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At least 19 recordsLinked to original sources
PubMed2003

Subcortical projections of the parietal lobes.

Parietal lobe visual areas project to several subcortical targets. Three of the most prominent of these are to the basal ganglia, superior colliculus, and pontine nuclei. All three are probably involved in some aspect of visually guided movement. One of the largest systems of fiber connections in the human brain arises in the cerebral cortex, and relays to the cerebellum via the pontine nuclei. Pontocerebellar axons terminate within the cerebellar cortex as mossy fibers. Cells in the cerebral cortex that project to the pontine nuclei are all pyramidal in shape, and all are located in lamina V of the cerebral cortex. Subcortical projections from the somatosensory cortex of rats shows that cells that project to the basal ganglia and cerebellum occupy different sublaminae of layer V. Some cortical pyramidal cells' axons may divide, with one branch projecting to the superior colliculus, the other to the pontine nuclei. Temporal lobe visual areas, which are involved in form recognition and learning, do not project to the cerebellum. Reciprocal connections from the cerebellum back to the parietal lobe may play a role in converting visual information from retinotopic to head-centered coordinates.

Animals↗
PubMed1998

A neuropsychological examination of the underlying deficit in attention deficit hyperactivity disorder: frontal lobe versus right parietal lobe theories.

A neuropsychological approach was used to examine the frontal lobe and right parietal lobe theories of attention deficit hyperactivity disorder (ADHD). Considerable attempts were made to select as pure a group of ADHD boys as possible. The performance of 10-14-year-old ADHD boys (n = 22), both on and off stimulant medication, was compared with the performance of non-ADHD control boys (n = 22) on tasks purported to assess frontal lobe functioning (Stopping Task, Antisaccade Task, Tower of Hanoi) and right parietal lobe functioning (Visual-Spatial Cuing Task, Turning Task, Spatial Relations). Three important findings emerged: (a) unmedicated ADHD boys exhibited performance deficits on tasks in both frontal and parietal domains compared with control boys, (b) unmedicated ADHD boys appeared to be more severely impaired on the frontal tasks than on the parietal tasks, and (c) medicated ADHD boys performed better in both task domains compared with unmedicated ADHD boys. Several alternative interpretations of the results are discussed.

Adolescent↗
PubMed2003

Surgical management of parietal lobe epilepsy.

Parietal lobe seizure foci are difficult to localize unless there is an MRI lesion or contralateral sensory aura. Rapid network projection often makes scalp EEG and semiology misleading. However, seizure control can be achieved with reasonable success when concordant information guides the physician to a parietal ictal onset. Perhaps the most important messages that this small surgical series provides is that of neurologic outcome. The parietal lobe is a highly convergent cortical region and a major network way station. Except for primary sensory phenomena and language, one cannot temporarily ablate parietal cortical association area within a presumed epileptogenic region and predict the visuospatial, cognitive, and neurologic outcome. Therefore, data demonstrating that one can resect regions of parietal cortex and not cause serious dysfunction are helpful. The mild morbidity encountered in this group of patients would not be necessarily predicted if the same region of normal parietal lobe was resected. Therefore, one must consider cortical plasticity and functional redistribution as possible reasons for this, particularly when most of these substrates are of developmental origin.

Adolescent↗
PubMed1986

A case of parietal lobe atrophy.

Bilateral parietal lobe atrophy was revealed by CT scan in a 48 year-old man, with a history of learning difficulties since childhood, encopretic up to the age of eight, and left-handedness. Nevertheless, he earned his living as a skilled potter, though unable to cope with the administration of the business.

Atrophy↗
PubMed1989

[The occurrence of tyrosine hydroxylase-immunoreactive neurons in a parietal lobe ganglioglioma].

