Changes in sodium appetite evoked by lesions of the commissural nucleus of the tractus solitarius

Ablation of the area postrema/caudal nucleus of the tractus solitarius (NTS) complex increases sodium intake, but the effect of selective lesions of the caudal NTS is not known. We measured depletion-induced sodium intake in rats with electrolytic lesions of the commissural NTS that spared the area postrema. One day after the lesion, rats were depleted of sodium with furosemide (10 mg/kg body weight, sc) and then had access to water and a sodium-deficient diet for 24 h when 1.8% NaCl was offered. Water and saline intakes were measured for 2 h. Saline intake was higher in lesioned than in sham-lesioned rats (mean ± SEM: 20 ± 2 vs 11 ± 3 mL/2 h, P < 0.05, N = 6-7). Saline intake remained elevated in lesioned rats when the tests were repeated 6 and 14 days after the lesion, and water intake in these two tests was increased as well. Water intake seemed to be secondary to saline intake both in lesioned and in sham-lesioned rats. A second group of rats was offered 10% sucrose for 2 h/day before and 2, 7, and 15 days after lesion. Sucrose intake in lesioned rats was higher than in sham-lesioned rats only 7 days after lesioning. A possible explanation for the increased saline intake in rats with commissural NTS lesions could be a reduced gastrointestinal feedback inhibition. The commissural NTS is probably part of a pathway for inhibitory control of sodium intake that also involves the area postrema and the parabrachial nucleus.

Tonic and reflex cardiovascular autonomic control in trained-female rats

The effects of exercise training on cardiovascular and autonomic functions were investigated in female rats. After an aerobic exercise training period (treadmill: 5 days/week for 8 weeks), conscious female Wistar (2 to 3 months) sedentary (S, N = 7) or trained rats (T, N = 7) were cannulated for direct arterial pressure (AP) recording in the non-ovulatory phases. Vagal (VT) and sympathetic tonus (ST) were evaluated by vagal (atropine) and sympathetic (propranolol) blockade. Baroreflex sensitivity was evaluated by the heart rate responses induced by AP changes. Cardiopulmonary reflex was measured by the bradycardic and hypotensive responses to serotonin. Resting bradycardia was observed in T (332 ± 7 bpm) compared with S animals (357 ± 10 bpm), whereas AP did not differ between groups. T animals exhibited depressed VT and ST (32 ± 7 and 15 ± 4 bpm) compared to S animals (55 ± 5 and 39 ± 10 bpm). The baroreflex and cardiopulmonary bradycardic responses were lower in T (-1.01 ± 0.27 bpm/mmHg and -17 ± 6 bpm) than in the S group (-1.47 ± 0.3 bpm/mmHg and -41 ± 9 bpm). Significant correlations were observed between VT and baroreflex (r = -0.72) and cardiopulmonary (r = -0.76) bradycardic responses. These data show that exercise training in healthy female rats induced resting bradycardia that was probably due to a reduced cardiac ST. Additionally, trained female rats presented attenuated bradycardic responses to baro- and cardiopulmonary receptor stimulation that were associated, at least in part, with exercise training-induced cardiac vagal reduction.

Reliability and validity of heart rate variability threshold assessment during an incremental shuttle-walk test in middle-aged and older adults

Studies on the assessment of heart rate variability threshold (HRVT) during walking are scarce. We determined the reliability and validity of HRVT assessment during the incremental shuttle walk test (ISWT) in healthy subjects. Thirty-one participants aged 57 ± 9 years (17 females) performed 3 ISWTs. During the 1st and 2nd ISWTs, instantaneous heart rate variability was calculated every 30 s and HRVT was measured. Walking velocity at HRVT in these tests (WV-HRVT1 and WV-HRVT2) was registered. During the 3rd ISWT, physiological responses were assessed. The ventilatory equivalents were used to determine ventilatory threshold (VT) and the WV at VT (WV-VT) was recorded. The difference between WV-HRVT1 and WV-HRVT2 was not statistically significant (median and interquartile range = 4.8; 4.8 to 5.4 vs4.8; 4.2 to 5.4 km/h); the correlation between WV-HRVT1 and WV-HRVT2 was significant (r = 0.84); the intraclass correlation coefficient was high (0.92; 0.82 to 0.96), and the agreement was acceptable (-0.08 km/h; -0.92 to 0.87). The difference between WV-VT and WV-HRVT2 was not statistically significant (4.8; 4.8 to 5.4 vs 4.8; 4.2 to 5.4 km/h) and the agreement was acceptable (0.04 km/h; -1.28 to 1.36). HRVT assessment during walking is a reliable measure and permits the estimation of VT in adults. We suggest the use of the ISWT for the assessment of exercise capacity in middle-aged and older adults.

