Browsing by Subject "CORTEX"

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  • Lin, Hai; Li, Wei-ping; Carlson, Synnöve (2019)
    Top-down modulation is engaged during multiple stages of working memory (WM), including expectation, encoding, and maintenance. During WM maintenance period, an "incidental cue" can bring one of the two items into a privileged state and make the privileged item be recalled with higher precision, despite being irrelevant to which one to be probed as the target. With regard to the different representational states of WM, it's unclear whether there is top-down modulation on earth sensory cortical areas. Here, We used this behavioral paradigm of "incidental cue" and event-related fMRI to investigate whether there were a privileged WM state and top-down modulation for complex stimuli including faces and natural scenes. We found that faces, not scenes, could enter into the privileged state with improved accuracy and response time of WM task. Meanwhile, cue-driven baseline activity shifts in fusiform face area (FFA) were identified by univariate analysis in the recognition of privileged faces, compared to that of nonprivileged ones. In addition, the functional connectivity between FFA and right inferior frontal junction (IFJ), middle frontal gyrus (MFG), inferior frontal gyrus, right intraparietal sulcus (IPS), right precuneus and supplementary motor area was significantly enhanced, corresponding to the improved WM performance. Moreover, FFA connectivity with IFJ and IPS could predict WM improvements. These findings indicated that privileged WM state and potential top-down modulation existed for faces, but not scenes, during WM maintenance period.
  • Kauppi, Jukka-Pekka; Pajula, Juha; Tohka, Jussi (2014)
    In the inter-subject correlation (ISC) based analysis of the functional magnetic resonance imaging (fMRI) data, the extent of shared processing across subjects during the experiment is determined by calculating correlation coefficients between the fMRI time series of the subjects in the corresponding brain locations. This implies that ISC can be used to analyze fMRI data without explicitly modeling the stimulus and thus ISC is a potential method to analyze fMRI data acquired under complex naturalistic stimuli. Despite of the suitability of ISC based approach to analyze complex fMRI data, no generic software tools have been made available for this purpose, limiting a widespread use of ISC based analysis techniques among neuroimaging community. In this paper, we present a graphical user interface (GUI) based software package, ISC Toolbox, implemented in Matlab for computing various ISC based analyses. Many advanced computations such as comparison of ISCs between different stimuli, time window ISC, and inter-subject phase synchronization are supported by the toolbox. The analyses are coupled with resampling based statistical inference. The ISC based analyses are data and computation intensive and the ISC toolbox is equipped with mechanisms to execute the parallel computations in a cluster environment automatically and with an automatic detection of the cluster environment in use. Currently, SGE-based (Oracle Grid Engine, Son of a Grid Engine, or Open Grid Scheduler) and Slurm environments are supported. In this paper, we present a detailed account on the methods behind the ISC Toolbox, the implementation of the toolbox and demonstrate the possible use of the toolbox by summarizing selected example applications. We also report the computation time experiments both using a single desktop computer and two grid environments demonstrating that parallelization effectively reduces the computing time.
