Cortical activation pattern during shoulder simple versus vibration exercises： a functional near infrared spectroscopy study

To date, the cortical effect of exercise has not been fully elucidated. Using the functional near infrared spectroscopy, we attempted to compare the cortical effect between shoulder vibration exercise and shoulder simple exercise. Eight healthy subjects were recruited for this study. Two different exercise tasks（shoulder vibration exercise using the flexible pole and shoulder simple exercise） were performed using a block paradigm. We measured the values of oxygenated hemoglobin in the four regions of interest： the primary sensory-motor cortex（SM1 total, arm somatotopy, and leg and trunk somatotopy）, the premotor cortex, the supplementary motor area, and the prefrontal cortex. During shoulder vibration exercise and shoulder simple exercise, cortical activation was observed in SM1（total, arm somatotopy, and leg and trunk somatotopy）, premotor cortex, supplementary motor area, and prefrontal cortex. Higher oxygenated hemoglobin values were also observed in the areas of arm somatotopy of SM1 compared with those of other regions of interest. However, no significant difference in the arm somatotopy of SM1 was observed between the two exercises. By contrast, in the leg and trunk somatotopy of SM1, shoulder vibration exercise led to a significantly higher oxy-hemoglobin value than shoulder simple exercise. These two exercises may result in cortical activation effects for the motor areas relevant to the shoulder exercise, especially in the arm somatotopy of SM1. However, shoulder vibration exercise has an additional cortical activation effect for the leg and trunk somatotopy of SM1.

Photosensitivity detection using diffusion tensor imaging in a traumatic brain injury patient

The present study examined a patient with traumatic brain injury who exhibited visual photosensitivity and axonal iniury of the left optic radiation, which was detected by diftusion tensor imaging. The patient was a 41-year-old man. He began to complain of photosensitivity at 4 months after head trauma. Ophthalmic evaluation, including visual-evoked potential and conventional brain magnetic resonance imaging, did not reveal a pathologic basis for photosensitivity. Axonal injury in the left optic radiation was detected via diffusion tensor imaging at 36 months after head trauma. The lesion was almost recovered at 76 months. However, photosensitivity continued. Therefore, the photosensitivity was considered to be a result of axonal injury to the left optic radiation, which could be a symptom of maladaptive plasticity that occurs during recovery of axonal injury of the left optic radiation.

Weak phonation due to unknown injury of the corticobulbar tract in a patient with mild traumatic brain injury: a diffusion tensor tractography study

In this study,we report on a patient who showed weak phonation following mild traumatic brain injury（TBI）,which was demonstrated by diffusion tensor tractography（DTT）.

Appearance of a neural bypass between injured cingulum and brainstem cholinergic nuclei of a patient with traumatic brain injury on follow-up diffusion tensor tractography images

The human brain is known to contain a maximum of eight cholinergic nuclei： the basal forebrain region： the medial septal nucleus （Ch 1）, the vertical nucleus of the diagonal band （Ch 2）, the horizontal limb of the diago- nal band （Ch 3）, and the nucleus basalis of Meynert （Ch 4）; the brainstem： the pedunculopontine nucleus （Ch 5）, the laterodorsal tegmental nucleus （Ch 6）, and the para- bigeminal nucleus （Ch 8）; and the thalamus： the medial habenular nucleus （Ch 7） （Nieuwenhuys et al., 2008; Naidich and Duvernoy, 2009）. The cingulum is the neu- ral tract extending from the orbitofrontal cortex to the medial temporal lobe （Mufson and Pandya, 1984）. The cingulum plays an important role in memory because it is a passage of the medial cholinergic pathway, which pro- vides cholinergic innervations to the cerebral cortex after originating from Ch 1 and Ch 2 as well as Ch 4 （mainly） （Selden et al., 1998; Nieuwenhuys et al., 2008; Hong and lang, 2010）.

Recovery of multiply injured ascending reticular activating systems in a stroke patient

Consciousness is controlled by ular activating system （ARAS）. lower and upper parts between activation of the ascending retic- The ARAS consists mainly of the the thalamus and cerebral cortex （Edlow et al., 2012; Yeo et al., 2013; Jang et al., 2014）. Because the ARAS is composed of several neuronal circuits connecting the brainstem to the cortex. These neuronal connections begin from the reticular formation （RF） of the brainstem and the intralaminar nucleus of thalamus to the cerebral cortex （Gosseroes et al., 2011）. In addition, the ARAS system also includes several brainstem nuclei （such as dorsal raphe, locus coeruleus, pedun-culopontine nucleus, median raphe and parabrachial nucleus）, non-specific thalamic nuclei, hypothalamus, and basal forebrain （Fuller et al., 2011）.

