemic injury and the establishment of novel connections within a distant target. These results support the hypothesis that, after a cortical injury, such as occurs after stroke, cortical areas distant from the injury undergo major neuroanatomical reorganization. Our results reveal an extraordinary anatomical rewiring capacity in the adult CNS after injury that may potentially play a role in recovery.

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Section: Neurophysiological Mapping Resultssupporting

confidence: 91%

Extensive Cortical Rewiring after Brain Injury

Dancause¹,

Barbay²,

Frost³

et al. 2005

J. Neurosci.

629

476

View full text Add to dashboard Cite

show abstract

“…Less noticeable septa separate representations of other body parts in the part of 3b devoted to the body as well. Most notably, thin septa separate territories for the representation of each digit of the hand in cortex just medial to the hand-face junction (Jain et al, 1998). These isolating septa are also apparent in area 3b of macaque monkeys, where they can be identified as early as 2 weeks after birth .…”

Section: Representation Of Tongue and Teeth In Area 3b And Adjoining mentioning

confidence: 89%

Cortical network for representing the teeth and tongue in primates

Kaas

Iyengar

2006

Anat. Rec.

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Sensory information from the tongue and teeth is used to evaluate and distinguish food and nonfood items in the mouth, reject some and masticate and swallow others. While it is known that primates have a complex array of 10 or more somatosensory areas that contribute to the analysis of sensory information from the hand, less is known about what cortical areas are involved in processing information from receptors of the tongue and teeth. The tongue contains taste receptors, as well as mechanoreceptors. Afferents from taste receptors and mechanoreceptors of the tongue access different ascending systems in the brainstem. However, it is uncertain how these two sources of information are processed in cortex. Here the parts of somatosensory areas 3b, 3a, and presumptive 1 that represent the mechanoreceptors of the teeth and tongue are identified, and evidence is presented that the representations of the tongue also get information from the taste nucleus of the thalamus, VPMpc. As areas 3b, 3a, and 1 project to other areas of somatosensory cortex, and those areas to additional areas, some or all of the currently defined somatosensory areas of cortex may be involved in processing gustatory, as well as tactile, information from the tongue and thus have a role in the biologically important function of evaluating food in the mouth. © 2006 Wiley-Liss, Inc.Key words: somatosensory cortex; area 3b; ventroposterior nucleus; parietal cortex; taste; gustatory system Sensory inputs from the tongue and teeth are obviously very important to the health and survival of most mammals. Based on inputs from receptors in the tongue and periodontal receptors around the teeth, distinctions are made between food and nonfood objects in the mouth, how much pressure can be delivered via the teeth on such items in the mouth, and how to guide tongue and jaw movements in food processing (Jacobs et al., 1998). For judgments about the desirability of food objects, taste information is integrated with somatosensory information on texture, compliance, and item size. Thus, inputs from taste receptors and mechanoreceptors in the mouth, in part, must be evaluated together in order to facilitate the basic function of eating. But where and how is this done? As neocortex is obviously important in the processing of sensory information, how are sensory systems, which are related to sensory afferents from the tongue and teeth, organized at the cortical level? Given the obvious importance of this issue, it may come as a surprise that little is known about the anatomical framework in cortex for processing information, and most of this understanding is focused on the cortical processing of taste. Because the system for processing somatosensory information at the cortical level has been well studied in monkeys, and many of the recent studies of cortical structures related to taste have been in monkeys, this review is focused on these primates. We argue that it is likely that the rather extensive cortical network for processing tactile information from the...

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“…In owl monkeys and squirrel monkeys, myelin-rich isomorphs associated with the oral structures and digits vary in size (Fig. 5 D and E) (45,46), as do the digit isomorphs for the digits in macaque monkeys, particularly D1 (27). Ocular dominance columns in V1 of squirrel monkeys can show extreme variability (47).…”

Section: Within-species Variabilitymentioning

confidence: 95%

Cortical evolution in mammals: The bane and beauty of phenotypic variability

Krubitzer

Seelke

2012

Proc. Natl. Acad. Sci. U.S.A.

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Evolution by natural selection, the unifying theory of all biological sciences, provides a basis for understanding how phenotypic variability is generated at all levels of organization from genes to behavior. However, it is important to distinguish what is the target of selection vs. what is transmitted across generations. Physical traits, behaviors, and the extended phenotype are all selected features of an individual, but genes that covary with different aspects of the targets of selection are inherited. Here we review the variability in cortical organization, morphology, and behavior that have been observed across species and describe similar types of variability within species. We examine sources of variability and the constraints that limit the types of changes that evolution has and can produce. Finally, we underscore the importance of how genes and genetic regulatory networks are deployed and interact within an individual, and their relationship to external, physical forces within the environment that shape the ultimate phenotype.E volution is the change in heritable, phenotypic characteristics within a population that occurs over successive generations. The notion that biological life evolves and that animal forms descend from ancient predecessors has been considered for centuries and, in fact, predates Aristotle (1). However, Charles Darwin was the first to articulate a scientific argument based on extensive observations for a theory of evolution through natural selection. Darwin's theory contains three basic tenets: individuals within a group are variable, variations are heritable, and not all individuals survive (2). Survival is based on selective advantages that particular phenotypic characteristics or behaviors confer to some individuals within a given environmental context. Although in Darwin's time our understanding of the brain was in its infancy and Mendel's Laws of Inheritance were little appreciated, Darwin's assertions regarding evolution through natural selection of adaptive traits, was, and still is, compelling.Recently our understanding of the mechanisms underlying evolution has become more sophisticated, and we appreciate that slight variations in gene sequence can be correlated with alterations of traits and behaviors within and across species. However, an important but often overlooked distinction is the difference between the targets of selection (i.e., phenotypic variations) vs. what natural selection passes on to the next generation (i.e., genes). Although genes are the heritable part of the equation and have a causal, although not always direct, link with some characteristic of the phenotype, genes are not the targets of selection. Genes are indirectly selected for because they covary with the targets of selection, and if the target of selection is adaptive, then genes or portions of the genome replicate and produce a long line of descendants. The direct target of selection is multilayered but can be thought to center around the individual and the unique phenotypic characteristics a...

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A histologically visible representation of the fingers and palm in primate area 3b and its immutability following long-term deafferentations

Cited by 110 publications

References 56 publications

Extensive Cortical Rewiring after Brain Injury

Extensive Cortical Rewiring after Brain Injury

Cortical network for representing the teeth and tongue in primates

Cortical evolution in mammals: The bane and beauty of phenotypic variability

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