Utility of a novel risk score for prediction of ventricular tachycardia and cardiac death in chronic Chagas disease - the SEARCH-RIO study

The SEARCH-RIO study prospectively investigated electrocardiogram (ECG)-derived variables in chronic Chagas disease (CCD) as predictors of cardiac death and new onset ventricular tachycardia (VT). Cardiac arrhythmia is a major cause of death in CCD, and electrical markers may play a significant role in risk stratification. One hundred clinically stable outpatients with CCD were enrolled in this study. They initially underwent a 12-lead resting ECG, signal-averaged ECG, and 24-h ambulatory ECG. Abnormal Q-waves, filtered QRS duration, intraventricular electrical transients (IVET), 24-h standard deviation of normal RR intervals (SDNN), and VT were assessed. Echocardiograms assessed left ventricular ejection fraction. Predictors of cardiac death and new onset VT were identified in a Cox proportional hazard model. During a mean follow-up of 95.3 months, 36 patients had adverse events: 22 new onset VT (mean±SD, 18.4±4‰/year) and 20 deaths (26.4±1.8‰/year). In multivariate analysis, only Q-wave (hazard ratio, HR=6.7; P<0.001), VT (HR=5.3; P<0.001), SDNN<100 ms (HR=4.0; P=0.006), and IVET+ (HR=3.0; P=0.04) were independent predictors of the composite endpoint of cardiac death and new onset VT. A prognostic score was developed by weighting points proportional to beta coefficients and summing-up: Q-wave=2; VT=2; SDNN<100 ms=1; IVET+=1. Receiver operating characteristic curve analysis optimized the cutoff value at >1. In 10,000 bootstraps, the C-statistic of this novel score was non-inferior to a previously validated (Rassi) score (0.89±0.03 and 0.80±0.05, respectively; test for non-inferiority: P<0.001). In CCD, surface ECG-derived variables are predictors of cardiac death and new onset VT.

Differentiating origins of outflow tract ventricular arrhythmias: a comparison of three different electrocardiographic algorithms

Our objective is to evaluate the accuracy of three algorithms in differentiating the origins of outflow tract ventricular arrhythmias (OTVAs). This study involved 110 consecutive patients with OTVAs for whom a standard 12-lead surface electrocardiogram (ECG) showed typical left bundle branch block morphology with an inferior axis. All the ECG tracings were retrospectively analyzed using the following three recently published ECG algorithms: 1) the transitional zone (TZ) index, 2) the V2 transition ratio, and 3) V2 R wave duration and R/S wave amplitude indices. Considering all patients, the V2 transition ratio had the highest sensitivity (92.3%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (93.9%). The latter finding had a maximal area under the ROC curve of 0.925. In patients with left ventricular (LV) rotation, the V2 transition ratio had the highest sensitivity (94.1%), while the R wave duration and R/S wave amplitude indices in V2 had the highest specificity (87.5%). The former finding had a maximal area under the ROC curve of 0.892. All three published ECG algorithms are effective in differentiating the origin of OTVAs, while the V2 transition ratio, and the V2 R wave duration and R/S wave amplitude indices are the most sensitive and specific algorithms, respectively. Amongst all of the patients, the V2 R wave duration and R/S wave amplitude algorithm had the maximal area under the ROC curve, but in patients with LV rotation the V2 transition ratio algorithm had the maximum area under the ROC curve.

