Improved Functionnectome by dissociating the contributions of white matter fiber classes to functional activation
AbstractIntegrating the underlying brain circuit's structural and functional architecture is required to explore the functional organization of cognitive networks. In that regard, we recently introduced the Functionnectome. This structural –functional method combines an fMRI acquisition with tractography-derived white matter connectivity data to map cognitive processes onto the white matter. However, this multimodal integration faces three significant challenges: (1) the necessarily limited overlap between tractography streamlines a nd the grey matter, which may reduce the amount of functional signal associated with the ...
Source: Anatomy and Embryology - October 7, 2023 Category: Anatomy Source Type: research
Resting-state functional connectivity in an auditory network differs between aspiring professional and amateur musicians and correlates with performance
AbstractAuditory experience-dependent plasticity is often studied in the domain of musical expertise. Available evidence suggests that years of musical practice are associated with structural and functional changes in auditory cortex and related brain regions. Resting-state functional magnetic resonance imaging (MRI) can be used to investigate neural correlates of musical training and expertise beyond specific task influences. Here, we compared two groups of musicians with varying expertise: 24 aspiring professional musicians preparing for their entrance exam at Universities of Arts versus 17 amateur musicians without any ...
Source: Anatomy and Embryology - October 4, 2023 Category: Anatomy Source Type: research
Electrical stimulation of the cerebellum facilitates automatic but not controlled word retrieval
AbstractRecent research has indicated that the cerebellum is engaged in language functions, yet the role of the cerebellum in lexical-semantic memory is poorly understood. In a double-blind randomized controlled experiment, we therefore targeted the cerebellum by transcranial direct current stimulation (tDCS) to assess and compare the contribution of the cerebellar processing to automatic and controlled retrieval of words in healthy adults (n = 136). Anodal cerebellar tDCS facilitated retrieval of semantically related words in free-associative chains, which was not due to a non-specific acceleration of processing spee...
Source: Anatomy and Embryology - October 2, 2023 Category: Anatomy Source Type: research
Sleep-physiological correlates of brachycephaly in dogs
AbstractThe shape of the cranium is one of the most notable physical changes induced in domestic dogs through selective breeding and is measured using the cephalic index (CI). High CI (a ratio of skull width to skull length > 60) is characterized by a short muzzle and flat face and is referred to as brachycephaly. Brachycephalic dogs display some potentially harmful changes in neuroanatomy, and there are implications for differences in behavior, as well. The path from anatomy to cognition, however, has not been charte d in its entirety. Here, we report that sleep-physiological markers of white-matter loss (high de...
Source: Anatomy and Embryology - September 24, 2023 Category: Anatomy Source Type: research
Alterations in rat brain modular organization during unconsciousness are dependent on communication efficiency and metabolic cost
We examined alterations in brain modular variability during loss of consciousness from mild sedation to deep anesthesia. We also investigated the relationships between modular variability with glucose metabolism and functional connectivity strength as well as their alterations during unconsciousness. We observed that modular variability increased during loss of consciousness. Critically, across-individual modular variability is oppositely associated with functional connectivity strength and cerebral metabolism, and with deepening dosage of anesthesia, becoming increasingly dependent on basal metabolism over functional conn...
Source: Anatomy and Embryology - September 21, 2023 Category: Anatomy Source Type: research
Prominent and conspicuous astrocyte atrophy in human sporadic and familial Alzheimer ’s disease
In this study, we report prominent atrophic changes in GFAP and GS astrocytes in the EC of both SAD and FAD characterised by a decrease in area and volume when compared with non-demented control samples (ND). Furthermore, we did not find neither astrocytic loss nor astrocyte proliferation or hypertrophy (gliosis). In contrast with the astrogliosis classically accepted hypothesis, our r esults show a highly marked astrocyte atrophy that could have a major relevance in AD pathological processes being fundamental and key for AD mnesic and cognitive alterations equivalent in both SAD and FAD. (Source: Anatomy and Embryology)
Source: Anatomy and Embryology - September 20, 2023 Category: Anatomy Source Type: research
Development of the prosencephalic structures, ganglionic eminence, basal ganglia and thalamus at 11 + 3 to 13 + 6 gestational weeks on 3D transvaginal ultrasound including normative data
ConclusionTransvaginal 3D neurosonography allows visualization and measurement of normal structures in the fetal prosencephalon at 11 + 3 to 13 + 6 weeks of gestation (GW) including details of ganglionic eminence (GE), basal ganglia (BG), and thalamus/hypothalamus (Th/HyT). Further scientific work is needed before using the results to decide on pathological changes in patients. (Source: Anatomy and Embryology)
Source: Anatomy and Embryology - September 15, 2023 Category: Anatomy Source Type: research
Why do different motor cortical areas activate the same muscles?
AbstractThe cortex contains multiple motor areas, including the primary motor cortex (M1) and supplementary motor area (SMA). Many muscles are represented in both the M1 and SMA, but the reason for this dual representation remains unclear. Previous work has shown that the M1 and SMA representations of a specific human muscle can be differentiated according to their functional connectivity with different brain areas located outside of the motor cortex. It is our perspective that this differential functional connectivity may be the neural substrate that allows an individual muscle to be accessed by distinct neural processes,...