  • Laursen, Jens Christian; Sondergaard-Heinrich, Niels; de Melo, Joana Mendes Lopes; Haddock, Bryan; Rasmussen, Ida Kirstine Bull; Safavimanesh, Farzaneh; Hansen, Christian Stevns; Storling, Joachim; Larsson, Henrik Bo Wiberg; Groop, Per-Henrik; Frimodt-Moller, Marie; Andersen, Ulrik Bjorn; Rossing, Peter (2021)
    Background: Inhibitors of the sodium-glucose cotransporter 2 (SGLT2) slow the progression of diabetic kidney disease, possibly by reducing the proximal tubule transport workload with subsequent improvement of renal oxygenation. We aimed to test this hypothesis in individuals with type 1 diabetes and albuminuria. Methods: A randomised, double-blind, placebo-controlled, crossover trial with a single 50 mg dose of the SGLT2 inhibitor dapagliflozin and placebo in random order, separated by a two-week washout period. Magnetic resonance imaging (MRI) was used to assess renal R-2* (a low value corresponds to a high tissue oxygenation), renal perfusion (arterial spin labelling) and renal artery flow (phase contrast imaging) at baseline, three- and six hours from tablet ingestion. Exploratory outcomes, including baroreflex sensitivity, peripheral blood oxygen saturation, peripheral blood mononuclear cell mitochondrial oxygen consumption rate, and biomarkers of inflammation were evaluated at baseline and 12 h from medication. The study is registered in the EU Clinical Trials Register (EudraCT 2019-004,557-92), on (NCT04193566), and is completed. Findings: Between February 3, 2020 and October 23, 2020, 31 individuals were screened, and 19 eligible individuals were randomised. Three dropped out before receiving any of the interventions and one dropped out after receiving only placebo. We included 15 individuals (33% female) in the per-protocol analysis with a mean age of 58 (SD 14) years, median urinary albumin creatinine ratio of 46 [IQR 21-58] mg/g and an eGFR of 73 (32) ml/min/1.73m(2). The mean changes in renal cortical R-2* from baseline to six hours were for dapagliflozin -1.1 (SD 0.7) s(-1) and for placebo +1.3 (0.7) s(-1), resulting in a difference between interventions of -2.3 s(-1) [95% CI -4.0 to -0.6]; p = 0.012. No between-intervention differences were found in any other MRI outcomes, physiological parameters or exploratory outcomes. There were no adverse events. Interpretation: A single dose of 50 mg dapagliflozin acutely improved renal cortical R-2* without changing renal perfusion or blood flow. This suggests improved renal cortical oxygenation due to a reduced tubular transport workload in the proximal tubules. Such improved oxygenation may in part explain the long-term beneficial renal effects seen with SGLT2 inhibitors, but it remains to be determined whether the observed effects can be achieved with lower doses, with chronic treatment and if they occur in type 2 diabetes as well. (C) 2021 The Author(s). Published by Elsevier Ltd.
  • Jönsson, Emma H.; Kotilahti, Kalle; Heiskala, Juha; Backlund Wasling, Helena; Olausson, Håkan; Croy, Ilona; Mustaniemi, Hanna; Hiltunen, Petri; Tuulari, Jetro J.; Scheinin, Noora M.; Karlsson, Linnea; Karlsson, Hasse; Nissilä, Ilkka (2018)
    Caressing touch is an effective way to communicate emotions and to create social bonds. It is also one of the key mediators of early parental bonding. The caresses are generally thought to represent a social form of touching and indeed, slow, gentle brushing is encoded in specialized peripheral nerve fibers, the C-tactile (CT) afferents. In adults, areas such as the posterior insula and superior temporal sulcus are activated by affective, slow stroking touch but not by fast stroking stimulation. However, whether these areas are activated in infants, after social tactile stimulation, is unknown. In this study, we compared the total hemoglobin responses measured with diffuse optical tomography (DOT) in the left hemisphere following slow and fast stroking touch stimulation in 16 2-month-old infants. We compared slow stroking (optimal CT afferent stimulation) to fast stroking (non-optimal CT stimulation). Activated regions were delineated using two methods: one based on contrast between the two conditions, and the other based on voxel-based statistical significance of the difference between the two conditions. The first method showed a single activation cluster in the temporal cortex with center of gravity in the middle temporal gyrus where the total hemoglobin increased after the slow stroking relative to the fast stroking (p = 0.04 uncorrected). The second method revealed a cluster in the insula with an increase in total hemoglobin in the insular cortex in response to slow stroking relative to fast stroking (p = 0.0005 uncorrected; p = 0.04 corrected for multiple comparisons). These activation clusters encompass areas that are involved in processing of affective, slow stroking touch in the adult brain. We conclude that the infant brain shows a pronounced and adult-like response to slow stroking touch compared to fast stroking touch in the insular cortex but the expected response in the primary somatosensory cortex was not found at this age. The results imply that emotionally valent touch is encoded in the brain in adult-like manner already soon after birth and this suggests a potential for involvement of touch in bonding with the caretaker.
