Intermediate-Term Memory as a Bridge between Working and Long-Term Memory

Working memory is the ability to maintain information in an active and readily available state for short periods of time. It is a key component of many cognitive processes, including inference, decision-making, mental calculations, and awareness. One of the dominant models of working memory postulates that memoranda are stored through persistent neuronal activity (Goldman-Rakic, 1995). This model is supported by numerous single-neuron recordings from different brain areas in animals using a variety of paradigms (Constantinidis et al., 2001; Warden and Miller, 2010). Recently, we have corroborated this hypothesis in humans at the single-neuron level (Kamiński et al., 2017). However, results from other studies have led to the proposition of alternative models of working memory. Recently, Lundqvist et al. (2016) recorded local field potentials and single neurons in the prefrontal cortex of macaque monkeys performing a working memory task and found that information in working memory could be maintained through neuronal activity linked to discrete bursts of gamma oscillations. Additionally, Stokes et al. (2013) in another macaque study did not observe stimulus-specific persistent activity in their recordings, and instead suggested that working memory was encoded through complex neuronal dynamics. This led to the proposition that synaptic changes, which are not visible in single-neuron recordings, may represent content held in working memory (the “activity-silent working memory” hypothesis; Stokes, 2015)

Typology of rural public places. On examples from Eastern Poland

The paper proposes a typology of rural public places currently functioning in the social life of villages that indicates how this system is distinct from the public space of cities or even suburban villages. The research was conducted using the method of interviews in 21 villages in eastern Poland. The result of the analyses is a typology that includes eight basic types of rural public places: Multifunctional village squares; Grocery surroundings; Other service facilities surroundings; Sacred sites; Village streets; Neighborhood space; Recreational places; Semi-natural places. Most of them are unintentionally created places. The research shows that multifunctional places – both central and typically recreational – are crucial for rural areas, while semi-natural places are the most characteristic. However, due to the specific character of the rural landscape and rural community, we did not find any basis for distinguishing a separate category including arranged greenery, representative places or club spaces

Between persistently active and activity‐silent frameworks: novel vistas on the cellular basis of working memory

Recent work has revealed important new discoveries on the cellular mechanisms of working memory (WM). These findings have motivated several seemingly conflicting theories on the mechanisms of short‐term memory maintenance. Here, we summarize the key insights gained from these new experiments and critically evaluate them in light of three hypotheses: classical persistent activity, activity‐silent, and dynamic coding. The experiments discussed include the first direct demonstration of persistently active neurons in the human medial temporal lobe that form static attractors with relevance to WM, single‐neuron recordings in the macaque prefrontal cortex that show evidence for both persistent and more dynamic types of WM representations, and noninvasive neuroimaging in humans that argues for activity‐silent representations. A key insight that emerges from these new results is that there are several neural mechanisms that support the maintenance of information in WM. Finally, based on established cognitive theories of WM, we propose a coherent model that encompasses these seemingly contradictory results. We propose that the three neuronal mechanisms of persistent activity, activity‐silent, and dynamic coding map well onto the cognitive levels of information processing (within focus of attention, activated long‐term memory, and central executive) that Cowan's WM model proposes

The development of Moszczenica valley river in the Late Quaternary in the site of Swędów near Stryków in the light of geological situation, pollen analysis and radiocarbon dating

Wyżyna Łódzka jest położona w obszarze zlodowacenia środkowopolskiego. Według większości poglądów, centralne partie wyżynnego półwyspu, zwanego Garbem Łódzkim (D y l i k o w a 1973), po raz ostatni były zlodowacone w czasie stadiału radomki, podczas gdy części bardziej zewnętrzne, w szerokim tego słowa znaczeniu - stokowe, objęte były lądolodem stadiału warty. Tak więc w centralnych częściach Wyżyny Łódzkiej warunki dla vistuliańskich przekształceń rzeźby były różne od tych z obszaru zlodowacenia warciańskiego. Vistuliańskie procesy morfogenetyczne nakładały się tu na efekty przemodelowań rzeźby w interstadiale pilicy. Garb Wyżyny Łódzkiej wywarł istotny wpływ na przebieg glacjacji w czasie zlodowacenia środkowopolskiego stadium warty. Lądolód warciański wskutek napotkanej na swej drodze wyniosłości podłoża rozdzielił się na dwa loby: Widawki na zachodzie i Rawki na wschodzie. Granicom maksymalnego rozprzestrzenienia lądolodu warciańskiego na zachodzie i północy garbu odpowiadają w przybliżeniu strefy struktur i form glacitektonicznych, szczególnie silnie wykształcone w obszarze północnej krawędzi garbu, gdzie genezę szeregu stopni krawędziowych wiąże się ze spiętrzającą, a jednocześnie wyrównującą powierzchnię stopni, działalnością napierającego lądolodu (K l a t k o w a 1972)

Cellular Classes in the Human Brain Revealed In Vivo by Heartbeat-Related Modulation of the Extracellular Action Potential Waveform

Determining cell types is critical for understanding neural circuits but remains elusive in the living human brain. Current approaches discriminate units into putative cell classes using features of the extracellular action potential (EAP); in absence of ground truth data, this remains a problematic procedure. We find that EAPs in deep structures of the brain exhibit robust and systematic variability during the cardiac cycle. These cardiac-related features refine neural classification. We use these features to link bio-realistic models generated from in vitro human whole-cell recordings of morphologically classified neurons to in vivo recordings. We differentiate aspiny inhibitory and spiny excitatory human hippocampal neurons and, in a second stage, demonstrate that cardiac-motion features reveal two types of spiny neurons with distinct intrinsic electrophysiological properties and phase-locking characteristics to endogenous oscillations. This multi-modal approach markedly improves cell classification in humans, offers interpretable cell classes, and is applicable to other brain areas and species

