Observing Action Sequences Elicits Sequence-Specific Neural Representations in Frontoparietal Brain Regions.

Learning new skills by watching others is important for social and motor development throughout the lifespan. Prior research has suggested that observational learning shares common substrates with physical practice at both cognitive and brain levels. In addition, neuroimaging studies have used multivariate analysis techniques to understand neural representations in a variety of domains, including vision, audition, memory, and action, but few studies have investigated neural plasticity in representational space. Therefore, although movement sequences can be learned by observing other people's actions, a largely unanswered question in neuroscience is how experience shapes the representational space of neural systems. Here, across a sample of male and female participants, we combined pretraining and posttraining fMRI sessions with 6 d of observational practice to determine whether the observation of action sequences elicits sequence-specific representations in human frontoparietal brain regions and the extent to which these representations become more distinct with observational practice. Our results showed that observed action sequences are modeled by distinct patterns of activity in frontoparietal cortex and that such representations largely generalize to very similar, but untrained, sequences. These findings advance our understanding of what is modeled during observational learning (sequence-specific information), as well as how it is modeled (reorganization of frontoparietal cortex is similar to that previously shown following physical practice). Therefore, on a more fine-grained neural level than demonstrated previously, our findings reveal how the representational structure of frontoparietal cortex maps visual information onto motor circuits in order to enhance motor performance.SIGNIFICANCE STATEMENT Learning by watching others is a cornerstone in the development of expertise and skilled behavior. However, it remains unclear how visual signals are mapped onto motor circuits for such learning to occur. Here, we show that observed action sequences are modeled by distinct patterns of activity in frontoparietal cortex and that such representations largely generalize to very similar, but untrained, sequences. These findings advance our understanding of what is modeled during observational learning (sequence-specific information), as well as how it is modeled (reorganization of frontoparietal cortex is similar to that previously shown following physical practice). More generally, these findings demonstrate how motor circuit involvement in the perception of action sequences shows high fidelity to prior work, which focused on physical performance of action sequences

Anodal tDCS over Primary Motor Cortex Provides No Advantage to Learning Motor Sequences via Observation.

When learning a new motor skill, we benefit from watching others. It has been suggested that observation of others' actions can build a motor representation in the observer, and as such, physical and observational learning might share a similar neural basis. If physical and observational learning share a similar neural basis, then motor cortex stimulation during observational practice should similarly enhance learning by observation as it does through physical practice. Here, we used transcranial direct-current stimulation (tDCS) to address whether anodal stimulation to M1 during observational training facilitates skill acquisition. Participants learned keypress sequences across four consecutive days of observational practice while receiving active or sham stimulation over M1. The results demonstrated that active stimulation provided no advantage to skill learning over sham stimulation. Further, Bayesian analyses revealed evidence in favour of the null hypothesis across our dependent measures. Our findings therefore provide no support for the hypothesis that excitatory M1 stimulation can enhance observational learning in a similar manner to physical learning. More generally, the results add to a growing literature that suggests that the effects of tDCS tend to be small, inconsistent, and hard to replicate. Future tDCS research should consider these factors when designing experimental procedures.This work was supported by the Ministry of Defence of the United Kingdom Defence Science and Technology Laboratory (Grant no. DSTLX-1000083177 to Emily S. Cross and Richard Ramsey), the Economic and Social Research Council (Grant no. ES/K001884/1 to Richard Ramsey and ES/K001892/1 to Emily S. Cross), and the funding from the European Commission to Emily S. Cross (CIG11- 2012-322256 and ERC-2015-STG-677270)

Dynamic targeting enables domain-general inhibitory control over action and thought by the prefrontal cortex.

Over the last two decades, inhibitory control has featured prominently in accounts of how humans and other organisms regulate their behaviour and thought. Previous work on how the brain stops actions and thoughts, however, has emphasised distinct prefrontal regions supporting these functions, suggesting domain-specific mechanisms. Here we show that stopping actions and thoughts recruits common regions in the right dorsolateral and ventrolateral prefrontal cortex to suppress diverse content, via dynamic targeting. Within each region, classifiers trained to distinguish action-stopping from action-execution also identify when people are suppressing their thoughts (and vice versa). Effective connectivity analysis reveals that both prefrontal regions contribute to action and thought stopping by targeting the motor cortex or the hippocampus, depending on the goal, to suppress their task-specific activity. These findings support the existence of a domain-general system that underlies inhibitory control and establish Dynamic Targeting as a mechanism enabling this ability

In vivo functional neurochemistry of human cortical cholinergic function during visuospatial attention

Cortical acetylcholine is involved in key cognitive processes such as visuospatial attention. Dysfunction in the cholinergic system has been described in a number of neuropsychiatric disorders. Levels of brain acetylcholine can be pharmacologically manipulated, but it is not possible to directly measure it in vivo in humans. However, key parts of its biochemical cascade in neural tissue, such as choline, can be measured using magnetic resonance spectroscopy (MRS). There is evidence that levels of choline may be an indirect but proportional measure of acetylcholine availability in brain tissue. In this study, we measured relative choline levels in the parietal cortex using functional (event-related) MRS (fMRS) during performance of a visuospatial attention task, with a modelling approach verified using simulated data. We describe a task-driven interaction effect on choline concentration, specifically driven by contralateral attention shifts. Our results suggest that choline MRS has the potential to serve as a proxy of brain acetylcholine function in humans

Fluid intelligence and working memory support dissociable aspects of learning by physical but not observational practice.