Feasibility of industrial implementation of laser cutting into paper making machine

Laser cutting implementation possibilities into paper making machine was studied as the main objective of the work. Laser cutting technology application was considered as a replacement tool for conventional cutting methods used in paper making machines for longitudinal cutting such as edge trimming at different paper making process and tambour roll slitting. Laser cutting of paper was tested in 70’s for the first time. Since then, laser cutting and processing has been applied for paper materials with different level of success in industry. Laser cutting can be employed for longitudinal cutting of paper web in machine direction. The most common conventional cutting methods include water jet cutting and rotating slitting blades applied in paper making machines. Cutting with CO2 laser fulfils basic requirements for cutting quality, applicability to material and cutting speeds in all locations where longitudinal cutting is needed. Literature review provided description of advantages, disadvantages and challenges of laser technology when it was applied for cutting of paper material with particular attention to cutting of moving paper web. Based on studied laser cutting capabilities and problem definition of conventional cutting technologies, preliminary selection of the most promising application area was carried out. Laser cutting (trimming) of paper web edges in wet end was estimated to be the most promising area where it can be implemented. This assumption was made on the basis of rate of web breaks occurrence. It was found that up to 64 % of total number of web breaks occurred in wet end, particularly in location of so called open draws where paper web was transferred unsupported by wire or felt. Distribution of web breaks in machine cross direction revealed that defects of paper web edge was the main reason of tearing initiation and consequent web break. The assumption was made that laser cutting was capable of improvement of laser cut edge tensile strength due to high cutting quality and sealing effect of the edge after laser cutting. Studies of laser ablation of cellulose supported this claim. Linear energy needed for cutting was calculated with regard to paper web properties in intended laser cutting location. Calculated linear cutting energy was verified with series of laser cutting. Practically obtained laser energy needed for cutting deviated from calculated values. This could be explained by difference in heat transfer via radiation in laser cutting and different absorption characteristics of dry and moist paper material. Laser cut samples (both dry and moist (dry matter content about 25-40%)) were tested for strength properties. It was shown that tensile strength and strain break of laser cut samples are similar to corresponding values of non-laser cut samples. Chosen method, however, did not address tensile strength of laser cut edge in particular. Thus, the assumption of improving strength properties with laser cutting was not fully proved. Laser cutting effect on possible pollution of mill broke (recycling of trimmed edge) was carried out. Laser cut samples (both dry and moist) were tested on the content of dirt particles. The tests revealed that accumulation of dust particles on the surface of moist samples can take place. This has to be taken into account to prevent contamination of pulp suspension when trim waste is recycled. Material loss due to evaporation during laser cutting and amount of solid residues after cutting were evaluated. Edge trimming with laser would result in 0.25 kg/h of solid residues and 2.5 kg/h of lost material due to evaporation. Schemes of laser cutting implementation and needed laser equipment were discussed. Generally, laser cutting system would require two laser sources (one laser source for each cutting zone), set of beam transfer and focusing optics and cutting heads. In order to increase reliability of system, it was suggested that each laser source would have double capacity. That would allow to perform cutting employing one laser source working at full capacity for both cutting zones. Laser technology is in required level at the moment and do not require additional development. Moreover, capacity of speed increase is high due to availability high power laser sources what can support the tendency of speed increase of paper making machines. Laser cutting system would require special roll to maintain cutting. The scheme of such roll was proposed as well as roll integration into paper making machine. Laser cutting can be done in location of central roll in press section, before so-called open draw where many web breaks occur, where it has potential to improve runability of a paper making machine. Economic performance of laser cutting was done as comparison of laser cutting system and water jet cutting working in the same conditions. It was revealed that laser cutting would still be about two times more expensive compared to water jet cutting. This is mainly due to high investment cost of laser equipment and poor energy efficiency of CO2 lasers. Another factor is that laser cutting causes material loss due to evaporation whereas water jet cutting almost does not cause material loss. Despite difficulties of laser cutting implementation in paper making machine, its implementation can be beneficial. The crucial role in that is possibility to improve cut edge strength properties and consequently reduce number of web breaks. Capacity of laser cutting to maintain cutting speeds which exceed current speeds of paper making machines what is another argument to consider laser cutting technology in design of new high speed paper making machines.

