Effect of S-Ketamine on Self and Body Perception in Healthy Adults

Study description

The aim of the present study is to determine how an intravenous infusion of S-ketamine compared to a placebo affects implicit body and space perception and the sense of agency. To this end we will use state-of-the-art experimental paradigms, including a robotic rubber hand illusion setup, a heartbeat discrimination task, an audio-tactile interaction task and a sensory suppression task. This way we aim to replicate and extend previous research, building on existing theories and models and conducting confirmatory analyses using pre-specified hypotheses and analysis plans that will be made available on the open science framework (OSF.org) prior to starting the study.

Specifically, the study has the following primary objectives:

(1) To investigate the neural effects of S(+)-ketamine, and specifically if S(+)-ketamine:
a. Increases bottom-up compared to top-down signals and results in an increased coherence between canonical brain networks, as measured using EEG frequency and coherence measures;
b. Decreases the sensory suppression that is typically observed for event-related potentials (ERPs) to self- compared to externally generated sounds;
c. Decreases the distinction between self- and other-related processing, as measured by the N400-response and recognition memory for self- compared to other-attributed adjectives.

(2) To investigate effects of S(+)-ketamine on body and self-perception and specifically if S(+)-ketamine results in:
a. A shrinking of the perception of one’s peripersonal space (i.e., the space surrounding the body) through the use of an audio-tactile interaction task;
b. Increased feelings of body ownership over alien body parts as measured using the rubber hand illusion task;
c. Increased sensitivity to bottom-up cardiac signals and increased interoceptive accuracy as measured using the heartrate discrimination task;

The secondary objectives are:
1. To investigate the effects of S(+)-ketamine on self-report measures and subjective experiences, as measured using standardized scales and an interview.
2. To investigate the relationship between the self-report measures and the experimental measures of S(+)-ketamine-induced changes in self- and body-perception.
3. To investigate how individual differences in personality and absorption moderate ketamine-induced changes in body and self-perception.

 

Study Qualifications

We intend to obtain usable data from 24 participants for this study. We will have 2 testing sessions per participant.

Inclusion criteria: 

1. Healthy male or female volunteers;
2. Age: 18 – 40 years;
3. Body mass index < 30 kg/m2
4. Right-handed
5. Sufficient command of the English language.

Exclusion criteria: 

1. Known or suspected neuromuscular or a (family) history of any neuromuscular disease
2. A history of allergic reaction to food or medication including study medication
3. Any current or previous medical (including high blood pressure), neurological or psychiatric illness (including a history of anxiety)
4. Alcohol abuse (> 21 units/week)
5. Illicit/recreational drug use in the past 14 days before inclusion. Note that participants who have used illicit / recreational drugs prior to this 14-day period can still be included, provided that they remain abstinent for the duration of the study, including the 14-day pre-study period.
6. Concurrent use of xanthine derivatives, ergometrine, sympathomimetics, thyroid hormone, vasopressin, hypnotics, benzodiazepines, antipsychotics, barbiturates, opioids, inhalation anesthetics, CYP3A4 inhibitors and inducers (e.g., St. John’s Wort), and muscle relaxants. A medical doctor will evaluate the subject’s current medication and supplement use during the online screening to exclude subjects currently using these or any other potentially contraindicated substances.
7. Pregnancy or lactation
8. Participation in any medical or drug trial in the month prior to the current study

 

Participate in this study

Contact Josephine Marschall – via email provided below.

Contact the research team
Involved Lab Members