A parietal lobe ganglioglioma in a 61-year-old male was investigated ultrastructurally and immunohistochemically, using antiserum against tyrosine hydroxylase (TH), a rate-limiting enzyme of the catecholamine (CA)-synthesizing pathway. On light microscopy, the tumor was composed mainly of neuronal and astrocytic cells. The neuronal cells had typical round vesicular nuclei with prominent nucleoli and showed abundant cytoplasm with variable amounts of Nissl bodies. Bi-nucleated neuronal cells were occasionally found. The astrocytic cells had eosinophilic cytoplasm of variable shapes and hyperchromatic small nuclei. Electron microscopy revealed numerous dense core vesicles (DCVs) in the neuronal cytoplasm and processes. Immunohistochemically, TH-immunoreactive neuronal cells were found sporadically in the tumor tissue. They were often binucleated or multinucleated. The presence of TH-immunoreactive neuronal cells in the present case is of interest in considering the origin of neuronal cells in ganglioglioma. Some investigators have considered that they may arise from the ectopic autonomic neuronal cell nests in view of the presence of DCVs. However, Gasper et al. have recently demonstrated the presence of TH-immunoreactive neurons in the normal human cerebral cortex. Therefore, it may also be possible to consider that TH-immunoreactive neuronal cells in this tumor originated from a certain dysgenetic focus containing such TH-immunoreactive neurons in the developmental stage.

Brain Neoplasms↗
PubMed2002

Transcortical mixed aphasia due to cerebral infarction in left inferior frontal lobe and temporo-parietal lobe.

We present a case of transcortical mixed aphasia caused by a cerebral embolism. A 77-year-old right-handed man was admitted to our hospital with speech disturbance and a right hemianopia. His spontaneous speech was remarkably reduced, and object naming, word fluency, comprehension, reading and writing were all severely disturbed. However, repetition of phonemes and sentences and reading aloud were fully preserved. Although magnetic resonance imaging (MRI) showed cerebral infarcts in the left frontal and parieto-occipital lobe which included the inferior frontal gyrus and angular gyrus, single photon emission CT revealed a wider area of low perfusion over the entire left hemisphere except for part of the left perisylvian language areas. The amytal (Wada) test, which was performed via the left internal carotid artery, revealed that the left hemisphere was dominant for language. Hence, it appears that transcortical mixed aphasia may be caused by the isolation of perisylvian speech areas, even if there is a lesion in the inferior frontal gyrus, due to disconnection from surrounding areas.

Aged↗
PubMed1997

Spatial orientation and the representation of space with parietal lobe lesions.

Damage to the human parietal cortex leads to disturbances of spatial perception and of motor behaviour. Within the parietal lobe, lesions of the superior and of the inferior lobule induce quite different, characteristic deficits. Patients with inferior (predominantly right) parietal lobe lesions fail to explore the contralesional part of space by eye or limb movements (spatial neglect). In contrast, superior parietal lobe lesions lead to specific impairments of goal-directed movements (optic ataxia). The observations reported in this paper support the view of dissociated functions represented in the inferior and the superior lobule of the human parietal cortex. They suggest that a spatial reference frame for exploratory behaviour is disturbed in patients with neglect. Data from these patients' visual search argue that their failure to explore the contralesional side is due to a disturbed input transformation leading to a deviation of egocentric space representation to the ipsilesional side. Data further show that this deviation follows a rotation around the earth-vertical body axis to the ipsilesional side rather than a translation towards that side. The results are in clear contrast to explanations that assume a lateral gradient ranging from a minimum of exploration in the extreme contralesional to a maximum in the extreme ipsilesional hemispace. Moreover, the failure to orient towards and to explore the contralesional part of space appears to be distinct from those deficits observed once an object of interest has been located and releases reaching. Although patients with neglect exhibit a severe bias of exploratory movements, their hand trajectories to targets in peripersonal space may follow a straight path. This result suggests that (i) exploratory and (ii) goal-directed behaviour in space do not share the same neural control mechanisms. Neural representation of space in the inferior parietal lobule seems to serve as a matrix for spatial exploration and for orienting in space but not for visuomotor processes involved in reaching for objects. Disturbances of such processes rather appear to be prominent in patients with more superior parietal lobe lesions and optic ataxia.

Adult↗
PubMed2003

Ictal onset and spreading of seizures of parietal lobe origin.

The characteristics of seizures associated with parietal lobe epilepsy were investigated in six consecutive patients with medically intractable epilepsy due to parietal lobe lesions. Intracranial electrode recordings were retrospectively reviewed to investigate the seizure onset symptoms and spreading patterns associated with the disorder. All six patients underwent implantation of subdural or depth electrodes and subsequent video/electroencephalography monitoring. Common symptoms included motionless stare, contralateral eye deviation, and head turn. Tonic posturing, contralateral sensory disturbance, and motor weakness were also seen. Asymmetrical generalized tonic and clonic seizures were seen in all six patients. All seizure activities began in the parietal lobe harboring the lesions, and then spread immediately to the adjacent lobes in most seizures, where the clinical symptoms were produced. The parietal lobe is a pure generator of seizures, whereas most clinical symptoms originate from adjacent lobes following seizure onset. No apparent specific symptoms other than sensory disturbance arising from the parietal lobe proper were recognized. Regardless of clinical symptoms, the seizure onset occurred in the parietal lobe harboring the lesion.

