TY  - JOUR
A1  - Verner, Martin
A1  - Herrmann, Martin J.
A1  - Troche, Stefan J.
A1  - Roebers, Claudia M.
A1  - Rammsayer, Thomas H.
T1  - Cortical oxygen consumption in mental arithmetic as a function of task difficulty: a near-infrared spectroscopy approach
JF  - Frontiers in Human Neuroscience
N2  - The present study investigated changes in cortical oxygenation during mental arithmetic using near-infrared spectroscopy (NIRS). Twenty-nine male volunteers were examined using a 52-channel continuous wave system for analyzing activity in prefrontal areas. With the help of a probabilistic mapping method, three regions of interest (ROIs) on each hemisphere were defined: The inferior frontal gyri (IFG), the middle frontal gyri (MFG), and the superior frontal gyri (SFG). Oxygenation as an indicator of functional brain activation was compared over the three ROI and two levels of arithmetic task difficulty (simple and complex additions). In contrast to most previous studies using fMRI or NIRS, in the present study arithmetic tasks were presented verbally in analogue to many daily life situations. With respect to task difficulty, more complex addition tasks led to higher oxygenation in all defined ROI except in the left IFG compared to simple addition tasks. When compared to the channel positions covering different gyri of the temporal lobe, the observed sensitivity to task complexity was found to be restricted to the specified ROIs. As to the comparison of ROIs, the highest oxygenation was found in the IFG, while MFG and SFG showed significantly less activation compared to IFG. The present cognitive-neuroscience approach demonstrated that NIRS is a suitable and highly feasible research tool for investigating and quantifying neural effects of increasing arithmetic task difficulty.
KW  - cortical activation
KW  - working memory
KW  - individual differences
KW  - prefrontal cortex
KW  - FMRI
KW  - brain-regions
KW  - subsctraction
KW  - activation
KW  - bold
KW  - intelligibility
KW  - NIRS
KW  - oxygen consumption
KW  - task difficulty
KW  - mental arithmetic
KW  - near-infrared spectroscopy
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-122449
SN  - 1662-5161
VL  - 7
IS  - 217
ER  - 
TY  - JOUR
A1  - Schecklmann, Martin
A1  - Giani, Anette
A1  - Tupak, Sara
A1  - Langguth, Berthold
A1  - Raab, Vincent
A1  - Polak, Thomas
A1  - Varallyay, Csanad
A1  - Harnisch, Wilma
A1  - Herrmann, Martin J.
A1  - Fallgatter, Andreas J.
T1  - Functional Near-Infrared Spectroscopy to Probe State- and Trait-Like Conditions in Chronic Tinnitus: A Proof-of-Principle Study
JF  - Neural Plasticity
N2  - Objective. Several neuroscience tools showed the involvement of auditory cortex in chronic tinnitus. In this proof-of-principle study we probed the capability of functional near-infrared spectroscopy (fNIRS) for the measurement of brain oxygenation in auditory cortex in dependence from chronic tinnitus and from intervention with transcranial magnetic stimulation. Methods. Twenty-three patients received continuous theta burst stimulation over the left primary auditory cortex in a randomized sham-controlled neuronavigated trial (verum = 12; placebo = 11). Before and after treatment, sound-evoked brain oxygenation in temporal areas was measured with fNIRS. Brain oxygenation was measured once in healthy controls (n = 12). Results. Sound-evoked activity in right temporal areas was increased in the patients in contrast to healthy controls. Left-sided temporal activity under the stimulated area changed over the course of the trial; high baseline oxygenation was reduced and vice versa. Conclusions. By demonstrating that rTMS interacts with auditory evoked brain activity, our results confirm earlier electrophysiological findings and indicate the sensitivity of fNIRS for detecting rTMS induced changes in brain activity. Moreover, our findings of trait-and state-related oxygenation changes indicate the potential of fNIRS for the investigation of tinnitus pathophysiology and treatment response.
KW  - transcranial magnetic stimulation
KW  - positron-emission-tomography
KW  - auditory cortex
KW  - FNIRS
KW  - RTMS
KW  - neural activity
KW  - FMRI
KW  - brain
KW  - activation
KW  - humans
Y1  - 2014
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-117801
SN  - 1687-5443
IS  - 894203
ER  -