New developmental stages for common marmosets (Callithrix jacchus) using mass and age variables obtained by K-means algorithm and self-organizing maps (SOM)

LEÃO, Adriano de Castro; DÓRIA NETO, Adrião Duarte; SOUSA, Maria Bernardete Cordeiro de. New developmental stages for common marmosets (Callithrix jacchus) using mass and age variables obtained by K-means algorithm and self-organizing maps (SOM). Computers in Biology and Medicine, v. 39, p. 853-859, 2009

Utilização de mapas conceituais como ferramenta de ensino para o desenvolvimento do raciocínio clínico no curso de medicina da Universidade Federal do Rio Grande do Norte

BACKGROUND: Among the wide range of skills displayed by a medical doctor is undoubtedly the need to use cohesive and well grounded clinical reasoning in order for medical care to be indeed effective. It is in this respect that conceptual maps emerge; these are a methodological innovation that allows a comprehensive, panoramic and associative outlook of theoretical content, making it more practical and applicable to the reality of clinical observation. Promoting learning, learning resources and a feedback system between professor and students, as well as assessing and monitoring the performance of students during their academic training, are the main features of this tool. OBJETIVE: Assess the use of conceptual maps as a teaching-learning tool in the training of undergraduate medical students at Universidade Federal do Rio Grande do Norte (UFRN). METHODOLOGY: Interventional, randomized, cross-sectional study conducted with students from the 3rd and 5th periods of the medical course at UFRN, during the second semester of 2014, totaling 86 participants, divided into two groups: GI (intervention – clinical case resolution with a conceptual map) and GII (control – clinical case resolution without a conceptual map) in each period. RESULTS: The use of conceptual maps to teach liver failure syndrome resulted in a statistically significant cognitive gain for G1 students from the 5th period (GI: 6.8±1.6 and 8.0±1.5, p = 0.024; GII: 7.2±2.1 and 8.0±1.7, p = 0.125, pre and post-intermediate means, respectively), a result not observed in the period 3rd (GI: 7.7±1.3 and 8.0±1.4, p = 0.501; GII: 6.7±1.8 and 7.8±1.8; p=0.068, pre and post-intermediate means, respectively). Students in the 3 rd period gave better responses to the first clinical case, with a larger number of suitable concepts and crosslinks, when they used conceptual maps (GI: 91.3±13.15 and GII: 64.84±22.84, p=0,002). Students in the 5th period exhibited better clinical reasoning and more complete responses using the tool (p=0,01). Most of the students were not aware of the tool (53.8% from the 3rd period and 65.3% from the 5th period). Among those who knew about conceptual maps, most (59.3%) had only used them during high school, 14.8% had never used them and only seven students (25.9%) used them during the medical course. Analysis of open responses, obtained in process assessment showed clear satisfaction and enthusiasm with learning about the new tool, and frequent suggestions to use it at other moments in the course. Assessment of learning profile, using the VARK questionnaire, showed that most students from both periods exhibited a multimodal style. CONCLUSION: Despite their scant knowledge regarding the tool, good acceptability and understanding was observed in the study participants. The conceptual maps allowed cognitive gains, better responses and clinical reasoning in teaching liver failure syndrome to 5th period students.

The influence of interhemispheric connections on ongoing and evoked orientation preference maps and spiking activity in the cat primary visual cortex

