The Reunified Split Brain

Bureš, Jan; Burešová, O.

doi:10.1016/b978-0-12-745050-6.50017-5

Cited by 13 publications

(15 citation statements)

References 48 publications

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“…Through active “write in,” which may occur over the course of just a few trials or on even a single trial (Fenton and Bures, 1994), a duplicate “motor engram” is formed in the untrained hemisphere—a mode of transfer that has been termed imperative . Direct “read-out” of a lateralized engram that does not require an equivalent active process has been designated facultative transfer (Bureš et al, 1988). …”

Section: Bilateral Access Approachmentioning

confidence: 99%

Neural pathways mediating cross education of motor function

Ruddy¹,

Carson²

2013

Front. Hum. Neurosci.

156

160

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Cross education is the process whereby training of one limb gives rise to enhancements in the performance of the opposite, untrained limb. Despite interest in this phenomenon having been sustained for more than a century, a comprehensive explanation of the mediating neural mechanisms remains elusive. With new evidence emerging that cross education may have therapeutic utility, the need to provide a principled evidential basis upon which to design interventions becomes ever more pressing. Generally, mechanistic accounts of cross education align with one of two explanatory frameworks. Models of the “cross activation” variety encapsulate the observation that unilateral execution of a movement task gives rise to bilateral increases in corticospinal excitability. The related conjecture is that such distributed activity, when present during unilateral practice, leads to simultaneous adaptations in neural circuits that project to the muscles of the untrained limb, thus facilitating subsequent performance of the task. Alternatively, “bilateral access” models entail that motor engrams formed during unilateral practice, may subsequently be utilized bilaterally—that is, by the neural circuitry that constitutes the control centers for movements of both limbs. At present there is a paucity of direct evidence that allows the corresponding neural processes to be delineated, or their relative contributions in different task contexts to be ascertained. In the current review we seek to synthesize and assimilate the fragmentary information that is available, including consideration of knowledge that has emerged as a result of technological advances in structural and functional brain imaging. An emphasis upon task dependency is maintained throughout, the conviction being that the neural mechanisms that mediate cross education may only be understood in this context.

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Section: Bilateral Access Approachmentioning

confidence: 99%

Neural pathways mediating cross education of motor function

Ruddy¹,

Carson²

2013

Front. Hum. Neurosci.

156

160

View full text Add to dashboard Cite

show abstract

“…To further determine the generality of the behavioral impairment, we decided to subject the mice to an additional learning task, CTA, which depends on association capabilities and sensory modalities (gustatory, visceral) not taxed by the water maze tasks. CTA tolerates long delays between stimulus (a novel taste) and reinforcement (LiCl injection) and is subserved by several brain areas, including brainstem and gustatory cortex (37,42).…”

mentioning

confidence: 99%

Overexpression of urokinase-type plasminogen activator in transgenic mice is correlated with impaired learning.

Meiri

Masos

Rosenblum

et al. 1994

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

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Transgenic mice desi ated aMUPA overproduce in the brain murine urokinase-type plainogen activator (uPA), an extracellular protease implicated in tissue remodeling. We have now lid, by in situ hybridization, extensive signal of uPA mRNA in the aMUPA cortex, hippocampus, and amygdala, sites that were not labeled in counterpart wild-type mice. Furthermore, biochemical measurements reveal a remarkably high level of enzymatic activity of uPA in the cortex and hippocampus of aMUPA compared with wildtype mice. We have used the aMUPA mice to exami whether the abnormal level of uPA in the cortex and the limbic system affects lrning ability. We report that aMUPA mice perform poorly in tasks of spatial, olfactory, and taste-aversion learning, while displaying normal sensory and motor capabiliti. Our results snuest that uPA is involved in neural processes subserving a variety of laing types.

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“…The functional state of the central nervous system was followed up using a set of behavioral tests characterizing the cognitive function of the brain (learning and memory). Disturbances of brain integrative activity were studied by a modification of the conditioned passive avoidance response (CPAR) [5] using a method [1] with unavoidable punishment. CPAR was elaborated 6 days after resuscitation and neurotransplantation.…”

Section: Methodsmentioning

confidence: 99%

Threshold of seizure activity of the brain and higher nervous activity in the postresuscitation period for intracerebral allotransplantation of fetal neocortex tissue

1996

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The threshold of seizure activity of the brain, long-term memory, and learning ability are studied in Wistar rats for bilateral transplantation of fetal nervous tissue in area CA1 of the hippocampus. The grafts are performed on the 2nd, 7th, 14th and 30th days after clinical death caused by asphyxia. A neurotransplantation performed on the 2nd day of the postresuscitation period is found to prevent seizure activity, whereas that performed on the 7th-14th days results in a sharp decline or cessation of spontaneous and induced epileptiform convulsive seizures, prolonged preservation of the long-term memory trace, an improvement of learning ability, and a lessening of defensive and phobic behavior in a large proportion of the animals. Key Words: seizure activity; higher nervous activity; postresuscitation oeriod; fetal nervous tissue transplantationThe homeostatic control mechanisms regulating the seizure readiness of the brain are known to fail after clinical death (CD), resulting in spontaneous convulsive seizures and enhanced sensitivity to the epileptogenic effect of different stimuli, as well as a lowering of the threshold of brain seizure activity (TBSA) and disturbances of long-term memory [9,11]. Other sequelae in the postresuscitation period are disturbances of the cerebral microcirculation and metabolic processes, a reduction in the density of neurons and synapses, reorganization of the synaptoarchitectonics, and a shrinking of the receptive area of neurons in the neocortex, hippocampus, amygdaloid complex, and ventrolateral nucleus of the thalamus [8,9]. It is known that transplantation of fetal nervous tissue leads to a TBSA increase, and improvement of higher nervous activity values in rats of the Krushinsky-Molodkina line with a genetically determined high brain seizure readiness and focal lesions of the hippocampus and amygdaloid complex [4,5]. However, the influence of neurotransplantation on TBSA and higher nervous activity for diffuse lesions of the brain in the postresuscitation period after CD has been analyzed insufficiently.The aim of this investigation was to study the effect of intracerebral allotransplantation of fetal neocortex tissue on the TBSA and higher nervous activity on rats after CD. MATERIALS AND METHODSCD was modeled on animals under ether anesthesia by interruption of the systemic blood flow as a result of 6-min mechanical asphyxia [12]. The animals were revived with closed chest massage and artificial pulmonary ventilation.TBSA was determined using dosed sound stimuli (86 dB) in a transparent soundproof chamber 1 day after the procedure and then every 3rd day for 180

show abstract

The Reunified Split Brain

Cited by 13 publications

References 48 publications

Neural pathways mediating cross education of motor function

Neural pathways mediating cross education of motor function

Overexpression of urokinase-type plasminogen activator in transgenic mice is correlated with impaired learning.

Threshold of seizure activity of the brain and higher nervous activity in the postresuscitation period for intracerebral allotransplantation of fetal neocortex tissue

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