The role of the basal ganglia and cerebellum in language processing

The roles of the cerebellum and basal ganglia have typically been confined in the literature to motor planning and control. However, mounting evidence suggests that these structures are involved in more cognitive domains such as language processing. In the current study, we looked at effective connectivity (the influence that one brain region has on another) of the cerebellum and basal ganglia with regions thought to be involved in phonological processing, i.e. left inferior frontal gyrus and left lateral temporal cortex. We analyzed functional magnetic resonance imaging data (fMRI) obtained during a rhyming judgment task in adults using dynamic causal modeling (DCM). The results showed that the cerebellum has reciprocal connections with both left inferior frontal gyrus and left lateral temporal cortex, whereas the putamen has unidirectional connections into these two brain regions. Furthermore, the connections between cerebellum and these phonological processing areas were stronger than the connections between putamen and these areas. This pattern of results suggests that the putamen and cerebellum may have distinct roles in language processing. Based on research in the motor planning and control literature, we argue that the putamen engages in cortical initiation while the cerebellum amplifies and refines this signal to facilitate correct decision making.     

Hemolytic-uremic syndrome with involvement of basal ganglia and cerebellum

Hemolytic-uremic syndrome is a microangiopathy often associated with neurologic symptoms. Several patients with persistent lesions in cerebrum and basal ganglia have been reported. We present two children with bilateral basal ganglia and additional unilateral cerebellar lesions in magnetic resonance imaging. These resolved completely in one child. In the other child there were still residuals after 11 weeks. The neurologic symptoms of both improved after several therapeutic plasma exchanges and disappeared after months.     

Contributions of the prefrontal cortex and basal ganglia to set shifting

Impairments of set shifting have been associated with damage to both the prefrontal cortex (PFC) and to the basal ganglia. The purpose of these experiments was to determine whether damage to the PFC was associated with shifting impairments per se or whether any switching deficits could be attributed to a reduction of working memory capacity. In contrast, shifting impairments were expected for Parkinson patients regardless of memory load, given that these patients seem to have no cognitive deficits other than when having to shift set. To vary working memory demands, a cue to the relevant dimension (letter or shape) in an odd-man-out task was presented or withheld. Pathology to prefrontal areas associated with normal aging was not linked to shifting deficits when working memory load was reduced in a comparison of older and younger adults (Experiment 1). In contrast, set-shifting abilities were still impaired for stroke patients with prefrontal damage regardless of working memory demands (Experiment 2). Parkinson patients were relatively unimpaired on this task (Experiment 2), but began to display shifting deficits when response competition was present in the display (Experiment 3).     

Cortex, basal ganglia and cerebellum in motor control.

For voluntary movement, function generators are necessary that are located in the brain-stem, cerebellum and basal ganglia. Following lesions of these generators, voluntary movements are impaired while stimulus-dependent movements are still possible. This discussion also applies to speech production. The motor function generators cooperate with the whole cerebral cortex since both tactical adaptation to the environment and strategic guidance by the motivation system contribute to voluntary action. The motor cortex plays an epicritical role, adding advanced tactile and proprioceptive guidance for those movements that need this kind of regulation, especially the fine finger movements which depend entirely on the motor cortex. The complexity of the cerebral potentials preceding voluntary movement corresponds to the activity of several motor subsystems acting in concert.     

The roles of the cerebellum and basal ganglia in timing and error prediction

Recent evidence that the cerebellum and the basal ganglia are activated during the performance of cognitive and attention tasks challenges the prevailing view of their primary function in motor control. The specific roles of the basal ganglia and the cerebellum in cognition, however, have been difficult to identify. At least three functional hypotheses regarding their roles have been proposed. The first hypothesis suggests that their main function is to switch attentional set. The second hypothesis states that they provide error signals regarding stimuli or rewards. The third hypothesis is that they operate as an internal timing system, providing a precise representation of temporal information. Using functional magnetic resonance imaging, we tested these three hypotheses using a task-switching experiment with a 2 x 2 factorial design varying timing (random relative to fixed) and task order (unpredictable relative to predictable). This design allowed us to test whether switching between tasks, timing irregularity and/or task order unpredictability activate the basal ganglia and/or the cerebellum. We show that the cerebellum is primarily activated with timing irregularity while the anterior striatum is activated with task order unpredictability, supporting their distinctive roles in two forms of readjustment. Task order unpredictability alone, independent of reward delivery, is sufficient to induce striatal activation. In addition, activation of the cerebellum and basal ganglia were not specific to switching attention because these regions were both activated during switching between tasks and during the simultaneous maintenance of two tasks without switching between them.     

Motor system: cortex, basal ganglia, and cerebellum

In this article, the authors summarize results from imaging studies, analyzing the functional anatomy of motor sequence learning and timing. Emphasis is on the relationship between the cortical motor areas, the basal ganglia, and the cerebellum.     

