Immediate effects of deep brain stimulation of anterior thalamic nuclei on executive functions and emotion-attention interaction in humans.
BACKGROUND
Deep brain stimulation (DBS) of anterior thalamic nuclei (ANT) is a novel promising therapeutic method for treating refractory epilepsy. Despite reports of subjective memory impairments and mood disturbances in patients with ANT-DBS, little is known of its effects on cognitive and affective processes.


OBJECTIVE
The anterior thalamus has connections to prefrontal and limbic networks important for cognitive control and emotional reactivity. More specifically, anterior cingulate cortex (ACC), linked with ANT, has been assigned roles related to response inhibition and attention allocation to threat. Thus, we hypothesized ANT-DBS to influence executive functions, particularly response inhibition, and modulate emotional reactivity to threat.


METHODS
Twelve patients having undergone ANT-DBS for intractable epilepsy participated in the study. Patients performed a computer-based executive reaction time (RT) test--that is, a go/no-go visual discrimination task with threat-related emotional distractors and rule switching, while the DBS was switched ON (5/5 mA constant current) and OFF every few minutes.


RESULTS
ANT-DBS increased the amount of commission errors--that is, errors where subjects failed to withhold from responding. Furthermore, ANT-DBS slowed RTs in context of threat-related distractors. When stimulation was turned off, threat-related distractors had no distinct effect on RTs.


CONCLUSIONS
We found immediate objective effects of ANT-DBS on human cognitive control and emotion-attention interaction. We suggest that ANT-DBS compromised response inhibition and enhanced attention allocation to threat due to altered functioning of neural networks that involve the DBS-target, ANT, and the regions connected to it such as ACC. The results highlight the need to consider affective and cognitive side-effects in addition to the therapeutic effect when adjusting stimulation parameters. Furthermore, this study introduces a novel window into cognitive and affective processes by modulating the associative and limbic networks with direct stimulation of key nodes in the thalamus.
a Behavioral Neurology Research Unit, Tampere University Hospital , Tampere , Finland.
Kaisa M
KM
Hartikainen
Lihua
L
Sun
Markus
M
Polvivaara
Maarja
M
Brause
Kai
K
Lehtimäki
Joonas
J
Haapasalo
Timo
T
Möttönen
Kirsi
K
Väyrynen
Keith H
KH
Ogawa
Juha
J
Öhman
Jukka
J
Peltola
D000328:Adult; D020643:Anterior Thalamic Nuclei / Q000502:physiology*; D001288:Attention / Q000502:physiology*; D046690:Deep Brain Stimulation; D004644:Emotions / Q000502:physiology*; D004827:Epilepsy / Q000503:physiopathology / Q000601:surgery; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
Anterior thalamic nuclei; Deep brain stimulation; Emotion; Executive functions; epilepsy