There’s no shortage of apps and technology that claim to shift the brain into a “theta” state – said to help with relaxation, inward focus and sleep.

But what exactly does it mean to change one’s “mental state”? And is that even possible? For now, the evidence remains murky. But our understanding of the brain is growing exponentially as our methods of investigation improve.

Brain-measuring tech is evolving

Currently, no single approach to imaging or measuring brain activity gives us the whole picture. What we “see” in the brain depends on which tool we use to “look”. There are myriad ways to do this, but each one comes with trade-offs.

We learnt a lot about brain activity in the 1980s thanks to the advent of magnetic resonance imaging (MRI).

Eventually we invented “functional MRI”, which allows us to link brain activity with certain functions or behaviours in real time by measuring the brain’s use of oxygenated blood during a task.

We can also measure electrical activity using EEG (electroencephalography). This can accurately measure the timing of brain waves as they occur, but isn’t very accurate at identifying which specific areas of the brain they occur in.

Alternatively, we can measure the brain’s response to magnetic stimulation. This is very accurate in terms of area and timing, but only as long as it’s close to the surface.

What are brain states?

All of our simple and complex behaviours, as well as our cognition (thoughts) have a foundation in brain activity, or “neural activity”. Neurons – the brain’s nerve cells – communicate by a sequence of electrical impulses and chemical signals called “neurotransmitters”.

Neurons are very greedy for fuel from the blood and require a lot of support from companion cells. Hence, a lot of measurement of the site, amount and timing of brain activity is done via measuring electrical activity, neurotransmitter levels or blood flow.

We can consider this activity at three levels. The first is a single-cell level, wherein individual neurons communicate. But measurement at this level is difficult (laboratory-based) and provides a limited picture.

As such, we rely more on measurements done on a network level, where a series of neurons or networks are activated. Or, we measure whole-of-brain activity patterns which can incorporate one or more so-called “brain states”.

According to a recent definition, brain states are “recurring activity patterns distributed across the brain that emerge from physiological or cognitive processes”. These states are functionally relevant, which means they are related to behaviour.

Brain states involve the synchronisation of different brain regions, something that’s been most readily observed in animal models, usually rodents. Only now are we starting to see some evidence in human studies.

Various kinds of states

The most commonly-studied brain states in both rodents and humans are states of “arousal” and “resting”. You can picture these as various levels of alertness.

Studies show environmental factors and activity influence our brain states. Activities or environments with high cognitive demands drive “attentional” brain states (so-called task-induced brain states) with increased connectivity. Examples of task-induced brain states include complex behaviours such as reward anticipation, mood, hunger and so on.

In contrast, a brain state such as “mind-wandering” seems to be divorced from one’s environment and tasks. Dropping into daydreaming is, by definition, without connection to the real world.

We can’t currently disentangle multiple “states” that exist in the brain at any given time and place. As mentioned earlier, this is because of the trade-offs that come with recording spatial (brain region) versus temporal (timing) brain activity.

Brain states vs brain waves

Brain state work can be couched in terms such as alpha, delta and so forth. However, this is actually referring to brain waves which specifically come from measuring brain activity using EEG.

EEG picks up on changing electrical activity in the brain, which can be sorted into different frequencies (based on wavelength). Classically, these frequencies have had specific associations:

• gamma is linked with states or tasks that require more focused concentration
• beta is linked with higher anxiety and more active states, with attention often directed externally
• alpha is linked with being very relaxed, and passive attention (such as listening quietly but not engaging)
• theta is linked with deep relaxation and inward focus
• and delta is linked with deep sleep.

Brain wave patterns are used a lot to monitor sleep stages. When we fall asleep we go from drowsy, light attention that’s easily roused (alpha), to being relaxed and no longer alert (theta), to being deeply asleep (delta).

Can we control our brain states?

The question on many people’s minds is: can we judiciously and intentionally influence our brain states?

For now, it’s likely too simplistic to suggest we can do this, as the actual mechanisms that influence brain states remain hard to detangle. Nonetheless, researchers are investigating everything from the use of drugs, to environmental cues, to practising mindfulness, meditation and sensory manipulation.

Controversially, brain wave patterns are used in something called “neurofeedback” therapy. In these treatments, people are given feedback (such as visual or auditory) based on their brain wave activity and are then tasked with trying to maintain or change it. To stay in a required state they may be encouraged to control their thoughts, relax, or breathe in certain ways.

The applications of this work are predominantly around mental health, including for individuals who have experienced trauma, or who have difficulty self-regulating – which may manifest as poor attention or emotional turbulence.

However, although these techniques have intuitive appeal, they don’t account for the issue of multiple brain states being present at any given time. Overall, clinical studies have been largely inconclusive, and proponents of neurofeedback therapy remain frustrated by a lack of orthodox support.

Other forms of neurofeedback are delivered by MRI-generated data. Participants engaging in mental tasks are given signals based on their neural activity, which they use to try and “up-regulate” (activate) regions of the brain involved in positive emotions. This could, for instance, be useful for helping people with depression.

Another potential method claimed to purportedly change brain states involves different sensory inputs. Binaural beats are perhaps the most popular example, wherein two different wavelengths of sound are played in each ear. But the evidence for such techniques is similarly mixed.