Maantien 370 ja valtatien 15 parantaminen välillä Kouvola–Valkeala : Aluevaraussuunnitelma

Valtatie 15 on tärkein yhteys Etelä-Savon ja Kymenlaakson välillä. Sen merkitys on suuri tavaraliikenteelle ja metsäteollisuuden kuljetuksille Sisä-Suomesta HaminaKotkan satamaan. Asiointi- ja työmatkaliikenne on vilkasta Valkealasta Kouvolaan ja pohjoisempana sijaitsevaan Vekaranjärven varuskuntaan, joka on maan suurimpia varuskuntia. Pohjoisesta Kouvolaan tuleva liikenne käyttää valtatieltä 15 Heparosta jatkuvaa maantietä 370. Valtatien 15 liikenne etelään (vt 6) ja länteen (vt 12) kiertää nykyisin Tykkimäen kautta. Suunnittelualue kattaa maantien 370 lähes kokonaan Ahlmannintien (maantie 14594) liittymän pohjoispuolelta Heparon eritasoliittymään ja jatkuu siitä itään Mikkelin suuntaan valtatienä 15 Toikkalantien liittymään asti. Tieosuuden pituus on noin 10 kilometriä. Aluevaraussuunnitelmassa on selvitetty ensin Kouvolan kohdalla valtateiden 6 ja 15 sekä muun keskeisen väyläverkon puutteet ja ongelmat sekä palvelutasotavoitteet. Tämän jälkeen on suunniteltu valtateiden ja muiden väylien periaateratkaisut sekä selvitetty niin tilantarve, suhde ympäröivään maankäyttöön ja vaikutukset. Myös mahdollisuudet hankkeen vaiheittain toteuttamiseksi on käsitelty. Aluevaraussuunnitelmassa on tarkennettu ratkaisuja, vaikutusarviota ja liikenteen, maankäytön ja ympäristön lähtötietoja. Päätavoitteena on ollut selvittää pääteiden ja muun tie- ja katuverkon kehittämisen periaatteet niin, että nykyiset palvelutasopuutteet saadaan poistettua ja valtatie 15 sekä maantien 370 vastaavat niille asetettuja vaatimuksia liikenteen sujuvuuden ja turvallisuuden kannalta. Osana suunnitelmaa on esitetty toimenpiteet meluhaittojen torjumiseksi ja ympäristövaikutusten lieventämiseksi.

[Kirja-arvostelu]

Kirjallisuusarvostelu

Vuorovaikutusrituaalin käsitteen kritiikki

Kirjallisuusarvostelu

Impact of training at ventilatory threshold on cardiopulmonary and functional capacity in overweight patients with chronic kidney disease

INTRODUCTION: Chronic kidney disease (CKD) and obesity are both associated with reduced physical capacity. The potential benefit of aerobic training on physical capacity has been recognized. The exercise intensity can be established using different methods mostly subjective or indirect. Ventilatory threshold (VT) is a direct and objective method that allows prescribing exercise intensity according to individual capacity. OBJECTIVES: To evaluate the impact of aerobic training at VT intensity on cardiopulmonary and functional capacities in CKD patients with excess of body weight. METHODS: Ten CKD patients (eight men, 49.7 ± 10.1 years; BMI 30.4 ± 3.5 kg/m², creatinine clearance 39.4 ± 9.8 mL/min/1.73 m²) underwent training on a treadmill three times per week during 12 weeks. Cardiopulmonary capacity (ergoespirometry), functional capacity and clinical parameters were evaluated. RESULTS: At the end of 12 weeks, VO2PEAK increased by 20%, and the speed at VO2PEAK increased by 16%. The training resulted in improvement in functional capacity tests, such as six-minute walk test (9.2%), two-minute step test (20.3%), arm curl test (16.3%), sit and stand test (35.7%), and time up and go test (15.3%). In addition, a decrease in systolic and diastolic blood pressures was observed despite no change in body weight, sodium intake and antihypertensive medication. CONCLUSION: Aerobic exercise performed at VT intensity improved cardipulmonary and functional capacities of overweight CKD patients. Additional benefit on blood pressure was observed. These results suggest that VT can be effectively applied for prescribing exercise intensity in this particular group of patients.

