FAQs for PAR-MH-19-289 Building in vivo Preclinical Assays of Circuit Engagement for Application in Therapeutic Development (R01 Clinical Trial Not Allowed)
1. What is the purpose of this FOA?
This initiative supports the development of innovative, non-invasive measures of brain activity in preclinical species as assays for the therapeutic development pipeline. Assay measures to be optimized and evaluated will emulate neurophysiological processes or behavioral measures that are directly relevant to functional domains that may be impaired in mental illnesses. If successful, the preclinical measures developed through this initiative could be evaluated for cross-species conservation with humans in future studies. In all, the goal is to identify those assay measure with a strong research-based rationale for inclusion in early phase preclinical screening of clinical therapeutic for predicting effects in humans.
2. What are the key requirements for responsive applications?
All responsive applications must include the following phases:
- Optimization, in animals, of novel, predominantly non-invasive neurophysiological or behavioral measures reflecting activity of clinically relevant brain processes or functional domains that are disrupted within or across mental illnesses. Optimization should focus on mirroring testing parameters or measures used in human experiments where human assays exist or developing tests that have potential application in future studies in humans.
- Evaluation of the performance of the physiological or behavioral measures as potential assays in a therapeutic pipeline across a range of levels (i.e., doses) of a perturbation (e.g., drugs, transcranial magnetic stimulation, etc.). This phase provides a measure of the sensitivity of the assay.
- Mechanistic testing of brain processes and/or circuits proposed as key drivers of the neurophysiological or behavioral assay measures. For example, a study might include optogenetic or chemogenetic approaches to manipulate specific circuits in combination with in vivo electrophysiological measures to verify circuits contributing to specific EEG power spectral changes elicited by a cognitive challenge. Studies in this phase are also expected to test the effects of the same perturbations used in the evaluation phase.
An illustrative example: A study might propose to optimize an operant paradigm that is presumed to assess multiple aspects of anhedonia that are disrupted in patients with mood disorders. Optimization phase here might involve modifications of existing methods to mimic rates of acquisition and performance of a comparable task in humans. For a study aimed at developing an assay of task driven spectral EEG signatures, the optimization phase might address technical barriers to maximize the ability to compare data from the rodent with human EEG measures in the future. The evaluation phase would involve administering a perturbation expected to affect the measure. In our example, a dopamine modulator might be given across doses to assess the sensitivity and responsiveness of the measure in this phase. In our example, the mechanistic testing phase would address the underlying biological rationale for focusing on the measure and the choice of perturbation. Perhaps in our example, a circuit including D1 dopamine receptor signaling is proposed to enable reward memory coding changes in dopaminergic neural activity. One can imagine several hypotheses one might test using combinations of methods, including single cell recording in striatum during performance with optogenetic stimulation or inhibition of DA neurons.
3. What is meant by “predominantly non-invasive” measurements?
Some degree of invasive manipulation might be necessary in animals to measure something that can be assessed non-invasively in humans. For example, human scalp EEG might be best modeled by invasive LFP recordings from animals in some cases.
4. What if the circuits underlying the physiological or behavioral measure are already well established? For example, I want to develop an assay using changes in sleep spindles underlying learning as a dependent measure, but the circuits underlying this phenomenon are already well established. Do I still need to propose a mechanistic test of the circuit?
Yes, it is important to validate the physiological and/or behavioral measure and response to perturbations are indeed mediated through the same the proposed circuits.
5. What if my mechanistic test fails to identify a critical circuit, would that suggest the assay measure is not useful?
Not necessarily, but it would suggest that the neurobiology behind the assay is not established, suggesting a need for caution in implementing it in a therapeutic pipeline. Ideally, alternate hypotheses are proposed that could be tested. The mechanistic validation component is included to eliminate the need to guess what a behavioral assay represents.
6. How many years may I request for the project?
The maximum duration is 5 years. All projects must propose a timeline and milestones they will implement to accomplish all 3 required components of the projects.
7. What does it mean to “Describe how the results will add value to a therapeutic development pipeline regardless of outcome?”
A plan needs to be in place or making the data available to the research community regardless of whether the work succeeded in identifying a novel potential assay or if it suggested the measure was sub-optimal for further development.
8. Are there any special considerations in selecting the preclinical species?
The FOA supports assay development around those measures that assess the highest level of shared function across species (i.e., the highest common denominator). In most cases, this will limit the selection of the non-human species to mammals.
9. I would like to test a novel treatment candidate in animals. Is this research goal aligned with the intent of the FOA?
No. The main purpose of this FOA is to develop and evaluate novel brain-based measures as assays and not to evaluate novel targets or therapeutic candidates. Applications aimed at therapeutics development or clinical evaluation of new potential therapeutic s are directed to the FOAs listed on The NIMH Therapeutics Development website.
10. Can studies in humans be included?
No human studies are allowed for this FOA. However, the assay measures developed in animals through this FOA should be designed so the coherence, or lack of concurrence, of the assay performance across species to humans can be assessed in future projects. In this way, assays developed here may be considered the preclinical prequel to subsequent projects aimed at evaluating the assays for coherence of performance between the preclinical species and healthy humans (see PAR-16-065; Novel Assays to Address Translational Gaps in Treatment Development (UG3/UH3).
11. I am interested in developing and testing a physiological measure. Is it necessary to have the behavioral output as well?
No, a behavioral measure is not required.
12. Are stress manipulations or genetically modified animals appropriate manipulations for this FOA?
No, only normal, wildtype, non-stressed animals may be used for these studies. Perturbations used to evaluate the performance of the measures must be selected based on their potential cross species evaluation, including humans in future studies, and the ability to evaluate more than one dose or level.
13. I am interested in looking at circadian activity rhythms as therapeutic assays, is this acceptable?
No, studies aimed solely at developing measures of circadian rhythmicity or clock regulatory mechanisms as assays are not appropriate. In contrast, studies aimed at examining sleep microstructure in relation to learning and plasticity (spindles) would be encouraged.
14. Are industry partners allowed?
Collaborations between academic and industry partners are encouraged as long as the data and protocol sharing plan goals can be maintained.
15. How is the evaluation of applications from foreign investigators different from U.S. investigators?
Non-U.S. institutions are eligible to apply, and collaborations with non-U.S. investigators are allowed. For applications submitted by foreign organizations, reviewers will assess whether the project presents special opportunities for furthering research programs through the use of unusual talent, resources, populations, or environmental conditions that exist in other countries and either are not readily available in the United States or augment existing U.S. resources. Additional information is available at http://grants.nih.gov/grants/foreign/.