Source: Anatomy and Embryology - September 14, 2023 Category: Anatomy Source Type: research
Comprehensive voxel-wise, tract-based, and network lesion mapping reveals unique architectures of right and left visuospatial neglect
AbstractVisuospatial neglect is a common, post-stroke cognitive impairment which is widely considered to be a disconnection syndrome. However, the patterns of disconnectivity associated with visuospatial neglect remain unclear. Here, we had 480 acute stroke survivors [age = 72.8 (SD = 13.3), 44.3% female, 7.5 days post-stroke (SD = 11.3)] undertake routine clinical imaging and standardised visuospatial neglect testing. The data were used to conduct voxel-wise, tract-level, and network-level lesion-mapping analyses aimed at localising the neural correlat es of left and right egocentric (body-centred) and alloc...
Source: Anatomy and Embryology - September 11, 2023 Category: Anatomy Source Type: research
Differentiated somatic gene expression is triggered in the dorsal hippocampus and the anterior retrosplenial cortex by hippocampal synaptic plasticity prompted by spatial content learning
AbstractHippocampal afferent inputs, terminating on proximal and distal subfields of the cornus ammonis (CA), enable the functional discrimination of ‘what’ (item identity) and ‘where’ (spatial location) elements of a spatial representation. This kind of information is supported by structures such as the retrosplenial cortex (RSC). Spatial content learning promotes the expression of hippocam pal synaptic plasticity, particularly long-term depression (LTD). In the CA1 region, this is specifically facilitated by the learning of item-place features of a spatial environment. Gene-tagging, by means of time-locked fluo...
Source: Anatomy and Embryology - September 10, 2023 Category: Anatomy Source Type: research
Social isolation leads to mild social recognition impairment and losses in brain cellularity
AbstractChronic social stress is a significant risk factor for several neuropsychiatric disorders, mainly major depressive disorder (MDD). In this way, patients with clinical depression may display many symptoms, including disrupted social behavior and anxiety. However, like many other psychiatric diseases, MDD has a very complex etiology and pathophysiology. Because social isolation is one of the multiple depression-inducing factors in humans, this study aims to understand better the link between social stress and MDD using an animal model based on social isolation after weaning, which is known to produce social stress in...
Source: Anatomy and Embryology - September 10, 2023 Category: Anatomy Source Type: research
Morphological changes in motoneurons of the oculomotor nucleus of mice after a 30-day space flight and through a 7-day period of readaptation to earth gravity
AbstractThe cellular mechanisms of neuroplastic changes in the structure of motoneurons and neuropils of the oculomotor (III) nuclei in mice after a 30-day space flight and 7 days after landing were studied. The results showed that microgravity caused degenerative phenomena in neurons: a decrease in the number of terminal dendritic branches was found both after flight and after readaptation to Earth's gravity. In mice after the flight, the number of axodendritic synapses was less than in the control, and their number was not restored after the readaptation. The number of mitochondria in the motoneurons of animals after the...
Source: Anatomy and Embryology - September 9, 2023 Category: Anatomy Source Type: research
Intrinsic neural network dynamics underlying the ability to down-regulate emotions in male perpetrators of intimate partner violence against women
AbstractResearch has pointed to difficulties in emotion regulation as a risk factor for perpetrating intimate partner violence against women (IPVAW). While efforts have been made to understand the brain mechanisms underlying emotion regulation strategies such as reappraisal, little is known about the intrinsic neural dynamics supporting this strategy in male perpetrators. Resting-state functional magnetic resonance imaging was used to characterise the network dynamics underlying reappraisal. Spectral dynamic causal modelling was performed to examine the effective connectivity (EC) within a predefined reappraisal-related br...
Source: Anatomy and Embryology - September 9, 2023 Category: Anatomy Source Type: research
Anatomical characterisation of three different psychosurgical targets in the subthalamic area: from the basal ganglia to the limbic system
AbstractEffective neural stimulation for the treatment of severe psychiatric disorders needs accurate characterisation of surgical targets. This is especially true for the medial subthalamic region (MSR) which contains three targets: the anteromedial STN for obsessive compulsive disorder (OCD), the medial forebrain bundle (MFB) for depression and OCD, and the “Sano triangle” for pathological aggressiveness. Blocks containing the subthalamic area were obtained from two human brains. After obtaining 11.7-Tesla MRI, blocks were cut in regular sections for immunohistochemistry. Fluorescentin situ hybridisation was performe...
Source: Anatomy and Embryology - September 5, 2023 Category: Anatomy Source Type: research
Axo-glial interactions between midbrain dopamine neurons and oligodendrocyte lineage cells in the anterior corpus callosum
AbstractOligodendrocyte progenitor cells (OPCs) receive synaptic innervation from glutamatergic and GABAergic axons and can be dynamically regulated by neural activity, resulting in activity-dependent changes in patterns of axon myelination. However, it remains unclear to what extent other types of neurons may innervate OPCs. Here, we provide evidence implicating midbrain dopamine neurons in the innervation of oligodendrocyte lineage cells in the anterior corpus callosum and nearby white matter tracts of male and female adult mice. Dopaminergic axon terminals were identified in the corpus callosum of DAT-Cre mice after inj...
Source: Anatomy and Embryology - September 5, 2023 Category: Anatomy Source Type: research