Central post-stroke pain due to injury of the spinothalamic tract in patients with cerebral infarction： a diffusion tensor tractography imaging study

Many studies using diffusion tensor tractography（DTT） have demonstrated that injury of the spinothalamic tract（STT） is the pathogenetic mechanism of central post-stroke pain（CPSP） in intracerebral hemorrhage; however, there is no DTT study reporting the pathogenetic mechanism of CPSP in cerebral infarction. In this study, we investigated injury of the STT in patients with CPSP following cerebral infarction, using DTT. Five patients with CPSP following cerebral infarction and eight age-and sex-matched healthy control subjects were recruited for this study. STT was examined using DTT. Among DTT parameters of the affected STT, fractional anisotropy and tract volume were decreased by more than two standard deviations in two patients（patients 1 and 2） and three patients（patients 3, 4, and 5）, respectively, compared with those of the control subjects, while mean diffusivity value was increased by more than two standard deviations in one patient（patient 2）. Regarding DTT configuration, all affected STTs passed through adjacent part of the infarct and three STTs showed narrowing. These findings suggest that injury of the STT might be a pathogenetic etiology of CPSP in patients with cerebral infarction.

Optic radiation injury in patients with aneurismal subarachnoid hemorrhage: a preliminary diffusion tensor imaging report

Visual field defect is one of the various clinical manifestations in patients with subarachnoid hemorrhage（SAH）. Little is known about the pathogenic mechanism of visual field defect in SAH. In the current study,we investigated the diffusion tensor imaging （DTI） finding of the optic radiation in patients with SAH followingrupture of a cerebral artery aneurysm. We recruited 21 patients with aneurismal SAH （12 males, 9 females, mean age, 52.67 years; range, 41–68 years） who showed no definite lesion along the visual pathway.Twenty-one age-and sex-matched normal control subjects were also recruited. DTI data were acquired at an average of 5.9 weeks （range： 3–12 weeks） after onset and reconstruction of the optic radiation was performed using DTI-Studio software. The fractional anisotropy value, apparent diffusion coefficient value,and fiber number of the optic radiation were measured. The fractional anisotropy value of the optic radiation was significantly decreased, and the apparent diffusion coefficient value was significantly increased, in patients with aneurismal SAH than in normal control subjects. However, there was no significant difference in the fiber number of the optic radiation between patients with aneurismal SAH and normal control subjects. The decrement of fractional anisotropy value and increment of apparent diffusion coefficient value of the optic radiation in patients with aneurismal SAH suggest optic radiation injury. Therefore, we recommend a thorough evaluation for optic radiation injury in patient with aneurismal SAH.

Medial reorganization of motor function in corona radiata following middle cerebral artery infarction A case report

Peri-lesional reorganization is one of the motor recovery mechanisms following stroke. A 23-year-old female who presented with complete paralysis of the right extremities at the onset of infarct in the left middle cerebral artery territory was included. She slowly recovered some function, and could extend the affected knee with resistance after 9 months. Diffusion tensor tractography, functional MRI, and transcranial magnetic stimulation testing were performed at 7 years after onset. Results showed that diffusion tensor tractography of the affected （left） hemisphere passed through the medial corona radiata at, or around, the wall of the lateral ventricle. The contralateral primary sensorimotor cortex was activated during affected knee movements. The motor-evoked potential, which was obtained from the affected leg, exhibited corticospinal tract characteristics. Results indicated that motor function of the affected leg recovered via the corticospinal tract, which descended through the corona radiata medial to the infarct. The motor function of the affected leg was reorganized to the medial corona radiata following infarct to the middle cerebral artery territory.