  • Price, D.; Tyler, L. K.; Henriques, R. Neto; Campbell, K. L.; Williams, N.; Treder, M. S.; Taylor, J. R.; Henson, R. N. A.; Cam-CAN (2017)
    Slowing is a common feature of ageing, yet a direct relationship between neural slowing and brain atrophy is yet to be established in healthy humans. We combine magnetoencephalo-graphic (MEG) measures of neural processing speed with magnetic resonance imaging (MRI) measures of white and grey matter in a large population-derived cohort to investigate the relationship between age-related structural differences and visual evoked field (VEF) and auditory evoked field (AEF) delay across two different tasks. Here we use a novel technique to show that VEFs exhibit a constant delay, whereas AEFs exhibit delay that accumulates over time. White-matter (WM) microstructure in the optic radiation partially mediates visual delay, suggesting increased transmission time, whereas grey matter (GM) in auditory cortex partially mediates auditory delay, suggesting less efficient local processing. Our results demonstrate that age has dissociable effects on neural processing speed, and that these effects relate to different types of brain atrophy.
  • Laaksonen, Kristina; Helle, Liisa; Parkkonen, Lauri; Kirveskari, Erika; Mäkelä, Jyrki; Mustanoja, Satu; Tatlisumak, Turgut; Kaste, Markku; Forss, Nina (2013)
  • Zhdanov, Andrey; Nurminen, Jussi; Baess, Pamela; Hirvenkari, Lotta; Jousmaki, Veikko; Makela, Jyrki P.; Mandel, Anne; Meronen, Lassi; Hari, Riitta; Parkkonen, Lauri (2015)
    Hyperscanning Most neuroimaging studies of human social cognition have focused on brain activity of single subjects. More recently, "two-person neuroimaging" has been introduced, with simultaneous recordings of brain signals from two subjects involved in social interaction. These simultaneous "hyperscanning" recordings have already been carried out with a spectrum of neuroimaging modalities, such as functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and functional near-infrared spectroscopy (fNIRS). Dual MEG Setup We have recently developed a setup for simultaneous magnetoencephalographic (MEG) recordings of two subjects that communicate in real time over an audio link between two geographically separated MEG laboratories. Here we present an extended version of the setup, where we have added a video connection and replaced the telephone-landline-based link with an Internet connection. Our setup enabled transmission of video and audio streams between the sites with a one-way communication latency of about 130 ms. Our software that allows reproducing the setup is publicly available. Validation We demonstrate that the audiovisual Internet-based link can mediate real-time interaction between two subjects who try to mirror each others' hand movements that they can see via the video link. All the nine pairs were able to synchronize their behavior. In addition to the video, we captured the subjects' movements with accelerometers attached to their index fingers; we determined from these signals that the average synchronization accuracy was 215 ms. In one subject pair we demonstrate inter-subject coherence patterns of the MEG signals that peak over the sensorimotor areas contralateral to the hand used in the task.
  • Eyherabide, Hugo Gabriel; Samengo, Ines (2018)
    The study of the neural code aims at deciphering how the nervous system maps external stimuli into neural activitythe encoding phaseand subsequently transforms such activity into adequate responses to the original stimulithe decoding phase. Several information-theoretical methods have been proposed to assess the relevance of individual response features, as for example, the spike count of a given neuron, or the amount of correlation in the activity of two cells. These methods work under the premise that the relevance of a feature is reflected in the information loss that is induced by eliminating the feature from the response. The alternative methods differ in the procedure by which the tested feature is removed, and the algorithm with which the lost information is calculated. Here we compare these methods, and show that more often than not, each method assigns a different relevance to the tested feature. We demonstrate that the differences are both quantitative and qualitative, and connect them with the method employed to remove the tested feature, as well as the procedure to calculate the lost information. By studying a collection of carefully designed examples, and working on analytic derivations, we identify the conditions under which the relevance of features diagnosed by different methods can be ranked, or sometimes even equated. The condition for equality involves both the amount and the type of information contributed by the tested feature. We conclude that the quest for relevant response features is more delicate than previously thought, and may yield to multiple answers depending on methodological subtleties.
