Xylanase and xylo- oligosaccharide prebiotic improve the growth performance and concentration of potentially prebiotic oligosaccharides in the ileum of broiler chickens.

1. The objective of this study was to investigate the effect of supplementing broiler diets with xylanase or xylo- oligosaccharide (XOS) on growth performance, the concentration of non-starch polysaccharide (NSP) hydrolysis products in the ileum and concentration of short chain fatty acids (SCFA) in the caeca of broiler chickens.2. In total, 500 male Ross 308 broilers were used in this 29-day (d) study. The treatments were organised into a 2 × 2 plus 1 factorial arrangement consisting of two additives (xylanase or XOS) at two levels (low or high) plus a control treatment with no additives. This gave five treatments with 100 birds in each treatment group. The diets were slightly deficient in protein by 20 g/kg and energy by 1 MJ/kg.3. On d 14 and 28, two birds per pen were euthanised, the caeca content collected and analysed for short chain fatty acid (SCFA) concentration. On d 29, six birds per pen were euthanised and ileal digesta were collected and analysed for the concentration of NSP fractions.4. On d 14, caecal acetic acid, iso-butyric acid, iso-valeric acid, n-valeric acid and total SCFA concentrations were significantly greater (P ≤ 0.05) when diets were supplemented with XOS compared with xylanase.5. Ileal concentration of arabinose, galactose and glucuronic acid (GlucA2) were significantly greater (P ≤ 0.05) in the insoluble NSP fraction when diets were supplemented with a high level of xylanase, compared with the control treatment. Ileal concentration of fructose was significantly greater (P ≤ 0.05) in the water soluble NSP when a high level of xylanase or low level of XOS were included in the diet compared with the control.6. It was concluded that xylanase and XOS had similar effects on NSP concentration and SCFA in the caeca, although there was little effect on performance. This observation demonstrated further benefits of xylanase supplementation in wheat-based broiler diets beyond digesta viscosity reduction and the release of extra nutrients.

Ten years of Nature Reviews Neuroscience: insights from the highly cited.

To celebrate the first 10 years of Nature Reviews Neuroscience, we invited the authors of the most cited article of each year to look back on the state of their field of research at the time of publication and the impact their article has had, and to discuss the questions that might be answered in the next 10 years. This selection of highly cited articles provides interesting snapshots of the progress that has been made in diverse areas of neuroscience. They show the enormous influence of neuroimaging techniques and highlight concepts that have generated substantial interest in the past decade, such as neuroimmunology, social neuroscience and the 'network approach' to brain function. These advancements will pave the way for further exciting discoveries that lie ahead.

How do you feel--now? The anterior insula and human awareness.

The anterior insular cortex (AIC) is implicated in a wide range of conditions and behaviours, from bowel distension and orgasm, to cigarette craving and maternal love, to decision making and sudden insight. Its function in the re-representation of interoception offers one possible basis for its involvement in all subjective feelings. New findings suggest a fundamental role for the AIC (and the von Economo neurons it contains) in awareness, and thus it needs to be considered as a potential neural correlate of consciousness.

Expectation of pain and relief: A dynamical model of the neural basis for pain-trauma co-morbidity.

Posttraumatic Stress Disorder (PTSD) is highly co-morbid with chronic pain conditions. When present, PTSD significantly worsens chronic pain outcomes. Likewise, pain contributes to a more severe PTSD as evidenced by greater disability, more frequent use of harmful opioid analgesics and increased pain severity. The biomechanism behind this comorbidity is incompletely understood, however recent work strongly supports the widely-accepted role of expectation, in the entanglement of chronic pain and trauma symptoms. This work has shown that those with trauma have a maladaptive brain response while expecting stress and pain, whereas those with chronic pain may have a notable impairment in brain response while expecting pain relief. This dynamical expectation model of the interaction between neural systems underlying expectation of pain onset (traumatic stress) and pain offset (chronic pain) is biologically viable and may provide a biomechanistic insight into pain-trauma comorbidity. These predictive mechanisms work through interoceptive pathways in the brain critically the insula cortex. Here we highlight how the neural expectation-related mechanisms augment the existing models of pain and trauma to better understand the dynamics of pain and trauma comorbidity. These ideas will point to targeted complementary clinical approaches, based on mechanistically separable neural biophenotypes for the entanglement of chronic pain and trauma symptoms.

Brain responses to visceral stimuli reflect visceral sensitivity thresholds in patients with irritable bowel syndrome.

