Nav: Home

Thalamus and cerebral cortex interactions influence the decision on sensory perceptions

April 01, 2019

When we receive a stimulus, sensory information is transmitted by the afferent nerves to the thalamus which in turn, like a relay, forwards the information to the sensory cortex to process it and consciously perceive the stimulus. But, does this information travel only in the thalamus-cortex direction? And, is this 'journey' a determining factor in the subsequent conscious perception of this stimulus?

To answer these questions, a study carried out between the Center for Brain and Cognition (CBC) of the Department of Information and Communication Technologies (DTIC) at UPF, and the Cellular Neurophysiology Group of the Autonomous University of Mexico, has determined the influence that functional interactions between the neurons in the thalamus and the sensory cortex have on the sensory perception of tactile stimuli. The authors published their work on 25 March in Proceedings of the National Academy of Sciences.

For the experiment, simultaneous recordings of neuron stimuli were taken and vibrotactile stimuli were used

For the experimental phase of the study, the researchers recorded the neural activity of two monkeys within the same receptive field of the ventral posterolateral nucleus of the thalamus and of the primary somatosensory area simultaneously, while the specimens performed a vibrotactile detection task. This task consisted of the random presentation of trials in which the animal received a tactile vibration of variable intensity on the hand and trials without vibration. At the end of each trial, the animal had to indicate the presence or absence of the stimulus by pressing a button. To dissociate sensory representation and decision phenomena, the recordings are repeated during a control task, in which the monkeys received the same pattern of stimulation, but did not have to indicate their decision.

During these paradigms, the researchers used 84 simultaneous pairs of neurons and over 10,000 trials to estimate the directional interdependencies established between the activity of neurons (action potential trains) in each area in each individual trial and how these interdependencies relate with experimental parameters such as the amplitude of the stimulus and the monkey's response.

"Feedforward" and "feedback" interactions between the thalamus and the cortex during sensory perception


The results show that during stimulus reception, the level of neuronal interactions in the thalamus-cortex direction ("feedforward") significantly increases, while this does not take place in the opposite direction ("feedback"). In addition, the authors show that the levels of "feedforward" interactions are statistically associated with the context of the task and the accurate perception of those stimuli that are at the subject's detection threshold". As the first author of the work, Adrià Tauste says, "hitherto it was known that these two areas (thalamus and primary somatosensory area) were essentially sensorial in that their neural activity represented information about stimuli, regardless of whether they were later detected by the subject or not. "We now know that the functional connections established by the neurons in each area in the thalamus-cortex direction may also determine the decision taken by the monkey on the existence of the tactile stimulation received".

The need to detect an existing stimulus synchronizes thalamus and cortex

In addition, the authors have identified a second type of interactions that are cognitively relevant, which express the simultaneous (not delayed) synchronization of the two sensory areas, and that they only manifest when the stimulus appears and this must be processed to determine its existence. In this regard, the authors Adrià Tauste and Gustavo Deco add: "these interactions may reflect the necessary participation of third cortical areas exerting a "top-down" influence in the two areas of the study, which shows that sensory perception is the result of a complex neural network from the time the sensory information reaches the brain".
-end-


Universitat Pompeu Fabra - Barcelona

Related Neurons Articles:

New tool to identify and control neurons
One of the big challenges in the Neuroscience field is to understand how connections and communications trigger our behavior.
Neurons that regenerate, neurons that die
In a new study published in Neuron, investigators report on a transcription factor that they have found that can help certain neurons regenerate, while simultaneously killing others.
How neurons use crowdsourcing to make decisions
When many individual neurons collect data, how do they reach a unanimous decision?
Neurons can learn temporal patterns
Individual neurons can learn not only single responses to a particular signal, but also a series of reactions at precisely timed intervals.
A turbo engine for tracing neurons
Putting a turbo engine into an old car gives it an entirely new life -- suddenly it can go further, faster.
Brain neurons help keep track of time
Turning the theory of how the human brain perceives time on its head, a novel analysis in mice reveals that dopamine neuron activity plays a key role in judgment of time, slowing down the internal clock.
During infancy, neurons are still finding their places
Researchers have identified a large population of previously unrecognized young neurons that migrate in the human brain during the first few months of life, contributing to the expansion of the frontal lobe, a region important for social behavior and executive function.
How many types of neurons are there in the brain?
For decades, scientists have struggled to develop a comprehensive census of cell types in the brain.
Molecular body guards for neurons
In the brain, patterns of neural activity are perfectly balanced.
Engineering researchers use laser to 'weld' neurons
University of Alberta researchers have developed a method of connecting neurons, using ultrashort laser pulses -- a breakthrough technique that opens the door to new medical research and treatment opportunities.

Related Neurons Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#532 A Class Conversation
This week we take a look at the sociology of class. What factors create and impact class? How do we try and study it? How does class play out differently in different countries like the US and the UK? How does it impact the political system? We talk with Daniel Laurison, Assistant Professor of Sociology at Swarthmore College and coauthor of the book "The Class Ceiling: Why it Pays to be Privileged", about class and its impacts on people and our systems.