sleep FAQs: a neuroscientist answers your biggest sleep questions

1. why is sleep so important for our health and wellbeing?

Professor Badre explains that sleep is not simply a period of inactivity. It is one of the body's most important biological processes, during which the brain carries out functions essential to our physical and mental health.

"Sleep is not simply a period of rest. It's one of the body's most active biological processes. It's as important as nutrition, exercise.

During sleep, the brain is very active. It consolidates memory, it regulates emotion, it removes metabolic waste, it strengthens immunity, and it restores energy.

So even one poor night's sleep can impair attention, mood, and decision-making, while of course, chronic sleep loss increases the risk of many diseases.

So sleep should be ... there should be much more respect to sleep than what we have today."

— Associate Professor Gaby Badre

His explanation highlights why sleep is fundamental to overall wellbeing. It is during sleep that the brain supports memory consolidation, emotional processing and several restorative functions.

For Professor Badre, understanding the importance of sleep is the first step towards recognising why we need to protect it, rather than treating it as something we can continually sacrifice to accommodate busy lives.

2. why am I exhausted but still can't fall asleep?

One of the most important distinctions Professor Badre makes is between feeling tired and feeling sleepy. Although we often use these words interchangeably, they describe different biological states.

"So you're exhausted. You have a lack of energy. And you go to bed, you cannot sleep. You are hyperalert.

Whereas when you are sleepy, you know, you cannot fight... If you are sleepy, you yawn... You don't know when you fall asleep. Suddenly you are sleepy.

Whereas when you are tired, you can be tired a long time without falling asleep. They are two different things."

— Associate Professor Gaby Badre

Professor Badre explains that tiredness can result from the physical and mental demands placed on us throughout the day. Sleepiness, however, is associated with the body's biological drive for sleep.

This distinction helps explain why someone can feel completely exhausted after a demanding day but still struggle to fall asleep.

The problem may be that the brain remains in a state of heightened alertness, despite the body feeling depleted of energy.

Understanding this difference is central to the science of switching off. Feeling tired does not necessarily mean the brain is biologically ready to sleep.

3. what is sleep pressure, and how does it help us fall asleep?

Professor Badre describes sleep pressure as one of the fundamental systems controlling when we become sleepy.

"When we wake up in the morning, we are alert, completely alert, and we get activated. So during the day, we are using and burning out our level of alertness.

So that means we start developing a sleep pressure. So if the sleep pressure is synchronised with the circadian rhythm, that means the sleep pressure is maximum in the evening, while the rhythm is favourable for sleep.

That's very efficient. However, if your sleep pressure is... if you wake up later on, let's say if you wake up at 12 o'clock in the day... you get your sleep pressure at 11:00, 12:00 at night... of course, you are desynchronised with the circadian rhythm."

— Associate Professor Gaby Badre

Sleep pressure is the biological need for sleep that accumulates throughout our waking hours. It is regulated by the homeostatic sleep system.

However, Professor Badre emphasises that sleep pressure must work alongside our circadian rhythm, the internal biological clock that helps determine when our bodies are prepared for sleep.

When these systems are aligned, we are more likely to feel sleepy at an appropriate time.

When they become desynchronised, for example through irregular waking times or changes in our daily routine, falling asleep can become more difficult.

4. why can some people sleep anywhere while others struggle?

Professor Badre introduces the concept of sleep adaptability: the brain's ability to adjust to different environments and still achieve sleep.

"Some people can sleep very well on a plane, in a noisy hotel, or almost anywhere, while others struggle in their own bedroom, even though this difference reflects the variation in the brain arousal, in stress sensitivity, personality, and previous experience.

Some people have a naturally flexible sleep system. Others are more vigilant. So the encouraging message is that adaptability is not fixed. It can often be improved."

— Associate Professor Gaby Badre

He explains that our brains have evolved to remain alert to potential threats, particularly when sleeping in unfamiliar environments.

