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Brain Imaging and Behavior Aug 2023Little information is available on the magnetic resonance imaging (MRI) determination of the hippocampal formation (HF) during the perinatal period. However, this...
Little information is available on the magnetic resonance imaging (MRI) determination of the hippocampal formation (HF) during the perinatal period. However, this exploration is increasingly used, which requires defining visible HF landmarks on MRI images, validated through histological analysis. This study aims to provide a protocol to identify HF landmarks on MRI images, followed by histological validation through serial sections of the temporal lobe of the samples examined, to assess the longitudinal extent of the hippocampus during the perinatal period. We examined ex vivo MRI images from nine infant control brain samples. Histological validation of the hippocampal formation MRI images was obtained through serial sectioning and examination of Nissl-stained sections at 250 μm intervals along the entire length of the hippocampal formation. Up to six landmarks were identified both in MRI images and the serial histological sections. Proceeding in an anterior to posterior (rostrocaudal) direction, these were as follows: 1) the limen insulae (fronto-temporal junction); 2) the beginning of the amygdaloid complex; 3) the beginning of the lateral ventricle; 4) the caudal limit of the uncus, indicated by the start of the lateral geniculate nucleus (at the level of the gyrus intralimbicus); 5) the end of the lateral geniculate nucleus (beginning of the pulvinar); and 6) the beginning of the fornix. After histological validation of each of these landmarks, the full longitudinal length of the hippocampal formation and distances between landmarks were calculated. No statistically significant differences were found in total length or between landmarks. While the HF is anatomically organized at birth, its annotation is particularly challenging to perform. The histological validation of HF landmarks allows a better understanding of MRI images. The proposed protocol could be useful to assess MRI hippocampal quantification in children and possible variations due to different neurological diseases.
Topics: Infant; Child; Infant, Newborn; Humans; Magnetic Resonance Imaging; Hippocampus; Temporal Lobe; Brain; Magnetic Resonance Spectroscopy
PubMed: 37024762
DOI: 10.1007/s11682-023-00768-4 -
The European Journal of Neuroscience Feb 2024The interruption of sleep by a nociceptive stimulus is favoured by an increase in the pre-stimulus functional connectivity between sensory and higher level cortical...
The interruption of sleep by a nociceptive stimulus is favoured by an increase in the pre-stimulus functional connectivity between sensory and higher level cortical areas. In addition, stimuli inducing arousal also trigger a widespread electroencephalographic (EEG) response reflecting the coordinated activation of a large cortical network. Because functional connectivity between distant cortical areas is thought to be underpinned by trans-thalamic connections involving associative thalamic nuclei, we investigated the possible involvement of one principal associative thalamic nucleus, the medial pulvinar (PuM), in the sleeper's responsiveness to nociceptive stimuli. Intra-cortical and intra-thalamic signals were analysed in 440 intracranial electroencephalographic (iEEG) segments during nocturnal sleep in eight epileptic patients receiving laser nociceptive stimuli. The spectral coherence between the PuM and 10 cortical regions grouped in networks was computed during 5 s before and 1 s after the nociceptive stimulus and contrasted according to the presence or absence of an arousal EEG response. Pre- and post-stimulus phase coherence between the PuM and all cortical networks was significantly increased in instances of arousal, both during N2 and paradoxical (rapid eye movement [REM]) sleep. Thalamo-cortical enhancement in coherence involved both sensory and higher level cortical networks and predominated in the pre-stimulus period. The association between pre-stimulus widespread increase in thalamo-cortical coherence and subsequent arousal suggests that the probability of sleep interruption by a noxious stimulus increases when it occurs during phases of enhanced trans-thalamic transfer of information between cortical areas.
Topics: Humans; Pulvinar; Sleep; Arousal; Electroencephalography; Thalamus
PubMed: 36889675
DOI: 10.1111/ejn.15958 -
The Canadian Journal of Neurological... Nov 2023Quantitative susceptibility mapping (QSM) demonstrates elevated iron content in Parkinson's disease (PD) patients within the basal ganglia, though it has infrequently...
BACKGROUND
Quantitative susceptibility mapping (QSM) demonstrates elevated iron content in Parkinson's disease (PD) patients within the basal ganglia, though it has infrequently been studied in relation to gait difficulties including freezing of gait (FOG). Our purpose was to relate QSM of basal ganglia and extra-basal ganglia structures with qualitative and quantitative gait measures in PD.
METHODS
This case-control study included PD and cognitively unimpaired (CU) participants from the Comprehensive Assessment of Neurodegeneration and Dementia study. Whole brain QSM was acquired at 3T. Region of interests (ROIs) were drawn blinded manually in the caudate nucleus, putamen, globus pallidus, pulvinar nucleus of the thalamus, red nucleus, substantia nigra, and dentate nucleus. Susceptibilities of ROIs were compared between PD and CU. Items from the FOG questionnaire and quantitative gait measures from PD participants were compared to susceptibilities.
RESULTS
Twenty-nine participants with PD and 27 CU participants were included. There was no difference in susceptibility values in any ROI when comparing CU versus PD ( > 0.05 for all). PD participants with gait impairment ( = 23) had significantly higher susceptibility in the putamen ( = 0.008), red nucleus ( = 0.01), and caudate nucleus ( = 0.03) compared to those without gait impairment ( = 6). PD participants with FOG ( = 12) had significantly higher susceptibility in the globus pallidus ( = 0.03) compared to those without FOG ( = 17). Among quantitative gait measures, only stride time variability was significantly different between those with and without FOG ( = 0.04).
CONCLUSION
Susceptibilities in basal ganglia and extra-basal ganglia structures are related to qualitative measures of gait impairment and FOG in PD.
PubMed: 36351571
DOI: 10.1017/cjn.2022.316 -
British Journal of Neurosurgery Aug 2023Fahr disease is an uncommon disorder defined as prominent calcification in basal ganglia, dentate nuclei of cerebellum, pulvinar thalami and subcortical white matter and...
BACKGROUND AND IMPORTANCE
Fahr disease is an uncommon disorder defined as prominent calcification in basal ganglia, dentate nuclei of cerebellum, pulvinar thalami and subcortical white matter and it has been shown that calcium is the major factor that causes the hyperdensity on computer tomography (CT). Spontaneous subarachnoid hemorrhage from an aneurysm in a patient with Fahr disease was first reported by Al-Jehani in 2012 in a 54-year-old female patient with calcification of basal ganglia and deep cerebellar nuclei and a subarachnoid hemorrhage from a right posterior communicating artery aneurysm.
CLINICAL PRESENTATION
We present a 17 years old patient with Fahr disease with an anterior communicating artery aneurysm rupture.
CONCLUSION
There are few reports of intracranial hemorrhage with Fahr's disease. It may be suggested that excessive calcium accumulation contributes to aneurysm formation or rupture.
Topics: Female; Humans; Middle Aged; Adolescent; Intracranial Aneurysm; Calcium; Basal Ganglia Diseases; Neurodegenerative Diseases
PubMed: 31718303
DOI: 10.1080/02688697.2019.1690128