Älykkään vaihtuvan ohjausjärjestelmän pilotointi, esiselvitys : Valtatie 4 Koskela, Helsinki - Järvenpää

Valtatie 4 Helsingin Koskelan ja Järvenpään eritasoliittymien välillä on erittäin vilkkaasti liikennöity väylä, joka ruuhkautuu sekä aamun että iltapäivän ruuhkatunteina ja jonka turvallisuustilanne on heikko. Ongelmien ratkaisemiseksi on aiemmissa suunnitteluvaiheissa esitetty nykyaikaisen vaihtuvan ohjausjärjestelmän toteuttamista valtatielle 4 Järvenpäähän saakka sekä valtatielle 7 välille vt 4–Kehä III. Tämän esiselvityksen tavoitteena oli laatia alustava suunnitelma laadukkaan ja monipuolisen liikennetieto-ohjauksen mahdollistavasta ohjausjärjestelmästä, jossa on huomioitu uusien seurantateknologioiden luomat mahdollisuudet. Laadittu suunnitelma sisältää tavanomaisiin liikenteen vaihtuviin ohjausjärjestelmiin nähden uusina elementteinä aiempaa monipuolisemman ja tarkemman liikenteen seurantajärjestelmän sekä aiempaa proaktiivisemman ja hienojakoisemman liikenteen ohjausjärjestelmän ja –politiikan. Lisäksi järjestelmän operointi tieliikennekeskuksessa poikkeaa totutusta, koska ohjauksen automaatiotaso on korkeampi. Uutta on myös järjestelmän integraatio tieliikenteen ohjauksen integroidun käyttöliittymän ympäristöön (TLOIK) sekä muista piloteista, kuten kooperatiivisista järjestelmistä, saatavat herätteet. Suunnitellun vaihtuvan ohjausjärjestelmän voidaan kansainvälisten kokemusten valossa arvioida ehkäisevän henkilövahinkoihin johtavia onnettomuuksia Suomen olosuhteissa noin 10 % ja pienentävän ruuhka-aikojen viivytyksiä vähintään 20 %. Pääkaupunkiseudun säteittäisväylien vaihtuvan ohjauksen hyöty-kustannussuhteeksi on aiemmin laskettu 3,3–6,3, eli investointi on erittäin kannattava. Hanke kannattaa toteuttaa kaksivaiheisena pilottina, jonka tavoitteena on selvittää toimivimmat teknologiat ja ohjauspolitiikat laajempaa hyödyntämistä varten. Valtakunnallisesta ulottuvuudesta johtuen hanketta kannattaa viedä eteenpäin Liikenneviraston ja Uudenmaan ELY-keskuksen yhteishankkeena. Järjestelmästä saatavia kokemuksia voidaan hyödyntää sekä muiden pääkaupunkiseudun pääväylien liikenteen hallintajärjestelmien uusimisen/toteutuksen yhteydessä että muiden kaupunkiseutujen vastaavien järjestelmien toteutuksessa. Pilottihankkeen ensimmäisen osan, seurantapilotin alustava kustannusarvio on 320 000 euroa ja toisen, varsinaisen ohjauspilotin kustannusarvio 6,0 miljoonaa euroa sisältäen koko ohjausjärjestelmän toteutuksen.