"When you sleep in a new environment, there is every time what we call the first night effect. It's something new. I mentioned before the sentinel. You are in a new environment, your brain is wondering what's happening.

Is there any predator? Is there any danger here? So of course, we are more aroused, more on our awake, so this is a normal situation that one should not dramatise."

— Associate Professor Gaby Badre

The first-night effect describes how the brain can remain more vigilant when sleeping somewhere unfamiliar.

For Professor Badre, this is an important reminder that sleep difficulties are not always caused by poor habits. They can also reflect the brain's natural protective mechanisms.

His message is that we should focus not only on creating the perfect sleeping environment, but also on improving our ability to adapt when that environment changes.

5. can we train our brains to become better sleepers?

Professor Badre believes that improving sleep adaptability requires understanding three interconnected biological factors.

"Sleep is a combination of three things. It's a result of sleep pressure. So that means one has to develop a sleep pressure in order to be able to fall asleep.

The second point is the biological clock. So we have the circadian rhythm, so there is a time where ... the gate of sleep is opening.

And the third point is a level of brain arousal.

So we have to combine these three things in order to be able to get the sleep adaptability. So feeling safe, relaxed, and confident that sleep will come is just as important as the physical environment."

— Associate Professor Gaby Badre

These three factors are sleep pressure, circadian rhythm and brain arousal.

Even when someone has accumulated sufficient sleep pressure and their biological clock is aligned with bedtime, heightened brain arousal can interfere with falling asleep.

Professor Badre therefore encourages us to think beyond conventional sleep hygiene.

"Don't think so much about sleep hygiene, think about sleep adaptability. How can I make my brain more adaptable? Think about that."

— Associate Professor Gaby Badre

Rather than trying to control every detail of our surroundings, his approach focuses on understanding and supporting the biological systems that regulate sleep.

6. what happens in the nervous system when we're trying to fall asleep?

Professor Badre explains that the autonomic nervous system plays an important role in regulating our levels of alertness.

"Everything which triggers the sympatheticus makes you more alert. That's why we try to instead slow down the sympatheticus and ... impact the parasympatheticus, which is the second branch of the autonomic nervous system.

And that's why, for instance, what we are using can be aroma, it can be anything else.

We try to see whether we can address the parasympatheticus to slow down and to avoid this increase of alertness."

— Associate Professor Gaby Badre

The autonomic nervous system has two important branches: the sympathetic nervous system, associated with alertness and the fight-or-flight response, and the parasympathetic nervous system, which supports rest and restorative processes.

Professor Badre's explanation highlights why reducing excessive arousal is important when preparing for sleep.

He also discusses how sensory inputs, including aroma, can be investigated for their potential to influence these physiological responses.

The aim is not to eliminate alertness entirely, but to create conditions in which the brain and body can move more naturally towards sleep.

7. can fragrance and sensory cues help us prepare for sleep?

Professor Badre explains that sleep is influenced by a combination of environmental and biological factors, rather than one perfect condition.

"It's not only a good bed, it's not only a nice temperature, it's a combination of many things. And what we call the multi-sensory stimulation.

If we have the ability to stimulate in a positive way, we can get an interesting result, and we can promote sleep, considering again that we respect the circadian rhythm when it's time to go to bed, we have a sleep pressure, and... the cues are helping us to decrease the brain arousal."

— Associate Professor Gaby Badre

He describes multisensory stimulation as the combined influence of sensory inputs such as aroma, light, sound and temperature.

These inputs can affect how alert or relaxed we feel, making them relevant to the transition from wakefulness to sleep.

However, Professor Badre is clear that sensory cues must work alongside the body's underlying sleep mechanisms.

A calming fragrance or familiar bedtime environment cannot replace the need for sufficient sleep pressure or appropriate circadian timing.

This relationship between sensory inputs and brain arousal is central to This Works' approach to Functional Fragrance and sensory care.

8. can trying too hard to sleep actually keep us awake?

