SEED BANK DYNAMICS WITHIN A METAPOPULATION FRAMEWORK: A STUDY OF AN ANT-DISPERSED SPECIES

Questions. How do spatial and temporal landscape dynamics, including past disturbance, affect the distribution of the seed bank of an early-succession species? Do these factors ultimately influence above-ground subpopulation persistence within a metapopulation framework? Location. Granite-gneiss outcrops within mixed hardwood-conifer forest in Michigan, USA Methods. We studied the distribution of the Capnoides sempervirens seed bank on outcrops and within the forest matrix in relation to landscape and physiographic (n = 517). Above-ground plant persistence (n = 144) in relation to landscape and habitat variables was also investigated. Results. Seeds were found up to 175 m from outcrops, but seed presence generally decreased with increased distance to outcrops. Areas of recent fire had both increased abundance and greater frequency of occurrence of seeds. Seed presence on outcrops shared no relationship with adult plants, but instead corresponded to increased groundcover at sampling locations. Conclusions. Results indicated seed distribution is not random but reliant upon spatial and temporal predictors. Increased seed presence in relation to adult-plant habitat demonstrated seed bank distribution has some dependence on distance from source populations and primary disperser activity, but the presence of seeds within the greater forest matrix also indicated reliance on landscape, physiographic, or disturbance-related factors. Seed distribution has the potential to influence subpopulation persistence

A PHYLOGENETIC REEVALUATION OF THE GENUS GAVIA (AVES: GAVIIFORMES) USING NEXT-GENERATION SEQUENCING

Avian phylogenetic analysis based on DNA sequences, rather than morphological characters, has been used in recent decades to resolve systematic relationships. Advancements in molecular techniques have improved avian phylogenetics and have led to new insights on the relationships between and within taxa. Loons (Aves: Gaviiformes) are one of the oldest living lineages of birds, and the order includes five extant species. The morphological cladogram of Gavia placed G. arctica as a sister species to G. pacifica. However, a more recent study based on mtDNA resulted in a discordant tree splitting the G. arctica/G. pacifica clade, and placed G. pacifica as sister to the (G. immer, G. adamsii) clade. These hypotheses were tested using next-generation sequencing (NGS) data in the form of a RAD-tag dataset comprising 232,094 bps from 2502 variable loci. Bayesian inference, Maximum Likelihood, and Maximum Parsimony phylogenetic analyses of a concatenated dataset strongly supported the traditional phylogeny (G. stellata, ((G. arctica, G. pacifica), (G. adamsii, G. immer))), and differed from the largely mitochondrially-based hypothesis that placed G. pacifica sister to the (G. immer, G. adamsii) clade. Both internally- and externally-calibrated molecular clock based estimates of divergence dates placed the most recent common ancestor of modern loons in the early Miocene, which is earlier than previously thought, ~21.4 mya (20-22.8 mya) provides a more parsimonious explanation for body size evolution in loons

Disgust implicated in obsessive-compulsive disorder

Psychiatric classificatory systems consider obsessions and compulsions as forms of anxiety disorder. However, the neurology of diseases associated with obsessive-compulsive symptoms suggests the involvement of fronto-striatal regions likely to be involved in the mediation of the emotion of disgust, suggesting that dysfunctions of disgust should be considered alongside anxiety in the pathogenesis of obsessive-compulsive behaviours. We therefore tested recognition of facial expressions of basic emotions (including disgust) by groups of participants with obsessive-compulsive disorder (OCD) and with Gilles de la Tourette's syndrome (GTS) with and without co-present obsessive-compulsive behaviours (GTS with OCB; GTS without OCB). A group of people suffering from panic disorder and generalized anxiety were also included in the study. Both groups with obsessive-compulsive symptoms (OCD; GTS with OCB) showed impaired recognition of facial expressions of disgust. Such problems were not evident in participants with panic disorder and generalized anxiety, or for participants with GTS without obsessions or compulsions, indicating that the deficit is closely related to the presence of obsessive-compulsive symptoms. Participants with OCD were able to assign words to emotion categories without difficulty, showing that their problem with disgust is linked to a failure to recognize this emotion in others and not a comprehension or response criterion effect. Impaired recognition of disgust is consistent with the neurology of OCD and with the idea that abnormal experience of disgust may be involved in the genesis of obsessions and compulsions

Emotionserkennung bei Gesunden und Patienten mit Chorea Huntington, Zwangsstörungen und Schizophrenie

