The Nervous System and Its Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
The surface of the cerebral cortex is a series of raised ridges called convolutions or gyri (singular is "gyrus," indicating "turning," as in gyroscope) separated by small slitlike depressions called sulci (singular: "sulcus"). The effect of these structures is to increase the surface area of the cortex, increasing the proportion of gray matter to underlying white matter. Two deep grooves cross the cortex: the longitudinal fissure (from the Latin for "crack"), which separates the two cerebral hemispheres, and the transverse cerebral fissure, which separates the cerebrum from the cerebellum.
ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
The cerebral cortex represents the GREY MATTER at the outer surface of the CEREBRAL HEMISPHERES. Evolutionarily, it is the most recent development of the CENTRAL NERVOUS SYSTEM. The human cerebral cortex contains billions of NEURONS and represents the seat of higher psychological functions. As a result of rapid increase in size, the cerebral cortex in higher mammals shows extensive foldings called convolutions. Unfolded, the human cerebral cortex measures about 1600-2500 cm2 in area. The crest of a fold is called a GYRUS, while a groove that separates gyri is called a SULCUS. Deep sulci are often called FISSURES. The longitudinal fissure separates the two cerebral hemispheres at the midline. Although there are individual differences in detail, certain gyri and sulci are more constant than others, and are used as landmarks. Beneath the cerebral cortex is the WHITE MATTER which consists of descending and ascending fibres, association fibres interconnecting different cortical regions, and commissural fibres connecting the two sides of the hemisphere. The commissural fibres form the CORPUS CALLOSUM.
Neurosurgery And Clinical Tales
Andrew P. Wickens in A History of the Brain, 2014
Around the same time as Freeman and Watt were performing their first lobotomies, a new surgical technique was being considered for the relief of epilepsy. This was the severing or splitting of the corpus callosum, otherwise known as commissurotomy, to halt the spread of seizure activity in the brain. The corpus callosum, which stands out as a white arched structure between the two cortical hemispheres, has a long history. First recognised by Galen who referred to it as a ‘callous’ since it resembled hard or thickened skin, the corpus callosum was also mentioned by Vesalius in 1543, who thought it did little more than support the brain mass above and maintain the shapes of the ventricles. By the seventeenth century, the corpus callosum had become implicated in mental function when Thomas Willis recognised it as a pathway allowing cerebral spirits to travel from one hemisphere to another. It was even regarded as ‘the seat of the soul, which imagines, deliberates and judges’ by Italian Giovanni Maria Lancisi in 1712. However, it was not until the later part of the eighteenth century the true function of the corpus callosum was identified when anatomists such as Giovanni Morgagni and Felix Vicq d’Azyr realised it was a bundle of nerve fibres (i.e. a commissure) connecting the grey regions of the two cerebral hemispheres. Today, we now know the corpus callosum contains in the region of 300 million ‘white’ myelinated nerve fibres, which allows the two cerebral hemispheres to communicate with each other.
Georg Büchner: Anatomist of the animal brain and the human mind
Published in Journal of the History of the Neurosciences, 2020
Oken’s analogical idea was further developed by Carus. He divided the brain into three large regions from front to back: the cerebral hemispheres, the quadrigeminal region together with the medulla oblongata, and the cerebellum (Carus 1814, 117–21, 266, 287). Carus assigned these areas corresponding functions based on the developmental stage of the species in question (including humans). Carus’s ambition went so far as to encompass all mental life (Hagner 2004, 76–93), resulting in a comprehensive theory of identity. He argued: [O]riginally, each of the three large cranial vertebrae corresponds to a brain mass, that each brain mass likewise originally has its parallel in one of the senses (hearing, sight, smell) as the elements of our mental development, and that consequently, depending on individual human differences, one of the senses will stand out more and this prominence will be externally reflected in the more pronounced formation of the cranial vertebra pertaining to it. (Carus 1828, 176)
Suckling in litters with different sizes, and early and late swimming exercise differentially modulates anxiety-like behavior, memory and electrocorticogram potentiation after spreading depression in rats
Published in Nutritional Neuroscience, 2019
Mariana Barros e Silva-Gondim, Thays Kallyne Marinho de Souza, Marcelo Cairrão Araújo Rodrigues, Rubem Carlos Araújo Guedes
On P90–120, animals were intraperitoneally anesthetized with a mixture of 1000 mg/kg urethane plus 40 mg/kg chloralose (Sigma, St Louis, USA). The level of anesthesia was monitored as previously described.15 Three holes were drilled at the level of the right cerebral hemisphere, lined up in the frontal-to-occipital direction and parallel to the midline. We used the first orifice (2 mm diameter; drilled at the frontal bone; hole limits between AP coordinates +1 to +3) for stimulation with 2% potassium chloride solution (approximately 270 mM), which is necessary to elicit CSD. The two other holes (2–3 mm diameter drilled on the parietal bone) served as recording places and were designated, respectively, as the n (near) and r (remote) recording points in relation to the CSD elicitation point. The hole limits for the n and r recording points were between AP −1/−4 and −5/−8, respectively.
Effects of constraint-induced movement therapy on brain glucose metabolism in a rat model of cerebral ischemia: a micro PET/CT study
Published in International Journal of Neuroscience, 2018
Ying-Ying Li, Bei Zhang, Ke-Wei Yu, Ce Li, Hong-Yu Xie, Wei-Qi Bao, Yan-Yan Kong, Fang-Yang Jiao, Yi-Hui Guan, Yu-Long Bai
The corpus callosum is the largest intercommunication neural pathway of the two cerebral hemispheres in mammals [42]. It is hypothesized that the corpus callosum inhibits transfer of information between the two hemispheres so as to enhance the function of the dominant hemisphere and suppress the non-dominant hemisphere activity ‘inhibitory model’. This will ultimately lead to independent information processing in each hemisphere and increase the degree of the cerebral functional lateralization [43]. CIMT increased FDG uptake in the contralateral brain regions associated with decreased glucose utilization in the ipsilateral hemisphere. The ‘inhibitory model’ can partly explain the decreased FDG uptake (decreased glucose utilization) in brain regions observed in the ipsilateral hemisphere in the CIMT group compared to the Control group (Figure 7 and 8(A)). In addition, the Sham group showed decreased FDG uptake in the ipsilateral cingulate and motor cortex compared to the Normal group (Figure 7), which might be attributed to the constraint of movement in the unaffected limb.
Related Knowledge Centers
- Anterior Commissure
- Axon
- Cerebral Cortex
- Corpus Callosum
- Posterior Commissure
- Cerebrum
- White Matter
- Brain
- Longitudinal Fissure
- Grey Matter