Humans have a remarkable ability to learn by watching others, whether learning to tie an elaborate knot or play the piano. However, the mechanisms that translate visual input into motor skill execution remain unclear. It has been proposed that common cognitive and neural mechanisms underpin learning motor skills by physical and observational practice. Here we provide a novel test of the common mechanism hypothesis by testing the extent to which certain individual differences predict observational as well as physical learning. Participants (N = 92 per group) either physically practiced a five-element key-press sequence or watched videos of similar sequences before physically performing trained and untrained sequences in a test phase. We also measured cognitive abilities across participants that have previously been associated with rates of learning, including working memory and fluid intelligence. Our findings show that individual differences in working memory and fluid intelligence predict improvements in dissociable aspects of motor learning following physical practice, but not observational practice. Working memory predicts general learning gains from pre- to post-test that generalise to untrained sequences, whereas fluid intelligence predicts sequence-specific gains that are tied to trained sequences. However, neither working memory nor fluid intelligence predict training gains following observational learning. Therefore, these results suggest limits to the shared mechanism hypothesis of physical and observational learning. Indeed, models of observational learning need updating to reflect the extent to which such learning is based on shared as well as distinct processes compared to physical learning. We suggest that such differences could reflect the more intentional nature of learning during physical compared to observational practice, which relies to a greater extent on higher-order cognitive resources such as working memory and fluid intelligence.This work was supported by the Ministry of Defence of the United Kingdom Defence Science and Technology Laboratory [grant number DSTLX-1000083177 to ESC and RR], the Economic and Social Research Council [grant numbers ES/K001884/1 to RR and ES/K001892/1 to ESC], a Marie Curie Actions/FP7 [CIG11-2012-322256 to ESC], and a European Research Council grant [ERC-2015-StG-677270 to ESC]

Magnetic resonance spectroscopy and the menstrual cycle: a multi-centre assessment of menstrual cycle effects on GABA & GSH

BackgroundGamma-aminobutyric acid (GABA) and glutathione (GSH) play a significant role in the functioning of a healthy brain and can both be quantified using magnetic resonance spectroscopy (MRS). Several small-scale studies have suggested MRS measured GABA may fluctuate with the menstrual cycle, but the effects on GSH are unknown. Utilising recent developments in MRS acquisition, this multi-lab study explores this issue across 4 distinctive brain regions.New methodsData were analysed from 12 independent sites from which a total of 30 women were scanned during three phases of their menstrual cycle corresponding to early follicular, ovulation and mid luteal phases. HERMES and HERCULES sequences were used to measure GABA and GSH in voxels located in the left motor cortex, left posterior insular, medial parietal and medial frontal. Linear mixed models were used to assess the variability contributed by site, participant and menstrual cycle phase.ResultsSimilar variance was attributed to site and menstrual cycle phase for both GABA and GSH data. No systematic changes in GABA or GSH were revealed for any voxel as a consequence of menstrual cycle phase.Comparison with existing methodsDespite our larger sample size and inclusion of more brain regions we fail to replicate previous findings of GABA change as a consequence of menstrual cycle phase. We also show for the first time that MRS measures of GSH so not significantly alter with cycle.ConclusionsOur findings suggest that the menstrual cycle has minimal impact on MRS measures of GABA and GSH. The presence of a menstrual cycle should not be used as justification for exclusion of women in MRS studies

