- Scientists studied changes in brain region known as the ‘locus ceruleus’
- Area is mainly responsible for the body’s responses to panic and stress
- They found that a traumatic event could permanently increase its activity
- This could explain why it may take years to learn dates, but only seconds to develop post-traumatic stress disorder, from a shock or sudden event
The sound of just one gunshot can form permanent brain connections that increase a person’s ‘fight or flight’ response for life.
This is according to a US study that has modelled how a brain region known as the ‘locus ceruleus’ changes as a result of traumatic experience.
Researchers say this could explain why it may take years to learn dates in a history class but only seconds to develop post-traumatic stress disorder from a shock or sudden event.
The sound of just one gunshot can form permanent brain connections that increase a person’s ‘fight or flight’ response for life. This is according to a US study that has modelled how a brain region known as the ‘locus ceruleus’ permanently changes as a result of traumatic experience
The brain’s locus ceruleus helps to trigger the body’s ‘fight or flight’ response by flooding it with norepinephrine.
When this hormone spikes in the body, muscles tense, perspiration increases, pupils dilate and hearing becomes sharper.
NYU Langone Medical Center say they have been able to chemically stimulate biological pathways in the locus coeruleus to trigger the same response in rats.
Their findings, which appears in the journal Nature Neuroscience, provide an insight into how and where traumatising events stick in our minds.
Researchers say their study could explain why it may take years to learn dates in a history class but only seconds to develop post-traumatic stress disorder, from a shock or sudden event
‘Our study gives us deeper insight into the functions of the locus coeruleus as a powerful amplifier in the brain, controlling how and where the brain stores and transforms sudden, traumatising sounds and events into memories,’ says senior study investigator Dr Robert Froemke.
‘Our findings, if confirmed by future studies in animals and people, should help us better understand how to improve hearing and memory abilities in those suffering from hearing loss or possibly even Alzheimer’s disease, as well as how to alter or minimise memories involved in disorders like post-traumatic stress disorder.’
As part of the Froemke team’s four-year study, led by Dr Ana Raquel Martins, the researchers chemically stimulated the locus coeruleus in rats while simultaneously playing them a sound paired with a food reward.
After a two-week training period to make sure that the rats associated the sound with food, the same sound was played much more quietly.
The researchers recorded activity in the same regions of their brain, as well as in the auditory cortex area responsible for interpreting sounds.
They found that the locus coeruleus and auditory cortex still responded to the sound, even at nearly imperceptible levels, for the subsequent and remaining two weeks of the experiments.
However, chemically stimulating the locus coeruleus led to 100 per cent neural activity in the auditory cortex, even in the absence of the same triggering sounds.
Neural activity in the auditory cortex in response to the sounds was at least 10 times greater than when activity in the locus coeruleus was chemically suppressed.
According to Froemke, the results clearly demonstrate that the memory of the sound and its associated reward was encoded by the locus coeruleus.
This helped improve the rats’ ability to perceive the sound.
Froemke says he next plans to investigate how information is encoded within the locus coeruleus and to identify which cells are activated by cochlear implants and in animal models of PTSD.
He is also planning experiments to identify patterns formed in the locus coerelus during other behavioural events involving hearing, such as mothers responding to the cries and calls of their child.