Global patterns of kelp forest change over the past half-century.

Kelp forests (Order Laminariales) form key biogenic habitats in coastal regions of temperate and Arctic seas worldwide, providing ecosystem services valued in the range of billions of dollars annually. Although local evidence suggests that kelp forests are increasingly threatened by a variety of stressors, no comprehensive global analysis of change in kelp abundances currently exists. Here, we build and analyze a global database of kelp time series spanning the past half-century to assess regional and global trends in kelp abundances. We detected a high degree of geographic variation in trends, with regional variability in the direction and magnitude of change far exceeding a small global average decline (instantaneous rate of change = -0.018 y-1). Our analysis identified declines in 38% of ecoregions for which there are data (-0.015 to -0.18 y-1), increases in 27% of ecoregions (0.015 to 0.11 y-1), and no detectable change in 35% of ecoregions. These spatially variable trajectories reflected regional differences in the drivers of change, uncertainty in some regions owing to poor spatial and temporal data coverage, and the dynamic nature of kelp populations. We conclude that although global drivers could be affecting kelp forests at multiple scales, local stressors and regional variation in the effects of these drivers dominate kelp dynamics, in contrast to many other marine and terrestrial foundation species.

On the diversity and distribution of a data deficient habitat in a poorly mapped region: The case of Sabellaria alveolata L. in Ireland.

Data that can be used to monitor biodiversity through time are essential for conservation and management. The reef-forming worm, Sabellaria alveolata (L. 1767) is currently classed as 'Data Deficient' due to an imbalance in the spread of data on its distribution. Little is known about the distribution of this species around Ireland. Using data archaeology, we collated past and present distribution records and discovered that S. alveolata has a discontinuous distribution with large gaps between populations. Many regions lack data and should be targeted for sampling. Biodiversity surveys revealed that S. alveolata supported diverse epibiotic algal communities. Retrograding (declining) reefs supported greater infaunal diversity than prograding (growing) reefs or sand, suggesting that S. alveolata is a dynamic ecosystem engineer that has a lasting legacy effect. Similar research should be carried out for other Data Deficient species, habitats and regions. Such data are invaluable resources for management and conservation.

Novelty-related activation within the medial temporal lobes.

Functional magnetic resonance imaging (fMRI) was used to examine whether (1) verbal associative encoding activates the medial temporal lobes (MTL) and related regions more than non-associative encoding, (2) verbal associative novelty is related to enhanced MTL activation, and (3) verbal item novelty is related to enhanced MTL activation and, if so, whether these activations are in different or overlapping sites. No increase in MTL activation was found during verbal associative encoding relative to non-associative encoding, although associative encoding was related to a relative increase in activation in the posterior cingulate cortex. In contrast, verbal associative novelty was found to activate the MTL and posterior cingulate cortex. Verbal item novelty did not significantly activate any brain region. The verbal associative novelty-related effect occurred despite subjects having little awareness of associative novelty. The verbal associative novelty-related activation in the MTL may be related either to unconscious novelty detection or to a priming effect at encoding. We argue that if the priming explanation is correct then this may account for our failure to observe an associative encoding MTL activation.

Neuropsychological Outcome and the Extent of Resection in the Unilateral Temporal Lobectomy.

Thirty-eight patients who had undergone either a right (RTL, n = 19) or left (RTL, n = 19) en bloc unilateral temporal lobectomy were scanned using magnetic resonance imaging, and the extent of removal of the superior lateral (SL), inferolateral (IL), basal, parahippocampal, and hippocampal regions was rated using semiautomated analysis. Brain regional ratings were correlated against pre- versus postoperative changes in memory functioning. The results showed overall significant postoperative decline in verbal memory only in the LTL group. Despite this, in the RTL group basal and hippocampal region removal was correlated with visuospatial memory outcome. In the LTL group, IL and basal region removal was correlated with Performance Intelligence outcome. In each case, more resection was associated with worse functioning and vice versa. It was concluded that variability in neuropsychological outcome can be explained in part by variations in the extent of tissue removal within the en bloc operation.

Executive function assessed by memory updating and random generation in schizotypal individuals.

Individuals scoring high (N=32) and low (N=27) on the unusual experiences (UnEx) scale of the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE) were selected from a large sample (N=265) of normal volunteer undergraduates. The high- and low-UnEx groups were compared on two tasks, random generation and memory updating, which target executive functions that inhibit prepotent responses and update current information. The groups differed only on the R measure of random generation that assesses inequality in the relative frequencies of response alternatives, a result attributed to superstitious behaviour rather than to executive deficit. The results suggest that the executive impairments previously observed in high schizotypal individuals using the Wisconsin Card Sorting Test and other measures are selective rather than global.

Perceptual organization deficits in psychotic patients.

It has been proposed that a characteristic of schizophrenic processing is an abnormality of top-down processing. The relationship between impaired top-down processing and symptoms of reality distortion was investigated using a 'degraded interference' task. In this task, fragmented stimuli (Stroop words, control words and crosses) are presented on a computer screen, and the extent to which they are visually integrated is inferred by their interfering properties. It was predicted that psychotic individuals would fail to show an interference effect with degraded Stroop stimuli. This predicts the absence of a delay in reaction time in the experimental condition, which therefore cannot be attributed to a generalized deficit. A sample of inpatients experiencing positive symptoms was compared to a healthy control group. The results provided support for a deficiency in top-down processing, with the psychotic group failing to show the significant degraded interference effect found in the healthy controls. Degraded interference was associated with low verbal IQ, but with no other symptomatic or demographic variables.

Storage of verbal associations is sufficient to activate the left medial temporal lobe.

Neuroimaging studies have shown that memory encoding activates the medial temporal lobe (MTL). Many believe that these activations are related to novelty but it remains unproven which is critical - novelty detection or the rich associative encoding it triggers. We examined MTL activation during verbal associative encoding using functional magnetic resonance imaging. First, associative encoding activated left posterior MTL more than single word encoding even though novelty detection was matched, indicating not only that associative encoding activates the MTL particularly strongly, but also that activation does not require novelty detection. Moreover, it remains to be convincingly shown that novelty detection alone does produce such activation. Second, repetitive associative encoding produced less MTL activation than initial associative encoding, indicating that priming of associative information reduces MTL activation. Third, re-encoding familiar associations in a well-established way had a minimal effect on both memory and MTL activation, indicating that MTL activation reflects storage of associations, not merely their initial representation.