Adult↗
PubMed1987

The occurrence of catecholamine neurons in a parietal lobe ganglioglioma.

A parietal lobe ganglioglioma in a 2-year-old girl was investigated ultrastructurally and immunohistochemically, using antiserum against tyrosine hydroxylase (TH), a rate-limiting enzyme of the catecholamine (CA)-synthesizing pathway. The tumor was composed essentially of neuronal and astrocytic cells. Ultrastructurally, numerous dense core vesicles measuring between 56 nm and 136 nm (mean, 90 nm) in diameter were observed in the neuronal cytoplasm and processes. The fact that the TH immunohistochemistry revealed many positive neuronal cells in the tumor tissue was of considerable interest. The implications and possible significance of the presence of CA neurons in this ganglioglioma are discussed.

Brain Neoplasms↗
PubMed1982

Performance of normal older adults on tests designed to measure parietal lobe functions.

Symptoms referrable to the parietal lobes, such as difficulty with dressing, unilateral neglect, or manual apraxia, are a frequent rehabilitation problem among stroke patients. Occupational therapists need an evaluation tool for parietal lobe functions and performance expectations for adults 40 years and older. A battery of tests designed to measure functions of the parietal lobes was given to 68 normal adults from 40 to 88 years of age. The test battery included drawings, stick designs, finger identifications, right-left identifications, arithmetic, clock settings, map localizations, block constructions, visual organization tasks, and visual discrimination tasks. Statistical analysis of the data revealed significant age-related changes on the constructional tasks, finger identifications, clock settings, visual organization tasks, and visual discrimination tasks. No significant age effect was found on right-left identifications, map localizations, or arithmetic. Implications for the evaluation and treatment of older adults in occupational therapy are discussed.

Adult↗
PubMed2000

Parietal lobe epilepsy.

When symptoms such as lateralized paresthesias or pain occur prominently and early in partial seizures, parietal lobe seizure origin should be suspected. Most patients with parietal lobe seizures, however, have no symptoms or signs suggesting the parietal lobe. In the absence of detectable epileptogenic lesions, these patients without clinical seizure characteristics suggesting parietal lobe origin can present with misleading findings, resulting in erroneous localization, which can, in turn, lead to ineffective surgical intervention (23,25). Although ictal SPECT might provide vital evidence of parietal lobe seizure origin (25), as noted previously, this technology also can produce misleading data in some patients (52). Even when parietal lobe seizure origin is suspected, in the absence of a structural lesion, documenting this with invasive monitoring can be difficult. The parietal lobes, like the frontal lobes, are large, diffuse structures, and the potential for sampling error is high (19). Spread patterns are unpredictable and can result in false localization (23). Even with extensive and repetitive invasive studies, localization can prove elusive (53). No well-documented series of patients with non-lesional parietal lobe epilepsy in the modern literature who have been cured by surgery have been reported as a result of a combination of the rarity of the condition, the lack of correct recognition, as well as the difficulty of localization. Patients with medically intractable parietal lobe seizures, however, can experience excellent surgical results (23,24). Postoperative parietal lobe symptoms and signs, even when extreme, are usually not enduring (patient 3). One of our patients, however, did develop a chronic pain syndrome (48).

Epilepsy↗
PubMed2002

[A case of Gogi aphasia with predominantly left temporal and parietal lobe atrophy].

We report a 68-year-old right-handed Japanese woman who had a history of progressive difficulty in understanding speech and naming. Neuropsychological examination presented Gogi (word meaning) aphasia and impairment of semantic memory for some common objects. She also presented acalculia and mild constructional impairment. There was no evidence of impairment in elementary perception and motor skills. Her memory performance of visual task was within normal range. She had neither personality change nor behavioral disorder. Magnetic resonance (MR) imaging showed atrophy in the left temporal lobe and the left parietal lobe. Single photon emission computed tomography (SPECT) scans demonstrated a decrease of regional cerebral blood flow in the atrophic sites and the left frontal lobe. We pointed out that the atrophy of the parietal lobe was atypical in the early stage of cortical degenerative disease presenting Gogi aphasia, in addition to in the light of classification of Fronto-Temporal Lobar Degeneration (FTLD).

