Emmanuel Zarco - Academia.edu (original) (raw)

Papers by Emmanuel Zarco

. Alnas, and Ranulfo Romo. Functional properties of primate putamen though this was not tested du... more . Alnas, and Ranulfo Romo. Functional properties of primate putamen though this was not tested during a sensory task, recordings neurons during the categorization of tactile stimuli. J. Neurophysiol. of single neurons in the putamen have revealed somesthetic 77: 1132-1154, 1997. We used psychometric techniques and neuroinput (Alexander and DeLong 1985; Crutcher and DeLong physiological recordings to study the role of the putamen in somes-1984;. In addition to this input thetic perception. Four monkeys were trained to categorize the speed from SI cortex, bilateral input to the putamen from the priof moving tactile stimuli. Animals performed a task in which one of mary motor (MI) cortex and supplementary motor area two target switches had to be pressed with the right hand to indicate (SMA) has been demonstrated (Künzle 1975; whether the speed of probe movement across the glabrous skin of the left, restrained hand was low or high. During the task we recorded al. 1991). It has been shown that SMA neurons respond to the activity of neurons in the putamen contralateral (right) and ipsilatsomesthetic stimuli during a somesthetic categorization task eral (left) to the stimulated hand. We found different types of neuronal ). Interestingly, a portion of the SMA responses, all present in the right and left putamen. Some neurons neurons reflect in their activity the animal's decision during responded during the stimulus period, others responded during the the categorization task ). In the same hand-arm movement used to indicate categorization, and others retask, neurons of SI cortex contralateral to the stimulated sponded during both of these periods. The responses of many neurons hand respond to the tactile stimuli; however, their responses did not vary either with the speed of the stimuli or in relation to are independent of the categorization process (Romo et al. the categorization process. In contrast, neurons of a particular type 1996). responded differentially: their activity reflected whether the stimulus speed was low or high. These differential responses occurred during In view of these anatomic and neurophysiological results, the stimulus and hand-arm motion periods. A number of the nondifferwe decided to explore the possibility that the putamen is ential and differential neurons were studied when the same stimuli involved in processing somesthetic information. To this end, used in the categorization task were delivered passively. Few neurons we trained monkeys in a somesthetic task (Romo et al. with nondifferential discharges, and none of the differential neurons, 1996). Animals performed the task by pressing one of two responded in this condition. In a visually cued control task we studied push buttons with the right hand to indicate whether the the possibility that the differential responses were associated with the stimulus speed across the left, restrained hand was low or intention to press or with the trajectory of the hand to one of the high. Sensory performance was evaluated with psychometric target switches. In this condition, a light turned on instructed the animal which target switch to press for a reward. Very few neurons techniques, and motor responses were monitored by measurin both hemispheres maintained the differential responses observed ing the reaction time (RT) and movement time (MT). Beduring the categorization task. Those neurons that discharged seleccause of the bimanual nature of the task, we made the simplitively for low or high speeds were analyzed quantitatively to produce fying assumption that the right putamen (contralateral to a measure comparable with the psychometric function. The thresholds the stimulated hand), could be considered as ''sensory,'' of the resulting neurometric curves for the neuronal populations were whereas the left putamen (contralateral to the responding very similar to the psychometric thresholds. The activity of a large hand-arm), could be considered as ''motor.'' To demonstrate fraction of these neurons could be used to accurately predict whether the possible sensory input to the putamen, we analyzed the the stimulus speed was low or high. The results indicate that the putamen, both contralateral and ipsilateral to the stimulated hand, neuronal responses in terms of their response latencies and contains neurons that discharge in response to the somesthetic stimuli discharge rates associated with the somesthetic stimuli. We during the categorization task. Those neurons that respond irrespective also analyzed the correlations between the neuronal disof the stimulus speed appear to be involved in the general sensorimotor charges and the categorization process. We were particularly behavior of the animal during the execution of the task. The results interested in revealing any difference between the sensory suggest that the putamen may play a role in bimanual tasks. The and the motor putamen, and in exploring whether this region recording of neurons in the right and left putamen whose activities of the striatum is involved in the animal's decision. The correlate with the speed categories suggests that this region of the results indicate that there is neuronal activity in the putamen basal ganglia, in addition to its role in motor functions, is also involved in the animal's decision process. that is time locked to the somesthetic stimuli and that some of these neurons also discharge during the responding handarm motion. These neuronal responses were found in both I N T R O D U C T I O N hemispheres, suggesting a role in bimanual sensorimotor tasks. However, the most interesting finding was that the Anatomic studies have shown a cortical input to the putamen from the primary somatosensory (SI) cortex (Flaherty activity of neurons in the right and left putamen predicted 1132 0022-3077/97 $5.00

