fMRI Randomized Study of Mental and Motor Task Performance and Cortisol Levels to Potentiate Cortisol as a New Diagnostic Biomarker.

Cortisol is an important hormone in the protective stress response system, the Hypothalamus-Pituitary-Adrenal (HPA axis). It becomes especially salient in immune suppression syndromes such as multiple sclerosis and Cushing’s disease. Fatigue is a common symptom and mental and motor tasks are difficult and labored. The role of cortisol is mental and motor tasks and the recruitment of key brain regions in completion of these tasks is explored together with functional magnetic resonance imaging in healthy participants. Cortisol levels were found to be higher and had greater reduction in levels during mental versus motor tasks. Recruitment of brain stem and hypothalamus regions, important in cortisol activity, was affected differently. At low cortisol levels, mental task participants had less activity in the regions than their physical task counterparts. When cortisol levels were higher, widerspread recruitment of these brain regions was seen in the mental task participants, and for the physical task participants, the spread was at comparative low levels of cortisol. It is concluded that cortisol is implicated in these brain regions supporting the Thompson Cortisol Hypothesis and that brain region recruitment is likely to be dependent upon factors including cortisol levels as well as perception of stress in the task. It is suggested that mental tasks are perceived more stressful than physical but demand higher cortisol levels to promote wider spread brain region activity. Implication for neurological disease includes the use of cortisol in the proposed development of a potential new diagnostic biomarker for early detection of neurological sequelae

Cingulate Cortex Atrophy Is Associated With Hearing Loss in Presbycusis With Cochlear Amplifier Dysfunction

Age-related hearing loss is associated with cognitive decline and has been proposed as a risk factor for dementia. However, the mechanisms that relate hearing loss to cognitive decline remain elusive. Here, we propose that the impairment of the cochlear amplifier mechanism is associated with structural brain changes and cognitive impairment. Ninety-six subjects aged over 65 years old (63 female and 33 male) were evaluated using brain magnetic resonance imaging, neuropsychological and audiological assessments, including distortion product otoacoustic emissions as a measure of the cochlear amplifier function. All the analyses were adjusted by age, gender and education. The group with cochlear amplifier dysfunction showed greater brain atrophy in the cingulate cortex and in the parahippocampus. In addition, the atrophy of the cingulate cortex was associated with cognitive impairment in episodic and working memories and in language and visuoconstructive abilities. We conclude that the neural abnormalities observed in presbycusis subjects with cochlear amplifier dysfunction extend beyond core auditory network and are associated with cognitive decline in multiple domains. These results suggest that a cochlear amplifier dysfunction in presbycusis is an important mechanism relating hearing impairments to brain atrophy in the extended network of effortful hearing

Dynamics of copepod faecal pellets in relation to a <i>Phaeocystis</i> dominated phytoplankton bloom: characteristics, production and flux

Copepod faecal pellet characteristics and production were measured in spring 1995, 1996 and 1997 in the North Sea Southern Bight in order to define changes due to the development of the phytoplankton bloom. Changes were related to the succession from diatoms to a Phaeocystis sp. bloom. Mean monthly pellet production decreased during the Phaeocystis bloom development to 0.27 pellets ind.-1 h-1, approximately 80% lower than before and after the bloom. Although phytoplanktonic pigments showed significant differences between inshore and offshore stations, there mar no such significant difference for faecal pellet production. Faecal pellet sinking-rate decreased from 100 to 70 m day-1 during the transition from a diatom- to a Phaeocystis-dominated bloom. This was due to a decrease in pellet density and/or a decrease of the pellet volume. These results supported the idea of lower feeding of copepods under Phaeocystis bloom conditions. As mean seasonal density of copepod faecal pellets war higher (1.37 g cm-3) than in other seas, accidental ingestion of sedimentary material as the cause of this high density is discussed

Cingulate cortex atrophy is associated with hearing loss in presbycusis with cochlear amplifier dysfunction

Age-related hearing loss is associated with cognitive decline and has been proposed as a risk factor for dementia. However, the mechanisms that relate hearing loss to cognitive decline remain elusive. Here, we propose that the impairment of the cochlear amplifier mechanism is associated with structural brain changes and cognitive impairment. Ninety-six subjects aged over 65 years old (63 female and 33 male) were evaluated using brain magnetic resonance imaging, neuropsychological and audiological assessments, including distortion product otoacoustic emissions as a measure of the cochlear amplifier function. All the analyses were adjusted by age, gender and education. The group with cochlear amplifier dysfunction showed greater brain atrophy in the cingulate cortex and in the parahippocampus. In addition, the atrophy of the cingulate cortex was associated with cognitive impairment in episodic and working memories and in language and visuoconstructive abilities. We conclude that the neural abnormalities observed in presbycusis subjects with cochlear amplifier dysfunction extend beyond core auditory network and are associated with cognitive decline in multiple domains. These results suggest that a cochlear amplifier dysfunction in presbycusis is an important mechanism relating hearing impairments to brain atrophy in the extended network of effortful hearing

Insula and Amygdala Atrophy Are Associated With Functional Impairment in Subjects With Presbycusis

