Mueller_et_al_2023_Nicotine_and_fear
This repository consists of fMRI-imaging data in form of beta/con images for different analyses of each subject, as well as .csv files of subjective ratings and SCR data for each subject. Subjects underwent a fear conditioning protocol with a fear acquisition (ACQ) on day 1 and 24 hours later an extinction training (EXT) with subsequent return of fear manipulation. Group 1 received nicotine before ACQ, Group 2 received nicotine before EXT, Group 3 received Placebo before both days.
Nicotine reduces discrimination between threat and safety in the hippocampus, nucleus accumbens and amygdala
The two-day paradigm consisted of a Fear Acquisition (ACQ) on the first day, followed approximately 24h later by
an Extinction training (EXT) with a Return of Fear manipulation (RoF) in form of a reinstatement. Both experimental days
were conducted in the fMRI scanner. Depending on the pseudo-randomly assigned group, either 1mg nicotine or 1mg placebo
was administered double-blinded before participants were placed in the scanner and started the experiment. During the
Acqusition 3 blocks with each 8 CS+ and 8 CS- were presented. The reinforcement rate for the CS+ was 75%. On the second
day EXT and the subsequent reinstatement were executed. The EXT consisted of two blocks with each 8 CS+ and 8 CS- presentations.
The reinforcement rate was now 0%. Subsequently, the reinstatement took place, where four electric stimuli were presented
without any context or cue information. That was followed by a reinstatement test with one block with 8 CS+ and 8 CS-
presentations without presentation of an US (reinforcement rate=0%).
To test the effect of acute nicotine on aversive learning in a Fear Acquisition and Extinction training protocol including a
reinstatement test, we compared three groups. Group 1 (Nic1) received 1mg nicotine before ACQ on day 1 and then placebo before
EXT on day 2. Accordingly group 2 (Nic2) received a placebo before ACQ on day 1 and then 1mg nicotine before the EXT on day 2.
Group 3 (Pla) as the control group received placebo before both days.
Participants rated how much fear/stress they felt towards the CSs and the ITIs on a visual Analogue Scale [VAS, 0 (none) –
100 (maximally)] before and after ACQ as well as before and after EXT and after the reinstatement test. Preceding the US
presentation, subjects rated their US expectancy as a binary choice (yes/no) trialwise on both experimental days when the CSs
were presented on the screen, (without any rating scale).
Skin conductance responses were measured on the hypothenar on the left hand of the participant. Criteria for a valid
response were an occurrence between 1000ms and 4000ms after stimulus onset, a duration between 0.5s and 5s and an amplitude
larger than 10nS. Null-reactions were defined as responses taking place later than 4000ms after stimulus onset or when there
was no response. A missing response was defined as a response that starts before 1000ms after stimulus onset or if the responses
were undefinable due to artifacts. Scored data was normalized for each day and participant (logarithmized and range-corrected).
Participants gave information on age, gender, alcohol and coffee consumption. Furthermore,
participants completed the State-Trait Anxiety Inventory (STAI-S/STAI-T).
To check if nicotine has a general effect on attention, participants completed the d2 Test of attention after each experimental
day.
Description of the data and file structure
fMRI data is structured by experimental procedure (Day 1: ACQ, Day 2: EXT & RoF). Within these folders the analyses of each procedure can be found for each subject sorted by group.
ACQ:
first block ACQ
--> CS+ = s6beta0001.nii
--> CS- = s6beta0003.nii
middle block ACQ
--> CS+ = s6beta0005.nii
--> CS- = s6beta0006.nii
last block ACQ
--> CS+ = s6beta0002.nii
--> CS- = s6beta0004.nii
EXT: D2_EXT_2sepblocks
first block EXT
--> CS+ = s6beta0001.nii
--> CS- = s6beta0003.nii
second block EXT
--> CS+ = s6beta0002.nii
--> CS- = s6beta0004.nii
RoF: D2_RoF_EXT_2sepblocks
--> CS+ = s6beta0005.nii
--> CS- = s6beta0006.nii
excluded subjects in imaging analyses:
001 - has provided false information
002 - technical difficulties
031 - technical difficulties
039 - only day 1 data (only day 2 exclusion)
040 - only day 1 data (only day 2 exclusion)
069 - has provided false information
081 - only day 1 data (only day 2 exclusion)
086 - stated too high alcohol consumption
Rating data is structured by experimental day and rating type (US expectancy/Fear Rating) in individual .csv files with the following content:
subject --> subject number
stimulus --> ITI: Inter Trial Interval, CSP: conditioned stimulus with unconditioned stimulus (CS+), CSM: conditioned stimulus without unconditioned stimulus (CS-)
time --> for Fear Rating: 1=pre ACQ/EXT, 2=post ACQ/EXT, 3=post RoF
trial --> trial number
block --> block number, 8 trials per block
rating --> rating data, US Expectency: 1=subject expects US, 0=subject does not expect US, no value = missing data; Fear Rating: scale from 0-100, 0= no fear, 100=very much fear
group --> 1= nicotine before ACQ, 2= nicotine before EXT, 3= placebo
sex --> 1=female, 2=male, 3=diverse
attentionTestD1 --> concentration level, higher levels means equals concentration
age --> age of sibject in years
alcohol --> alcohol consumption as glasses per week
coffee --> coffe consumption as glasses per day
bmi --> body mass index
stait --> Trait Anxiety Inventory
staisd1 --> State Anxiety Inventory on day 1
Normalized SCR data is structured by experimental day in individual .csv files:
sub --> subject number
CSP + number X --> SCR towards CS+ during trial X
CSM + number X --> SCR towards CS- during trial X
excluded from ratings and SCR
001 - has provided false information
039 - only day 1 data (only day 2 exclusion)
040 - only day 1 data (only day 2 exclusion)
069 - has provided false information
081 - only day 1 data (only day 2 exclusion)