Hypomyelination with atrophy of the basal ganglia and cerebellum: case report

Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a rare disease that has been recently described. It must be remembered as a possible etiology of leukoencephalopathies in children. We describe a typical case of H-ABC in a 11-month-old boy. He presents with global development delay, oral dyskinesia, and global dystonia and spasticity. Magnetic resonance imaging disclosed typical features of H-ABC and clinical laboratory tests were all negative. A slow neurological deterioration has been detected with worsening of involuntary movements.     

Pathways for control of face and neck musculature by the basal ganglia and cerebellum

The basal ganglia are believed to influence movement via thalamo-cortical projections. However, the basal ganglia may also affect brainstem areas involved in movement control such as the red nucleus. The red nucleus receives input from the cerebellum and projects to motor neurons and premotor neurons in the contralateral brainstem and spinal cord. Are there pathways that allow output from the basal ganglia to influence processing in the red nucleus? This study uses the bidirectional tracer, WGA-HRP, to demonstrate that regions of the cat red nucleus receive input from the basal ganglia as well as from the cerebellum. Output from the entopeduncular nucleus, the feline equivalent of the internal segment of the globus pallidus, provides a modest direct input to the red nucleus as well as a more substantial indirect input via projections to the zona incerta and the fields of Forel. Regions of the red nucleus with input from the basal ganglia also receive input from the cerebellar dentate nucleus and lateral regions of interpositus. The regions of the red nucleus receiving basal gangliar input project to the contralateral facial nucleus and upper segments of the cervical spinal cord. Therefore, the red nucleus provides a junction where output from the basal ganglia can interact with output of the cerebellum for movement control of the head and face. The pathway may provide a substrate for a variety of movement disorders that are seen with diseases of the basal ganglia such as cervical dystonia and Parkinson's facies.     

Distinct effects of the basal ganglia and cerebellum on the thalamocortical pathway in idiopathic generalized epilepsy

The aberrant thalamocortical pathways of epilepsy have been detected recently, while its underlying effects on epilepsy are still not well understood. Exploring pathoglytic changes in two important thalamocortical pathways, that is, the basal ganglia (BG)‐thalamocortical and the cerebellum‐thalamocortical pathways, in people with idiopathic generalized epilepsy (IGE), could deepen our understanding on the pathological mechanism of this disease. These two pathways were reconstructed and investigated in this study by combining diffusion and functional MRI. Both pathways showed connectivity changes with the perception and cognition systems in patients. Consistent functional connectivity (FC) changes were observed mainly in perception regions, revealing the aberrant integration of sensorimotor and visual information in IGE. The pathway‐specific FC alterations in high‐order regions give neuroimaging evidence of the neural mechanisms of cognitive impairment and epileptic activities in IGE. Abnormal functional and structural integration of cerebellum, basal ganglia and thalamus could result in an imbalance of inhibition and excitability in brain systems of IGE. This study located the regulated cortical regions of BG and cerebellum which been affected in IGE, established possible links between the neuroimaging findings and epileptic symptoms, and enriched the understanding of the regulatory effects of BG and cerebellum on epilepsy.     

The role of the basal ganglia in the control of automatic visuospatial attention.

Cognitive impairments in patients with basal ganglia dysfunction are primarily revealed where performance relies on internal, voluntary control processes. Evidence suggests that this also extends to impaired control of more automatic processes, including visuospatial attention. The present study used a non-predictive peripheral cueing paradigm to compare and contrast visuospatial deficits in patients with Parkinson's disease (PD) with those previously revealed in patients with Huntington's disease (HD) (Fielding et al., 2006a). Compared to age-matched controls, both PD and HD patients exhibited increased distractibility or poor fixation, however only PD patients responded erroneously to cue stimuli more frequently than control subjects. All subjects demonstrated initial facilitation for valid versus invalid cues following the shorter stimulus-onset asynchronies (SOAs) and a performance decrement at the longer SOAs (inhibition of return), although there was a clear differentiation between these groups for immediate SOAs. Unlike both control and PD subjects, where IOR manifested between 350 and 1000 msec, IOR was evident as early as 150 msec for HD patients. Further, for PD patients, spatially valid cues resulted in hyper-reflexivity following 150 msec SOAs, with saccadic latencies shorter than those generated in response to un-cued targets. Thus contrasting deficits were revealed in PD and HD, emphasizing the important contribution of the basal ganglia in the control of more automatic behaviors     

How do the basal ganglia and cerebellum gain access to the cortical motor areas?

