Tactile-Evoked Potentials in Schizophrenia

1983 ◽  
Vol 143 (2) ◽  
pp. 156-164 ◽  
Author(s):  
Kathleen H. Tress ◽  
David J. Caudrey ◽  
Bharat Mehta
Keyword(s):  
Corpus Callosum ◽  
Evoked Potentials ◽  
Tactile Stimulation ◽  
The Other ◽  
Cerebral Hemispheres ◽  
Negative Wave ◽  
Control Subjects ◽  
Healthy Control ◽  
Lateralization Effect ◽  
Stimulation Of

SummaryEEG potentials evoked by tactile stimulation of the forearm (tactile-evoked potentials or TEPs) were recorded simultaneously from both cerebral hemispheres in a group of schizophrenics and a group of healthy control subjects. Differences between the groups were found for the early waves of the TEPs: in the control subjects the first two positive waves (P25 and P50) and the first negative wave (N35) recorded from the hemisphere on the same side as the stimulation were slower (i.e. had longer latency) than those recorded from the hemisphere contralateral to the stimulation. This lateralization effect’ was not seen in the schizophrenic subjects. It was concluded that the TEPs recorded from the hemisphere ipsilateral to the stimulus were not being transmitted from the other hemisphere via the corpus callosum and must therefore have been transmitted via direct ipsilateral pathways from the periphery.In a second experiment the drug pindolol was administered to schizophrenic subjects but differences in P50 latency between ipsilateral and contralateral hemispheres were found equally in both drug and placebo groups. We also found slight evidence to suggest that the more severely ill the patient the more similar the TEP latencies recorded from the contralateral and the ipsilateral hemispheres.

Localization of Stereotactic Targets by Microrecording of Thalamic Somatosensory Evoked Potentials

Neurosurgery ◽  
1991 ◽  
Vol 28 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Fumio Shima ◽  
Takato Morioka ◽  
Shozo Tobimatsu ◽  
Omiros Kavaklis ◽  
Motohiro Kato ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Median Nerve ◽  
Somatosensory Evoked Potentials ◽  
Practical Method ◽  
The Other ◽  
Basal Region ◽  
Thalamic Nuclei ◽  
Median Nerve Stimulation ◽  
Lower Amplitude ◽  
Stimulation Of

Abstract To improve the localization of stereotactic targets, somatosensory evoked potentials (SEPs) were recorded from the thalamus and subthalamic area using a specially designed semimicroelectrode in 61 patients and a conventional “macroclectrode” in 17 patients. By means of the semimicroelectrode, median nerve stimulation evoked two distinct SEPs, consisting of a diphasic wave with a huge positivity restricted to the nucleus ventrocaudalis (Vc) and a triphasic wave of lower amplitude with a major negativity in the ventral part of the nucleus ventrointermedius (Vim) and nucleus ventrooralis posterior (Vop) as well as the subthalamic lemniscal pathway. The Vim-Vc junction could thus be clearly delineated by an abrupt transition of SEPs from one type to the other with a precision of 1 mm. The parvicellular part of the Vc (Vcpc). situated in its basal region, was distinguishable from the Vc proper by a significant reduction of the positivity elicited by stimulation of the median nerve and by a rapid growth of a diphasic SEPs to stimulation of the posterior tibial nerve. In the other thalamic nuclei, stimulation of the median nerve elicited triphasic SEPs of a very small amplitude, suggesting a volume conduction current from the lemniscal pathway. With the macroclectrode, the positivity in the Vc was sensitive to electrode manipulation and the thalamic nuclei could not be distinctly outlined. SEP monitoring using the semimicroelectrode significantly improved the precision of target localization, which allowed minimizing of the volume of the therapeutic lesion without losing surgical effectiveness, while avoiding complications associated with increased penetration of the coagulating electrode. It is suggested that recording serial thalamic SEPs with the semimicroelectrode is a practical method to refine stereotactic targets in the thalamus.

Corpus Callosum Microstructural Alterations In Children With Memory Related Learning Disability: A Diffusion Tensor Imaging Study

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Abeer Maghawry Abd elhameed ◽  
Shaimaa Abdelsattar Mohammad ◽  
Neveen Hassan Nashaat ◽  
Amgad Samy Abdel-Rahman ◽  
Ehab Ragaa Abdol Raouf
Keyword(s):  
Learning Disabilities ◽  
White Matter ◽  
Corpus Callosum ◽  
Learning Disability ◽  
Diffusion Tensor ◽  
Digit Span ◽  
Clinical Test ◽  
Control Subjects ◽  
Healthy Control ◽  
With Memory

