Managing Big Sagebrush in a Changing Climate

This publication identifies areas where big sagebrush populations are most and least vulnerable to climate change and demonstrates where continued investment in sagebrush conservation and restoration could have the most impact

The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa

This study investigated whether dopaminergic systems are involved in the motivation to engage in behaviours associated with anorexia nervosa (AN), specifically, the drive to exercise. Women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15) were recruited. The acute phenylalanine/tyrosine depletion (APTD) method was used to transiently decrease dopamine synthesis and transmission. The effect of dopamine precursor depletion on drive to exercise was measured using a progressive ratio (PR) exercise breakpoint task. Both groups worked for the opportunity to exercise, and, at baseline, PR breakpoint scores were higher in AN REC than HC. Compared to values on the experimental control session, APTD did not decrease PR breakpoint scores in AN REC, but significantly decreased scores in HC. These data show that women recovered from AN are more motivated to exercise than HC, although in both groups, activity is more reinforcing than inactivity. Importantly, decreasing dopamine does not reduce the motivation to exercise in people recovered from AN, but in contrast, does so in HC. It is proposed that in AN, drive to exercise develops into a behaviour that is largely independent of dopamine mediated reward processes and becomes dependent on cortico-striatal neurocircuitry that regulates automated, habit- or compulsive-like behaviours. These data strengthen the case for the involvement of reward, learning, habit, and dopaminergic systems in the aetiology of AN

Evidence that Illness-Compatible Cues Are Rewarding in Women Recovered from Anorexia Nervosa: A Study of the Effects of Dopamine Depletion on Eye-Blink Startle Responses.

In anorexia nervosa (AN), motivational salience is attributed to illness-compatible cues (e.g., underweight and active female bodies) and this is hypothesised to involve dopaminergic reward circuitry. We investigated the effects of reducing dopamine (DA) transmission on the motivational processing of AN-compatible cues in women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15). This involved the acute phenylalanine and tyrosine depletion (APTD) procedure and a startle eye-blink modulation (SEM) task. In a balanced amino acid state, AN REC showed an increased appetitive response (decreased startle potentiation) to illness-compatible cues (underweight and active female body pictures (relative to neutral and non-active cues, respectively)). The HC had an aversive response (increased startle potentiation) to the same illness-compatible stimuli (relative to neutral cues). Importantly, these effects, which may be taken to resemble symptoms observed in the acute stage of illness and healthy behaviour respectively, were not present when DA was depleted. Thus, AN REC implicitly appraised underweight and exercise cues as more rewarding than did HC and the process may, in part, be DA-dependent. It is proposed that the positive motivational salience attributed to cues of emaciation and physical activity is, in part, mediated by dopaminergic reward processes and this contributes to illness pathology. These observations are consistent with the proposal that, in AN, aberrant reward-based learning contributes to the development of habituation of AN-compatible behaviours

Effect of Acute Phenylalanine and Tyrosine Depletion (APTD) on Non-Transformed (A) and Log Transformed (B) Progressive Ratio (PR) Exercise Breakpoint Scores in Individuals Recovered from Anorexia Nervosa (AN REC, N = 17) and Healthy Controls (HC, N = 15).

<p>Relative to the balanced condition (BAL), APTD resulted in a significant decrease in PR breakpoint scores among HC only (HC BAL: 1.18 ± 0.76; HC APTD: 0.39 ± 0.68). Relative to HC, AN REC performed significantly more on the PR task during both BAL (1.70 ± 0.61) and APTD (1.74 ± 0.44). In AN REC, raw PR exercise breakpoint scores for were 113.53 ± 200.56 during BAL and 107.94 ± 200.76 during APTD. In HC, they were 36.87 ± 26.38 during BAL and 8.00 ± 14.49 during APTD. Data are expressed as Means ± SD. **<i>P ≤ 0</i>.<i>01</i> *<i>P ≤ 0</i>.<i>05</i>. ANOVA: analysis of variance. SD: standard deviation.</p

Plasma phenylalanine (PHE) and tyrosine (TYR) concentrations (μmol/l), and ratios of tyrosine and phenylalanine to large neutral amino acids (LNAA) at baseline (am) and 4 hour following amino acid ingestion (pm).

<p>Plasma phenylalanine (PHE) and tyrosine (TYR) concentrations (μmol/l), and ratios of tyrosine and phenylalanine to large neutral amino acids (LNAA) at baseline (am) and 4 hour following amino acid ingestion (pm).</p

Effect of acute phenylalanine and tyrosine depletion (APTD) on startle eye-blink amplitudes to physically active and non-active body stimuli (relative to neutral cues) in individuals recovered from anorexia nervosa (AN REC, n = 15) and healthy controls (HC, n = 14).

