Distinct neurochemical predictors for different phases of decision-making learning

Poster No:

17 

Submission Type:

Abstract Submission 

Authors:

Paul Dux1, Matilda Gordon1, Shane Ehrhardt1, Reuben Rideaux2, Małgorzata Marjańska3, Dinesh Deelchand3, Zeinab Eftekhari1, Hannah Filmer4

Institutions:

1The University of Queensland, St Lucia, Queensland, 2University of Sydney, Sydney, NSW, 3University of Minneapolis, Minneapolis, MN, 4The University of Queensland, Brisbane, Queensland

First Author:

Paul Dux, PhD  
The University of Queensland
St Lucia, Queensland

Co-Author(s):

Matilda Gordon  
The University of Queensland
St Lucia, Queensland
Shane Ehrhardt  
The University of Queensland
St Lucia, Queensland
Reuben Rideaux  
University of Sydney
Sydney, NSW
Małgorzata Marjańska  
University of Minneapolis
Minneapolis, MN
Dinesh Deelchand  
University of Minneapolis
Minneapolis, MN
Zeinab Eftekhari  
The University of Queensland
St Lucia, Queensland
Hannah Filmer  
The University of Queensland
Brisbane, Queensland

Introduction:

Adaptive decision-making, reflected by fast and accurate sensory-motor mapping, is characteristic of successful interaction with our environment. Learning is crucial for the development of such decision-making processes and this, in turn, has been linked to the balance of excitatory (glutamate) and inhibitory (γ-aminobutyric acid [GABA]) neurochemicals in the cortex. Learning is not a unitary phenomenon and occurs across distinct time scales. Key neurochemicals may be involved in different phases of learning, however the mechanisms are not yet understood. Further, how interventions like transcranial direct current stimulation (tDCS) relate to learning phases and neurochemical concentrations remains unclear.

Methods:

Here, we assess how neurochemical balance is associated with the impact of brain stimulation on early- and later-phase sensory-motor mapping/learning using in vivo 7 T ultra-high field magnetic resonance spectroscopy (MRS) of the right motor cortex (M1), right intraparietal sulcus (IPS), and left prefrontal cortex (PFC). Specifically, offline cathodal tDCS was employed during a session featuring a single-dual task decision-making paradigm, assessed pre-stimulation, immediately post stimulation (early learning) and 20 minutes post-stimulation (late learning).

Results:

tDCS modulations of sensory-motor learning for both the single- and dual-task trials were associated with neurochemical balance in the right IPS during early learning, whereas this shifted to the right M1 for later learning during the session.

Conclusions:

Collectively, the present results shed light on the neurochemical mechanisms at play as sensory-response mapping shifts from executive to motoric operations.

Brain Stimulation:

Non-invasive Electrical/tDCS/tACS/tRNS 1

Learning and Memory:

Skill Learning 2

Keywords:

Cognition
FUNCTIONAL MRI
GABA
Glutamate
Learning
MRI

1|2Indicates the priority used for review

Abstract Information

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Please indicate below if your study was a "resting state" or "task-activation” study.

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Healthy subjects only or patients (note that patient studies may also involve healthy subjects):

Healthy subjects

Was this research conducted in the United States?

No

Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.

Yes

Were any animal research approved by the relevant IACUC or other animal research panel? NOTE: Any animal studies without IACUC approval will be automatically rejected.

Not applicable

Please indicate which methods were used in your research:

Functional MRI
Behavior
Other, Please specify  -   tDCS

For human MRI, what field strength scanner do you use?

7T

Which processing packages did you use for your study?

SPM
Other, Please list  -   LCModel

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not applicable

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