New aspects in limestone dissolution for wet flue gas desulfurization

Fortsättningsvis tillgodoses största delen av världens energibehov genom förbränning av fossila bränslen, dessutom forsätter världens totala energibehov att öka. Eftersom förbränning av fossila bränslen som t.ex. olja och kol orsakar utsläpp av svaveldioxid som är skadligt för både människa och natur, finns det fortfarande ett akut behov av forskning och utveckling av metoder för svavelrening. De vanligaste teknikerna för svavelrening är våt- och semitorrskrubbning, där svaveldioxiden absorberas av en skrubbervätska. Det är allmänt känt att våtskrubbning är en av de effektivaste teknikerna för svavelrening både ekonomiskt och tekniskt sett samt den mest använda. Våtskrubbningsprocessen har dock flera nackdelar, som dess höga vatten- och energiförbrukning. I större kraftverk går ca 1-3% av dess eleffekt åt till rökgasreningsprocessen, vilket kraftigt motiverar utveckling av nya reningsprocesser samt effektivering av existerande reningsanläggningar. Skrubbervätskan som till huvudsak består av vatten innehåller vanligtvis även kalcium vars syfte är att binda svavlet. Kalciumet kan tillsättas i flera former varav bränd kalk och kalksten är de vanligaste formerna. Kalksten används ofta i svavelreningsprocessen p.g.a. dess låga pris och för att den ger upphov till den användbara biprodukten gips. Kalkstenens upplösningshastighet är en de av faktorer som kraftigast påverkar reningsprocessen. En detaljerad experimentell karakterisering och analys av kalkstenspartiklar i fast form och i vätskeform har utförts i detta arbete. En experimentell metod för att studera kalkstenens upplösningshastighet vid låg till obegränsad massöverföring har även utvecklats i detta arbete. Metoden möjliggör identifieringen av systemoberoende kinetiska parametrar, vilka kan användas för att undersöka reningsprocesser samt för att planera nya reningsanläggningar. Kinetiska modeller utvecklades genom att använda kalkstenpartiklars specifika yta, som mättes genom kväveadsorption. Efter att de kinetiska parametrarna bestämts experimentellt utvecklades en skrubbermodell för att optimera en i driftvarande skrubber. Genom att kombinera experimentellt bestämda modeller med matematisk optimering erhölls en djupare insikt i hur olika råmaterial påverkar processen och hur driftparameterar bör justeras för att minska elförbrukningen.

Family rivalry in the testis: Retinoblastoma protein and E2F transcription factors in testicular development and adult spermatogenesis

Disorders of male reproductive health are becoming increasingly prevalent globally. These defects, ranging from decreasing sperm counts to an increasing rate of infertility and testicular cancer, have a common origin in the early phases of testicular development, but the exact mechanisms that cause them remain unknown. Testicular development and adult spermatogenesis are complex processes in which different cell types undergo mitosis, meiosis, differentiation and apoptosis. The retinoblastoma protein family and its associated E2F transcription factors are key regulators of these cellular events. In the present study, the functions of these factors in postnatal testicular development and adult spermatogenesis were explored using different animal models. In addition, a new application of flow cytometry to study testicular cell dynamics was developed. An ablation of retinoblastoma protein in mouse Sertoli cells resulted in their cell cycle re-entry in adult testes, dedifferentiation and a severe spermatogenic defect. We showed that deregulated E2F3 contributed to these changes. Our results indicated that the E2F1 transcription factor is critical for the control of apoptosis in the developing postnatal testis. In the adult testis, E2F1 controls the maintenance of the spermatogonial stem cell pool, in addition to inhibiting apoptosis of spermatocytes. In summary, this study elucidated the complex interdependencies of the RB and E2F transcription factor families in the control of postnatal testicular development and adult spermatogenesis. Furthermore, this study provided a new methodology for the analysis of testicular cells.

