23 research outputs found
A practical application of text mining to literature on cognitive rehabilitation and enhancement through neurostimulation
Get PDFThe exponential growth in publications represents a major challenge for researchers. Many scientific domains, including neuroscience, are not yet fully engaged in exploiting large bodies of publications. In this paper, we promote the idea to partially automate the processing of scientific documents, specifically using text mining (TM), to efficiently review big corpora of publications. The “cognitive advantage” given by TM is mainly related to the automatic extraction of relevant trends from corpora of literature, otherwise impossible to analyze in short periods of time. Specifically, the benefits of TM are increased speed, quality and reproducibility of text processing, boosted by rapid updates of the results. First, we selected a set of TM-tools that allow user-friendly approaches of the scientific literature, and which could serve as a guide for researchers willing to incorporate TM in their work. Second, we used these TM-tools to obtain basic insights into the relevant literature on cognitive rehabilitation (CR) and cognitive enhancement (CE) using transcranial magnetic stimulation (TMS). TM readily extracted the diversity of TMS applications in CR and CE from vast corpora of publications, automatically retrieving trends already described in published reviews. TMS emerged as one of the important non-invasive tools that can both improve cognitive and motor functions in numerous neurological diseases and induce modulations/enhancements of many fundamental brain functions. TM also revealed trends in big corpora of publications by extracting occurrence frequency and relationships of particular subtopics. Moreover, we showed that CR and CE share research topics, both aiming to increase the brain's capacity to process information, thus supporting their integration in a larger perspective. Methodologically, despite limitations of a simple user-friendly approach, TM served well the reviewing process.Version of Recor
An Open Resource for Non-human Primate Optogenetics
No full texthttp://dx.doi.org/10.13039/100014147 Charles E. Kaufman Foundatio
Effects of Gaze Shifts on Maintenance of Spatial Memory in Macaque Frontal Eye Field
No full textThe activity of 91 neurons in the frontal eye fields (FEFs) of two macaque monkeys was recorded while the animals performed a delayed spatial match-to-sample task. During the delay, the animals were required to shift their gaze to one of four eccentric locations. Neuronal activity during the delay was analyzed for sensitivity to cue location and eye position. One-third of the neurons showed significant delay activity selective for cue location, whereas slightly more than one-half of the neurons showed significant modulation of delay activity when the gaze was shifted to an eccentric location. Despite this modulation, the neurons continued to signal their preferred cue location during most of the delay. However, after recentering saccades, the memory signal was temporarily abolished and then reemerged over a period of few hundred milliseconds. This is consistent with the idea that spatial working memory is buffered outside of the FEF. For most neurons, delay activity tended to increase when the gaze was shifted away from the preferred location and to decrease when the gaze was shifted toward the preferred location. This pattern of modulation is consistent with a vector subtraction mechanism that allows for the superposition of multiple saccade plans.</jats:p
Effects of Spontaneous Eye Movements on Spatial Memory in Macaque Periarcuate Cortex
No full textPersistent activity in prefrontal cortex during delayed response tasks is a putative neural correlate of spatial working memory. We tested whether this activity was sensitive to eye movements made during the memory interval by recording from prefrontal neurons while monkeys performed a delayed spatial matching saccade task in which they were allowed to make eye movements freely. We found that eye movements degraded the spatial tuning of persistent activity even as there was an improvement in behavioral performance. Although the strength of the memory signal decreased, delay activity continued to signal the location of cue. The results suggest that free eye movements reduce neuronal gain rather than add variability. The saccades performed during the delay suggest the existence of a rehearsal mechanism that could contribute to working memory maintenance. The results do not provide support for a segregation of storage and executive functions in the periarcuate cortex.</jats:p
Neuronal correlates of the set-size effect in monkey lateral intraparietal area.
No full textIt has long been known that the brain is limited in the amount of sensory information that it can process at any given time. A well-known form of capacity limitation in vision is the set-size effect, whereby the time needed to find a target increases in the presence of distractors. The set-size effect implies that inputs from multiple objects interfere with each other, but the loci and mechanisms of this interference are unknown. Here we show that the set-size effect has a neural correlate in competitive visuo-visual interactions in the lateral intraparietal area, an area related to spatial attention and eye movements. Monkeys performed a covert visual search task in which they discriminated the orientation of a visual target surrounded by distractors. Neurons encoded target location, but responses associated with both target and distractors declined as a function of distractor number (set size). Firing rates associated with the target in the receptive field correlated with reaction time both within and across set sizes. The findings suggest that competitive visuo-visual interactions in areas related to spatial attention contribute to capacity limitations in visual searches
Franchise in Romanian tourism
Get PDFBoth on national and international scale, tourism business is improving continuously, by adjusting to the tourists' demands, resulting in modification and adaptation of organization and association forms in this area. One of these is the franchise affiliation, an original way of doing business that combines the entrepreneurs interest in keeping their own undertaking with that belongs to a group with well-known brand which aims to expand on national and international market. This paper will discuss two important areas of the Romanian tourism industry in which franchise agreement is applied: travel agencies franchise and hotel franchise. On a national scale, franchise was adopted as an expanding strategy by the travel agencies, on one hand, notorious tour-operators that has accumulated know-how and has proven its successful applicability, and, on the other hand, small and medium entrepreneurs who saw in the franchise affiliation an opportunity to develop faster and more reliable business. Also, the Romanian hotel owners with financial resources have seen in hotel franchise an easier way to obtain higher profits. In today's competitive and global hotel market, being part of a group of hotels that share a recognized brand and provide quality services might mean the difference between financial success and failure.franchise, know-how, brand, travel agents franchise, hotel franchise
Selective TMS-induced modulation of functional connectivity correlates with changes in behavior
No full textDespite the increasing use of functional connectivity (FC) studies in fundamental and clinical research, the link
between FC and behavior is still poorly understood. To test the hypothesis that artificial modulation of FC
correlates with changes in behavior in a quantitative manner, we performed behavioral and resting state fMRI
experiments in monkeys while perturbing, offline, the frontal eye fields (FEF) using unilateral continuous theta
burst transcranial magnetic stimulation (FEF-cTBS). Stimulation of left and right FEF caused remarkably
specific decreases in FC, which were symmetric for intra-hemispheric and asymmetric for inter-hemispheric FC.