  • Quarto, Tiziana; Blasi, Giuseppe; Maddalena, Chiara; Viscanti, Giovanna; Lanciano, Tiziana; Soleti, Emanuela; Mangiulli, Ivan; Taurisano, Paolo; Fazio, Leonardo; Bertolino, Alessandro; Curci, Antonietta (2016)
    The human ability of identifying, processing and regulating emotions from social stimuli is generally referred as Emotional Intelligence (EI). Within EI, Ability EI identifies a performance measure assessing individual skills at perceiving, using, understanding and managing emotions. Previous models suggest that a brain "somatic marker circuitry" (SMC) sustains emotional sub-processes included in EI. Three primary brain regions are included: the amygdala, the insula and the ventromedial prefrontal cortex (vmPFC). Here, our aim was to investigate the relationship between Ability EI scores and SMC activity during social judgment of emotional faces. Sixty-three healthy subjects completed a test measuring Ability EI and underwent fMRI during a social decision task (i.e. approach or avoid) about emotional faces with different facial expressions. Imaging data revealed that EI scores are associated with left insula activity during social judgment of emotional faces as a function of facial expression. Specifically, higher EI scores are associated with greater left insula activity during social judgment of fearful faces but also with lower activity of this region during social judgment of angry faces. These findings indicate that the association between Ability EI and the SMC activity during social behavior is region- and emotionspecific.
  • Sarkamo, Teppo; Tervaniemi, Mari; Soinila, Seppo; Autti, Taina; Silvennoinen, Heli M.; Laine, Matti; Hietanen, Marja; Pihko, Elina (2010)
    Acquired amusia is a common disorder after damage to the middle cerebral artery (MCA) territory. However, its neurocognitive mechanisms, especially the relative contribution of perceptual and cognitive factors, are still unclear. We studied cognitive and auditory processing in the amusic brain by performing neuropsychological testing as well as magnetoencephalography (MEG) measurements of frequency and duration discrimination using magnetic mismatch negativity (MMNm) recordings. Fifty-three patients with a left (n = 24) or right (n = 29) hemisphere MCA stroke (MRI verified) were investigated 1 week, 3 months, and 6 months after the stroke. Amusia was evaluated using the Montreal Battery of Evaluation of Amusia (MBEA). We found that amusia caused by right hemisphere damage (RHD), especially to temporal and frontal areas, was more severe than amusia caused by left hemisphere damage (LHD). Furthermore, the severity of amusia was found to correlate with weaker frequency MMNm responses only in amusic RHD patients. Additionally, within the RHD subgroup, the amusic patients who had damage to the auditory cortex (AC) showed worse recovery on the MBEA as well as weaker MMNm responses throughout the 6-month follow-up than the non-amusic patients or the amusic patients without AC damage. Furthermore, the amusic patients both with and without AC damage performed worse than the non-amusic patients on tests of working memory, attention, and cognitive flexibility. These findings suggest domain-general cognitive deficits to be the primary mechanism underlying amusia without AC damage whereas amusia with AC damage is associated with both auditory and cognitive deficits.
  • Tervo, Aino E.; Metsomaa, Johanna; Nieminen, Jaakko O.; Sarvas, Jukka; Ilmoniemi, Risto J. (2020)
    Transcranial magnetic stimulation (TMS) protocols often include a manual search of an optimal location and orientation of the coil or peak stimulating electric field to elicit motor responses in a target muscle. This target search is laborious, and the result is user-dependent. Here, we present a closed-loop search method that utilizes automatic electronic adjustment of the stimulation based on the previous responses. The electronic adjustment is achieved by multi-locus TMS, and the adaptive guiding of the stimulation is based on the principles of Bayesian optimization to minimize the number of stimuli (and time) needed in the search. We compared our target-search method with other methods, such as systematic sampling in a predefined cortical grid. Validation experiments on five healthy volunteers and further offline simulations showed that our adaptively guided search method needs only a relatively small number of stimuli to provide outcomes with good accuracy and precision. The automated method enables fast and user-independent optimization of stimulation parameters in research and clinical applications of TMS.