Pulssitettu laserablaatio mikrofluidisten kanavistojen sarjatuotantomenetelmänä

Puolijohteiden yleistyttyä vuodesta 1948 alkaen, ovat elektroniset laitteet pienentyneet jatkuvasti tehojen kuitenkin kasvaessa. Kasvaneet tehotiheydet kuitenkin vaikeuttavat laitesuunnittelua, sillä puoljohdekomponenttien suorituskyvylle ja eliniälle on oleellista lämpötilojen ja lämpötilavaihteluiden minimointi. Perinteisen ilmajäähdytyksen lähestyessä rajojaan niin kokonaistehon kuin järkevän energiatehokkuudenkin suhteen, on parhaaksi seuraavaksi teknologiaksi ennustettu kaksifaasijäähdytystä, jonka suorituskyky ja energiatehokkuus ovat vaaditulla tasolla. Kaksifaasijäähdytyksen optimaaliselle toiminnalle tärkeää on hyvin suunniteltu ja tarkasti valmistettu lämmönsiirtopinta, jota kutsutaan mikrokanavistoksi. Pulssitettu laserkaiverrus on edistynyt valmistustekniikka, jonka tarkkuus ja luotettavuus sopisivat mikrokanavistojen valmistamiseen. Laserkaiverruksella saavutettavat lopputulokset vaihtelevat kuitenkin materiaalista riippuen ja kupari – jota käytetään yleisesti lämmönjohteena – on eräs huonoimmin lasertyöstöön reagoivista materiaaleista ja siksi on oleellista selvittää laser-kaiverruksen toimivuutta kuparisten mikrokanavistojen valmistuksessa. Pulssitetun laser-kaiverruksen eri variaatioista nanosekunti-luokan pulssinpituuksilla toimivat laitteet ovat jatkuvan tuotannon kannalta paras vaihtoehto niiden hyvän tuottavuuden, saatavuuden sekä kohtuullisen alkuinvestoinnin vuoksi. Käytännön kaiverruskokeiden perusteella selvisi, että menetelmä on laatunsa ja tarkkuutensa puolesta sopiva varsinaiseen tuotantoon. Kaiverruksen tehokkuus kuparia työstettäessä on kuitenkin ennakoituakin heikompi ja niin valmistus- kuin suunnitelu-prosessikin vaativat vielä jatkotutkimusta ja -kehitystä.

Autonomic prediction of error-related ERP components in perceptual and conceptual tasks in older and younger adults

In studies of cognitive processing, the allocation of attention has been consistently linked to subtle, phasic adjustments in autonomic control. Both autonomic control of heart rate and control of the allocation of attention are known to decline with age. It is not known, however, whether characteristic individual differences in autonomic control and the ability to control attention are closely linked. To test this, a measure of parasympathetic function, vagal tone (VT) was computed from cardiac recordings from older and younger adults taken before and during performance of two attentiondemanding tasks - the Eriksen visual flanker task and the source memory task. Both tasks elicited event-related potentials (ERPs) that accompany errors, i.e., error-related negativities (ERNs) and error positivities (Pe's). The ERN is a negative deflection in the ERP signal, time-locked to responses made on incorrect trials, likely generated in the anterior cingulate. It is followed immediately by the Pe, a broad, positive deflection which may reflect conscious awareness of having committed an error. Age-attenuation ofERN amplitude has previously been found in paradigms with simple stimulus-response mappings, such as the flanker task, but has rarely been examined in more complex, conceptual tasks. Until now, there have been no reports of its being investigated in a source monitoring task. Age-attenuation of the ERN component was observed in both tasks. Results also indicated that the ERNs generated in these two tasks were generally comparable for young adults. For older adults, however, the ERN from the source monitoring task was not only shallower, but incorporated more frontal processing, apparently reflecting task demands. The error positivities elicited by 3 the two tasks were not comparable, however, and age-attenuation of the Pe was seen only in the more perceptual flanker task. For younger adults, it was Pe scalp topography that seemed to reflect task demands, being maximal over central parietal areas in the flanker task, but over very frontal areas in the source monitoring task. With respect to vagal tone, in the flanker task, neither the number of errors nor ERP amplitudes were predicted by baseline or on-task vagal tone measures. However, in the more difficult source memory task, lower VT was marginally associated with greater numbers of source memory errors in the older group. Thus, for older adults, relatively low levels of parasympathetic control over cardiac response coincided with poorer source memory discrimination. In both groups, lower levels of baseline VT were associated with larger amplitude ERNs, and smaller amplitude Pe's. Thus, low VT was associated in a conceptual task with a greater "emergency response" to errors, and at the same time, reduced awareness of having made them. The efficiency of an individual's complex cognitive processing was therefore associated with the flexibility of parasympathetic control of heart rate, in response to a cognitively challenging task.