Hearing loss is an important risk factor for dementia. However, the mechanisms that relate these disorders are still unknown. As a proxy of this relationship, we studied the structural brain changes associated with functional impairment in activities of daily living in subjects with age related hearing loss, or presbycusis. One hundred eleven independent, non-demented subjects older than 65 years recruited in the ANDES cohort were evaluated using a combined approach including (i) audiological tests: hearing thresholds and cochlear function measured by pure tone averages and the distortion product otoacoustic emissions respectively; (ii) behavioral variables: cognitive, neuropsychiatric, and functional impairment in activities of daily living measured by validated questionnaires; and (iii) structural brain imaging-assessed by magnetic resonance imaging at 3 Tesla. The mean age of the recruited subjects (69 females) was 73.95 +/- 5.47 years (mean +/- SD) with an average educational level of 9.44 +/- 4.2 years of schooling. According to the audiometric hearing thresholds and presence of otoacoustic emissions, we studied three groups: controls with normal hearing (n = 36), presbycusis with preserved cochlear function (n = 33), and presbycusis with cochlear dysfunction (n = 38). We found a significant association (R-D(2) = 0.17) between the number of detected otoacoustic emissions and apathy symptoms. The presbycusis with cochlear dysfunction group had worse performance than controls in global cognition, language and executive functions, and severe apathy symptoms than the other groups. The neuropsychiatric symptoms and language deficits were the main determinants of functional impairment in both groups of subjects with presbycusis. Atrophy of insula, amygdala, and other temporal areas were related with functional impairment, apathy, and language deficits in the presbycusis with cochlear dysfunction group. We conclude that (i) the neuropsychiatric symptoms had a major effect on functional loss in subjects with presbycusis, (ii) cochlear dysfunction is relevant for the association between hearing loss and behavioral impairment, and (iii) atrophy of the insula and amygdala among other temporal areas are related with hearing loss and behavioral impairment.Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT) CONICYT FONDECYT 1161155 Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT) CONICYT PIA/ANILLOS ACT1403 CONICYT BASAL FB008 Proyecto ICM P09015F Fundación Guillermo Puelm

Reduced suprathreshold auditory nerve responses are associated with slower processing speed and thinner temporal and parietal cortex in presbycusis

Epidemiological evidence shows an association between hearing loss and dementia in elderly people. However, the mechanisms that connect hearing impairments and cognitive decline are still unknown. Here we propose that a suprathreshold auditory-nerve impairment is associated with cognitive decline and brain atrophy. Methods: audiological, neuropsychological, and brain structural 3-Tesla MRI data were obtained from elders with different levels of hearing loss recruited in the ANDES cohort. The amplitude of waves I (auditory nerve) and V (midbrain) from auditory brainstem responses were measured at 80 dB nHL. We also calculated the ratio between wave V and I as a proxy of suprathreshold brainstem function. Results: we included a total of 101 subjects (age: 73.5 +/- 5.2 years (mean +/- SD), mean education: 9.5 +/- 4.2 years, and mean audiogram thresholds (0.5-4 kHz): 25.5 +/- 12.0 dB HL). We obtained reliable suprathreshold waves V in all subjects (n = 101), while replicable waves I were obtained in 92 subjects (91.1%). Partial Spearman correlations (corrected by age, gender, education and hearing thresholds) showed that reduced suprathreshold wave I responses were associated with thinner temporal and parietal cortices, and with slower processing speed as evidenced by the Trail-Making Test-A and digit symbol performance. Non-significant correlations were obtained between wave I amplitudes and other cognitive domains. Conclusions: These results evidence that reduced suprathreshold auditory nerve responses in presbycusis are associated with slower processing speed and brain structural changes in temporal and parietal regions

GET – A generic approach towards an acquisition system for TPCs in Nuclear Physics.

GET (Generic Electronics for TPCs) is today being deployed in a number (>20) experiments including, TPCs, trackersand solid-state devices at RIKEN, J-PARC, GANIL, IBS, NSCL, IRFU, INFN(Catania), ELI-NP, CERN, IMP, … Thesystem development covered the very front-end to data storage including basic software developments. It has beenspecifically tailored to respond to the needs in Nuclear Physics where i) a versatile multi-level numeric trigger isrequired, ii) the number of channels can are relatively small (256-32k), iii) having a wide dynamic range, iv) relativelyhigh rates(<5kHz) and in particular v) generic via slow control to cater for different instruments in the domain.Propose to present an overview of the GET system as coupled to ACTAR-TPC, AT-TPC (active targets) andSpIRIT(TPC). The performance of the recent (2015) integrated system will be given for recent experiments. Futureextensions of the system leading to a high dynamic range will be described

GET – A generic approach towards an acquisition system for TPCs in Nuclear Physics.

International audienceGET (Generic Electronics for TPCs) is today being deployed in a number (>20) experiments including, TPCs, trackersand solid-state devices at RIKEN, J-PARC, GANIL, IBS, NSCL, IRFU, INFN(Catania), ELI-NP, CERN, IMP, … Thesystem development covered the very front-end to data storage including basic software developments. It has beenspecifically tailored to respond to the needs in Nuclear Physics where i) a versatile multi-level numeric trigger isrequired, ii) the number of channels can are relatively small (256-32k), iii) having a wide dynamic range, iv) relativelyhigh rates(<5kHz) and in particular v) generic via slow control to cater for different instruments in the domain.Propose to present an overview of the GET system as coupled to ACTAR-TPC, AT-TPC (active targets) andSpIRIT(TPC). The performance of the recent (2015) integrated system will be given for recent experiments. Futureextensions of the system leading to a high dynamic range will be described

GET: A Generic Electronic System for TPCs for nuclear physics experiments

GET is an international program to develop a reconfigurable and scalable medium sized system to cover nuclear physics requirements for instruments with up to 30k electronic channels