Experimental Brain Research

Türker, Kemal S.

doi: 10.1007/s00221-021-06290-7pmid: 35028693

This is a note challenging the claim by Kudina and Andreeva’s recent publication in Experimental Brain Research. In that publication, Kudina and Andreeva (Exp Brain Res 239:719–730, 2021) put forward a new idea about discovering two spiking modes in human motoneurons. We suggest that what they have shown in their publication maybe is the motor unit firing indicating the end of a net synaptic potential. We reason this challenge from our previous publication in the same journal. In that publication, we have shown that the "second spiking mode" after the H-reflex was a return to the regular prestimulus discharge rate.

Kudina, L. P.; Andreeva, R. E.

doi: 10.1007/s00221-021-06262-xpmid: 34779879

This is the response to Prof. Tűrker on his note “challenging” our hypothesis assuming the possibility of two modes of spiking (direct and delayed) evoked by Ia-afferent electrical stimulation in human firing motoneurones. Besides, we touch on some common questions about the most relevant, functionally significant, estimations of motoneuronal firing behaviour in human motor control. In particular, in this context, the question arises: what is more important estimation, motoneurone spiking, itself, or a value of the corresponding interspike interval of the firing motoneurone?

Veleri, Shobi

doi: 10.1007/s00221-021-06244-zpmid: 34694467

The devastating COVID-19 pandemic is caused by the SARS-CoV-2 virus. It primarily affects the lung and induces acute respiratory distress leading to a decrease in oxygen supply to the cells. This lung insufficiency caused by SARS-CoV-2 virus contributes to hypoxia which can affect the brain and other organ systems. The heightened cytokine storm in COVID-19 patients leads to an immune reaction in the vascular endothelial cells that compromise the host defenses against the SARS-CoV-2 virus in various organs. The vascular endothelial cell membrane breach allows access for SARS-CoV-2 to infect multiple tissues and organs. The neurotropism of spike protein in SARS-CoV-2 rendered by furin site insertion may increase neuronal infections. These could result in encephalitis and encephalopathy. The COVID-19 patients suffered severe lung deficiency often showed effects in the brain and neural system. The early symptoms include headache, loss of smell, mental confusion, psychiatric disorders and strokes, and rarely encephalitis, which indicated the vulnerability of the nervous system to SARS-CoV-2. Infection of the brain and peripheral nervous system can lead to the dysfunction of other organs and result in multi-organ failure. This review focuses on discussing the vulnerability of the nervous system based on the pattern of expression of the receptors for the SARS-CoV-2 and the mechanisms of its cell invasion. The SARS-CoV-2 elicited immune response and host immune response evasion are further discussed. Then the effects on the nervous system and its consequences on neuro-sensory functions are discussed. Finally, the emerging information on the overall genetic susceptibility seen in COVID-19 patients and its implications for therapy outlook is discussed.

Job, Xavier E.; Kirsch, Louise P.; Auvray, Malika

doi: 10.1007/s00221-021-06221-6pmid: 34716457

Information can be perceived from a multiplicity of spatial perspectives, which is central to effectively understanding and interacting with our environment and other people. Sensory impairments such as blindness are known to impact spatial representations and perspective-taking is often thought of as a visual process. However, disturbed functioning of other sensory systems (e.g., vestibular, proprioceptive and auditory) can also influence spatial perspective-taking. These lines of research remain largely separate, yet together they may shed new light on the role that each sensory modality plays in this core cognitive ability. The findings to date reveal that spatial cognitive processes may be differently affected by various types of sensory loss. The visual system may be crucial for the development of efficient allocentric (object-to-object) representation; however, the role of vision in adopting another’s spatial perspective remains unclear. On the other hand, the vestibular and the proprioceptive systems likely play an important role in anchoring the perceived self to the physical body, thus facilitating imagined self-rotations required to adopt another’s spatial perspective. Findings regarding the influence of disturbed auditory functioning on perspective-taking are so far inconclusive and thus await further data. This review highlights that spatial perspective-taking is a highly plastic cognitive ability, as the brain is often able to compensate in the face of different sensory loss.