BACKGROUND & AIMS: Only a fraction of patients with irritable bowel syndrome (IBS) have increased perceptual sensitivity to rectal distension, indicating differences in processing and/or modulation of visceral afferent signals. We investigated the brain mechanisms of these perceptual differences. METHODS: We analyzed data from 44 women with IBS and 20 female healthy subjects (controls). IBS symptom severity was determined by a severity scoring system. Anxiety and depression symptoms were assessed using the hospital anxiety and depression score. Blood oxygen level-dependent signals were measured by functional magnetic resonance imaging during expectation and delivery of high (45 mmHg) and low (15 mmHg) intensity rectal distensions. Perception thresholds to rectal distension were determined in the scanner. Brain imaging data were compared among 18 normosensitive and 15 hypersensitive patients with IBS and 18 controls. Results were reported significant if peak P-values were ≤.05, with family-wise error correction in regions of interest. RESULTS: The subgroups of patients with IBS were similar in age, symptom duration, psychological symptoms, and IBS symptom severity. Although brain responses to distension were similar between normosensitive patients and controls, hypersensitive patients with IBS had greater activation of insula and reduced deactivation in pregenual anterior cingulate cortex during noxious rectal distensions, compared to controls and normosensitive patients with IBS. During expectation of rectal distension, normosensitive patients with IBS had more activation in right hippocampus than controls. CONCLUSIONS: Despite similarities in symptoms, hyper- and normosensitive patients with IBS differ in cerebral responses to standardized rectal distensions and their expectation, consistent with differences in ascending visceral afferent input.

Distinctive neurons of the anterior cingulate and frontoinsular cortex: a historical perspective.

Human anterior cingulate and frontoinsular cortices participate in healthy social-emotional processing. These regions feature 2 related layer 5 neuronal morphotypes, the von Economo neurons and fork cells. In this paper, we review the historical accounts of these neurons and provide a German-to-English translation of von Economo's seminal paper describing the neurons which have come to bear his name. We close with a brief discussion regarding the functional and clinical relevance of these neurons and their home regions.

An interoceptive neuroanatomical perspective on feelings, energy, and effort.

A homeostatic energy model of awareness proposes that the anterior insular cortex engenders feelings that provide an amodal valuation of homeostatic energy utilization in an opponent, bivalent emotional control system. Feelings are the "common currency" which enable optimal utilization in the physical and mental behavior of a highly social primate. This model offers a different perspective.

Insular cortex activation in a patient with "sensed presence"/ecstatic seizures.

OBJECTIVE: Seizures with an aura of a "sensed presence," a religious emotion, or feelings of euphoria (ecstatic seizures) are characterized by heightened self-awareness. A previous case report on a patient with epilepsy and "sensed presence" as an aura described hypoperfusion in both temporal lobes and a local ictal increase in the left frontoparietal area. A reexamination of the data was suggested by a recent study of patients with ecstatic seizures, which proposed that hyperactivation of the left anterior insula might be a potential cause. METHODS: We reanalyzed the laboratory data on the case with "sensed presence" aura using a fusion of SPECT and MR images of the brain, which had not previously been available, and a close examination of the subdural ictal EEG registrations. RESULTS: Examination of the ictal EEG recordings from subdural strip electrodes implanted subtemporally and temporally on both sides showed that seizure activity occurred first at the most medial subtemporal electrode on the left side. From an anatomical point of view, this electrode position is close to the ventral aspect of the left anterior insula, and it is possible that the seizure activity was initiated there. Reexamination of the SPECT data after fusion with contemporary MR images clearly indicated that the region of strong hyperactivation overlies the left anterior insula. Hyperactive regions also appear on the midinsula bilaterally. Together with the neurophysiological ictal EEG, this evidence supports a reinterpretation that this aura of "sensed presence" can be attributed to hyperactivation of the left anterior insula. CONCLUSION: The present findings support the proposal that ecstatic seizures or "sensed presence" auras can originate from the left anterior insula, a region that has been suggested to engender self-awareness associated with positive feelings.

The neurocircuitry of impaired insight in drug addiction.

More than 80% of addicted individuals fail to seek treatment, which might reflect impairments in recognition of severity of disorder. Considered by some as intentional deception, such 'denial' might instead reflect dysfunction of brain networks subserving insight and self-awareness. Here we review the scant literature on insight in addiction and integrate this perspective with the role of: (i) the insula in interoception, self-awareness and drug craving; (ii) the anterior cingulate in behavioral monitoring and response selection (relevant to disadvantageous choices in addiction); (iii) the dorsal striatum in automatic habit formation; and (iv) drug-related stimuli that predict emotional behavior in addicted individuals, even without conscious awareness. We discuss implications for clinical treatment including the design of interventions to improve insight into illness severity in addiction.