Sprengelmeyer A. Emotionserkennung bei Gesunden und Patienten mit Chorea Huntington, Zwangsstörungen und Schizophrenie. Bielefeld (Germany): Bielefeld University; 2005.Emotionale Gesichtsausdrücke und die emotionale Färbung gesprochener Sprache spielen eine bedeutende Rolle in der zwischenmenschlichen Kommunikation. Sie geben Hinweise auf die Empfindungen des Gegenübers und steuern oft auf subtile Weise den Umgang untereinander. Diese Art der nonverbalen Kommunikation kann nicht nur beim Menschen beobachtet werden, sondern findet sich auch im Tierreich. Dieses spricht für eine genetische und neuroanatomische Basis dieser Leistung. Gestützt wird diese Annahme durch eine Reihe von Studien, die nach Hirnschäden Beeinträchtigungen im Erkennen emotionaler Signale beschreiben. Dabei kann es zu generellen, aber auch zu hochselektiven Ausfällen kommen. Die neuroanatomischen Grundlagen, auf denen die Verarbeitung emotionaler Signale beruht, sind aber noch weitgehend unbekannt. Es ist deshalb von Interesse, die neurologischen Grundlagen der Verarbeitung und Produktion emotionaler Gesichtsausdrücke und emotionaler Intonation in gesprochener Sprache genauer zu untersuchen. Ziel der vorliegenden Arbeit ist es, die neuroanatomischen Grundlagen des Erkennens der von Ekman (1976) angenommenen 6 Grundemotionen (Freude, Trauer, Wut, Angst, Ekel und Erstaunen) näher zu beschreiben. Weiterhin soll dem Zusammenhang zwischen dem Erkennen und dem Empfinden von Emotionen nachgegangen werden. Es gibt Hinweise, dass die Verarbeitung der Emotion Angst eng mit der Amygdala verknüpft ist, die Verarbeitung der Emotion Ekel dagegen soll mit den Basalganglien assoziiert sein. Es wurden 4 Studien durchgeführt. In diesen Studien wurden Patientengruppen untersucht, die aufgrund ihrer besonderen Neuropathologien bestimmte Störungen in der emotionalen Verarbeitung erwarten lassen. Die ersten beiden Studien konzentrierten sich auf die Verarbeitung der Emotion Ekel. In der ersten Studie wurden Patienten mit Chorea Huntington untersucht, einer neurodegenerativen Erkrankung, die besonders die Basalganglien betrifft. In der zweiten Studie wurden Patienten mit Zwangsstörung untersucht. Auch bei dieser Erkrankung wird angenommen, dass die Basalganglien und frontostriatale Regionen in Mitleidenschaft gezogen sind. Die Studien 3 und 4 beschäftigen sich insbesondere mit der Rolle der Amygdala in der Emotionsverarbeitung. In Studie 3 wurden Schizophrenie-Patienten untersucht. Diese Gruppe ist deshalb interessant, weil morphometrische Analysen Volumenreduktionen im Bereich der Amygdala nachwiesen. In Studie 4 wurde der Frage nachgegangen, inwieweit Emotionen subcortikal verarbeitet werden können

Knowing no fear

People with brain injuries involving the amygdala are often poor at recognizing facial expressions of fear, but the extent to which this impairment compromises other signals of the emotion of fear has not been clearly established. We investigated N.M., a person with bilateral amygdala damage and a left thalamic lesion, who was impaired at recognizing fear from facial expressions. N.M. showed an equivalent deficit affecting fear recognition from body postures and emotional sounds. His deficit of fear recognition was not linked to evidence of any problem in recognizing anger (a common feature in other reports), but for his everyday experience of emotion N.M. reported reduced anger and fear compared with neurologically normal controls. These findings show a specific deficit compromising the recognition of the emotion of fear from a wide range of social signals, and suggest a possible relationship of this type of impairment with alterations of emotional experience

A causal role for the anterior mid-cingulate cortex in negative affect and cognitive control

Converging evidence has linked the anterior mid-cingulate cortex to negative affect, pain and cognitive control. Shackman and colleagues proposed this region uses information about punishment to control aversively motivated actions. Studies on the effects of lesions allow causal inferences about brain function; however, naturally occurring lesions in the anterior mid-cingulate cortex are rare. In two studies we therefore recruited 94 volunteers, comprising 15 patients with treatment-resistant depression who had received bilateral Anterior Cingulotomy, which consists of lesions made within the anterior mid-cingulate cortex, 20 patients with treatment-resistant depression who had not received surgery and 59 healthy controls. Using the Ekman 60 Faces paradigm and two Stroop paradigms, we tested the hypothesis that patients who received Anterior Cingulotomy were impaired in recognising negative facial affect expressions but not positive or neutral facial expressions, and impaired in Stroop cognitive control, with larger lesions being associated with more impairment. Consistent with hypotheses, we found that larger volume lesions predicted more impairment in recognising fear, disgust and anger, and no impairment in recognising facial expressions of surprise or happiness. However we found no impairment in recognising expressions of sadness. Also consistent with hypotheses, we found that larger volume lesions predicted impaired Stroop cognitive control. Notably, this relationship was only present when anterior mid-cingulate cortex lesion volume was defined as the overlap between cingulotomy lesion volume and Shackman and colleague’s meta-analysis derived binary masks for negative affect and cognitive control. Given substantial evidence from healthy subjects that the anterior mid-cingulate cortex is part of a network associated with the experience of negative affect and pain, engaging cognitive control processes for optimising behaviour in the presence of such stimuli, our findings support the assertion that this region has a causal role in these processes. Whilst the clinical justification for cingulotomy is empirical and not theoretical, it is plausible that lesions within a brain region associated with the subjective experience of negative affect and pain may be therapeutic for patients with otherwise intractable mood, anxiety and pain syndromes.PostprintPeer reviewe