One of Professor Badre's most distinctive pieces of advice is to avoid putting pressure on ourselves to fall asleep.

"I tell my patients, 'Don't stress yourself when you're in bed to try to fall asleep.' Having to make exercise, to breathe, to meditate, et cetera... don't pressure yourself because if you stress yourself to do that, there is a risk that you increase your alertness."

— Associate Professor Gaby Badre

He explains that even activities intended to encourage relaxation can become counterproductive if we begin to treat them as obligations.

"You need to have a period when you can really relax. Forget the word 'I must.'

And in bed also, avoid the musts in bed."

— Associate Professor Gaby Badre

This reflects the relationship between sleep and brain arousal.

When we become preoccupied with falling asleep, we may increase the very alertness that makes sleep difficult.

Professor Badre's advice is to avoid turning bedtime into another task to complete. Relaxation should help us disengage from the demands of the day, rather than creating additional pressure.

9. why do I feel sleepy on the sofa but wide awake when I get into bed?

Professor Badre explains that even brief periods of dozing can reduce the sleep pressure we have accumulated throughout the day.

"You have a lot of people watching the TV in the evening, and it's a dim light. The programme is perhaps not the most interesting.

They doze a little bit, and then they wake up, and then when it's time to go to bed, they're not sleepy. Their sleep pressure disappears.

I always compare that to if you eat small snacks all the time, you're not hungry when it's time to get your dinner.

The same thing, if you are getting the small, short sleep, not even sleeping, just dozing in front of the TV once or twice, then of course you will not have the sleep pressure at night."

— Associate Professor Gaby Badre

He also highlights how the activities we complete between feeling sleepy and actually getting into bed can interfere with that natural opportunity for sleep.

"If you watch the TV and you say, 'Well, now I'm sleepy, I'm going to bed', but you have to brush your teeth, you have to prepare your clothes for the next day, et cetera, that takes you about 20, 25 minutes.

Then you're on your way up and you go to bed and you're not sleepy."

— Associate Professor Gaby Badre

His practical recommendation is to prepare for bed before becoming sleepy, so that when sleepiness arrives, we can respond to it without unnecessary stimulation.

10. how important is a consistent sleep routine?

Professor Badre places considerable importance on regularity, explaining that sleep is part of a wider biological rhythm.

"We have a rhythm, and we should not forget that sleep is part of the rhythm. So it's very, very important to keep a regular rhythm."

— Associate Professor Gaby Badre

He also explains why maintaining a consistent schedule can be beneficial even when our lifestyle requires unusual sleeping hours.

"If you are a disc jockey, of course, you cannot go to bed at 11:00.

But you have to try, and as long as you keep the same rhythm, you can cope with that. The problem would be if you are changing... the social jet lag."

— Associate Professor Gaby Badre

His point is that regularity matters, even when someone's schedule differs from conventional working hours.

Our circadian rhythm helps regulate the timing of sleep and wakefulness. Frequent changes can interfere with the alignment between our internal biological clock and accumulated sleep pressure.

For Professor Badre, consistency is therefore one of the most useful foundations for supporting sleep.

11. can sleeping in at the weekend make monday mornings harder?

Professor Badre describes how differences between weekday and weekend sleep schedules can create a phenomenon known as social jet lag.

"They go to bed at 11 o'clock. They have to wake up at six o'clock... That gives them seven hours, six and a half hours.

So they have a lack of sleep perhaps half an hour on Monday to Tuesday. Tuesday or Wednesday is some other half an hour, et cetera, up to Friday.

Then Friday is a big evening, so we enjoy life... they want to recover during the weekend, and they sleep till 12, 1 o'clock.

But then on Sunday... tomorrow we have a working day. So they have to go to bed early.

So what's that? They are flying to New York every week, and coming back. Definitely. They have a sort of jet lag."

