Introduction to NIMH's Research Domain Criteria (RDoC) for Brain Research

NEURON MENA: Hi, this is Neuron Mena from NAMI Montana.

I want to speak to you for a few minutes today about

an important development in mental illness research.

The National Institute of Mental Health Research Domain Criteria, or RDoC.

RDoC grew out of an agency's goal to develop new ways of classifying

mental disorders based on behavioral dimensions and neural biological measures.

In the opinion of this humble neuron,

it's a great effort because the interactions of

over a hundred billion neurons in the brain are incredibly hard to understand.

The need for a more systematic framework to tie

together this research has only become clear

as the technology is capable of adding

valuable information about brain function has increased.

For instance, it's going to take a clear research framework to

ensure that the information gathered through combinations of psychological surveys,

fMRI brain scans, EEG recordings,

genetic testing, blood work and other tools clarifies our understanding of the brain

rather than making things murkier by piling on seemingly unconnected data.

Here is the RDoC matrix.

The domain's constructs and sub-constructs are on the left side of the matrix.

We'll get into those in more detail.

But in absolute layman's terms,

these are characteristics of brain functioning,

such as how our brain responds to fear.

How our brain responds to threat?

How do you visually perceive images?

How are your sleep cycles, etc?

The top of the graph is composed of the units of measure.

In layman's terms, these are different ways that you can measure brain function.

For instance, researchers may use psychological self-report surveys, genetics,

brain circuits shown in fMRI scans,

descriptions of the specific kinds of cells involved,

molecules that may function as neurotransmitters.

We'll go back to the broad view of our RDoC matrix in a second

but I think it helps to start with

the analysis of a very specific brain function characteristics.

Specifically, how does a person respond to acute fear?

Start by going to NIMH's web page for the Research Domain Criteria Matrix.

Then click on the acute threat fear link.

That link will open up and shows a number of different units

of analysis for research in acute threat fear.

Some of the units of analysis for acute threat study include

genes such as BDNF and 5-HT/5-HTRs,

molecules such as dopamine and serotonin,

cells like neurons, glia, and pyramidal cells,

circuits such as central nucleus.

Physiological characteristics like skin conductance and heart rate.

Behavioral characteristics such as freezing and response time.

Psychological self-report surveys such as the

fear survey schedule and fear questionnaire,

and psychological paradigms like fear conditioning.

This framework provides a comprehensive breakdown of

the methods and measures to analyze acute threat.

The units of analysis can eliminate

potential connections between brain function characteristics.

The list of the units of analysis can also help identify

brain function characteristics that have significant research gaps.

For instance, clearly, language doesn't happen

without molecules acting as neurotransmitters and cell transmitting information.

There's a likely need to reevaluate prior research or conduct

new research to better understand those units of

analysis for this brain function characteristic.

Now, they've given you a little depth on units of analysis,

let's look harder at the other side of

the graph and the brain function characteristics being mentioned.

NIMH describes the rows as

specific functional constructs representing a specific function dimension of behavior.

Those constructs that are grouped into domains

based upon the current understanding of emotion,

cognition, motivation, and social behavior.

There are currently five domains in the RDoC matrix.

The five domains are negative valence systems, positive valence systems,

cognitive systems, systems for social processes and the arousal of regulatory system.

The negative valence systems are the system primarily responsible for

responses to aversive situations or contexts such as fear, anxiety, and loss.

The positive valence systems are the systems primarily responsible for responses to

positively motivational situations or contexts such as reward seeking,

conservatory behavior, and reward or habit learning.

The cognitive systems are the systems responsible for various cognitive processes.

The systems for social processes are the systems that

mediate responses to interpersonal settings of various types,

including perception and interpretation of others' actions.

The arousal regulatory systems are the systems

responsible for generating activation of neural systems as

appropriate for various contexts and providing

the appropriate homeostatic regulation of such systems as energy,

balance, and sleep.

Once you've got a basic understanding of the RDoC matrix,

it's easy to see how it opens up the door for

really cool multi-dimensional brain research.

For instance, how many sub-constructs are impacted by

a deficiency in a specific molecule that acts as a neurotransmitter?

Similarly, what subcontracts are impacted by trauma?

What units of analysis identify factors related to resiliency to trauma?

There are so many questions in the field of mental illness research.

We're really excited to see what answers the research domain criteria framework

can help address and what new questions are opened up from there.