We have used retrograde transport of wheat germ agglutinin conjugated to horseradish peroxidase to examine the origin of the thalamic input to the two premotor areas with the densest projections to the motor cortex. These are: arcuate premotor area (APA) and the supplementary motor area (SMA). Retrograde transport demonstrated that the two premotor areas and the motor cortex each receive thalamic input from separate, cytoarchitectonically well-defined subdivisions of the ventrolateral thalamus. According to the nomenclature of Olszewski (1952), input to the APA originates largely from area X; input to the SMA originates largely from the pars oralis subdivision of the nucleus ventralis lateralis (VLo); and that to the motor cortex is largely from the pars oralis subdivision of the nucleus ventralis posterior lateralis (VPLo). These observations, when combined with prior studies on the termination of various subcortical efferents in the thalamus, lead to the following scheme of projections: rostral portions of the deep cerebellar nuclei project to motor cortex via VPLo, caudal portions of the deep cerebellar nuclei project to the APA via area X; and the globus pallidus projects to the SMA via VLo. Thus each thalamocortical pathway is associated with a distinct subcortical input.     

Neural activities in the monkey basal ganglia related to attention, memory and anticipation

Discharges of single neurons were recorded in the caudate nucleus of an awake monkey. The monkey was trained to perform a series of behavioral tasks which required him to fixate on a spot of light on a screen and if the spot jumped to another location to make a saccade to refixate it. A significant portion of the neurons in the head and body of the caudate nucleus showed increases in their activities in relation to the behavioral tasks. While some neurons responded to the visual stimulus (light spot), others showed activities preceding a saccade. Another group of neurons showed activities not directly related to such sensory or motor events but presumably related to monkey's cognitive states. Even the visual or saccade-related activities were highly dependent on the behavioral context in which a given visual stimulus was presented or a given saccade was elicited. This report presents typical examples of caudate neural activities related to selective attention, short-term memory and anticipation of future events, and explains how such complex signals in the caudate are converted to oculomotor outputs through a major efferent pathway of the basal ganglia, namely caudate--substantia nigra pars reticulate--superior colliculus.     

Distinct basal ganglia hyperechogenicity in idiopathic basal ganglia calcification

We report a 67‐year‐old patient with idiopathic basal ganglia calcification (IBGC). He presented with progressive cognitive impairment, frontal lobe dysfunction, mild leg spasticity, and levodopa (L ‐dopa)‐responsive parkinsonism. Transcranial sonography (TCS) revealed marked hyperechogenicity of the basal ganglia and periventricular spaces bilaterally. The detected signal alterations showed a fairly symmetric distribution and corresponded to the hyperintense calcifications depicted on the computer tomography brain scan. The combination of symmetric hyperechogenic areas adjacent to the lateral ventricles and of the basal ganglia may serve as an imaging marker characteristic of IBGC. Hyperechogenicity due to extended basal ganglia calcification as presented here is distinct from the pattern of hyperechogenicity caused by heavy metal accumulation, which is described to be less striking. In addition to atypical parkinsonian syndromes such as progressive supranuclear palsy and multiple system atrophy, IBGC is thus another differential diagnosis of parkinsonism with basal ganglia hyperechogenicity. © 2010 Movement Disorder Society.     

Apathy and the basal ganglia

Journal of Neurology - We should like to emphasize the following points: 1. Apathy is defined here as a quantified and observable behavioral syndrome consisting in a quantitative reduction of...     

Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC). Report of a new case

Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) syndrome is a new neurodegenerative entity, which was first described by van der Knaap in 2002 in 7 patients aged from 2 months to 2 years. We describe a new, 42-month-old female patient who developed progressive dystonia, spasticity and oculogyric eye movements since the age of 3 months. The diagnosis was made by characteristic MRI findings including supratentorial hypomyelination and progressive atrophy of basal ganglia and cerebellum. Oculogyric eye movements have not been described in patients with H-ABC syndrome before. When compared with the normal age-related myelination patterns, the degree of hypomyelination increased progressively over the time course of 32 months, indicating arrest but not loss of myelination. The H-ABC syndrome adds to the differential diagnosis of progressive pyramidal and extrapyramidal movement disorders and to the increasing number of genetically determined hypomyelination syndromes.     

基底节区脑出血临界体积下治疗方法的比较

目的 比较基底节区高血压脑出血临界体积(30 ±5)ml 以下的血肿非手术保守治疗、≤6 h 钻孔引流、6 ～48 h 钻孔引流的方法,分析3 种方式的优缺点.方法 对393 例出血性脑卒中患者,采用3 种不同的治疗方法,观察疗效.结果 术后3 个月随访,根据日常生活能力(ADL)分级法评定,≤6 h 钻孔引流组与保守组、6 ～48 h 内钻孔引流组均有显著性差异(P ＜0.05).保守治疗组与6 ～48 h 内钻孔引流组相比无显著性差异(P ＞0.05).保守治疗组与所有钻孔引流组相比无显著性差异(P ＞ 0.05).在住院天数、血肿消除时间、住院费用方面,钻孔引流组具有较大的优势.结论 基底节区高血压脑出血临界体积(30 ±5 )ml 以下的血肿保守治疗与钻孔引流在远期疗效方面无明显差异,但结合安全性、住院天数、血肿消除时间、住院费用等方面,我们认为6 ～48 h 内钻孔引流是治疗高血压脑出血的一个较好的方法.