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Alien Hand Syndrome
Published in Alexander R. Toftness, Incredible Consequences of Brain Injury, 2023
Each half of your brain contributes to controlling the muscles on the opposite half of your body, such that your right brain hemisphere is more in charge of controlling your left arm than is your left hemisphere and vice versa. When the hemispheres of your brain cannot communicate effectively because of a damaged corpus callosum, they may control their own half of the body with less discussion about it with the other hemisphere. For example, “damage to the corpus callosum results in the left [hand] being controlled only by the right hemisphere” without contribution from the left hemisphere (Scepkowski & Cronin-Golomb, 2003, p. 264). This may result in one half of the brain being surprised by the actions taken by the other half of the brain, because one hemisphere did not know what the other hemisphere was planning. Sometimes corpus callosum damage is accidental, but it can be performed intentionally as a treatment for seizures (see Seizures). Callosal alien hand syndrome is strongly associated with intermanual conflict as the two hemispheres of the brain end up disagreeing with one another because of the loss in communication efficiency (Feinberg et al., 1992).
Imaging of head trauma
Published in Helen Whitwell, Christopher Milroy, Daniel du Plessis, Forensic Neuropathology, 2021
In severe head trauma from road traffic accidents, shear-strain injuries may cause tears of the subependymal vein, fornix, septum pellucidum and choroid plexus. In a large series by Hashimoto et al., these were associated with more severe head injury and high mortality, 20 out of 32 with IVH died. The fornix and septum pellucidum were weak points for shearing injuries (Figure 3.24). In extreme cases, the corpus callosum may be disrupted (Figure 3.22b).
Paper 4
Published in Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw, The Final FRCR, 2020
Amanda Rabone, Benedict Thomson, Nicky Dineen, Vincent Helyar, Aidan Shaw
In lobar forms of the condition it is just the frontal lobes and the frontal horns of the lateral ventricles which remain fused. There is either complete or partial cleavage of the thalami and the falx and interhemispheric fissure is formed. The corpus callosum may be hypoplastic.
The association between White matter microstructure alterations detected by Diffusional kurtosis imaging in Neural circuit and post-stroke depression
Published in Neurological Research, 2021
Weijing Liang, Zexin Fan, Sha Cui, Xueyong Shen, Li Wang
Besides, the anterior and posterior limb of internal capsule and corpus callosum are important tissues connecting the bilateral neostriatum, thalamus and cerebral hemisphere. Corpus callosum is a transverse nerve fiber bundle and the largest commissural fiber in the hemisphere, which plays an important role in integration and transmission of information. White matter fibers communicate with the bilateral prefrontal cortex through the genu of corpus callosum. We found that MK value of PSD group in the genu of corpus callosum is lower, but there was no significant decrease of MK/RK value in anterior and posterior limb of internal capsule (p > 0.05), suggesting that the corpus callosum may be associated with the occurrence of PSD. However, there was no significant difference in FA value in corpus callosum between the depressive and control group in Nobuhara K’s study [29]. Therefore, the role of corpus callosum and internal capsule in the development of PSD needs further study.
Regional callosal integrity and bilaterality of limb weakness in amyotrophic lateral sclerosis
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2020
Sicong Tu, Chenyu Wang, Ricarda A.L. Menke, Kevin Talbot, Michael Barnett, Matthew C. Kiernan, Martin R. Turner
The underlying pathological process associated with laterality of limb weakness and subsequent spread in ALS remains unclear, but may involve abnormality in transcallosal inhibitory control (16). Degeneration affects excitatory callosal pyramidal neurons whose primary targets are inhibitory interneurons in the contralateral hemisphere (32) via a corticofugal transsynaptic glutamate excitotoxic process (33,34). The current findings of a clinical association between reduced corpus callosum integrity and unilateral limb weakness suggests obstruction of the primary interhemispheric commissure of the brain may influence spread of symptoms. There are of course smaller subcortical commissures, which may explain a progressive involvement of deep gray matter structures with disease progression in ALS (35,36). They have been shown to play a fundamental role in the functional reconfiguration of the brain when interhemispheric transfer is compromised, such as following callosotomy and congenital agenesis of the corpus callosum (29). Our findings would then suggest involvement of extra-motor callosal fibers, as the primary motor connected posterior midbody is selectively impacted across all ALS patients, irrespective of the bilaterality, or not, of limb weakness.
Nonketotic Hyperglycinemia: Two Case Reports and Review
Published in The Neurodiagnostic Journal, 2019
Rajesh P. Poothrikovil, Khalid Al Thihli, Amna Al Futaisi, Fathiya Al Murshidi
The infantile form presents in the first few months of life and is also characterized by hypotonia, developmental delay, and seizures. An increased cerebrospinal fluid (CSF) glycine level along with an elevated glycine index (CSF/plasma glycine ratio >0.08) suggests the diagnosis of NKH (Gallagher et al. 2017). EEG typically shows a burst-suppression pattern at the presentation that evolves into multifocal spikes and hypsarrhythmia. MRI can be normal or may show hypoplastic corpus callosum. Although no effective treatment exists for this condition, therapy is focused on managing seizures using antiepileptic medications, reducing the plasma concentration of glycine via administration of sodium benzoate, and N-methyl-D-aspartate (NMDA) receptor antagonism using ketamine injections or oral dextromethorphan. Classical glycine encephalopathy usually carries a very poor prognosis.