Abstract Purpose The purpose of this study is to assess the corpus callosum microstructural changes in children with memory related learning disability. Methods DTI was performed in 20 patients with memory related learning disabilities (MRLD +) and 22 matched healthy control subjects (MRLD -) aged 7– 13 years. Fractional anisotropy (FA), axial diffusivity, radial diffusivity (RD) and trace were calculated for corpus callosum. Comparison between patients with memory related learning disabilities (MRLD +) and healthy control subjects (MRLD -) was performed. DTI metrics were correlated to clinical digit span backward scores in (MRLD +) group. A pvalue less than .05 was considered significant. Results The corpus callosum showed a highly significant higher FA and lower diffusivity indices in (MRLD +) group compared to the (MRLD -) group (p < 0.001). No significant correlation between the clinical test “digit span backward” scores and DTI metrics of the corpus callosum was found. Conclusion Changes in DTI metrics of corpus callosum in patients with memory related learning disabilities reflects white matter micro-structural changes. Higher FA values and lower diffusivity indices do not necessarily indicate healthier white matter but, can indicate pathology.

scholarly journals Cortical Activation in Mental Rotation and the Role of the Corpus Callosum: Observations in Healthy Subjects and Split-Brain Patients

Symmetry ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1953
Author(s):  
Chiara Pierpaoli ◽  
Mojgan Ghoushi ◽  
Nicoletta Foschi ◽  
Simona Lattanzi ◽  
Mara Fabri ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Mental Rotation ◽  
Right Hemisphere ◽  
Body Part ◽  
Cortical Activation ◽  
Control Subjects ◽  
Healthy Control ◽  
The Difference ◽  
The Right

The mental rotation (MR) is an abstract mental operation thanks to which a person imagines rotating an object or a body part to place it in an other position. The ability to perform MR was belived to belong to the right hemisphere for objects, and to the left for one’s ownbody images. Mental rotation is considered to be basic for imitation with the anatomical perspective, which in turn is needed for social interactions and learning. Altered imitative performances have been reported in patients with resections or microstructure alterations of the corpus callosum (CC). These patients also display a reduced MR ability compared to control subjects, as shown in a recent behavioral study. The difference was statistically significant, leading us to hypothesize a role of the CC to integrate the two hemispheres’ asymmetric functions. The present study was designed to detect, by means of a functional MRI, the cortical activation evoked during an MR task in healthy control subjects and callosotomized patients. The results suggest that performing MR requires activation of opercular cortex and inferior parietal lobule in either hemispheres, and likely the integrity of the CC, thus confirming that the main brain commissure is involved in cognitive functions.

Self-Consciousness and "Split" Brains

2018 ◽  
Author(s):  
Elizabeth Schechter
Keyword(s):  
United States ◽  
Twentieth Century ◽  
Corpus Callosum ◽  
Human Brain ◽  
The United States ◽  
The Other ◽  
Cerebral Hemispheres ◽  
Experimental Conditions ◽  
Fiber Tract ◽  
Split Brain

The largest fiber tract in the human brain is the corpus callosum, which connects the two cerebral hemispheres. A number of surgeries severing this structure were performed on adults in the United States in the second half of the twentieth century. After they are surgically separated from each other in this way, a “split-brain” subject’s hemispheres begin to operate unusually independently of each other in the realms of perception, cognition, and the control of action—almost as if each had a mind of its own. But can a mere hemisphere really see? Speak? Feel? Know what it has done? The split-brain cases raise questions of psychological identity: How many subjects of experience are there within a split-brain subject? How many persons? How many minds? Under experimental conditions, split-brain subjects often act as though they were animated by two distinct conscious beings, evoking the duality intuition. On the other hand, a split-brain subject seems like one of us—not like two of us sharing one body. Split-brain subjects thus also evoke the unity intuition.This book is devoted to reconciling these two apparently opposing intuitions. The key to doing so are facts about the way self-consciousness operates in split-brain subjects. A split-brain subject is composed of two conscious psychological beings that fail to recognize each other’s existence and indeed cannot distinguish themselves from each other. Instead, each must first-personally identify with the split-brain subject as a whole, and in so doing, the two make themselves into one person.

Hopelessness and Psychiatric Symptomatology in Hospitalized Physically Ill Adolescents

1996 ◽  
Vol 26 (1) ◽  
pp. 47-51 ◽  
Author(s):  
Anthony L. Pillay ◽  
Douglas R. Wassenaar
Keyword(s):  
Psychiatric Symptoms ◽  
The Other ◽  
Psychiatric Disturbance ◽  
Psychiatric Symptomatology ◽  
Healthy Group ◽  
Matched Group ◽  
Control Subjects ◽  
Healthy Control ◽  
The One

This study compares scores on psychiatric disturbance and hopelessness in two adolescent samples. The one sample was a physically ill hospitalized group, and the other was a matched group of healthy control subjects. It was found that the hospitalized physically ill group scored significantly higher on both psychiatric disturbance and hopelessness than the healthy group. At six-month follow-up, the physically ill group's scores on psychiatric disturbance had declined significantly, but hopelessness scores remained significantly high. In line with other findings, this study suggests that insufficient clinical attention is paid to psychiatric symptoms in hospitalized physically ill patients, and that the high hopelessness scores after six months warrant clinical psychological evaluation.

