Acceptability and effectiveness study of therapist-assisted internet-delivered cognitive behaviour therapy for agriculture producers.

Agriculture producers are less likely to seek or to receive mental health services compared to the general population. Additional research is needed to identify effective and accessible mental health interventions for this underserved population. This study used a mixed-methods approach and open trial design to examine the acceptability and effectiveness of therapist-assisted internet-delivered cognitive behaviour therapy (ICBT) supplemented with an additional agricultural resource for clients from agricultural backgrounds receiving ICBT in routine care. Clients (n = 34) participated in an online, five-lesson course that provided psychoeducation and strategies for dealing with symptoms of anxiety and depression, with weekly therapist assistance. Clients also received a tailored resource (developed with input from those with an agricultural background) providing culturally specific information and case stories pertinent to agricultural communities. Intent-to-treat analyses showed that the ICBT program was effective in reducing anxiety and depression symptoms among the agricultural population. Large within-group pre-to-post-treatment Cohen's effect sizes of d = 1.14, 95 % CI [0.41, 1.86] and d = 1.15, 95 % CI [0.42, 1.87] were found for depression and anxiety, respectively and comparable to the same program offered to the general population. Clients also experienced reductions in perceived stress and significant improvements in resiliency from pre- to post-treatment. Semi-structured interviews conducted at post-treatment with the agricultural clients (n = 31) on their experiences with ICBT identified four main themes: perceived strengths of ICBT and the tailored resource, suggestions to improve service delivery for agriculture producers, clients experienced internal and external challenges to participating in ICBT, and the positive impact of the course reached beyond the client. Very high satisfaction rates were found. These results provide support for the acceptability and effectiveness of ICBT with a tailored resource offered in routine care among agriculture producers.

Learning performance of normal and mutant Drosophila after repeated conditioning trials with discrete stimuli.

A new olfactory conditioning procedure is described using short training trials with discrete presentation of conditioned stimuli (CS) and unconditioned stimuli (US). A short odor presentation along with a single-shock stimulus produced modest but reliable and reproducible learning. Multiple trials presented sequentially improved performance with increasing trial number. Trial spacing had a significant impact on performance. Two trials presented with a short intertrial interval (ITI) produced no improvement over a single trial; two trials with a 15 min ITI significantly boosted performance. This effect required two associative trials, because substituting one of the trials with the CS alone, US alone, or an unpaired CS-US failed to boost performance. The increase in initial performance with two trials decayed within 15 min after training. Thus, the effect is short-lived. The utility of using a battery of tests, including a single short trial, two massed trials, and two spaced trials, to investigate parameters of memory formation in several mutants was demonstrated.

Integrin-mediated short-term memory in Drosophila.

Volado is a new memory mutant of Drosophila. The locus encodes two isoforms of a new alpha-integrin, a molecule that dynamically mediates cell adhesion and signal transduction. The Volado gene is expressed preferentially in mushroom body cells, which are neurons known to mediate olfactory learning in insects. Volado proteins are concentrated in the mushroom body neuropil, brain areas that contain mushroom body processes in synaptic contact with other neurons. Volado mutants display impaired olfactory memories within 3 min of training, indicating that the integrin is required for short-term memory processes. Conditional expression of a Volado transgene during adulthood rescues the memory impairment. This rescue of memory is reversible, fading over time along with expression of the transgene. Thus the Volado integrin is essential for the physiological processes underlying memory. We propose a model in which integrins act as dynamic regulators of synapse structure or the signalling events underlying short-term memory formation.

Characterization of a multicomponent receptor for GDNF.

Glial-cell-line-derived neurotrophic factor (GDNF) is a potent survival factor for central and peripheral neurons, and is essential for the development of kidneys and the enteric nervous system. Despite the potential clinical and physiological importance of GDNF, its mechanism of action is unknown. Here we show that physiological responses to GDNF require the presence of a novel glycosyl-phosphatidylinositol (GPI)-linked protein (designated GDNFR-alpha) that is expressed on GDNF-responsive cells and binds GDNF with a high affinity. We further demonstrate that GDNF promotes the formation of a physical complex between GDNFR-alpha and the orphan tyrosin kinase receptor Ret, thereby inducing its tyrosine phosphorylation. These findings support the hypothesis that GDNF uses a multi-subunit receptor system in which GDNFR-alpha and Ret function as the ligand-binding and signalling components, respectively.

Heat shock disrupts long-term memory consolidation in Caenorhabditis elegans.

Previous work has demonstrated that memory for habituation training is retained for > 24 hr in Caenorhabditis elegans. In this study the timing of memory consolidation was investigated by introducing heat shock (32 degrees C, 45 min) either before training, long after training, or during training. It was found that memory consolidation was disrupted by heat shock during training but not before or after training. In addition, heat shock before training failed to induce thermal tolerance to the effects of heat shock during training on long-term memory formation. When brief heat shock (32 degrees C, 15 min) was presented during training at different intervals, the results suggested that a narrow critical period for memory consolidation of habituation may exist. These findings demonstrate that in C. elegans long-term memory for habituation is disrupted by a temporally defined agent, heat shock. Therefore, heat shock can be used as a fine-grained tool to investigate the dynamics of memory consolidation.

Effects of aging on habituation in the nematode Caenorhabditis elegans.

The effects of aging on spontaneous locomotor behavior and habituation in a mechanosensory reflex were examined in the nematode Caenorhabditis elegans. Worms were tested at 4 days (at the peak of egg laying), at 7 days (when egg laying ends) and at 12 days post-hatching. Both spontaneous and reflexive movements were smaller in older worms than in younger worms. In addition the magnitude of these movements was related to life span; the shorter an animal's life span, the smaller its reversal movements while still young. Worms at all ages expressed habituation and dishabituation at a 10 s interstimulus interval (ISI); thus even aged worms were capable of non-associative learning. However, older worms showed greater habituation than did 4-day-old worms to stimuli delivered at a 60 s ISI. There was also an age-related change in the recovery from habituation. At days 4 and 7, worms had recovered from habituation by 30 min after training; However, responses of day 12 worms were still significantly smaller than baseline at 30 min after training. Further behavioral tests with normal and mutant worms may help elucidate the nature of the age-related changes in the learning and memory processes of C. elegans and the genetic mechanisms which underlie them.

Caenorhabditis elegans: a new model system for the study of learning and memory.

The extensive information on the neuroanatomy, development and genetics of Caenorhabditis (C.) elegans make it an ideal candidate model system for the analysis of the mechanisms underlying learning and memory. A first step in this analysis is the demonstration of the capacity of C. elegans to learn. In these experiments non-associative learning in C. elegans was investigated by observing changes in reversal reflex response amplitude to a mechanical vibratory stimulus. The results from these studies of non-associative learning show that C. elegans is capable of short-term habituation, dishabituation and sensitization, as well as long-term retention of habituation training lasting for at least 24 h. These findings set the stage for detailed developmental, genetic and physiological analyses of learning and memory.

Alpha-tocopherol and phylloquinone as non-competitive inhibitors of retinyl ester hydrolysis.

Inhibition of rat intestinal retinyl ester hydrolase by alpha-tocopherol (vitamin E) and phylloquinone (vitamin K1) was non-competitive. Maximum inhibition occurred within 10 min, and, particularly with alpha-tocopherol, was substantially reversible. Consequently, increasing tissue concentrations of retinyl esters, which might occur with advancing age or changes in diet, would not diminish the effects of the inhibitors. These data further support the notion that alpha-tocopherol may, at physiological concentrations, influence the concentration of vitamin A and its ester in tissues.