Conterno, Martina; Kümmerer, Dorothee; Dressing, Andrea; Glauche, Volkmar; Urbach, Horst; Weiller, Cornelius; Rijntjes, Michel

doi: 10.1007/s00221-021-06224-3pmid: 34652492

The anatomical relationship between speech apraxia (SA) and oral apraxia (OA) is still unclear. To shed light on this matter we studied 137 patients with acute ischaemic left-hemisphere stroke and performed support vector regression-based, multivariate lesion–symptom mapping. Thirty-three patients presented with either SA or OA. These two symptoms mostly co-occurred (n = 28), except for few patients with isolated SA (n = 2) or OA (n = 3). All patient with either SA or OA presented with aphasia (p < 0.001) and these symptoms were highly associated with apraxia (p < 0.001). Co-occurring SA and OA were predominantly associated with insular lesions, while the insula was completely spared in the five patients with isolated SA or OA. Isolated SA occurred in case of frontal lesions (prefrontal gyrus and superior longitudinal fasciculus), while isolated OA occurred in case of either temporoparietal or striatocapsular lesions. Our study supports the notion of a predominant, but not exclusive, role of the insula in verbal and non-verbal oral praxis, and indicates that frontal regions may contribute exclusively to verbal oral praxis, while temporoparietal and striatocapsular regions contribute to non-verbal oral praxis. However, since tests for SA and OA so far intrinsically also investigate aphasia and apraxia, refined tests are warranted.

Fan, Min; Yu, Gaowen; Zhang, Donghuan; Sun, Nan; Zheng, Xifu

doi: 10.1007/s00221-021-06279-2pmid: 34854933

Empathy for pain, the ability to share and understand the pain of others, plays an important role in the survival and development of individuals. Previous studies have found that social pain experience affects empathy for pain, but potential gender differences have not been considered. The stage of information processing during which gender is most likely to play a moderating role has yet to be clarified. In the current study, we set up two groups (social pain experience priming: social exclusion group; positive social interaction experience priming: social inclusion group) with a Cyberball game paradigm. We recorded the electrophysiological responses when participants were completing an empathy task. An early frontal P2 and N2 differentiation between painful stimuli and neutral stimuli was observed and females showed larger P2 amplitudes than males. At the P3 stage, in the social exclusion group, males showed similar parietal P3 amplitudes for painful and neutral stimuli, while females showed smaller P3 amplitudes for painful stimuli. At the central-parietal late positive potential (LPP) stage, females in the social inclusion group showed larger LPP amplitudes for painful stimuli than males. Our results suggest that gender plays a significant moderating role in how social pain experience affects empathy for pain during the late cognitive processing stage. Experiment 2 was designed to investigate the cognitive mechanism behind the results for the P3 component in females and the results partially confirmed our speculation. This study provides a neurophysiological basis for the dynamic gender differences in the effects of social pain experience on empathy for pain.

Wang, Ashley; Nikolin, Stevan; Moffa, Adriano H.; Loo, Colleen K.; Martin, Donel M.

doi: 10.1007/s00221-021-06233-2pmid: 34625838

Repetitive transcranial magnetic stimulation (rTMS) has the potential to be developed as a novel treatment for cognitive dysfunction. However, current methods of targeting rTMS for cognition fail to consider inter-individual functional variability. This study explored the use of a cognitive task to individualise the target site for rTMS administered to the left dorsolateral prefrontal cortex (L-DLPFC). Twenty-five healthy participants were enrolled in a sham-controlled, crossover study. Participants performed a random letter generation task under the following conditions: no stimulation, sham and active ‘online’ rTMS applied to F3 (International 10–20 System) and four standardised surrounding sites. Across all sites combined, active ‘online’ rTMS was associated with significantly reduced performance compared to sham rTMS for unique trigrams (p = 0.012), but not for unique digrams (p > 0.05). Using a novel localisation methodology based on performance outcomes from both measures, a single optimal individualised site was identified for 92% [n = 23] of participants. At the individualised site, performance was significantly poorer compared to a common standard site (F3) and both control conditions (ps < 0.01). The current results suggest that this localisation methodology using a cognitive task could be used to individualise the rTMS target site at the L-DLPFC for modulating and potentially enhancing cognitive functioning.