The discrete Anisotropic Radiative Transfer (DART) model, coupled with an adjusted version of the... more The discrete Anisotropic Radiative Transfer (DART) model, coupled with an adjusted version of the PROSPECT model, was used to retrieve total chlorophyll content (C ab ) of a complex Norway spruce (Picea abies (L.) Karst.) canopy from airborne hyperspectral data acquired at very high spatial resolution. The radiative transfer models were parameterized by using field measurements and observations collected from a young spruce stand growing at the permanent experimental site Bílý Kříž (the Moravian-Silesian Beskydy Mts., the Czech Republic, 18.53863°E, 49.50256°N, 936 m a.s.l.). A set of the hyperspectral images with a pixel-size of 0.4 m was acquired for the test site by an airborne AISA Eagle VNIR system in September 18 th , 2004. An operational canopy C ab estimation was carried out by means of a PROSPECT-DART inversion employing an artificial neural network (ANN) and a vegetation index ANCB 650-720 . Both retrieval approaches used continuum removed reflectance values of six AISA Eagle spectral bands located between 650 and 720 nm. The C ab inversion was only performed for direct sun exposed (sunlit) crown pixels in order to ensure a high quality (noiseless) reflectance signal. Results of both inversion approaches were similar, when validated against the ground measured C ab of nine Norway spruce crowns. Coefficients of determination (R 2 ) between ground truth and remote sensing C ab estimates were 0.78 and 0.76, respectively, with root mean square errors (RMSE) of 2.95 µg cm -2 for the ANN and 3.36 µg cm -2 for the ANCB 650-720 retrieval. The spatial patterns of C ab values estimated by both inversion methods were consistent with each other. About 80% of the C ab estimated values had an absolute difference smaller than 2 µg cm -2 .

Deberá entenderse por equipamiento urbano al conjunto de unidades físicas generadas tradicionalme... more Deberá entenderse por equipamiento urbano al conjunto de unidades físicas generadas tradicionalmente en el medio urbano, cuyo valor de uso es predominantemente público, donde se proporcionan servicios a la población.