Neuroimaging characterization of recovery of impaired consciousness in patients with disorders of consciousness

Elucidation of critical brain areas or structures that are responsible for recovery of impaired consciousness in patients with disorders of consciousness is important because it can provide information that is useful when developing therapeutic strategies for neurorehabilitation or neurointervention in patients with disorders of consciousness.In this review,studies that have demonstrated brain changes during recovery of impaired consciousness were reviewed.These studies used positron emission tomography,electroencephalography/transcranial magnetic stimulation,diffusion tensor tractography,and diffusion tensor tractography/electroencephalography.The majority of these studies reported on the importance of supratentorial areas or structures in the recovery of impaired consciousness.The important brain areas or structures that were identified were the prefrontal cortex,basal forebrain,anterior cingulate cortex,and parietal cortex.These results have a clinically important implication that these brain areas or structures can be target areas for neurorehabilitation or neurointervention in patients with disorders of consciousness.However,most of studies were case reports;therefore,further original studies involving larger numbers of patients with disorders of consciousness are warranted.In addition,more detailed information on the brain areas or structures that are relevant to the recovery of impaired consciousness is needed.

Peri-infarct reorganization of an injured corticospinal tract in a patient with cerebral infarction

Corticospinal tract(CST), a major neural tract in the human brain for motor function, is involved mainly in the movement of the distal extremities(Jang and Lee, 2019). Recovery of an injured CST is essential for good recovery of impaired motor function in stroke patients(Jang and Lee, 2019). Peri-infarct reorganization of an injured CST is an important mechanism underlying recovery of motor function in stroke patients(Jang, 2007). In this study, we reported on a patient with cerebral infarction who showed recovery of an injured CST by periinfarct reorganization using diffusion tensor tractography(DTT) and transcranial magnetic stimulation(TMS).

Traumatic axonal injury of the cingulum in patients with mild traumatic brain injury: a diffusion tensor tractography study

The cingulum,connecting the orbitofrontal cortex to the medial temporal lobe,involves in diverse cognition functions including attention,memory,and motivation.To investigate the relationship between the cingulum injury and cognitive impairment in patients with chronic mild traumatic brain injury,we evaluated the integrity between the anterior cingulum and the basal forebrain using diffusion tensor tractography in 73 patients with chronic mild traumatic brain injury(39 males,34 females,age 43.29±11.42 years)and 40 healthy controls(22 males,18 females,age 40.11±16.81 years).The patients were divided into three subgroups based on the integrity between the anterior cingulum and the basal forebrain on diffusion tensor tractography:subgroup A(n=19 patients)– both sides of the anterior cingulum were intact;subgroup B(n=36 patients)– either side of the anterior cingulum was intact;and subgroup C(18 patients)– both sides of the anterior cingulum were discontinued.There were significant differences in total Memory Assessment Scale score between subgroups A and B and between subgroups A and C.There were no significant differences in diffusion tensor tractography parameters(fractional anisotropy,apparent diffusion coefficient,and fiber volume)between patients and controls.These findings suggest that the integrity between the anterior cingulum and the basal forebrain,but not diffusion tensor tractography parameter,can be used to predict the cognitive function of patients with chronic mild traumatic brain injury.This study was approved by Yeungnam University Hospital Institutional Review Board(approval No.YUMC-2014-01-425-010)on August 16,2017.

Corticospinal tract recovery in a patient with traumatic transtentorial herniation

Transtentorial herniation is one of the causes of motor weakness in traumatic brain injury. In this study, we report on a patient who underwent decompressive craniectomy due to traumatic intracerebral hemorrhage. Brain CT images taken after surgery showed intracerebral hemorrhage in the left fronto-temporal lobe and left transtentorial herniation. The patient presented with severe paralysis of the right extremities at the time of intracerebral hemorrhage onset, but the limb motor function recovered partially at 6 months after onset and to nearly normal level at 27 months. Through diffusion tensor tractography, the left corticospinal tract was disrupted below the cerebral peduncle at 1 month after onset and the disrupted left corticospinal tract was reconstructed at 27 months. These findings suggest that recovery of limb motor function in a patient with traumatic transtentorial herniation can come to be true by recovery of corticospinal tract.

Motor outcomes of patients with a complete middle cerebral artery territory infarct

Detailed knowledge of motor outcomes enables to establish proper goals and rehabilitation strate-gies for stroke patients. Several previous studies have reported functional or motor outcomes in patients with a middle cerebral artery territory infarct. However, little is known about motor outcome in patients with a complete middle cerebral artery territory infarct. In this study, we investigated the motor outcomes in 23 patients with a complete middle cerebral artery territory infarct. All of these patients received comprehensive rehabilitative management, including movement therapy and neuromuscular electrical stimulation of the affected finger extensors and ankle dorsiflexors, for more than 3 months. Motor outcomes were measured at 6 months after stroke onset using the Medical Research Council, Motricity Index, the modified Brunnstrom Classification, and Functional Ambula-tion Category scores. The motor function of the lower extremities was found to be better than that of the upper extremities. After receiving rehabilitation treatments for 3–6 months, about 70% of these patients were able to walk independently （Functional Ambulation Category scores 3）, but no pa-tient achieved functional hand recovery.