  • Heikkinen, Noora; Kärkkäinen, Olli; Laukkanen, Eila; Kekkonen, Virve; Kaarre, Outi; Kivimäki, Petri; Könönen, Mervi; Velagapudi, Vidya; Nandania, Jatin; Lehto, Soili M.; Niskanen, Eini; Vanninen, Ritva; Tolmunen, Tommi (2019)
    Our aim was to analyze metabolite profile changes in serum associated with moderate-to-heavy consumption of alcohol in young adults and to evaluate whether these changes are connected to reduced brain gray matter volumes. These study population consisted of young adults with a 10-year history of moderate-to-heavy alcohol consumption (n = 35) and light-drinking controls (n = 27). We used the targeted liquid chromatography mass spectrometry method to measure concentrations of metabolites in serum, and 3.0 T magnetic resonance imaging to assess brain gray matter volumes. Alterations in amino acid and energy metabolism were observed in the moderate-to-heavy drinking young adults when compared to the controls. After correction for multiple testing, the group of moderate-to-heavy drinking young adults had increased serum concentrations of 1-methylhistamine (p = 0.001, d = 0.82) when compared to the controls. Furthermore, concentrations of 1-methylhistamine (r = 0.48, p = 0.004) and creatine (r = 0.52, p = 0.001) were negatively correlated with the brain gray matter volumes in the females. Overall, our results show association between moderate-to-heavy use of alcohol and altered metabolite profile in young adults as well as suggesting that some of these changes could be associated with the reduced brain gray matter volume. (C) 2018 Elsevier Inc. All rights reserved.
  • Steinzeig, Anna; Molotkov, Dmitry; Castren, Eero (2017)
    Growing interest in long-term visualization of cortical structure and function requires methods that allow observation of an intact cortex in longitudinal imaging studies. Here we describe a detailed protocol for the "transparent skull" (TS) preparation based on skull clearing with cyanoacrylate, which is applicable for long-term imaging through the intact skull in mice. We characterized the properties of the TS in imaging of intrinsic optical signals and compared them with the more conventional cranial window preparation. Our results show that TS is less invasive, maintains stabile transparency for at least two months, and compares favorably to data obtained from the conventional cranial window. We applied this method to experiments showing that a four-week treatment with the antidepressant fluoxetine combined with one week of monocular deprivation induced a shift in ocular dominance in the mouse visual cortex, confirming that fluoxetine treatment restores critical-period-like plasticity. Our results demonstrate that the TS preparation could become a useful method for long-term visualization of the living mouse brain.
  • Vainio, Lari; Tiainen, Mikko; Tiippana, Kaisa; Vainio, Martti (2019)
    It has been shown recently that when participants are required to pronounce a vowel at the same time with the hand movement, the vocal and manual responses are facilitated when a front vowel is produced with forward-directed hand movements and a back vowel is produced with backward-directed hand movements. This finding suggests a coupling between spatial programing of articulatory tongue movements and hand movements. The present study revealed that the same effect can be also observed in relation to directional leg movements. The study suggests that the effect operates within the common directional processes of movement planning including at least tongue, hand and leg movements, and these processes might contribute sound-to-meaning mappings to the semantic concepts of 'forward' and 'backward'.
  • Afdile, Mamdooh; Jääskeläinen, Iiro P.; Glerean, Enrico; Smirnov, Dmitry; Alho, Jussi; Äimälä, Anna; Sams, Mikko (2019)
    We are constantly categorizing other people as belonging to our in-group (one of us') or out-group (one of them'). Such grouping occurs fast and automatically and can be based on others' visible characteristics such as skin color or clothing style. Here we studied neural underpinnings of implicit social grouping not often visible on the face, male sexual orientation. A total of 14 homosexuals and 15 heterosexual males were scanned in functional magnetic resonance imaging while watching a movie about a homosexual man, whose face was also presented subliminally before (subjects did not know about the character's sexual orientation) and after the movie. We discovered significantly stronger activation to the man's face after seeing the movie in homosexual but not heterosexual subjects in medial prefrontal cortex, frontal pole, anterior cingulate cortex, right temporal parietal junction and bilateral superior frontal gyrus. In previous research, these brain areas have been connected to social perception, self-referential thinking, empathy, theory of mind and in-group perception. In line with previous studies showing biased perception of in-/out-group faces to be context dependent, our novel approach further demonstrates how complex contextual knowledge gained under naturalistic viewing can bias implicit social perception.
