German scientists design model to study how visual brain processes natural stimuli

German researchers have designed a new computational model to study how nerve cells in the visual cortex process natural stimuli, the University of Freiburg announced on Tuesday.

At any given moment, the neuronal circuits in the brain receive and process sensory information that permits human to perceive and interact with the environment. However, it remains unclear how the visual brain processes natural stimuli.

For decades, researchers have used simple artificial stimuli like moving bars to study the function of neuronal circuits in the visual system.

In recent years, natural stimuli from the perception of daily life have taken on an increasingly important role in neuroscientific experiments, according to the university.

Together with an international team of researchers, German neuroscientists from the Bernstein Center Freiburg have developed a new computational model that simulates how neurons in the visual cortex process sensory stimuli.

This model may help neuroscientists to better understand how neuronal networks in the visual system process natural stimuli.

"Studies revealed that the activity of neurons in the primary visual cortex was fundamentally different when they were exposed to artificial stimuli or to natural stimuli," said Jens Kremkow from the Bernstein Center Freiburg.

While artificial stimuli evoked strong but temporally variable neuronal responses, neuronal responses to natural stimuli were weak but temporally precise.

With the help of their model, Kremkow and his colleagues can now explain why the neuronal networks change their activity dynamics in these cases.

The distinctive neuronal responses may be the result of features commonly found in the pathways between the retina and the cortex. In particular, the precise interplay of excitatory and inhibitory synaptic inputs in the receptive fields of neurons in the visual cortex turned out to play a significant role, said the study.

Meanwhile, the so-called push-and-pull mechanism could also be applied to the neuronal processing of natural stimuli in other sensory systems.

The study has now been published in the journal Frontiers in Neural Circuits. Enditem