. Alnas, and Ranulfo Romo. Functional properties of primate putamen though this was not tested du... more . Alnas, and Ranulfo Romo. Functional properties of primate putamen though this was not tested during a sensory task, recordings neurons during the categorization of tactile stimuli. J. Neurophysiol. of single neurons in the putamen have revealed somesthetic 77: 1132-1154, 1997. We used psychometric techniques and neuroinput (Alexander and DeLong 1985; Crutcher and DeLong physiological recordings to study the role of the putamen in somes-1984;. In addition to this input thetic perception. Four monkeys were trained to categorize the speed from SI cortex, bilateral input to the putamen from the priof moving tactile stimuli. Animals performed a task in which one of mary motor (MI) cortex and supplementary motor area two target switches had to be pressed with the right hand to indicate (SMA) has been demonstrated (Künzle 1975; whether the speed of probe movement across the glabrous skin of the left, restrained hand was low or high. During the task we recorded al. 1991). It has been shown that SMA neurons respond to the activity of neurons in the putamen contralateral (right) and ipsilatsomesthetic stimuli during a somesthetic categorization task eral (left) to the stimulated hand. We found different types of neuronal ). Interestingly, a portion of the SMA responses, all present in the right and left putamen. Some neurons neurons reflect in their activity the animal's decision during responded during the stimulus period, others responded during the the categorization task ). In the same hand-arm movement used to indicate categorization, and others retask, neurons of SI cortex contralateral to the stimulated sponded during both of these periods. The responses of many neurons hand respond to the tactile stimuli; however, their responses did not vary either with the speed of the stimuli or in relation to are independent of the categorization process (Romo et al. the categorization process. In contrast, neurons of a particular type 1996). responded differentially: their activity reflected whether the stimulus speed was low or high. These differential responses occurred during In view of these anatomic and neurophysiological results, the stimulus and hand-arm motion periods. A number of the nondifferwe decided to explore the possibility that the putamen is ential and differential neurons were studied when the same stimuli involved in processing somesthetic information. To this end, used in the categorization task were delivered passively. Few neurons we trained monkeys in a somesthetic task (Romo et al. with nondifferential discharges, and none of the differential neurons, 1996). Animals performed the task by pressing one of two responded in this condition. In a visually cued control task we studied push buttons with the right hand to indicate whether the the possibility that the differential responses were associated with the stimulus speed across the left, restrained hand was low or intention to press or with the trajectory of the hand to one of the high. Sensory performance was evaluated with psychometric target switches. In this condition, a light turned on instructed the animal which target switch to press for a reward. Very few neurons techniques, and motor responses were monitored by measurin both hemispheres maintained the differential responses observed ing the reaction time (RT) and movement time (MT). Beduring the categorization task. Those neurons that discharged seleccause of the bimanual nature of the task, we made the simplitively for low or high speeds were analyzed quantitatively to produce fying assumption that the right putamen (contralateral to a measure comparable with the psychometric function. The thresholds the stimulated hand), could be considered as ''sensory,'' of the resulting neurometric curves for the neuronal populations were whereas the left putamen (contralateral to the responding very similar to the psychometric thresholds. The activity of a large hand-arm), could be considered as ''motor.'' To demonstrate fraction of these neurons could be used to accurately predict whether the possible sensory input to the putamen, we analyzed the the stimulus speed was low or high. The results indicate that the putamen, both contralateral and ipsilateral to the stimulated hand, neuronal responses in terms of their response latencies and contains neurons that discharge in response to the somesthetic stimuli discharge rates associated with the somesthetic stimuli. We during the categorization task. Those neurons that respond irrespective also analyzed the correlations between the neuronal disof the stimulus speed appear to be involved in the general sensorimotor charges and the categorization process. We were particularly behavior of the animal during the execution of the task. The results interested in revealing any difference between the sensory suggest that the putamen may play a role in bimanual tasks. The and the motor putamen, and in exploring whether this region recording of neurons in the right and left putamen whose activities of the striatum is involved in the animal's decision. The correlate with the speed categories suggests that this region of the results indicate that there is neuronal activity in the putamen basal ganglia, in addition to its role in motor functions, is also involved in the animal's decision process. that is time locked to the somesthetic stimuli and that some of these neurons also discharge during the responding handarm motion. These neuronal responses were found in both I N T R O D U C T I O N hemispheres, suggesting a role in bimanual sensorimotor tasks. However, the most interesting finding was that the Anatomic studies have shown a cortical input to the putamen from the primary somatosensory (SI) cortex (Flaherty activity of neurons in the right and left putamen predicted 1132 0022-3077/97 $5.00

The discrete Anisotropic Radiative Transfer (DART) model, coupled with an adjusted version of the... more The discrete Anisotropic Radiative Transfer (DART) model, coupled with an adjusted version of the PROSPECT model, was used to retrieve total chlorophyll content (C ab ) of a complex Norway spruce (Picea abies (L.) Karst.) canopy from airborne hyperspectral data acquired at very high spatial resolution. The radiative transfer models were parameterized by using field measurements and observations collected from a young spruce stand growing at the permanent experimental site Bílý Kříž (the Moravian-Silesian Beskydy Mts., the Czech Republic, 18.53863°E, 49.50256°N, 936 m a.s.l.). A set of the hyperspectral images with a pixel-size of 0.4 m was acquired for the test site by an airborne AISA Eagle VNIR system in September 18 th , 2004. An operational canopy C ab estimation was carried out by means of a PROSPECT-DART inversion employing an artificial neural network (ANN) and a vegetation index ANCB 650-720 . Both retrieval approaches used continuum removed reflectance values of six AISA Eagle spectral bands located between 650 and 720 nm. The C ab inversion was only performed for direct sun exposed (sunlit) crown pixels in order to ensure a high quality (noiseless) reflectance signal. Results of both inversion approaches were similar, when validated against the ground measured C ab of nine Norway spruce crowns. Coefficients of determination (R 2 ) between ground truth and remote sensing C ab estimates were 0.78 and 0.76, respectively, with root mean square errors (RMSE) of 2.95 µg cm -2 for the ANN and 3.36 µg cm -2 for the ANCB 650-720 retrieval. The spatial patterns of C ab values estimated by both inversion methods were consistent with each other. About 80% of the C ab estimated values had an absolute difference smaller than 2 µg cm -2 .

Deberá entenderse por equipamiento urbano al conjunto de unidades físicas generadas tradicionalme... more Deberá entenderse por equipamiento urbano al conjunto de unidades físicas generadas tradicionalmente en el medio urbano, cuyo valor de uso es predominantemente público, donde se proporcionan servicios a la población.