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.

A investigação criminal e a vedação ao anonimato no sistema jurídico brasileiro

The thesis, prepared with basis on deductive reasoning (through the utilization of general concepts of the fundamental rights theory) and on inductive logic (by means of the consideration of particular situations in which the theme has been approached) deals with the criminal investigation and the prohibition of anonymity in the Brazilian law system. The state criminal investigation activity presents not only a substantial constitutional basis, due to the objective dimension of fundamental rights (which imposes an obligation to protect these essential values), but also a formal constitutional basis, arising from the administrative principles of rule of law, morality and efficiency, referred to in article 37 of the Constitution. The criminal investigation, however, is not an unlimited pursuit, being restrained by the duty to consider fundamental rights that oppose to its realization. One of the limits of the state investigation activity, in the Brazilian law system, is the prohibition of anonymity, referred to in article 5°, IV, of the Constitution. This prohibition is a direct constitutional restriction to the freedom of expression that aims to ensure the credibility of the diffusion of ideas and prevent the abusive exercise of this fundamental right, which could harm both persons and the state, with no possibility of punishment to the offending party. Generally, based on this prohibition, it is affirmed that a criminal investigation cannot begin and progress founded on anonymous communication of crimes. Informations about crimes to the investigative authorities require the correct identification of the stakeholders. Therefore, it is sustained that the prohibition of anonymity also comprehends the prohibition of utilization of pseudonyms and heteronyms. The main purpose of this essay is to recognize the limits and possibilities in starting and conducting criminal investigations based on communication of crimes made by unidentified persons, behind the veil of anonymity or hidden by pseudonyms or heteronyms. Although the prohibition of article 5°, IV, of the Constitution is not submitted to direct or indirect constitutional restrictions, this impediment can be object of mitigation in certain cases, in attention to the constitutional values that support state investigation. The pertinence analysis of the restrictions to the constitutional anonymity prohibition must consider the proportionality, integrated by the partial elements of adequacy, necessity and strict sense proportionality. The criminal investigation is a means to achieve a purpose, the protection of fundamental rights, because the disclosure of facts, through the investigatory activity, gives rise to the accomplishment of measures in order to prevent or punish the violations eventually verified. So, the start and the development of the state criminal investigation activity, based on a crime communication carried out by an unidentified person, will depend on the demonstration that the setting up and continuity of an investigation procedure, in each case, are an adequate, necessary and (in a strict sense) proportional means to the protection of fundamental rights

Abordagem clínica da atividade de trabalho do cozinheiro: interação de saberes, gênero profissional e inovação criativa

The focus of this dissertation is the study of work activities developed in the context of professional occupations characterized by varied previous schooling levels amongst those that work in them, and, at the same time, a high degree of complexity related to the typical tasks performed in the context of such professional practices. This dissertation intends to investigate the cook s professional activity, based on data from a determined specific professional genre in Natal (RN), in order to establish aspects related not only to the activity performed (activity which manifests itself empirically in registered behaviors), but also related to the real aspects of the work activity, that also compromises the non-realized options of the guiding of professional activity, be it by a matter of choice, be it due to the activity s own impediment. In this context, we tried to evaluate how much the professional activity observed keeps in relation to the reference practices of the professional genre, be it in terms of conformity, be it in terms of innovation (stylization) in relation to this genre. In addition, we tried to verify the contribution of the school and extra-school knowledge to the professional activity observed. Such work plan took on a preliminary step of the description of the socialprofessional profile of a cook in the city of Natal (RN), followed by a step of clinical labor approach, specifically utilizing as a methodological tool the simple and crossed self-confrontation procedure guided by the francophone theoretical referential of the Activity Clinic. The preliminary step in the description of profile of cooks from Natal (RN), of which 138 cooks took part in, evidenced three professional groupings, all predominantly masculine in their composition and fundamentally differentiated amongst each other by the time of professional activity, schooling type and time, work place and salary. The clinical approach step, composed by a pair of cooks, allowed us to verify elements of the cooks subordination to the professional genre, but also evidences of individual innovation (stylization) by these cooks, as well as the predominance of usage of extra-school knowledge when compared to school knowledge. We tried, in this step, to demonstrate how much the inclusion and submission to the genre dynamic, coordinated with the stylization initiatives, was able to contribute to the maintenance and amplification of the cook s power of acting in his professional practice.