Inconsistent emotion recognition deficits across stimulus modalities in Huntington's disease

This study has been supported by the European Union - PADDINGTON project, Contract no. HEALTH-F2-2010-261358. SJT acknowledges support of the National Institute for Health Research through the Dementias and Neurodegenerative Research Network, DeNDRoN.Background: Recognition of negative emotions is impaired in Huntington's Disease (HD). It is unclear whether these emotion-specific problems are driven by dissociable cognitive deficits, emotion complexity, test cue difficulty, or visuoperceptual impairments. This study set out to further characterise emotion recognition in HD by comparing patterns of deficits across stimulus modalities; notably including for the first time in HD, the more ecologically and clinically relevant modality of film clips portraying dynamic facial expressions. Methods: Fifteen early HD and 17 control participants were tested on emotion recognition from static facial photographs, non-verbal vocal expressions and one second dynamic film clips, all depicting different emotions. Results: Statistically significant evidence of impairment of anger, disgust and fear recognition was seen in HD participants compared with healthy controls across multiple stimulus modalities. The extent of the impairment, as measured by the difference in the number of errors made between HD participants and controls, differed according to the combination of emotion and modality (p=0.013, interaction test). The largest between-group difference was seen in the recognition of anger from film clips. Conclusions: Consistent with previous reports, anger, disgust and fear were the most poorly recognised emotions by the HD group. This impairment did not appear to be due to task demands or expression complexity as the pattern of between-group differences did not correspond to the pattern of errors made by either group; implicating emotion-specific cognitive processing pathology. There was however evidence that the extent of emotion recognition deficits significantly differed between stimulus modalities. The implications in terms of designing future tests of emotion recognition and care giving are discussed.PostprintPeer reviewe

Detection of emotions in Parkinson's disease using higher order spectral features from brain's electrical activity

Non-motor symptoms in Parkinson's disease (PD) involving cognition and emotion have been progressively receiving more attention in recent times. Electroencephalogram (EEG) signals, being an activity of central nervous system, can reflect the underlying true emotional state of a person. This paper presents a computational framework for classifying PD patients compared to healthy controls (HC) using emotional information from the brain's electrical activity

Effects of Dopamine on Sensitivity to Social Bias in Parkinson's Disease

Patients with Parkinson's disease (PD) sometimes develop impulsive compulsive behaviours (ICBs) due to their dopaminergic medication. We compared 26 impulsive and 27 non-impulsive patients with PD, both on and off medication, on a task that examined emotion bias in decision making. No group differences were detected, but patients on medication were less biased by emotions than patients off medication and the strongest effects were seen in patients with ICBs. PD patients with ICBs on medication also showed more learning from negative feedback and less from positive feedback, whereas off medication they showed the opposite effect

Evaluation of multi-modal, multi-site neuroimaging measures in Huntington's disease: Baseline results from the PADDINGTON study.

BACKGROUND: Macro- and micro-structural neuroimaging measures provide valuable information on the pathophysiology of Huntington's disease (HD) and are proposed as biomarkers. Despite theoretical advantages of microstructural measures in terms of sensitivity to pathology, there is little evidence directly comparing the two. METHODS: 40 controls and 61 early HD subjects underwent 3 T MRI (T1- and diffusion-weighted), as part of the PADDINGTON study. Macrostructural volumetrics were obtained for the whole brain, caudate, putamen, corpus callosum (CC) and ventricles. Microstructural diffusion metrics of fractional anisotropy (FA), mean-, radial- and axial-diffusivity (MD, RD, AD) were computed for white matter (WM), CC, caudate and putamen. Group differences were examined adjusting for age, gender and site. A formal comparison of effect sizes determined which modality and metrics provided a statistically significant advantage over others. RESULTS: Macrostructural measures showed decreased regional and global volume in HD (p < 0.001); except the ventricles which were enlarged (p < 0.01). In HD, FA was increased in the deep grey-matter structures (p < 0.001), and decreased in the WM (CC, p = 0.035; WM, p = 0.053); diffusivity metrics (MD, RD, AD) were increased for all brain regions (p < 0.001). The largest effect sizes were for putamen volume, caudate volume and putamen diffusivity (AD, RD and MD); each was significantly larger than those for all other metrics (p < 0.05). CONCLUSION: The highest performing macro- and micro-structural metrics had similar sensitivity to HD pathology quantified via effect sizes. Region-of-interest may be more important than imaging modality, with deep grey-matter regions outperforming the CC and global measures, for both volume and diffusivity. FA appears to be relatively insensitive to disease effects