Detail Planning as Limitation of the Right to Use Property

Darbā „Detālplānojums kā īpašuma tiesību aprobežojums” autors pēta detālplānojuma tiesisko regulējumu Latvijā uzmanību pievēršot problēmjautājumiem, kas skar minēto jomu. Detālplānojums ir viens no teritorijas plānošanas instrumentiem, kam teritorijas plānošanā ir vissīkākā detalizāciju (detalizē vietējās pašvaldības teritorijas plānojumu) un kas palīdz nodrošināt ilgtspējīgu un līdzsvarotu attīstību valstī. Būtībā detālplānojums ir beidzamais posms jebkādai darbībai ar zemi normatīvajos aktos noteiktajos gadījumos un nosaka tās lietošanas un apbūves iespējas un aprobežojumus. Līdz ar to detālplānojums ir uzskatāms par sava veida īpašuma lietošanas tiesību aprobežojumu. Tādēļ darbā autors pievērsis uzmanību tieši ievērojamākām problēmām, kas sastopamas detālplānojuma izstrādes un apstiprināšanas procesā, apsverot minēto problēmu iespējamos risinājumus. Darba tiek secināts, ka ievērojamākās problēmas izriet no pašvaldības lielās rīcības brīvības, kas tai piešķirta savu autonomo funkciju pildīšanai un ir šķietami neierobežotas, kas savukārt noved pie pienākumu nepildīšanas vai to nepienācīgas pildīšanas. Šajā sakarā autors darbā ir norādījis uz kontroles nepietiekamību galvenokārt detālplānojuma izstrādes stadijā, izvērtējot iespēju ar likumu noteikt pašvaldības rīcības ierobežojošus faktorus kā arī vairāk konkretizēt gadījumus, kuros nepieciešama detālplānojumu izstrāde, paredzot normatīvajos aktos iestrādāt tikai izņēmuma gadījumus, kad detālplānojuma izstrāde nebūtu nepieciešama. Darbā autors īpaši izdala divas aktuālākās problēmas, kuras visbiežāk ir par iemeslu detālplānojuma atzīšanai par prettiesisku – sabiedrības līdzdalības neievērošana un kompetento iestāžu nosacījumu un/vai atzinumu nesaņemšana vai neievērošana. Pašvaldības nereti neievēro sabiedriskās līdzdalības nozīmīgumu detālplānojuma izstrādes stadijā, jo īpaši sabiedrības informēšanā un viedokļu izvērtēšanā, kas nereti noved pie detālplānojuma atzīšanas par prettiesisku, kas savukārt nelabvēlīgi ietekmē gan jau izlietotās tiesības, gan tiesisko paļāvību kopumā. Līdzīgi pašvaldība nereti nepievērš uzmanību kompetento iestāžu atzinumu saņemšanas un izvērtēšanas procesam, kas tādejādi arī var novest pie detālplānojuma atcelšanas. Līdz ar to autors iesaka sīkāk reglamentēt iepriekš minētā svarīgumu un noteikt papildu normas labākai detālplānojuma izstrādes procesa tiesiskuma nodrošināšanai, papildus izstrādājot metodiskos norādījums pašvaldībām. Īpaša uzmanība arī tiek vērsta uz detālplānojuma, kura grafisko daļu un teritorijas apbūves un izmantošanas noteikumus pašvaldība izdod saistošo noteikumu veidā, apstrīdēšanas termiņa neesamību, kas neveicina ilgtspējīgas un līdzsvarotas attīstības mērķi un nepamatoti ierobežo īpašuma īpašnieku (lietotāju) tiesisko paļāvību, kas šajā gadījumā nav pieļaujams. Līdzīgi kā apstrīdēšanas termiņu neesamība, nesaprotams ir esošais regulējums saistībā ar detālplānojuma ierosināšanu un finansēšanu, kas būtībā noved pie attīstības stratēģijas plānošanas uzdevuma deleģēšanas privātpersonai, kas saskaņā ar Valsts pārvaldes iekārtas likumu nav atļauts. Darba nobeigumā autors izdara secinājumus par esošo situāciju teritorijas plānošanā Latvijā un iespējamajiem problēmu risinājumiem.The author of the thesis Detail Planning as Limitation of the Right to Use Property, studies the legal basis for detail planning in Latvia, paying attention to the problems related to this area. Detail planning is one of the territorial planning instruments with the most detail (detailing planning of municipality territories), which helps secure sustainable and balanced development in the country. Basically, detail planning is the final stage in any operations with land stipulated by the law, which sets possibilities and limitations of utilisation and construction of the land. Thus detail planning can be seen as a limitation of the right to use property. Therefore, the author pays attention to the most notable problems of the development and the approval stages of detail planning, considering possible solutions for the said problems. As a conclusion, the most notable problems arise out of excessive freedom of action granted to municipalities for fulfilment of their autonomous functions. Such freedom is seemingly unlimited, which, in its turn, leads to non-fulfilment or incomplete fulfilment of obligations. In this respect, the author points out to the lack of control mainly in the development stage of detail planning, evaluating the possibility to stipulate such factors in the law, which would limit the actions of municipalities. It is suggested more often to specify cases where detail planning is necessary, stipulating in the law only the exceptions when detail planning is necessary. The author points out to two most topical problems that are the most common reason for declaring detail planning as illegal – non-observance of social participation and non-receipt of statements and/or requirements from competent authorities. Municipalities often do not take into consideration the importance of social participation during development stage of detail planning, especially in informing society and judging opinions, which quite often leads to declaring detail planning as illegal, which, in its turn, has a negative effect on the rights already used, as well as on legal reliance in general. Likewise, municipalities often pay attention to the process of receiving and evaluating statements from competent authorities, which may lead to cancellation of detail planning. Therefore the author suggests to regulate in more detail the importance of the aforementioned and to set additional regulations for ensuring a better rule of law of the development process of detailed planning. Special attention is paid to the lack of an appeal period of detail planning, the graphical part of which and the terms of utilisation and construction are issued by municipalities in form of mandatory regulations. It does not further sustainable and balanced development and groundlessly limits the legal reliance of property owners (users), which in this case is inadmissible. Just like the lack of an appeal period, the existing regulations regarding initiating and financing detail planning are incomprehensible, which basically leads to delegating the development strategy of a planning task to private persons, which is not permitted according to the Public Administration Law. At the end of the thesis, the author makes conclusions about the existing situation in territorial planning in Latvia and mentions possible solutions to the problems