— Associate Professor Gaby Badre

Social jet lag occurs when our sleep schedules are repeatedly shifted by the difference between our biological rhythms and social commitments.

Professor Badre explains that these changes can affect how easily we return to our normal routine at the beginning of the working week.

His advice is to maintain as much consistency as possible and avoid repeatedly making large changes to sleeping and waking times.

12. can daytime naps affect how well i sleep at night?

Professor Badre explains that naps influence the homeostatic sleep system by reducing accumulated sleep pressure.

"This is my problem with my patients, and this is a problem with elderly people, for instance.

When they fall asleep during the day, they take a lot of naps.

Even short sleep, they remove the sleep pressure. So when it's time to go to bed, there is no more sleep pressure."

— Associate Professor Gaby Badre

However, he does not suggest that all daytime sleep should be avoided.

When discussing sleep adaptability, he explains that short naps can be useful in certain circumstances, particularly after insufficient nighttime sleep.

"If you sleep only five hours a night for a period, okay, try to compensate during daytime, but before 2:00 p.m. in order not to impede on your night sleep.

... It's better to have 20 minutes."

— Associate Professor Gaby Badre

His advice highlights the importance of timing, duration and individual circumstances.

For someone struggling to fall asleep at night, repeated or late naps may reduce the sleep pressure they need at bedtime. For someone recovering from an occasional short night, a brief early nap may be helpful.

13. can eating late affect my sleep?

Professor Badre explains that digestion is an important consideration when preparing for sleep.

"Depending if you take your dinner late in the evening, what's happening? There are many things happening.

First, you are distending your stomach, so you can have some problem digesting. You'll have some gas. You will have perhaps some acidity, et cetera.

So the time, you have to have a time for when you eat, and it has to be a regular time, as well as your time when you go to bed."

— Associate Professor Gaby Badre

He also discusses how the timing and content of evening meals can affect comfort during the night.

"You have to consider at what time you eat, it has to be very regular, what do you eat?

And of course, if you drink some alcohol, alcohol can help you fall asleep, but at the same time... you will get dehydration... or you'll have to go to the loo.

So you have to consider all that regarding your evening meal. So I usually recommend to my patients to eat at least three or four hours before going to bed."

— Associate Professor Gaby Badre

His recommendation reflects the relationship between digestive comfort, regular biological rhythms and sleep.

A late or substantial meal may cause discomfort that interferes with rest, while alcohol can disrupt sleep despite sometimes making it easier to fall asleep initially.

14. what is the connection between gut health and sleep?

Professor Badre explains that the gastrointestinal system and the brain are closely connected through the nervous system.

"There is a very close communication between the brain and the autonomic nervous system and the gastrointestinal system.

We know that the cells in the gastrointestinal system can release Serotonin, which is a neurotransmitter.

We know the microbiome is very active. I used to tell my patients that you have to consider your body as a hotel with a million guests, and they have to be happy. If they're not happy, they complain."

— Associate Professor Gaby Badre

He highlights the vagus nerve as an important communication pathway between the brain and internal organs.

"We have the longest nerve in our body, which is called the vagus nerve, comes from the brain... especially [to] the gastrointestinal system.

And if our guts are unhappy, they release substances which are taken from this vagus nerve to the brain and can impact the brain.

... And reversible also. If your brain is tired, it can send signals through the vagus nerve to the gastrointestinal and make you uncomfortable.

That's why we have many patients who have insomnia and IBS at the same time."

— Associate Professor Gaby Badre

This two-way communication is known as the gut–brain axis.

Professor Badre's clinical observations highlight why digestive symptoms, stress and sleep difficulties may need to be considered together.

Although the gut produces Serotonin, this does not mean that gut-derived Serotonin directly enters the brain. The relationship involves several interconnected neural, hormonal and immune pathways.

15. what's the difference between deep sleep and REM sleep?

Professor Badre explains that sleep is made up of different stages, each associated with distinct patterns of brain activity.

