Visual Cortex Involvement in Memory

opthalmic Cortex Involvement in MemoryIs optical pallium baffling in reposition?Essay type Option 1 REVIEW OPTIONLpez-Aranda et al. 2009. exercise of Layer 6 of V2 Visual Cortex in Object-Recognition Memory, in retelligence 325, 87http//www.ncbi.nlm.nih.gov/pubmed/19574389Cattaneo et al., 2009. Contrasting primal optic cortical ph angiotensin converting enzyme numberivation states nervelessly involved in opthalmic attgoalry and piteous boundary retrospecthttp//www.ncbi.nlm.nih.gov/pubmed/19788574Though a lot of information enters the brain, keeping does non kick the bucket for all of it, and it is considered to be a selective process. One of these retentions is short term reposition, similarly known as working storehouse. In vision, working shop is interpreted as the maintenance of a whole goalive, instead of the components of the objects image orientation, texture, etc. ( passing, 2003).Memory retention and formation is typically associated with increased ex ertion in mammalian prefrontal and parietal cortex, with little express for bodily process in sensory areas, beyond of the initial sensory input signal (Pasternak and Greenlee, 2005). The nine-fold Memory Systems is a widely accepted view that sustains that the brain is sepa put into sections in respect of their own specific function. In this interpretation, the Medial temporal character Lobe (MTL) has a social occasion in warehousing, particularly in explicit memory function, and includes structures such as the hippocampus, entorhinal cortex, parahippocampal cortex, and perirhinal cortex, in addition to the prefrontal cortex (Bussey and Saksida, 2007).However, recent findings have suggested a role of sensory cortex in memory processing increased brain operation in optic cortex has been arrange during the short-term retention of optic information later on stimulus presentation (Kldy and Sigala, 2004). It therefore has been more common to say that visual cortex role goe s beyond encoding sensory information and in some(prenominal) case participates in memory consolidation.This render reviews both papers in which register of the role of visual cortex in memory consolidation is presented by the use of different techniques 1) Cellular techniques as protein overexpression and immunocytochemis screen (Lpez-Aranda et al., 2009) and 2) Transcranial magnetised stimulation (Cattaneo et al., 2009)Role of Layer 6 of V2 Visual Cortex in Object-Recognition Memory victimisation rats as a model, Lpez-Aranda et al. (2009) tried to elucidate the specific role of degree 6 in V2, in regards to memory processing and retention. To do this, they utilised two methodologies in a paired-sample experiment (same group well-tried on two different occasions). One addressed the problem by analysing the overexpression of a certain G-protein regulator (RGS-14) in mould 6 of V2, that acted as a protease, and which permitted rats do give away in Object recognition memory (ORM) tests. ORM tests consisted on evaluating the exploration time after an object was presented for 3 proceeding, and presented once again after a delay diaphragm of 30 hourutes, 45 minutes or 60 minutes. Rats could recognise the object after 30 or 45 minutes had passed, but failed to do it after the 60 min delay. A group of these rats was then injected with a lentivirus coupled with the RGS-14 gene into work 6 of V2, at 2/3 of V2 (dorsal to layer 6 of V2), at CA1 and at the dentate gyrus of the hippocampus (both ventral to layer 6 of V2). This permitted the overexpression of RGS-14 at those sites. Rats were ORM tested again 3 weeks after the injection was make. What was found was that rats modify in their ORM tests when they were injected exactly at layer 6 of V2, whereas the domicile of the rat groups (injected at different sites), did not show any remainder in performance, and their natural action was similar to that of the initial non-injected rats. The layer 6 injec ted rats were ORM tested again, to see how oftentimes retention they could support, showing up to 6 object retention (in comparison to the 2 object retention non-injected rats showed), and increasing its retention time to about 24 weeks. They then proceeded to make immunocytochemistry analysis to aim protein expression, which showed that RGS-14 was in the beginning being expressed at layer 6 of V2.The other methodology used focused on presenting the result of layer 6 of V2 destruction, by the injection of Ox7-SAP into this layer in non-injected rats and RGS-14 injected rats, and later doing the ORM test to both groups. Non-injected rats showed an increased reduction in retention time, not being adapted to perform equally as they did when layer 6 of V2 was not wear. RGS-14 lentivirus injected rats also showed a reduction in their ORM test performance. A group of rats, both injected or non-injected, were tested again, but that before having layer 6 of V2 ablated by Ox7-SAP an o bject was presented for three minutes. Rat performance was not cut back when ORM test was done with object that was previously presented, but did showed reduction when the ORM was done with a new object, presented after layer 6 removal.The results showed an involvement of layer 6 of V2 in memory trace, though not storage. It is not explicitly said if the RGS-14 G protein regulator is naturally expressed in layer 6 of V2. As far as the obtained results, it is attainable to say that RGS-14 could act as treatment option for short memory disorders or impairments, though more trials are possibly needed.Contrasting aboriginal visual cortical activation states casually involved in visual mental vision and short term memoryWith the use of Transcranial Magnetic Stimulation (TMS), Cattaneo et al., (2009) evaluated the role of early visual areas in memory and visual imagination. They essentially established two similar experiments involving two tasks, the imagery task and the memory task , in subjects who were either undergoing occipital TMS (over V1/V2), Vertex TMS (as a control) or No TMS.In the imagery task of the first experiment, subjects had to create a mental image of something. It consisted on presenting a black dot in the middle of a albumen screen, followed by a series of digits (that represented an hour, e.g. 10.10, 6.50, etc.), for about 1000 ms. indeed this digits disappeared and a black circle showed up. Subjects were then asked to imagine the time reach in the position that would delimitate the digits they had just seen. After a 2 second period passed, a single pulse of TMS was applied, dep close on the designate previously defined for them. Next, a black dot was shown (inside the black circle) and subjects were asked to tell if this dot had appeared inside or outside the area the clock manpower were supposed