A new study published in the online open access journal BMC Neuroscience, shows that, in monkeys, the region involved in hearing can directly improve perception in the visual region, without the involvement of other structures to integrate the senses.
Integration of sensory stimuli has traditionally been thought of as hierarchical, involving brain areas that receive signals from distinct areas of the brain layer known as the cortex that recognise different stimuli. But the recent finding of nerve cells projecting from the auditory cortex (associated with the perception of sound) directly into the visual cortex (associated with sight), suggest that perception of one sense might affect that of another without the involvement of higher brain areas.
“Auditory or visual–auditory responses in the primary visual cortex are highly probable given the presence of direct projections from the primary auditory cortex”, explain P. Barone and colleagues from the Centre for Brain and Cognition Research, Toulouse, France. “We looked for modulation of the neuronal visual responses in the primary visual cortex by auditory stimuli in an awake monkey.”
The researchers recorded the neuronal responses with microelectrodes inserted directly into the primary visual cortex of a rhesus macaque. The monkey was then required to orient its gaze towards a visual stimulus. The time taken for the neurons in the visual cortex to respond to the stimulus, or latency, was recorded. Barone and colleagues then measured the latency when the visual stimulus was accompanied by a sound emanating from the same spot. When the visual signal was strong—i.e., high contrast—the auditory stimulus did not affect latency; however, if the visual signal was weaker—i.e., low contrast—latency decreased by 5-10%, suggesting that in some way the auditory stimulus speeds up the response to the visual stimulus.
“Our findings show that single neurons from one primary sensory cortex can integrate information from another sensory modality”, the researchers claim. They propose that the auditory cue is processed more quickly than the visual stimulus, and because the monkeys have learned to associate that sound and sight, the visual cortex is primed to perceive the weaker signal. “Our results argue against a strict hierarchical model of sensory integration in the brain and that integration of multiple senses should be added to the list of functions of the primary visual cortex.”
Charlotte Webber | alfa
Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory
Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP
Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
09.12.2016 | Life Sciences
09.12.2016 | Ecology, The Environment and Conservation
09.12.2016 | Health and Medicine