"When you sleep, you go through different stages. You have the light sleep, you enter into deeper, and then deep sleep.

And finally, you get what you call the dream sleep, or REM, rapid eye movement.

Deep sleep should dominate in the first half of the night, while REM sleep or dream sleep should dominate in the second part of the night."

— Associate Professor Gaby Badre

Deep sleep is a stage of non-rapid eye movement (NREM) sleep, while REM sleep is associated with distinctive brain activity, rapid eye movements and vivid dreaming.

Professor Badre highlights that the distribution of these stages changes throughout the night.

This is why sleep quality involves more than the total number of hours spent in bed.

Understanding the different stages, and how they are distributed, can help clinicians investigate sleep difficulties and assess whether normal sleep architecture is being maintained.

16. how do neuroscientists measure sleep quality?

Professor Badre explains that scientists can investigate sleep through objective measurements of brain activity and other physiological signals.

"We have been using EEG, for instance. EEG is electrical activity of the brain.

We know that when you sleep, you go through different stages. You have the light sleep, you enter into deeper, and then deep sleep. And finally, you get what you call the dream sleep or REM, rapid eye movement.

... EEG, which looks at the electrical activity of the brain, we try to differentiate the different parts and to see how the medication or how what we are doing would address that."

— Associate Professor Gaby Badre

EEG, or electroencephalography, records electrical activity in the brain and helps identify different sleep stages.

Professor Badre also discusses polysomnography, a more comprehensive clinical assessment that combines EEG with measurements such as eye movements and muscle activity.

These techniques can help specialists investigate sleep architecture and conditions such as sleep apnoea.

For Professor Badre, objective measurements are valuable because they allow researchers to investigate what is happening during sleep, rather than relying exclusively on how someone remembers or perceives their night.

17. can keeping a sleep diary help me understand my sleep?

Professor Badre explains that sleep diaries are an important part of his clinical approach to assessing sleep difficulties.

"I always give them a sleep diary to fill in during the two weeks, including the weekends, because the weekends are very important to see how they are, if they try to recover during the weekend."

— Associate Professor Gaby Badre

He describes how patterns of sleep deprivation can build throughout the working week before being followed by attempts to compensate at the weekend.

"They have a tendency to develop every night a sleep deprivation, one hour perhaps.

... Then Friday is a big evening, so we enjoy life.

... They want to recover during the weekend, and they sleep till 12, 1 o'clock."

— Associate Professor Gaby Badre

By recording sleep patterns across both weekdays and weekends, a sleep diary can reveal inconsistencies that may otherwise go unnoticed.

For Professor Badre, this information helps establish whether changes in sleep timing, accumulated sleep debt or other patterns could be contributing to a patient's difficulties.

18. what is chronic insomnia, and what happens in the brain?

Professor Badre explains that an occasional bad night's sleep is not the same as chronic insomnia.

"Everybody can get from time to time a bad sleep due to the circumstances, and this is not chronic insomnia.

... You have to have three times a week that you have a sleeping disorder.

And what kind of sleeping disorder? Difficulty in falling asleep, difficulty in maintaining sleep, waking up too early, or not feeling recovered during the day.

So you have to have that three times a week during three months."

— Associate Professor Gaby Badre

Chronic insomnia generally involves persistent difficulty initiating or maintaining sleep, despite adequate opportunity, with an impact on daytime functioning.

Professor Badre also explains that insomnia can involve heightened activity in the brain and nervous system.

"Today, we think it's a hyperarousal... condition. There is a cerebral arousal and the autonomic nervous system arousal.

The autonomic nervous system is our nerve system which addresses our fight or flight, our alertness, and our relaxing.

So insomnia is a hyperarousal system."

— Associate Professor Gaby Badre

He also highlights the hypothalamic–pituitary–adrenal (HPA) axis, which helps regulate the body's stress response and Cortisol production.

These systems interact with the biological mechanisms governing sleep, helping explain why someone experiencing chronic insomnia may remain highly alert despite feeling exhausted.