<p>In the balanced condition (BAL), AN REC tended towards decreased startle potentiation (an appetitive response) to active (5.21 ± 0.55) relative to non-active cues (5.30 ± 0.51), while HC displayed increased startle potentiation (an aversive response) to active (5.29 ± 0.68) relative to neutral (5.19 ± 0.75) cues. In the low DA condition (APTD), AN REC perceived active stimuli (5.44 ± 0.67) as more aversive than neutral cues (5.30 ± 0.50), while HC perceived neutral stimuli (5.43 ± 0.56) as more aversive than non-active cues (5.34 ± 0.54); however, differences did not reach significance during APTD. The repeated measures ANOVA was based on the log transformed startle eye-blink potentiations (in millivolts) for AN REC in the BAL (Neutral: 227.43 ± 124.19; Active: 207.19 ± 99.74; Non-active: 222.70 ± 101.74) and APTD conditions (Neutral: 224.77 ± 113.62; Active: 292.60 ± 263.04; Non-active: 221.80 ± 113.70) and for HC in the BAL (Neutral: 229.66 ± 165.67; Active: 243.64 ± 162.38; Non-active: 231.55 ± 160.60) and APTD conditions (Neutral: 259.87 ± 131.95; Active: 246.08 ± 113.52; Non-active: 235.52 ± 122.55). Data are expressed as Means ± SD. *P ≤ 0.10. ANOVA: analysis of variance. SD: standard deviation.</p

Participant Baseline Characteristics.

<p>Participant Baseline Characteristics.</p

Effect of acute phenylalanine and tyrosine depletion (APTD) on startle eye-blink amplitudes to underweight and healthy female body stimuli (relative to neutral cues) in individuals recovered from anorexia nervosa (AN REC, n = 15) and healthy controls (HC, n = 14).

<p>In the balanced condition (BAL), AN REC showed decreased startle potentiation (an appetitive response) to underweight (5.18 ± 0.58) relative to neutral (5.30 ± 0.54) cues, while HC displayed increased startle potentiation (an aversive response) to underweight (5.35 ± 0.65) relative to neutral (5.19 ± 0.75) cues. In the low DA condition (APTD), AN REC perceived underweight stimuli (5.32 ± 0.53) as more aversive than neutral cues (5.30 ± 0.50), while HC perceived neutral stimuli (5.43 ± 0.56) as more aversive than underweight cues (5.38 ± 0.69); however, during APTD, the differences were not significant. The repeated measures ANOVA was based on the log transformed startle eye-blink potentiations (in millivolts) for AN REC in the BAL (Neutral: 227.43 ± 124.19; Underweight: 204.39 ± 105.90; Healthy: 210.52 ± 94.51) and APTD conditions (Neutral: 224.77 ± 113.62; Underweight: 230.48 ± 118.95; Healthy: 223.19 ± 125.10), and for HC in the BAL (Neutral: 229.66 ± 165.67; Underweight: 254.88 ± 168.49; Healthy: 236.91 ± 159.35) and APTD conditions (Neutral: 259.87 ± 131.95; Underweight: 255.34 ± 133.09; Healthy: 255.01 ± 140.09). Data are expressed as Means ± SD. *<i>P ≤ 0</i>.<i>05</i>. ANOVA: analysis of variance. SD: standard deviation.</p

The Maudsley outpatient study of treatments for anorexia nervosa and related conditions (MOSAIC): comparison of the Maudsley model of anorexia nervosa treatment for adults (MANTRA) with specialist supportive clinical management (SSCM) in outpatients with broadly defined anorexia nervosa: a randomized controlled trial

Objective: Anorexia nervosa (AN) in adults has poor outcomes, and treatment evidence is limited. This study evaluated the efficacy and acceptability of a novel, targeted psychological therapy for AN (Maudsley Model of Anorexia Nervosa Treatment for Adults; MANTRA) compared with Specialist Supportive Clinical Management (SSCM). Method: One hundred forty-two outpatients with broadly defined AN (body mass index [BMI] ≤ 18.5 kg/m2) were randomly allocated to receive 20 to 30 weekly sessions (depending on clinical severity) plus add-ons (4 follow-up sessions, optional sessions with dietician and with carers) of MANTRA (n = 72) or SSCM (n = 70). Assessments were administered blind to treatment condition at baseline, 6 months, and 12 months after randomization. The primary outcome was BMI at 12 months. Secondary outcomes included eating disorders symptomatology, other psychopathology, neuro-cognitive and social cognition, and acceptability. Additional service utilization was also assessed. Outcomes were analyzed using linear mixed models. Results: Both treatments resulted in significant improvements in BMI and reductions in eating disorders symptomatology, distress levels, and clinical impairment over time, with no statistically significant difference between groups at either 6 or 12 months. Improvements in neuro-cognitive and social–cognitive measures over time were less consistent. One SSCM patient died. Compared with SSCM, MANTRA patients rated their treatment as significantly more acceptable and credible at 12 months. There was no significant difference between groups in additional service consumption. Conclusions: Both treatments appear to have value as first-line outpatient interventions for patients with broadly defined AN. Longer term outcomes remain to be evaluated