  • De Tiege, Xavier; Lundqvist, Daniel; Beniczky, Sandor; Seri, Stefano; Paetau, Ritva (2017)
    Purpose: This comprehensive survey aims at characterizing the current clinical use of magnetoencephalography (MEG) across European MEG centres. Methods: Forty-four MEG centres across Europe were contacted in May 2015 via personalized e-mail to contribute to survey. The web-based survey was available on-line for 1 month and the MEG centres that did not respond were further contacted to maximize participation. Results: Among the 57% of responders, 12 centres from 10 different countries reported to use MEG for clinical applications. A total of 524 MEG investigations were performed in 2014 for the pre-surgical evaluation of epilepsy, while in the same period 244 MEG investigations were performed for pre-surgical functional brain mapping. Seven MEG centres located in different European countries performed >50 MEG investigations for epilepsy mapping in 2014, both in children and adults. In those centres, time from patient preparation to MEG data reporting tends to be lower than those investigating a lower annual number of patients. Conclusion: This survey demonstrates that there is in Europe an increasing and widespread expertise in the field of clinical MEG. These findings should serve as a basis to harmonize clinical MEG procedures and promote the clinical added value of MEG across Europe. MEG should now be considered in Europe as a mature clinical neurophysiological technique that should be used routinely in two specific clinical indications, i.e, the pre-surgical evaluation of refractory focal epilepsy and functional brain mapping. (C) 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.
  • Heinonen, Jarmo; Numminen, Jussi; Hlushchuk, Yevhen; Antell, Henrik; Taatila, Vesa; Suomala, Jyrki (2016)
    Scientific findings have suggested a two-fold structure of the cognitive process. By using the heuristic thinking mode, people automatically process information that tends to be invariant across days, whereas by using the explicit thinking mode people explicitly process information that tends to be variant compared to typical previously learned information patterns. Previous studies on creativity found an association between creativity and the brain regions in the prefrontal cortex, the anterior cingulate cortex, the default mode network and the executive network. However, which neural networks contribute to the explicit mode of thinking during idea generation remains an open question. We employed an fMRI paradigm to examine which brain regions were activated when participants (n = 16) mentally generated alternative uses for everyday objects. Most previous creativity studies required participants to verbalize responses during idea generation, whereas in this study participants produced mental alternatives without verbalizing. This study found activation in the left anterior insula when contrasting idea generation and object identification. This finding suggests that the insula (part of the brain's salience network) plays a role in facilitating both the central executive and default mode networks to activate idea generation. We also investigated closely the effect of the serial order of idea being generated on brain responses: The amplitude of fMRI responses correlated positively with the serial order of idea being generated in the anterior cingulate cortex, which is part of the central executive network. Positive correlation with the serial order was also observed in the regions typically assigned to the default mode network: the precuneus/ cuneus, inferior parietal lobule and posterior cingulate cortex. These networks support the explicit mode of thinking and help the individual to convert conventional mental models to new ones. The serial order correlated negatively with the BOLD responses in the posterior presupplementarymotor area, left premotor cortex, right cerebellum and left inferior frontal gyrus. This finding might imply that idea generation without a verbal processing demand reflecting lack of need for new object identification in idea generation events. The results of the study are consistent with recent creativity studies, which emphasize that the creativity process involves working memory capacity to spontaneously shift between different kinds of thinking modes according to the context.
  • Poikonen, Hanna Liisa; Toiviainen, Petri; Tervaniemi, Mari Anni Irmeli (2016)
    The neural responses to simple tones and short sound sequences have been studied extensively. However, in reality the sounds surrounding us are spectrally and temporally complex, dynamic and overlapping. Thus, research using natural sounds is crucial in understanding the operation of the brain in its natural environment. Music is an excellent example of natural stimulation which, in addition to sensory responses, elicits vast cognitive and emotional processes in the brain. Here we show that the preattentive P50 response evoked by rapid increases in timbral brightness during continuous music is enhanced in dancers when compared to musicians and laymen. In dance, fast changes in brightness are often emphasized with a significant change in movement. In addition, the auditory N100 and P200 responses are suppressed and sped up in dancers, musicians and laymen when music is accompanied with a dance choreography. These results were obtained with a novel event-related potential (ERP) method for natural music. They suggest that we can begin studying the brain with long pieces of natural music using the ERP method of electroencephalography (EEG) as has already been done with functional magnetic resonance (fMRI), these two brain imaging methods complementing each other.
  • Hernandez-Pavon, Julio C.; Makela, Niko; Lehtinen, Henri; Lioumis, Pantelis; Makela, Jyrki P. (2014)