19. why do I keep waking up at 3am?

Professor Badre explains that waking during the night is not necessarily abnormal. As sleep progresses, the distribution of sleep stages changes and sleep can become lighter.

"If they are waking up quite often, I always ask, 'Is it within three, four hours or within one or two hours?'

If they tell me that it is within three, four hours, I feel more comfortable because it means that they got their deep sleep.

The sleep is getting shallower and shallower the longer you sleep."

— Associate Professor Gaby Badre

He also discusses how becoming alert after waking can make returning to sleep more difficult.

"If you wake up at 3:00 in the morning... what I advise is go to the loo, drink some cold water, don't put on the light.

Come back to your bed, turn up the pillow, it gets fresh, and try to fall asleep.

If you leave the bed and start watching TV or reading, you increase your alertness, you wake up completely."

— Associate Professor Gaby Badre

Professor Badre's personal clinical advice is to avoid unnecessary stimulation and allow the brain another opportunity to return to sleep.

He also suggests redirecting attention towards a recent, neutral experience rather than beginning to solve problems in the middle of the night.

"Give something trivial to the brain, but interesting. Nothing to do with yourself."

— Associate Professor Gaby Badre

His approach differs from some standard CBT-I stimulus-control recommendations, which may advise leaving the bed after prolonged wakefulness. The appropriate strategy can depend on the individual and whether chronic insomnia is present.

Importantly, waking at 3am does not automatically indicate an abnormal Cortisol spike, even though the body's stress-response systems can influence sleep.

20. how is chronic insomnia treated?

Professor Badre explains that chronic insomnia should be assessed in the context of the patient's wider health, rather than being treated as an isolated difficulty with sleeping.

He describes the three Ps of insomnia: predisposing, precipitating and perpetuating factors.

"The first P is if you have a predisposition to develop a sleeping problem. And predisposition can be a genetic predisposition.

... The second P is a precipitating factor, anything which happened during their life

... It could be a divorce, it could be a bankruptcy, it could be a disease, it could be a circadian dysrhythmia.

... The problem comes when the third P is appearing, a perpetuating factor.

So something which should have disappeared after a while still continues, and you are entering into a circle."

— Associate Professor Gaby Badre

He explains that recognising these factors is central to his clinical assessment.

"When I have a patient just coming to see me, I am spending at least one hour with them trying to recognise the three Ps."

— Associate Professor Gaby Badre

Professor Badre also discusses cognitive behavioural therapy for insomnia (CBT-I) and the role medication may play in selected cases.

"When you have someone coming with chronic insomnia, you have to see what's the best approach.

Medication is useful just to stop the process perhaps. But it's not enough.

What we call CBT or CBT-I, I for insomnia, is a very good approach ... Combining both of them brings a very good result."

— Associate Professor Gaby Badre

He emphasises the need to investigate underlying medical conditions, including hormonal disorders and other potential causes of insomnia.

"Before talking about CBT-I or anything else, we have to rule out any condition which could trigger insomnia."

— Associate Professor Gaby Badre

CBT-I is generally recommended as a first-line treatment for chronic insomnia in adults. Medication decisions require individual clinical assessment and are not necessary or appropriate for everyone.

21. what is Functional Fragrance, and how can scent influence the brain?

Professor Badre explains that our sense of smell has a particularly close relationship with brain systems involved in emotion and memory.

"Aroma is very interesting because the sense of smell is completely different [from] all the other senses.

First, most of the senses have to go through a relay, which is the thalamus, whereas the sense of smell goes directly from the nose to the brain, especially to what we call the limbic system, the area which is responsible for emotion, for memory, et cetera."

— Associate Professor Gaby Badre

He explains that our responses to aroma are influenced by the relationship between smell, memory and previous experience.

"It goes directly to the limbic system, the emotional part, which, based on the memory that you acquire before, tries to analyse the type of smell that we are receiving.