Surprisingly, FEF-cTBS improved the performance and compensated intrinsic choice biases in saccadic
behavior of four monkeys, independent of the initial bias direction. Moreover, the direction of the
stimulation-induced effects on both behavior (i.e. bias compensation) and FC (i.e. decrease) were independent
of the stimulated hemisphere, while their magnitude depended on the side of stimulation, choice bias and
monkey. Overall, the naturally-occurring saccade biases determined the FC changes following FEF-cTBS.
Finally, we showed that the average decreases in FC in the FEF network induced by cTBS can be used to predict,
with high specificity, both the direction (opposite to the saccadic biases) and the magnitude of the shift in
saccadic choice preference relative to the unperturbed state. To reconcile the apparent contradiction between
improved performance and bias compensation vs. decrease in functional connectivity, we propose that the main
functional consequences of FEF-cTBS relate to adjusting inter-hemispheric imbalances.sponsorship: The authors thank A. Coeman, C. Fransen, P. Kayenbergh, I. Puttemans, S. De Pril, A. Hermans, G. Meulemans, S. Verstraeten, and C. Van Eupen for technical support and S. Raiguel for his comments on the manuscript. This work was supported by InterUniversity Attraction Pole 7/11, the Research Foundation Flanders (G.0.622.08.N.10; G.0.831.11.N.10; G.0.A56.13.N; G.0.B86.17.N Odysseus G0007.12); KU Leuven (Programme Financing PFV/10/008), the European Union Seventh Framework under grant agreement no. 604102 (Human Brain Project) and the Hercules foundation. DM held a Sir Henry Dale Fellowship jointly funded by the Wellcome Trust and the Royal Society (Grant no. 101253/Z/13/Z). (InterUniversity Attraction Pole|7/11, Research Foundation Flanders|G.0.622.08.N.10, Research Foundation Flanders|G.0.831.11.N.10, Research Foundation Flanders|G.0.A56.13.N, Research Foundation Flanders|G.0.B86.17.N Odysseus G0007.12, KU Leuven|PFV/10/ 008, European Union Seventh Framework|604102, Hercules foundation, Wellcome Trust|101253/Z/13/Z, Royal Society|101253/Z/13/Z, Wellcome Trust|101253/Z/13/Z)status: Publishe
Task specific computations in attentional maps
No full textAbstractThe lateral intraparietal area (LIP), a portion of monkey posterior parietal cortex, has been implicated in spatial attention. We review recent evidence from our laboratory showing that LIP encodes a priority map of the external environment that specifies the momentary locus of attention and is activated in a variety of behavioral tasks. The priority map in LIP is shaped by task-specific variables. We suggest that the multifaceted responses in LIP represent mechanisms for allocating attention, and that the attentional system may flexibly configure itself to meet the cognitive, motor and motivational demands of individual tasks
MEBRAINS: a new population-based monkey template (v1.0)
No full textAn important limitation of existing anatomical templates for the macaque brain is their reliance on one subject and/or on unimodality (usually T1 images). The MEBRAINS template overcomes this limitation. It is constructed using the multi-brain toolbox for SPM12 and represents a population average of T1- and T2-weighted MRI scans from 10 macaque brains. In addition, 9 CT scans of the same monkeys (one missing) are registered to the T1 modality and co-registered to the population average. Through its main features (multi-subject based, multi-modal, volume-and-surface), MEBRAINS represents an essential step towards the integration of multi-level macaque data, fulfilling a similar role as the EBRAINS multilevel Human Brain Atlas
MEBRAINS 1.0: a new population-based macaque atlas
No full textDue to their fundamental relevance, the number of anatomical macaque brain templates is constantly growing. Novel templates aim to alleviate limitations of previously published atlases and offer the foundation to integrate multiscale multimodal data. Typical limitations of existing templates include their reliance on one subject, their unimodality (usually only T1 or histological images), or lack of anatomical details. The MEBRAINS template overcomes these limitations by using a combination of T1 and T2 images, from the same 10 animals (Macaca mulatta), which are averaged by the multi-brain toolbox for diffeomorphic registration and segmentation. The resulting volumetric T1 and T2 templates are supplemented with high quality white and gray matter surfaces built with FreeSurfer. Human-curated segmentations of pial surface, white/gray matter interface and major subcortical nuclei were used to analyse the relative quality of the MEBRAINS template. Recently published 3D maps of the macaque inferior parietal lobe and (pre)motor cortex were warped to the MEBRAINS surface template, thus populating it with a parcellation scheme based on cyto- and receptor architectonic analyses. Finally, 9 CT scans of the same monkeys were registered to the T1 modality and co-registered to the template. Through its main features (multi-subject, multi-modal, volume-and-surface, traditional and deep learning-based segmentations), MEBRAINS aims to improve integration of multi-modal multi-scale macaque data and is quantitatively equal or better compared to currently widely used macaque templates. The template is integrated in the EBRAINS and Scalable Brain Atlas web-based infrastructures, each of which comes with its own suite of spatial registration tools