Kolarik, Andrew J.; Moore, Brian C. J.; Cirstea, Silvia; Raman, Rajiv; Gopalakrishnan, Sarika; Pardhan, Shahina

doi: 10.1007/s00221-021-06235-0pmid: 34623459

Visual spatial information plays an important role in calibrating auditory space. Blindness results in deficits in a number of auditory abilities, which have been explained in terms of the hypothesis that visual information is needed to calibrate audition. When judging the size of a novel room when only auditory cues are available, normally sighted participants may use the location of the farthest sound source to infer the nearest possible distance of the far wall. However, for people with partial visual loss (distinct from blindness in that some vision is present), such a strategy may not be reliable if vision is needed to calibrate auditory cues for distance. In the current study, participants were presented with sounds at different distances (ranging from 1.2 to 13.8 m) in a simulated reverberant (T60 = 700 ms) or anechoic room. Farthest distance judgments and room size judgments (volume and area) were obtained from blindfolded participants (18 normally sighted, 38 partially sighted) for speech, music, and noise stimuli. With sighted participants, the judged room volume and farthest sound source distance estimates were positively correlated (p < 0.05) for all conditions. Participants with visual losses showed no significant correlations for any of the conditions tested. A similar pattern of results was observed for the correlations between farthest distance and room floor area estimates. Results demonstrate that partial visual loss disrupts the relationship between judged room size and sound source distance that is shown by sighted participants.

Guan, Hui-Lin; Guan, Yue; Li, Wen-Yuan; Liu, Jia-Wei; Zheng, Yu-Jia; Guan, Yan-Zhong; Liu, Hong-Feng; Guan, Li-Xin; Zhai, Feng-Guo

doi: 10.1007/s00221-021-06236-zpmid: 34661743

This study aimed to establish the role of miR-129 and miR-384-5p in cerebral ischemia-induced apoptosis. Using PC12 cells transfected with miR-129 or miR-384-5p mimics or inhibitors, oxygen glucose deprivation (OGD) conditions were applied for 4 h to simulate transient cerebral ischemia. Apoptotic phenotypes were assessed via lactate dehydrogenase (LDH) assay, MTT cell metabolism assay, and fluorescence-activated cell sorting (FACS). The effect of miR overexpression and inhibition was evaluated by protein and mRNA detection of bcl-2 and caspase-3, critical apoptosis factors. Finally, the direct relationship of miR-129 and bcl-2 and miR-384-5p and caspase-3 was measured by luciferase reporter assay. The overexpression of miR-384-5p and miR-129 deficiency significantly enhanced cell viability, reduced LDH release, and inhibited apoptosis. By contrast, overexpression of miR-129 and miR-384-5p deficiency aggravated hypoxia-induced apoptosis and cell injury. miR-129 overexpression significantly reduced mRNA and protein levels of bcl-2 and miR-129 inhibition significantly increased mRNA and protein levels of bcl-2 in hypoxic cells.miR-384-5p overexpression significantly reduced protein levels of caspase-3 while miR-384-5p deficiency significantly increased protein levels of caspase-3. However, no changes were observed in caspase-3 mRNA in either transfection paradigm. Finally, luciferase reporter assay confirmed caspase-3 to be a direct target of miR-384-5p; however, no binding activity was detected between bcl-2 and miR-129.Transient cerebral ischemia induces differential expression of miR-129 and miR-384-5p which influences apoptosis by regulating apoptotic factors caspase-3 and bcl-2, thereby participating in the pathological mechanism of cerebral ischemia, and becoming potential targets for the treatment of ischemic cerebral injury in the future.Graphic abstract[graphic not available: see fulltext]

Chetia Phukan, Banashree; Dutta, Ankumoni; Deb, Satarupa; Saikia, Rubul; Mazumder, Muhammed Khairujjaman; Paul, Rajib; Bhattacharya, Pallab; Sandhir, Rajat; Borah, Anupom

doi: 10.1007/s00221-021-06237-ypmid: 34633467