Treatments such as neurofeedback therapy are often very costly, and their success likely relies as much on the therapeutic relationship than the actual therapy.

On the bright side, there’s no evidence these treatment do any harm – other than potentially delaying treatments which have been proven to be beneficial.

Susan Hillier, Professor: Neuroscience and Rehabilitation, University of South Australia

This article is republished from The Conversation under a Creative Commons license. Read the original article.

To recover from abuse or another traumatic experience, some people turn to a therapy called eye-movement desensitisation and reprocessing, or EMDR.

But this may present problems if these people pursue justice in the courts. In New South Wales, for instance, evidence obtained using EMDR can’t be used in a case unless it has been approved by the director (or deputy) of public prosecutions.

Prosecutors are concerned that after EMDR, trauma memories can’t be relied on as valid testimony. This has resulted in court cases not proceeding.

But what does the evidence say?

What is EMDR?

EMDR is one of the common exposure-based treatments for post-traumatic stress disorder (PTSD).

This group of therapies – which encompass prolonged exposure, cognitive processing therapy, EMDR and other variants – all ask a patient to recall their trauma. The therapists integrates this information and aims to correct unhelpful thought patterns that may be prolonging their distress.

Each of these treatments is recommended in most international guidelines for treating PTSD.

EMDR is different from the other exposure-based therapies because the therapist also asks the patient to move their eyes in a rapid side-to-side movement. This will typically involve following the therapist’s fingers move back and forth.

Proponents of EMDR initially proposed eye movements triggered neural processes that help people better adjust to or process trauma memories. However, the actual role of eye movements has been subject to much debate.

Although the mechanism isn’t yet fully understood, the weight of evidence suggests eye movements may reduce distress while recounting trauma memories because it depletes our working memory capacity. This results in less focus on the negative emotions associated with the memory.

Where did concerns about EMDR affecting memories come from?

EMDR has been criticised for potentially distorting people’s memories of traumatic events dates since the 1990s when the treatment increased in popularity.

This was also a period when when a controversial movement of “recovered memory therapies” emerged. These were used to guide people to reconstruct memories that were purportedly “hidden” or “repressed”.

This involved therapists directing patients to focus attention on internal states, suspend reality and allow themselves to be guided by the therapist to recover so-called “repressed memories”, often of satanic or ritual abuse.

In the wake of this movement, many studies showed this sort of guided intervention could lead to false, or even implanted, memories.

At the same time, researchers were concerned about hypnotic techniques. During hypnosis, people could reconstruct false memories. They were particularly susceptible to misleading information and had stronger confidence in these memories.

For this reason, authorities around the world cautioned against using hypnosis in cases that may involve the person subsequently needing to give testimony in legal proceedings.

Some likened EMDR to hypnosis, others were sceptical of its claims

Some agencies and experts considered EMDR a hypnosis-like intervention because it focused the person’s attention on their internal state, promoted increased absorption in memories and actively guided memories.

Many also likened the finger waving in front of the patient’s face as inducing a hypnotic state.

Because EMDR guided patients to process memories in a way that made them less distressing, some concluded EMDR-elicited memories were comparably susceptible to distortion as hypnotically-induced memories.

This perception of EMDR at the time may also have been influenced by much initial scepticism of the therapy.

In the early period of its popularity, EMDR proponents made excessive claims of its success, such as being able to completely resolve trauma memories in a single session, despite the lack of evidence.

What does the evidence actually say?

It’s difficult to test the claim that EMDR increases the likelihood of false memories because you can’t readily study this in clinical settings.

Instead, researchers have used experimental designs in people without PTSD to determine if eye movements themselves are likely to lead to false memories. The results are mixed.

Multiple studies have shown eye movements can lead to false memories. One study showed healthy research participants a video of a car accident. Half the sample then used eye movements. Then all participants were read an eye-witness narrative that involved false information about the video.

This study found those who used eye movements were more susceptible to the misinformation. It seems this effect may occur because eye movements reduce the vividness and intensity of emotions in memories, thereby making them more susceptible to false memories.

However, other laboratory-based studies have not replicated this effect. One study using the same design found using eye movements didn’t make memory more likely, reduce correct memory details, or affect the vividness or emotional intensity of the memory.

What does this all mean?

EMDR is one of a suite of exposure-based treatments for PTSD that involve recounting trauma memories and integrating new information about the trauma. These appear to be key in helping people resolve their traumatic stress. Although EMDR is not better than other exposure-based treatment, it is as effective as the others.

Although some evidence points to eye movements making a person more susceptible to false memories, other studies do not find this. Importantly, these studies are not actually testing EMDR.

There is no direct evidence that EMDR leads to false memories, just as there is no evidence that prolonged exposure or other exposure-based treatments do. Singling EMDR out as being particularly susceptible to memory distortion doesn’t appear to be supported by the scientific evidence.

The position of legal authorities to not accept testimony following EMDR is therefore not justified and may deny trauma survivors the right to legal proceedings.

If this article has raised issues for you, or if you’re concerned about someone you know, call Lifeline on 13 11 14. The National Sexual Assault, Family and Domestic Violence Counselling Line – 1800 RESPECT (1800 737 732) – is also available 24/7 for any Australian who has experienced family violence or sexual assault.

Richard Bryant, Professor & Director of Traumatic Stress Clinic, UNSW Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.