In the primary visual cortex, neurons with similar physiological features are clustered together in columns extending through all six cortical layers. These columns form modular orientation preference maps. Long-range lateral fibers are associated to the structure of orientation maps since they do not connect columns randomly; they rather cluster in regular intervals and interconnect predominantly columns of neurons responding to similar stimulus features. Single orientation preference maps – the joint activation of domains preferring the same orientation - were observed to emerge spontaneously and it was speculated whether this structured ongoing activation could be caused by the underlying patchy lateral connectivity. Since long-range lateral connections share many features, i.e. clustering, orientation selectivity, with visual inter-hemispheric connections (VIC) through the corpus callosum we used the latter as a model for long-range lateral connectivity. In order to address the question of how the lateral connectivity contributes to spontaneously generated maps of one hemisphere we investigated how these maps react to the deactivation of VICs originating from the contralateral hemisphere. To this end, we performed experiments in eight adult cats. We recorded voltage-sensitive dye (VSD) imaging and electrophysiological spiking activity in one brain hemisphere while reversible deactivating the other hemisphere with a cooling technique. In order to compare ongoing activity with evoked activity patterns we first presented oriented gratings as visual stimuli. Gratings had 8 different orientations distributed equally between 0º and 180º. VSD imaged frames obtained during ongoing activity conditions were then compared to the averaged evoked single orientation maps in three different states: baseline, cooling and recovery. Kohonen self-organizing maps were also used as a means of analysis without prior assumption (like the averaged single condition maps) on ongoing activity. We also evaluated if cooling had a differential effect on evoked and ongoing spiking activity of single units. We found that deactivating VICs caused no spatial disruption on the structure of either evoked or ongoing activity maps. The frequency with which a cardinally preferring (0º or 90º) map would emerge, however, decreased significantly for ongoing but not for evoked activity. The same result was found by training self-organizing maps with recorded data as input. Spiking activity of cardinally preferring units also decreased significantly for ongoing when compared to evoked activity. Based on our results we came to the following conclusions: 1) VICs are not a determinant factor of ongoing map structure. Maps continued to be spontaneously generated with the same quality, probably by a combination of ongoing activity from local recurrent connections, thalamocortical loop and feedback connections. 2) VICs account for a cardinal bias in the temporal sequence of ongoing activity patterns, i.e. deactivating VIC decreases the probability of cardinal maps to emerge spontaneously. 3) Inter- and intrahemispheric long-range connections might serve as a grid preparing primary visual cortex for likely junctions in a larger visual environment encompassing the two hemifields.

The influence of interhemispheric connections on ongoing and evoked orientation preference maps and spiking activity in the cat primary visual cortex

In the primary visual cortex, neurons with similar physiological features are clustered together in columns extending through all six cortical layers. These columns form modular orientation preference maps. Long-range lateral fibers are associated to the structure of orientation maps since they do not connect columns randomly; they rather cluster in regular intervals and interconnect predominantly columns of neurons responding to similar stimulus features. Single orientation preference maps – the joint activation of domains preferring the same orientation - were observed to emerge spontaneously and it was speculated whether this structured ongoing activation could be caused by the underlying patchy lateral connectivity. Since long-range lateral connections share many features, i.e. clustering, orientation selectivity, with visual inter-hemispheric connections (VIC) through the corpus callosum we used the latter as a model for long-range lateral connectivity. In order to address the question of how the lateral connectivity contributes to spontaneously generated maps of one hemisphere we investigated how these maps react to the deactivation of VICs originating from the contralateral hemisphere. To this end, we performed experiments in eight adult cats. We recorded voltage-sensitive dye (VSD) imaging and electrophysiological spiking activity in one brain hemisphere while reversible deactivating the other hemisphere with a cooling technique. In order to compare ongoing activity with evoked activity patterns we first presented oriented gratings as visual stimuli. Gratings had 8 different orientations distributed equally between 0º and 180º. VSD imaged frames obtained during ongoing activity conditions were then compared to the averaged evoked single orientation maps in three different states: baseline, cooling and recovery. Kohonen self-organizing maps were also used as a means of analysis without prior assumption (like the averaged single condition maps) on ongoing activity. We also evaluated if cooling had a differential effect on evoked and ongoing spiking activity of single units. We found that deactivating VICs caused no spatial disruption on the structure of either evoked or ongoing activity maps. The frequency with which a cardinally preferring (0º or 90º) map would emerge, however, decreased significantly for ongoing but not for evoked activity. The same result was found by training self-organizing maps with recorded data as input. Spiking activity of cardinally preferring units also decreased significantly for ongoing when compared to evoked activity. Based on our results we came to the following conclusions: 1) VICs are not a determinant factor of ongoing map structure. Maps continued to be spontaneously generated with the same quality, probably by a combination of ongoing activity from local recurrent connections, thalamocortical loop and feedback connections. 2) VICs account for a cardinal bias in the temporal sequence of ongoing activity patterns, i.e. deactivating VIC decreases the probability of cardinal maps to emerge spontaneously. 3) Inter- and intrahemispheric long-range connections might serve as a grid preparing primary visual cortex for likely junctions in a larger visual environment encompassing the two hemifields.

New developmental stages for common marmosets (Callithrix jacchus) using mass and age variables obtained by K-means algorithm and self-organizing maps (SOM)

LEÃO, Adriano de Castro; DÓRIA NETO, Adrião Duarte; SOUSA, Maria Bernardete Cordeiro de. New developmental stages for common marmosets (Callithrix jacchus) using mass and age variables obtained by K-means algorithm and self-organizing maps (SOM). Computers in Biology and Medicine, v. 39, p. 853-859, 2009