Combined Phase-Rate Coding by Persistently Active Neurons as a Mechanism for Maintaining Multiple Items in Working Memory in Humans

Maintaining multiple items in working memory (WM) is central to human behavior. Persistently active neurons are thought to be a mechanism to maintain WMs, but it remains unclear how such activity is coordinated when multiple items are kept in memory. We show that memoranda-selective persistently active neurons in the human medial temporal lobe phase lock to ongoing slow-frequency (1–7 Hz) oscillations during WM maintenance. The properties of phase locking are dependent on memory content and load. During high memory loads, the phase of the oscillatory activity to which neurons phase lock provides information about memory content not available in the firing rate of the neurons. We provide a computational model that reveals that inhibitory-feedback-mediated competition between multiple persistently active neurons reproduces this phenomenon. This work reveals a mechanism for the active maintenance of multiple items in WM that relies on persistently active neurons whose activation is orchestrated by oscillatory activity

Combined Phase-Rate Coding by Persistently Active Neurons as a Mechanism for Maintaining Multiple Items in Working Memory in Humans

Maintaining multiple items in working memory (WM) is central to human behavior. Persistently active neurons are thought to be a mechanism to maintain WMs, but it remains unclear how such activity is coordinated when multiple items are kept in memory. We show that memoranda-selective persistently active neurons in the human medial temporal lobe phase lock to ongoing slow-frequency (1–7 Hz) oscillations during WM maintenance. The properties of phase locking are dependent on memory content and load. During high memory loads, the phase of the oscillatory activity to which neurons phase lock provides information about memory content not available in the firing rate of the neurons. We provide a computational model that reveals that inhibitory-feedback-mediated competition between multiple persistently active neurons reproduces this phenomenon. This work reveals a mechanism for the active maintenance of multiple items in WM that relies on persistently active neurons whose activation is orchestrated by oscillatory activity

Working Memory Load-related Theta Power Decreases in Dorsolateral Prefrontal Cortex Predict Individual Differences in Performance

Holding information in working memory (WM) is an active and effortful process that is accompanied by sustained load-dependent changes in oscillatory brain activity. These proportional power increases are often reported in EEG studies recording theta over frontal midline sites. Intracranial recordings, however, yield mixed results, depending on the brain area being recorded from. We recorded intracranial EEG with depth electrodes in 13 patients with epilepsy that were performing a Sternberg WM task. Here, we investigated patterns of theta power changes as a function of memory load during maintenance in three areas critical for WM: dorsolateral prefrontal cortex (DLPFC), dorsal ACC (dACC), and hippocampus. Theta frequency power in both hippocampus and dACC increased during maintenance. In contrast, theta frequency power in the DLPFC decreased during maintenance, and this decrease was proportional to memory load. Only the power decreases in DLPFC, but not the power increases in hippocampus and dACC, were predictive of behavior in a given trial. The extent of the load-related theta power decreases in the DLPFC in a given participant predicted a participant's RTs, revealing that DLPFC theta explains individual differences in WM ability between participants. Together, these data reveal a pattern of theta power decreases in the DLPFC that is predictive of behavior and that is opposite of that in other brain areas. This result suggests that theta band power changes serve different cognitive functions in different brain areas and specifically that theta power decreases in DLPFC have an important role in maintenance of information

Arytmiczna manifestacja kardiomiopatii z niescalenia obu komór

W pracy przedstawiono opis przypadku pacjenta, u którego rozpoznano rzadką kardiomiopatię z niescalenia mięśnia obu komór serca. Rozpoznania dokonano na podstawie echokardiografii, po wykluczeniu innych możliwych przyczyn uszkodzenia mięśnia sercowego. Powodem rozpoczęcia diagnostyki kardiologicznej był wywiad omdleń, za których przyczynę ostatecznie uznano napadowe częstoskurcze komorowe. W profilaktyce wtórnej nagłej śmierci sercowej implantowano choremu wszczepialny kardiowerter-defibrylator. Stwierdzoną w lewej komorze skrzeplinę skutecznie leczono lekami przeciwzakrzepowymi.W pracy przedstawiono opis przypadku pacjenta, u którego rozpoznano rzadką kardiomiopatię z niescalenia mięśnia obu komór serca. Rozpoznania dokonano na podstawie echokardiografii, po wykluczeniu innych możliwych przyczyn uszkodzenia mięśnia sercowego. Powodem rozpoczęcia diagnostyki kardiologicznej był wywiad omdleń, za których przyczynę ostatecznie uznano napadowe częstoskurcze komorowe. W profilaktyce wtórnej nagłej śmierci sercowej implantowano choremu wszczepialny kardiowerter-defibrylator. Stwierdzoną w lewej komorze skrzeplinę skutecznie leczono lekami przeciwzakrzepowymi

Neural activity and new methods of computational analysis in the model of mammalian brain cortex

Analysis of the real brain’s neural activity can be performed in many different ways like forexample electroencephalography. Sometimes the value of neural membrane potential is collectedeven from particular cells, using electrodes in neurophysiological experiments. However, thisinvasive method can be performed only on animals and in most cases leads to death of theexperiment’s subject. Computer modelling and simulation are often very important for the designof real experiments and in this paper we present the set of three new methods of neurodynamicalanalysis, two of them analogical to the probing used in neurophysiology andelectroencephalography. We show that in some cases our approach can be even more effectivethan the techniques used in bio-medical laboratories