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Neuroimaging in Nuclear Medicine
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Anne Larsson Strömvall, Susanna Jakobson Mo
The neurons have thin extensions, called axons, through which they interconnect via electrical impulses, causing the release of neurotransmitters. An isolating fatty covering called the myelin sheath often encases axons in order to enhance and speed up the transmission of the electrical impulses. The brain tissue beneath the cortex – that is, the subcortical white matter – is dominated by myelinated nerve fibres. Deep within the white matter of each cerebral hemisphere, there are defined areas, nuclei, of grey matter, for example, the basal ganglia. The basal ganglia include the striatum, which in turn is divided into the caudate nucleus and the putamen. A tiny, paired area of grey matter in the brainstem is called the substantia nigra, which is also considered part of the basal ganglia. The thalamus is another important subcortical nucleus lying medial to the striatum. The cerebellum also has two hemispheres and a middle part called the vermis. The cerebellum is heavily folded, and its proportion of white matter is smaller compared to the cerebrum.
Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The following should be noted: The basal ganglia are involved in a wide range of self-initiated or remembered movements, action selection related to reward or punishment, preparation for movement as well as its execution and sequencing, and control of some movement parameters, such as amplitude and velocity. However, it appears that the planning and execution functions are mediated by separate neuronal populations in the basal ganglia.The basal ganglia are also involved in oculomotor activity as well, specifically in the control of saccadic eye movements, which are very rapid eye movements of velocity up to about 1000/s, that underlie visual fixation and rapid eye movements. The pathway involved is from the caudate nucleus to the SNr to the superior colliculus (not shown in Figure 12.6), where motoneurons controlling eye saccades are located.The same regions of the putamen receive projections from both the cortical somatomotor areas concerned with a given movement as well as the cortical somatosensory areas involved in the movement. The putamen can thus integrate both the motor and sensory aspects of a given movement.
High frequency subthalamic nucleus stimulation
Published in Hans O Lüders, Deep Brain Stimulation and Epilepsy, 2020
Erwin B Montgomery, John T Gale, Kenneth B Baker
Preliminary studies in a non-human primate, as described above, included analysis of responses of neurons in the motor cortex and putamen (Figure 11.9). These analyses revealed very short duration narrow responses suggesting antidromic activation of neurons in the motor cortex. Longer latency and broader peak responses suggestive of polysynaptic orthodromic activation were also seen in the motor cortex and putamen. It is interesting to note the temporal relationships between the peaks of the increased polysynaptic activity in the putamen and globus pallidus internal segment. Increased activity within the putamen was followed by decreased activity in the globus pallidus internal segment with a lag time of approximately 1.6 ms, which is consistent with the monosynaptic connections between putamen and globus pallidus internal segment. There is a suggestion of a similar relationship between cortical and putamen activity.
Cognition, function and awareness of disease impact in early Parkinson’s and Huntington’s disease
Published in Disability and Rehabilitation, 2022
Filipa Júlio, Maria J. Ribeiro, Ana Morgadinho, Mário Sousa, Marieke van Asselen, Mário R. Simões, Miguel Castelo-Branco, Cristina Januário
Nevertheless, in the early disease stages, there is a greater involvement of the putamen in Parkinson’s disease and a greater involvement of the caudate nucleus in Huntington’s disease [7,14–16]. As the putamen is a structure more related to motor function and the caudate nucleus has a predominantly cognitive role [17–23], the disease-related cognitive and functional sequelae are expected to be different. Moreover, though motor symptoms are the hallmark of the formal diagnosis of both diseases (PD as a hypokinetic and HD as a hyperkinetic movement disorder [18,24]), patients exhibit a broad spectrum of motor, cognitive and emotional changes [4], and considerable phenotypic heterogeneity [25,26]. Therefore, the distinct clinico-neuropathological features of these two diseases could lead to diagnosis-specific cognitive and functional impairments in these patients [4,27–29].
Striatal asymmetry index and its correlation with the Hoehn & Yahr stage in Parkinson's disease
Published in International Journal of Neuroscience, 2021
Wei Lin, Chuan-Tao Zuo, Jian-Jun Wu, Li-Kun Yang, Jie Zhu, Yu-Hai Wang
The structure and functions of the posterior putamen have been widely studied. Carpenter et al. investigated the nigrostriatal projection in a monkey, and found that the oral nigra projects mainly to the head of the caudate, while the caudal nigra projects to the putamen and body of the caudate [11]. Gerfen et al. noted similar neural projections in rats [12]. In addition, an autopsy study in patients with PD demonstrated that neuronal loss was greatest in the lateral ventral tier, followed by the medial ventral tier and dorsal tier, in the substantia nigra [13]. Another study also revealed consistent results, in which neuronal loss began in the lateral ventral tier, and that this region involvement remained as the most severe during PD progression. Furthermore, the lateral ventral nigra projects to the dorsal putamen. This study also indicated the severe dopamine depletion in the putamen, within which the dorsal and intermediate areas were more depleted than the ventral area [14].
Efficiency of 123I-ioflupane SPECT as the marker of basal ganglia damage in acute methanol poisoning: 6-year prospective study
Published in Clinical Toxicology, 2021
Katerina Kotikova, David Zogala, Vaclav Ptacnik, Jiri Trnka, Karel Kupka, Manuela Vaneckova, Zdenek Seidl, Pavel Diblik, Jarmila Heissigerova, Tomas Navratil, Martin Komarc, Ivan Zak, Kamila Polakova, Hana Brozova, Sergey Zakharov
Of 108 patients hospitalized with acute methanol poisoning, 84 survived. These survivors were asked whether they would be willing to participate in a study that involved a long-term assessment of the effects of methanol poisoning. Of the 54 patients who agreed, in 42 patients (8 females), brain MRI and DaT SPECT were performed. The patients had not previously been diagnosed with neurological, neurodegenerative, neurovascular, or psychiatric disorders other than chronic alcohol abuse. In 15/42 patients (36%), brain MRI revealed signs of necrotic lesions of the putamen (patients classified as group I) and, in 27 patients, no signs of putaminal damage were detected (classified as group II). Focal necrotic lesions in the globus pallidus were found in 6 patients (14%), three of them were members of group I. Clinically, 18 (43%) patients had mild to moderate bradykinesia with rigidity and/or tremor with mean combined NNIPPS score 25 ± 9 and 24 patients had no signs of parkinsonism. Of the 42 patients that had undergone DaT SPECT and MRI of the brain, MRI-volumetry was measured in 35 patients (8 females, p = 0.682), 13 patients with necrotic lesions of the putamen and 22 without signs of putaminal damage (p = 0.897). In seven patients, volumetric measurements were technically unfeasible due to the low quality of primary imaging data.