| 1. |
- Oddo, Calogero M., et al.
(författare)
-
Artificial spatiotemporal touch inputs reveal complementary decoding in neocortical neurons
- 2017
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 8
-
Tidskriftsartikel (refereegranskat)abstract
- Investigations of the mechanisms of touch perception and decoding has been hampered by difficulties in achieving invariant patterns of skin sensor activation. To obtain reproducible spatiotemporal patterns of activation of sensory afferents, we used an artificial fingertip equipped with an array of neuromorphic sensors. The artificial fingertip was used to transduce real-world haptic stimuli into spatiotemporal patterns of spikes. These spike patterns were delivered to the skin afferents of the second digit of rats via an array of stimulation electrodes. Combined with low-noise intra-and extracellular recordings from neocortical neurons in vivo, this approach provided a previously inaccessible high resolution analysis of the representation of tactile information in the neocortical neuronal circuitry. The results indicate high information content in individual neurons and reveal multiple novel neuronal tactile coding features such as heterogeneous and complementary spatiotemporal input selectivity also between neighboring neurons. Such neuronal heterogeneity and complementariness can potentially support a very high decoding capacity in a limited population of neurons. Our results also indicate a potential neuroprosthetic approach to communicate with the brain at a very high resolution and provide a potential novel solution for evaluating the degree or state of neurological disease in animal models.
|
|
| 2. |
- Enander, Jonas M.D., et al.
(författare)
-
Ubiquitous neocortical decoding of tactile input patterns
- 2019
-
Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- Whereas functional localization historically has been a key concept in neuroscience, direct neuronal recordings show that input of a particular modality can be recorded well outside its primary receiving areas in the neocortex. Here, we wanted to explore if such spatially unbounded inputs potentially contain any information about the quality of the input received. We utilized a recently introduced approach to study the neuronal decoding capacity at a high resolution by delivering a set of electrical, highly reproducible spatiotemporal tactile afferent activation patterns to the skin of the contralateral second digit of the forepaw of the anesthetized rat. Surprisingly, we found that neurons in all areas recorded from, across all cortical depths tested, could decode the tactile input patterns, including neurons of the primary visual cortex. Within both somatosensory and visual cortical areas, the combined decoding accuracy of a population of neurons was higher than for the best performing single neuron within the respective area. Such cooperative decoding indicates that not only did individual neurons decode the input, they also did so by generating responses with different temporal profiles compared to other neurons, which suggests that each neuron could have unique contributions to the tactile information processing. These findings suggest that tactile processing in principle could be globally distributed in the neocortex, possibly for comparison with internal expectations and disambiguation processes relying on other modalities.
|
|
| 3. |
- Olstrup, Henrik, et al.
(författare)
-
Trends in air pollutants and health impacts in three Swedish cities over the past three decades
- 2018
-
Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 18:21, s. 15705-15723
-
Tidskriftsartikel (refereegranskat)abstract
- Air pollution concentrations have been decreasing in many cities in the developed countries. We have estimated time trends and health effects associated with exposure to NOx, NO2, O-3, and PM10 (particulate matter) in the Swedish cities Stockholm, Gothenburg, and Malmo from the 1990s to 2015. Trend analyses of concentrations have been performed by using the Mann-Kendall test and the Theil-Sen method. Measured concentrations are from central monitoring stations representing urban background levels, and they are assumed to indicate changes in long-term exposure to the population. However, corrections for population exposure have been performed for NOx, O-3, and PM10 in Stockholm, and for NOx in Gothenburg. For NOx and PM10, the concentrations at the central monitoring stations are shown to overestimate exposure when compared to dispersion model calculations of spatially resolved, population-weighted exposure concentrations, while the reverse applies to O-3. The trends are very different for the pollutants that are studied; NOx and NO2 have been decreasing in all cities, O-3 exhibits an increasing trend in all cities, and for PM10, there is a slowly decreasing trend in Stockholm, a slowly increasing trend in Gothenburg, and no significant trend in Malmo. Trends associated with NOx and NO2 are mainly attributed to local emis-sion reductions from traffic. Long-range transport and local emissions from road traffic (non-exhaust PM emissions) and residential wood combustion are the main sources of PM10. For O-3, the trends are affected by long-range transport, and there is a net removal of O-3 in the cities. The increasing trends are attributed to decreased net removal, as NOx emissions have been reduced. Health effects in terms of changes in life expectancy are calculated based on the trends in exposure to NOx, NO2, O-3, and PM10 and the relative risks associated with exposure to these pollutants. The decreased levels of NO x are estimated to increase the life expectancy by up to 11 months for Stockholm and 12 months for Gothenburg. This corresponds to up to one-fifth of the total increase in life expectancy (5470 months) in the cities during the period of 1990-2015. Since the increased concentrations in O-3 have a relatively small impact on the changes in life expectancy, the overall net effect is increased life expectancies in the cities that have been studied.
|
|
| 4. |
- Rongala, Udaya B., et al.
(författare)
-
Intracellular dynamics in cuneate nucleus neurons support self-stabilizing learning of generalizable tactile representations
- 2018
-
Ingår i: Frontiers in Cellular Neuroscience. - : Frontiers Media SA. - 1662-5102. ; 12
-
Tidskriftsartikel (refereegranskat)abstract
- How the brain represents the external world is an unresolved issue for neuroscience, which could provide fundamental insights into brain circuitry operation and solutions for artificial intelligence and robotics. The neurons of the cuneate nucleus form the first interface for the sense of touch in the brain. They were previously shown to have a highly skewed synaptic weight distribution for tactile primary afferent inputs, suggesting that their connectivity is strongly shaped by learning. Here we first characterized the intracellular dynamics and inhibitory synaptic inputs of cuneate neurons in vivo and modeled their integration of tactile sensory inputs. We then replaced the tactile inputs with input from a sensorized bionic fingertip and modeled the learning-induced representations that emerged from varied sensory experiences. The model reproduced both the intrinsic membrane dynamics and the synaptic weight distributions observed in cuneate neurons in vivo. In terms of higher level model properties, individual cuneate neurons learnt to identify specific sets of correlated sensors, which at the population level resulted in a decomposition of the sensor space into its recurring high-dimensional components. Such vector components could be applied to identify both past and novel sensory experiences and likely correspond to the fundamental haptic input features these neurons encode in vivo. In addition, we show that the cuneate learning architecture is robust to a wide range of intrinsic parameter settings due to the neuronal intrinsic dynamics. Therefore, the architecture is a potentially generic solution for forming versatile representations of the external world in different sensor systems.
|
|
