New study finds thalamus wakes the brain during development

October 11, 2018, George Washington University
Credit: CC0 Public Domain

Consciousness requires continuous, internally generated activity in the brain. The modulation of this activity is the basis of the electroencephalogram (EEG) and of generation of sleep, dreams, and perception. Achieving such activity is thus an important milestone in normal brain maturation, which occurs around birth. Successful transition to this activity indicates a good prognosis for babies born prematurely and/or suffering from damage to the brain.

To be functional as a dreaming, seeing, and thinking entity the need to achieve two milestones: continuity, which means that the brain is always active and state dependence, meaning is modulated by sleep, waking, and attention. The circuit mechanisms behind the of continuity and state dependence in the brain have remained unknown, but have been widely assumed to be located in the cerebral cortex, the convoluted brain structure responsible for thought and perception.

A team from the George Washington University (GW) has published a study in the Journal of Neuroscience suggesting instead that the thalamus, a tiny nucleus deep in the brain, actually controls the development of state dependence and continuity.

"Our results indicate that cellular changes in the thalamus relay function may be critical drivers for the maturation of background activity," Matthew Colonnese, Ph.D., associate professor of pharmacology and physiology at the GW School of Medicine and Health Sciences, said. "Humans undergo developmental transitions in brain activity before and near birth."

Drawing on previous work by Colonnese, his team used advanced techniques to record simultaneously from multiple brain regions to pinpoint the circuit change responsible for the acquisition of continuity and state dependence measured in the sensory cortex. They were surprised to learn that changes in the thalamus, rather than the local cortical circuitry or the interconnectivity of two structures, can explain most of these critical developmental milestones.

"From a clinical perspective, certain things can go wrong in birth, like hypoxic-ischemic encephalopathy, brain injury caused by lack of oxygen to the brain, and the brain can revert to a state of discontinuity or never develop continuity," said Colonnese. "These findings could help us understand the circuit basis of human EEG development to improve diagnosis and treatment of infants in vulnerable situations. By putting the development of the EEG on a mechanistic basis we hope to increase its utility in the clinic."

Colonnese and his team, which includes Yasunobu Murata, Ph.D., a research scientist in Colonnese's lab at GW and co-author of the study, are working to develop a comprehensive atlas of EEG patterns and brain lesions that cause them to aid in this process.

Now that they have established the thalamus is in control, he said, the next step is to further define what circuit changes occur in so clinicians can pinpoint from an EEG what's gone wrong in cases like hypoxic-ischemic encephalopathy.

The study, titled "Thalamus Controls Development and Expression of Arousal States in Visual Cortex" is published in the Journal of Neuroscience.

Explore further: New study finds 'amplifier' helps make connections in the fetal brain

More information: Yasunobu Murata et al, Thalamus Controls Development and Expression of Arousal States in Visual Cortex, The Journal of Neuroscience (2018). DOI: 10.1523/JNEUROSCI.1519-18.2018

Related Stories

New study finds 'amplifier' helps make connections in the fetal brain

October 11, 2016
Fetal brains use a special amplifier in order to transmit signals, according to research published in the journal eLife by George Washington University's (GW) Matthew Colonnese, Ph.D. and Yasunobu Murata, Ph.D. Early neural ...

Researcher develops mouse model for studying development of visual cortex

November 30, 2016
A day by day log of cortical electric activity in the mouse visual cortex was published in the Journal of Neuroscience by George Washington University (GW) researcher Matthew Colonnese, Ph.D. This research is the first to ...

Automated detection of focal epileptic seizures in a sentinel area of the human brain

August 17, 2018
Patients with focal epilepsy that does not respond to medications badly need alternative treatments.

How nature, nurture shape the sleeping brain

September 24, 2018
Some patterns of electrical activity generated by the brain during sleep are inherited, according to a study of teenage twins published in JNeurosci. Pinpointing the relative contributions of biology and experience to sleep ...

Deep sleep critical for visual learning

October 4, 2017
Remember those "Magic Eye" posters from the 1990s? You let your eyes relax, and out of the tessellating structures, a 3-D image of a dolphin or a yin yang or a shark would emerge.

Learning during development is regulated by an unexpected brain region

October 16, 2017
A half-century of research on how the brain learns to integrate visual inputs from the eyes has provided important insights in critical period regulation, leading to the conclusion that it occurs within the cortex. A group ...

Recommended for you

Research shows signalling mechanism in the brain shapes social aggression

October 19, 2018
Duke-NUS researchers have discovered that a growth factor protein, called brain-derived neurotrophic factor (BDNF), and its receptor, tropomyosin receptor kinase B (TrkB) affects social dominance in mice. The research has ...

Good spatial memory? You're likely to be good at identifying smells too

October 19, 2018
People who have better spatial memory are also better at identifying odors, according to a study published this week in Nature Communications. The study builds on a recent theory that the main reason that a sense of smell ...

How clutch molecules enable neuron migration

October 19, 2018
The brain can discriminate over 1 trillion odors. Once entering the nose, odor-related molecules activate olfactory neurons. Neuron signals first accumulate at the olfactory bulb before being passed on to activate the appropriate ...

Scientists discover the region of the brain that registers excitement over a preferred food option

October 19, 2018
At holiday buffets and potlucks, people make quick calculations about which dishes to try and how much to take of each. Johns Hopkins University neuroscientists have found a brain region that appears to be strongly connected ...

Gene plays critical role in noise-induced deafness

October 19, 2018
In experiments using mice, a team of UC San Francisco researchers has discovered a gene that plays an essential role in noise-induced deafness. Remarkably, by administering an experimental chemical—identified in a separate ...

Brain cells called astrocytes have unexpected role in brain 'plasticity'

October 18, 2018
When we're born, our brains have a great deal of flexibility. Having this flexibility to grow and change gives the immature brain the ability to adapt to new experiences and organize its interconnecting web of neural circuits. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.