Brain Disconnection and Schizophrenia

1973 ◽  
Vol 123 (577) ◽  
pp. 661-662 ◽  
Author(s):  
J. G. Beaumont ◽  
S. J. Dimond
Keyword(s):  
Corpus Callosum ◽  
The Body ◽  
The Other ◽  
Cerebral Hemispheres ◽  
Split Brain ◽  
Cross Match ◽  
As If

The concept of brain disconnection derives from work in which the two cerebral hemispheres are surgically separated by division of the corpus callosum. The patient behaves as if his two half-brains function to some degree independently. The syndrome of brain disconnection is exemplified by such split-brain cases (Geschwind, 1965). Neither hemisphere shows an awareness of the functions of the other, and there is a marked failure to cross-match stimuli across the midline of the body. The integrity of the corpus callosum is essential to normal integration between the hemispheres.

Measurement of Blood Cortisol and Acid Output in Patients with Duodenal Ulceration and Normal Subjects During Insulin Hypoglycaemia

1985 ◽  
Vol 69 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Anna C. Athow ◽  
Anna T. Sewerniak ◽  
Tina P. Barton ◽  
C. G. Clark ◽  
M. R. Lewin
Keyword(s):  
Duodenal Ulcer ◽  
Gastric Acid ◽  
Acid Output ◽  
Normal Subjects ◽  
Duodenal Ulceration ◽  
Control Subjects ◽  
Healthy Control ◽  
Peak Acid Output ◽  
Pituitary Adrenal Axis ◽  
Stimulation Of

1. The blood cortisol and gastric acid responses to insulin hypoglycaemia were investigated in 18 healthy control subjects and 14 patients with endoscopically proven duodenal ulceration. 2. In both controls and patients, insulin hypoglycaemia caused blood cortisol and acid output to rise and peak simultaneously, the rises being significantly greater in patients with duodenal ulcer than in control subjects. 3. The peak acid output and the base to peak cortisol increments were also found to be significantly greater in patients with duodenal ulcer than in control subjects (P < 0.001 and P < 0.005 respectively). 4. We conclude that insulin hypoglycaemia causes stimulation of the sympathetic and parasympathetic nervous systems and of the hypothalamo-pituitary-adrenal axis, resulting in the simultaneous elevation of gastric juice acidity and blood cortisol levels. We have shown that synchronous rises in gastric acid and blood cortisol occur during insulin hypoglycaemia and that these rises are greater in patients with duodenal ulcer.

scholarly journals Structural Changes in the Cerebrum, Cerebellum and Corpus Callosum in Migraine Patients

2016 ◽  
Vol 39 (6) ◽  
pp. 21 ◽  
Author(s):  
Berin T Demir ◽  
Nezihe A Bayram ◽  
Zübeyde Ayturk ◽  
Hüsamettin Erdamar ◽  
Pelin Seven ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Structural Changes ◽  
Resonance Imaging ◽  
Brain Images ◽  
Control Subjects ◽  
Healthy Control ◽  
Magnetic Resonance Imaging Mri ◽  
Faculty Department ◽  
And Control ◽  
The Relationship

Purpose: The purpose of this study was to demonstrate the relationship among the cerebrum, cerebellum and corpus callosum in migraine patients. Methods: This work was conducted with cooperation of the Turgut Özal Medical Faculty, Department of Anatomy and Neurology. Migraine patients were divided into four groups: new patients; 1-5 years; 5-10 years; and, more than 10 years. All patients (n=75) and control subjects (n=20) underwent Magnetic Resonance Imaging (MRI) and brain images were processed by ONIS and Image J. Data were analyzed using the planimetric method. Results: Cerebrum, cerebellum and corpus callosum volume were calculated for all subjects. The footprints of the callosum were as follows: healthy control subjects, new patients and 1-year patients: 12.8%, 5 years: 11.7% and more than 10 years: 10.7%. The cerebrum volume was as follows: healthy control subjects: 1152 cm3, 5-10 years: 1102 cm3 and more than 10 years: 1002 cm3. Discussion: The results of our study showed atrophy in the cerebrum, cerebellum and corpus callosum of chronic migraine patients. This atrophy was greater in the patients with aura migraines. Conclusion: Our study confirmed that a migraine is an episodic disease that seriously affects the CNS.

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