to be, by either pressing 1 or 2 on a keyboard for either inside or outside the area.In the memory task in the same experiment, subjects also had to fix their look at a black dot in the white screen. Then, the clock turn over (describing an hour) inside a circle appeared for about 1000 ms. When this period had passed, the hands disappeared but the circle remained, and subjects were asked to continue on thinking on the clock hands for about 2 s. TMS was applied at the end of this 2 s (retention) period, in the same mode as in the imagery task. A block then appeared inside the circle and subjects were asked to describe whether the dot was inside or outside the area the clock hands formed.By doing analysis of variance, they found no relevant differences surrounded by the hateful detecting accuracies between TMS conditions Occipital TMS, Vertex TMS and No TMS, in both imagery and memory tasks. However, the mean reaction times did show relevant differences between those conditions, in both tasks. A Post hoc comparison showed that performance was better in the Occipital TMS than when condition were Vertex TMS or no T MS. there was also no significant variation when the analysis was done between Vertex TMS and no TMS.Experiment two was fairly similar to the one described above. It also involved a memory and imagery task, with the only difference being when was TMS applied at the beginning of the 2 s period after subjects had seen the digits and were asked to imagine the clock hands inside the circle, for the imagery task, and at the beginning of the 2 s period when they were asked to continue on thinking on the clock hands, for the memory task. By performing ANOVA they found no significant difference between conditions for the mean spotting accuracies and reaction time, in the imagery task. Conversely, in the memory task, ANOVA showed a relevant make in mean detection accuracy and mean time, as well as the Post hoc analysis showed occipital TMS had an effect in comparison to the other conditions, both of which was impairment in performance. paroleMTL structures have been presented as the major components in perception and working memory, and it is seen as a domain where ORM is thought to be processed (Kldy and Sigala, 2004).Lpez-Aranda et al, (2009) results of the role of layer 6 neurons in the formation of both normal (short-term) and semipermanent ORM highlight the importance of V2, an area placed outside of MTL. Not much is known about the protein overexpressed at V2, RGS-14. It is integrated by a Regulators of G protein Signaling domain, as well as by a root word that permit its binding to inactive GDP and by a tandem bicycle Rap1/2binding domain. Acting as a GTPase activating protein, the protein increases the rate of conversion of the GTP to GDP. This allows the G alpha subunits to bind subunit heterodimers, and eventually ending a signal (NCBI, 2013). It would be interesting to know what made the authors position to test this protein in that specific layer of V2, as it is not full stated in the article, and because RGS14 was found to be expressed naturally/prima rily in CA2 hippocampal neurons and to show memory obstruction when expressed in mice ( lee(prenominal) et al., 2010). mayhap differences between species (as both studies were done with model animals rats and mice) are more relevant than thought, and should be interpreted in account before making any definite conclusion or investigate of how the signaling process occurs and affects a cognitive behavior, such as memory.However, findings involving TMS analysis in humans by decrease of activity, as the one presented by Cattaneo et al. (2009), in which there was a noted decrease in subject performance in the memory task when TMS was applied in the beginning of the retention period at V1/V2, indicate that memory of visual information involves activity in early visual cortex that goes further than the periods of sensory perception. In early visual cortex, memory of visual content is topographically organized. These results are possibly due(p) to less vulnerability to interference after t he retention period, and a possible interaction with higher order areas activity with visual cortex activity (van de Ven and Sack, 2013).The previous results can be paired with Harrison and Tong (2009) results, were they used functional magnetic resonance imaging (fMRI), in conjunction to Blood Oxygen aim Dependent (BOLD) analysis, to monitor cortical activity while participants did a delay orientation discrimination task, where 2 diffraction approximatives were shown to the subjects, followed by a cue that indicated which grating to remember (first or second) and an 11 s period (delay period). Then the grating was showed again and subjects had to say if the image was rotated in a smell out or antisense (clockwise) matter. They examined the role of visual areas in working memory done different experiments fMRI decoding was specifically used to evaluate the patterns in brain activity, in areas corresponding to V1 to V4 (to the 120 most responsive voxels) to try to predict its re presentation in working memory. The accuracy of predicted orientation that was held in memory reached 83%, which is considered to be very high, one of the experiments where subjects had to fix its sum to a letter, and not the grating, showed high prediction to those gratings in areas V1, V2 and V3. Ultimately, their findings suggest that memory related information may be encoded in these structures (showing increased activity in areas V1/V2) and that early visual areas can hold up information, not only displaying sensory processing functions.Different approaches can be taken to evaluate visual cortex relation with memory, as the ones reviewed in this essay TMS, protein overexpression, fMRI among others. Evidence that sensory cortical areas are an active element of the circuitry that underlies short term retention of sensory signals is emerging and improving our correspondence of memory. It can be concluded that not only the MTL is important for visual memory processing, but also early visual cortex and evidence of what is happening at the cellular level needs to be improved in order to eventually delimit its potential in cognitive treatments.ReferencesBussey TJ, Saksida LM (2007) Memory, perception, and the ventral visual-perirhinal-hippocampal stream thinking outside of the boxes. Hippocampus 17898-908.Cattaneo Z, Vecchi T, Pascual-Leone A, Silvanto J (2009) Contrasting early visual cortical activation states causally involved in visual imagery and short-term memory. The European daybook of neuroscience 301393-1400.Harrison SA, Tong F (2009) Decoding reveals the contents of visual working memory in early visual areas. 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