Recovery of a degenerated corticospinal tract after injury in a patient with intracerebral hemorrhage:confirmed by diffusion tensor tractography imaging

The corticospinal tract （CST） is a major neuronal tract of motor function in the human brain （York, 1987; Davidoff, 1990; Jang, 2014）. Recovery of an injured CST is one of the motor recovery mechanisms in stroke patients （Hendricks et al., 2003; Jang et al., 2006, 2007; Swayne et al., 2008; Kwon et al., 2011, 2013; Kwon and Jang, 2012; Yeo and Jang, 2013; Rong et al., 2014）. Diffusion tensor tractography （DTT）, derived from diffusion tensor imaging （DTI）, and transcra- nial magnetic stimulation （TMS） have been widely used in demonstrating the recovery of an injured CST （Hendricks et al., 2003; Jang et al., 2006, 2007; Swayne et al., 2008; Pannek et al., 2009; Kwon et al., 2011, 2013; Kwon and Jang, 2012; Yeo and Jang, 2013; Rong et al., 2014）. DTT has the advan- tage of enabling visualization of the architecture and integ- rity of the CST at the subcortical level in three dimensions （Mori et al., 1999; Kunimatsu et al., 2004）.

Severe bilateral anterior cingulum injury in patients with mild traumatic brain injury

The cingulum,the neural tract connecting the orbitofrontal cortex with the medial temporal lobe,plays an important role in cognition（Bush et al.,2000）.It is also important in memory because it provides cholinergic innervations to the cerebral cortex after obtaining innervation from the medial septal nucleus,the vertical nucleus of the diagonal band, and the nucleus basalis of Meynert via the medial cholinergic pathway （Nieuwenhuys et al., 2008; Naidich and Duvernoy, 2009; Hong and Jang, 2010a）.

Diffusion tensor tractography characteristics of axonal injury in concussion/mild traumatic brain injury

The main advantage of diffusion tensor tractography is that it allows the entire neural tract to be evaluated.In addition,configurational analysis of reconstructed neural tracts can indicate abnormalities such as tearing,narrowing,or discontinuations,which have been used to identify axonal injury of neural tracts in concussion patients.This review focuses on the characteristic features of axonal injury in concussion or mild traumatic brain injury(m TBI)patients through the use of diffusion tensor tractography.Axonal injury in concussion(m TBI)patients is characterized by their occurrence in long neural tracts and multiple injuries,and these characteristics are common in patients with diffuse axonal injury and in concussion(m TBI)patients with axonal injury.However,the discontinuation of the corticospinal tract is mostly observed in diffuse axonal injury,and partial tearing and narrowing in the subcortical white matter are frequently observed in concussion(m TBI)patients with axonal injury.This difference appears to be attributed to the observation that axonal injury in concussion(m TBI)patients is the result of weaker forces than those producing diffuse axonal injuries.In addition,regarding the fornix,in diffuse axonal injury,discontinuation of the fornical crus has been frequently reported,but in concussion(m TBI)patients,many collateral branches form in the fornix in addition to these findings in many case studies.It is presumed that the impact on the brain in TBI is relatively weaker than that in diffuse axonal injury,and that the formation of collateral branches occurs during the fornix recovery process.Although the occurrence of axonal injury in multiple areas of the brain is an important feature of diffuse axonal injury,case studies in concussion(m TBI)have shown that axonal injury occurs in multiple neural tracts.Because axonal injury lesions in m TBI patients may persist for approximately 10 years after injury onset,the characteristics of axonal injury in concussion(m TBI)patients,which are reviewed and categorized in this review,are expected to serve as useful supplementary information in the diagnosis of axonal injury in concussion(m TBI)patients.