Aged↗
PubMed2003

Contralateral coding of imagined body parts in the superior parietal lobe.

In monkeys, neurons in the superior parietal lobe (area 5) code for spatial position of contralateral body parts by combining visual and somatosensory signals. Using a modified version of the classical mental rotation task, we were able to demonstrate that in humans activation in the contralateral superior parietal lobe could be evoked when mental rotation was combined with motor imagery of hands. These findings show that even in the absence of visual and somatosensory input, information provided by motor imagery suffices to induce contralateral superior parietal lobe monitoring of the imagined limb configuration. This constitutes an important prerequisite for effective imagined motor practice that can be used to improve actual motor performance.

Analysis of Variance↗
PubMed2004

Parietal lobe epilepsy: surgical treatment and outcome.

OBJECTIVE: Parietal lobe epilepsy (PLE) is neither common nor easily diagnosed because of its variable clinical features. To elucidate its characteristics and surgical outcome, the authors reviewed their surgical experiences. METHODS: Between September 1994 and August 2001, 38 patients with PLE received surgical treatment at the Seoul National University Hospital. All patients underwent resection, mainly involving the parietal lobe. RESULTS: Preoperatively, over 60% of the cases were not considered to be PLE, even though PLE was the most common diagnosis (15/38, 39.8%). An invasive study was performed in 37 of the 38 patients. Awake operations under regional anesthesia were performed in 20 patients (52.6%). Seizure disappeared in 15 (Engel's classification I, 39.5%), and rare seizure remained in 5 (Engel II, 13.2%). Thirteen patients showed a worthwhile improvement (Engel III, 34.2%), whereas 5 exhibited no worthwhile improvement (Engel IV, 13.2%). Pathologies were diverse, the most common being cortical dysplasia (94.3%). CONCLUSION: Since PLE is difficult to diagnose preoperatively, an invasive study covering the parietal lobe is mandatory, if PLE is suspected. Cortical dysplasia was the most common etiology, thus awake operation under regional anesthesia and intraoperative brain mapping is helpful during extensive resection in order to spare the eloquent cortex.

Adolescent↗
PubMed1993

[Hemi-ballistic involuntary movement manifested as an parietal lobe syndrome].

A 28-year-old man had a asymptomatic meningioma in right parasagittal parietal lobe. At surgery, the parietal lobe remarkably swelled before completion of total removal of the tumor, although any suggestive factor causing brain swelling was not found intraoperatively. CT scan was examined immediately after surgery and only revealed a small hematoma in the tumor bed without any additional lesion in thalamus or basal ganglia. It was inexperienced post-operative complication that involuntary hemiballistic movement of left limbs appeared immediately after recovery from general anesthesia, although the post-operative complications of right parietal lobe syndromes, such as left hemi-anesthesia, hemi-agnosia, hemiparesis and hemi-ataxia were predictable. The hemiballistic movement persisted for 2 days postoperatively and the other complications completely recovered in the next 3 months. MRI, taken at post-operative 14th day, did not detect any abnormal lesion in well-known responsible areas for hemiballismus such as subthalamus, thalamus and basal ganglia. We suppose that the parietal lobe, especially Broadmann's area 7 may be one of the responsible areas for provoking hemiballistic involuntary movement.

Adult↗
PubMed2001

Spatial awareness is a function of the temporal not the posterior parietal lobe.

Our current understanding of spatial behaviour and parietal lobe function is largely based on the belief that spatial neglect in humans (a lack of awareness of space on the side of the body contralateral to a brain injury) is typically associated with lesions of the posterior parietal lobe. However, in monkeys, this disorder is observed after lesions of the superior temporal cortex, a puzzling discrepancy between the species. Here we show that, contrary to the widely accepted view, the superior temporal cortex is the neural substrate of spatial neglect in humans, as it is in monkeys. Unlike the monkey brain, spatial awareness in humans is a function largely confined to the right superior temporal cortex, a location topographically reminiscent of that for language on the left. Hence, the decisive phylogenetic transition from monkey to human brain seems to be a restriction of a formerly bilateral function to the right side, rather than a shift from the temporal to the parietal lobe. One may speculate that this lateralization of spatial awareness parallels the emergence of an elaborate representation for language on the left side.

Adult↗