... Then they activate the limbic system, and here they activate the centres of memories and emotion."

— Associate Professor Gaby Badre

This is why aroma is of particular interest when investigating how sensory inputs can influence emotional and physiological responses.

Professor Badre also discusses the field of aromachology, which examines the psychological and physiological effects of scent.

"There are functional aromas, what we call aromachology. So aroma is very efficient if it's used in the right way for the right person."

— Associate Professor Gaby Badre

At This Works, Functional Fragrance refers to the intentional use of aroma as part of sensory rituals designed to support a particular experience, such as preparing for sleep.

Professor Badre's research explores how these sensory inputs may influence brain activity and nervous system responses, while recognising that the effects depend on the fragrance, the individual and the conditions in which it is used.

22. can using the same fragrance every night train the brain to recognise bedtime?

Professor Badre explains that the brain can learn to associate a particular aroma with a repeated experience or situation.

"There is a conditioning situation. You associate the aroma with a certain situation, and that has an effect, an impact."

— Associate Professor Gaby Badre

This process is known as associative learning or conditioning.

When a fragrance is repeatedly paired with a particular environment or behaviour, the brain may begin to recognise that aroma as a familiar cue.

Professor Badre discusses this in the context of exploring non-pharmacological approaches to supporting sleep.

"We are using and testing today different non-pharmacological systems to help people who have difficulty with insomnia.

... We are looking for different things which can help. And very often a small thing can help a lot."

— Associate Professor Gaby Badre

During the podcast, Dr Anna Persaud builds on this explanation by discussing how aroma can be paired with behavioural and environmental changes, such as reducing stimulation, dimming the lights and establishing a consistent evening ritual.

The underlying principle is that repeated sensory experiences may become associated with relaxation and the transition towards bedtime.

This is the thinking behind incorporating Functional Fragrance into a consistent sleep routine.

However, a familiar fragrance cue is not a substitute for clinical treatment of chronic insomnia, and conditioning alone does not guarantee improved sleep.

23. how do scientists measure whether a fragrance affects the brain?

Professor Badre explains that scientific research can investigate how aromas affect brain activity and the autonomic nervous system.

"What we wanted to see first, we wanted to look at the impact of [the] autonomic nervous system first.

If we can, with aroma, say whether we can increase the activity of the parasympathetic system versus the sympathetic, which is another test.

... But the most interesting approach is to see whether we can have an impact on the brain directly and where in the brain."

— Associate Professor Gaby Badre

He discusses the use of functional magnetic resonance imaging (fMRI), a technique that measures changes in blood oxygenation associated with brain activity.

"We have been using a functional... [magnetic resonance technique]... In this case, we use what we call an olfactometer to push an aroma and see ... which part of the brain [is] activated by that.

... We want to see where does the aroma act first, at which level, and which connectome [is] activated."

— Associate Professor Gaby Badre

A connectome refers to the network of connections between different regions of the brain.

Professor Badre explains that researchers are interested not only in which brain regions respond to aroma, but also in how those regions interact.

He also describes the importance of comparing fragrance exposure with appropriate controls.

"We used three approaches: a puff of air, a placebo... and the different products that we wanted to test.

... By looking at these three different things, we can differentiate whether... receiving the smell would activate... some other nerves... or whether it activates the same area of the brain."

— Associate Professor Gaby Badre

Professor Badre acknowledges that there is still more to understand about the precise mechanisms involved.

"When I was a bit sceptical in the beginning when I started with you for many years about the impact of aroma, today I know that they have an impact. But how and what... we have to still look around that."

— Associate Professor Gaby Badre

This distinction is important. Neuroscientific techniques can demonstrate measurable responses to fragrance, but changes in brain activity do not automatically establish a clinical improvement in sleep.

Research into Functional Fragrance therefore requires careful interpretation of the methods used, the outcomes measured and the conclusions supported by the results.