Perilesional reorganization of motor function in stroke patients

Perilesional reorganization is an important recovery mechanism for stroke patients because it yields good motor outcomes. However, perilesional reorganization remains poorly understood. The scientific basis for stroke rehabilitation can be established when detailed mechanisms of recovery are clarified. In addition, studies at the subcortical level remain in the early stages. Therefore, the present study suggested that additional investigations should focus on perilesional reorganization at the subcortical level, identifying the critical period for this mechanism and determining treatment strategies and modalities to facilitate development. The present study reviews literature focused on perilesional reorganization in stroke patients with regard to demonstration, clinical characteristics, and rehabilitative aspects, as well as previous studies of perilesional reorganization at cortical and subcortical levels.

Is combined functional magnetic resonance imaging and diffusion tensor tractography a useful tool for evaluation of somatosensory dysfunction recovery after intracerebral hemorrhage?

Diffusion tensor tractography allows the sensory fiber course of the medial lemniscus to be visualized. But diffusion tensor tractography for accurate evaluation of the repair of injured somatosensory tracts in stroke patients has been rarely reported. A 55-year-old female patient presented with severe somatosensory dysfunction of the left side caused by a spontaneous intracerebral hemorrhage on the right side. The somatosensory function of the affected side recovered to a nearly normal state at 7 weeks from onset. Functional magnetic resonance imaging revealed that at 3 weeks from onset, there was no cortical activation by touch at each hand; at 7 weeks, the contralateral cortex centered on the primary sensory cortex was found to be activated during touch and passive movements, and activation by passive movements was increased compared with that at 3 weeks. Diffusion tensor tractography revealed that a medial lemniscus on the affected （right） hemisphere was not observed at 3 weeks from onset, however, at 7 weeks, the unaffected （left） hemisphere passed along the medial lemniscus pathway from the pons to the primary sensory cortex. These findings indicate that combined functional magnetic resonance imaging and diffusion tensor tractography would allow more accurate evaluation of the architecture and integrity of somatosensory tracts and is a useful method to investigate the recovery of somatosensory dysfunction in stroke patients.

Unusual long-term motor recovery in a patient with corona radiata infarct

The majority of motor recovery following stroke occurs within 6 months after onset.The present study examined a patient with a corona radiata infarct,who exhibited an unusual long-term recovery（24 months after onset）.The patient was a 64-year-old female,who presented with severe paralysis of the left extremities resulting from a corona radiate infarct.Motor recovery from the weakness progressed slowly over a 24-month period following onset,even at 6-12 months after onset.Diffusion tensor tractography at 2 weeks from onset showed disruption of the corticospinal tract of the affected hemisphere resulting from the infarct.However,at 12 and 24 months after onset,the corticospinal tract was elongated to the cortex level,as shown by diffusion tensor tractography.A 2-week transcranial magnetic stimulation showed no motor-evoked potential for the affected hemisphere,but a motor-evoked potential of the corticospinal tract was observed at12 and 24 months.These results suggest that motor function recovery in cerebral infarct patients can occur at least up to 24 months after stroke onset.

Changes in a cerebellar peduncle lesion in a patient with Dandy-Walker malformation A diffusion tensor imaging study

We report a patient with severe ataxia due to Dandy-Walker malformation, who showed functional recovery over 10 months corresponding to a change in a cerebellar peduncle lesion. A 20-month-old female patient who was diagnosed with Dandy-Walker syndrome and six age- and sex-matched healthy control subjects were enrolled. The superior cerebellar peduncle, the middle cerebellar peduncle, and the inferior cerebellar peduncle were evaluated using fractional anisotropy and the apparent diffusion coefficient. The patients＇ functional ambulation category was 0 at the initial visit, but improved to 2 at the follow-up evaluation, and Berg＇s balance scale score also improved from 0 to 7. Initial diffusion tensor tractography revealed that the inferior cerebellar peduncle was not detected, that the fractional anisotropy of the superior cerebellar peduncle and middle cerebellar peduncle decreased by two standard deviations below, and that the apparent diffusion coefficient increased by two standard deviations over normal control values. However, on follow-up diffusion tensor tractography, both inferior cerebellar peduncles could be detected, and the fractional anisotropy of superior cerebellar peduncle increased to within two standard deviations of normal controls. The functional improvement in this patient appeared to correspond to changes in these cerebellar peduncles. We believe that evaluating cerebellar peduncles using diffusion tensor imaging is useful in cases when a cerebellar peduncle lesion is suspected.