Claire Martin reflects on the recent progress of this programme at the crossroads of olfactory neuroscience and technology. She discusses the avenues being explored to better understand and ultimately restore the perception of odours, as well as the scientific and human challenges carried by this research.
Per Fumum Endowment Fund: Could you provide us with an update on the progress of your study aimed at developing a prototype olfactory implant ultimately compatible with the human brain?
Claire Martin : “Today, we have the entire implant chain in place. We have an odour sensor capable of detecting smells and sending them to a module that analyses them and can discriminate between two odours, which was a critical point. This module is connected to electrodes that stimulate the olfactory bulb.
We are now able to detect odours within a sufficiently short timeframe, process them, and send the stimulation to the implant. Having this complete chain already represents an important milestone. We will now be able to test the system as a whole and conduct behavioural studies in sheep under real-life conditions.
Regarding stimulation, we have made significant progress. We now have highly efficient electrodes, perfectly suited to our needs. We have two types of electrodes, compatible with both rats and sheep, which may later be used in humans.
We have already implanted sheep and rats with these electrodes, performed stimulations, and conducted tests. At this stage, we know that stimulation of the olfactory bulb causes neither pain nor discomfort in the animals. However, we still lack precise data on what this stimulation produces in the brain and on the possibility of inducing behaviour. We have begun this work, notably through MRI studies, and we are currently analysing the activated brain areas.”
Per Fumum Endowment Fund: At this stage, have you been able to carry out the first tests on sheep as planned? What conclusions have you drawn?
Claire Martin : “Yes, the implantations have been completed and the stimulations tested. We have also set up a behavioural test that works with real odours.
We now know that the stimulation does not cause pain or discomfort. The next step will be to render the sheep anosmic and then repeat the tests with the implant in order to assess whether the stimulation can recreate a perception that is behaviourally meaningful.”
Per Fumum Endowment Fund: What have been the main technical or biological challenges encountered in recent months?
Claire Martin : “The major difficulty has been odour detection. To elicit a behaviour in animals and this will be the same in humans the odour must be detected and processed very quickly. If the information reaches the brain five minutes after exposure, it is no longer relevant. Processing therefore had to occur within seconds.
Currently marketed detectors are designed to detect fires or air pollutants. They operate over long timeframes, sometimes several minutes, which is not problematic for those applications. For us, this slowness was a major technical barrier.
We worked extensively on this issue and have now achieved the necessary speed. However, we remain limited in the number of identifiable odours. We can discriminate between two odours, but we cannot yet identify a wide range. There are technological and expertise-related limitations in this field.
Our objective is not to recreate the entire olfactory spectrum. If we can restore a few odours linked to danger or pleasure, that would already represent a significant advance.
From a biological standpoint, we have not encountered any particular difficulties. Behavioural work with sheep requires time, but the protocol is functioning.”
Per Fumum Endowment Fund: Has your project led to new partnerships, particularly with start-ups or industrial players specialised in neurotechnologies?
Claire Martin : “Since the beginning of the project, a new partner has joined the team: the Swiss Federal Institute of Technology in Lausanne, more specifically Stéphanie Lacour’s team. They are developing tailor-made electrodes for our project.
This partnership is strategic, as this team has a strong commitment to developing neurostimulation devices for human use. Their involvement facilitates the prospect of future clinical translation.”
Per Fumum Endowment Fund: In your view, what would be a realistic timeline for the first clinical trials in humans?
Claire Martin : “The current project is focused on animals, but it obviously has a human objective. The goal is not to restore the sense of smell in sheep for its own sake.
Regarding a complete olfactory implant in humans, it is difficult to provide a precise timeline. However, tests involving stimulation of the olfactory bulb in humans as part of clinical trials are conceivable in the medium term.
Neurosurgeons are already working on this question. It is realistic to envisage, within a timeframe of one and a half to two years, clinical studies aimed at stimulating the olfactory bulb to assess whether such stimulation can evoke olfactory perceptions.
A complete implant will require a longer clinical phase. One might envisage a horizon of around ten years, but this remains prospective.”
Per Fumum Endowment Fund: Have you been able to speak with anosmic patients to understand their reactions to this innovation?
Claire Martin : “Yes. We are in partnership with the association anosmie.org, which brings together people who have lost their sense of smell. We conducted a survey among its members.
A total of 226 people responded. The vast majority expressed support for the olfactory implant. More than half of the respondents also indicated that they would be willing to participate in clinical trials.
There is strong demand from patients, particularly among those who currently have no therapeutic solution. We are currently preparing a scientific publication presenting these results in order to encourage the community to intensify research in this field.”
