Juan E Kamienkowski

University of Buenos Aires | UBA · Department of Computer Sciences (FCEN)

Visual search, driven by bottom-up and top-down processes, offers a unique framework for investigating decision-making. This study examines the awareness of the individuals to their own visual search by combining computational modeling with behavioral experiments. Fifty-seven participants performed a classical visual search task in which the goal w...

Background The persisting cognitive symptoms observed in individuals after a Covid‐19 infection (long‐Covid) remain an enigmatic aspect of the disease. Clinical descriptions in the literature are dissimilar, suggesting more than one clinical phenotype. Our study aims to explore cognitive performance and brain network of long‐Covid patients, to dete...

El área de las ciencias del desarrollo ha comenzado a comenzado a estudiar el rol de las diferencias individuales en el desempeño cognitivo de niños/as para el diseño de intervenciones más efectivas (Katz et al., 2021). Hasta el momento, dichos abordajes se enfocaron en estudiar si los desempeños totales (eficiencia) se encuentran por encima o por...

Visual search, where observers search for a specific item, is a crucial aspect of daily human interaction with the visual environment. Hybrid search extends this by requiring observers to search for any item from a given set of objects. While there are models proficient at simulating human eye movement in visual search tasks within natural scenes,...

The advancement of the Natural Language Processing field has enabled the development of language models with a great capacity for generating text. In recent years, Neuroscience has been using these models to better understand cognitive processes. In previous studies, we found that models like Ngrams and LSTM networks can partially model Predictabil...

Introduction In real-life scenarios, individuals frequently engage in tasks that involve searching for one of the distinct items stored in memory. This combined process of visual search and memory search is known as hybrid search. To date, most hybrid search studies have been restricted to average observers looking for previously well-memorized tar...

Background and purpose Subjective cognitive complaints post‐COVID‐19, known as long‐COVID, have unclear effects on neural activity. This study explores the neural basis of these cognitive impairments by comparing resting‐state functional networks of long‐COVID individuals to a control group. Methods Forty‐two individuals with cognitive complaints...

Positive and negative subsequent memory effects have been reported in the left supramarginal gyrus (LSMG) which is thought to mediate attention to memory. We performed a secondary analysis of 142 verbal free recall experiments, in patients with medically refractory epilepsy, undergoing pre-surgical evaluation with electrode contacts implanted in th...

When engaged in a conversation, one receives auditory information from the other’s speech but also from their own speech. However, this information is processed differently by an effect called Speech-Induced Suppression. Here, we studied brain representation of acoustic properties of speech in natural unscripted dialogues, using electroencephalogra...

In real-life scenarios, individuals frequently engage in tasks that involve searching for one of various items stored in memory. This combined process of visual search and memory search is known as hybrid search. To date, most hybrid search studies have been restricted to average observers looking for previously well-memorized targets in blank back...

Over the last years, several developments of remote webcam-based eye tracking (ET) prototypes have emerged, testing their feasibility and potential for web-based experiments. This growing interest is mainly explained by the possibility to perform tasks remotely, which allows the study of larger and hard-to-reach populations and potential applicatio...

Tasks we often perform in our everyday lives, such as reading or looking for a friend in the crowd, are seemingly straightforward but they actually require the orchestrated activity of several cognitive processes. Free-viewing visual search requires a plan to move our gaze on the different items, identifying them, and deciding on whether to continu...

Cognitive interventions that involve executive functions (EF)-demanding activities are effective in changing task-related brain activity in children from homes with low socioeconomic status (SES). However, less is known about the efficiency of EF-based interventions in modifying segregation and integration properties of the functional neural organi...

Preschool children show neural responses and make behavioral adjustments immediately following an error. However, there is a lack of evidence regarding how neural responses to error predict subsequent behavioral adjustments during childhood. The aim of our study was to explore the neural dynamics of error processing and associated behavioral adjust...

Predictions of incoming words performed during reading have an impact on how the reader moves their eyes and on the electrical brain potentials. Eye tracking (ET) experiments show that less predictable words are fixated for longer periods of times. Electroencephalography (EEG) experiments show that these words elicit a more negative potential aroun...

The Trail Making Test (TMT) is one of the most popular neuropsychological tests for executive functions (EFs) assessment. It presents several strengths: it is sensitive to executive dysfunction, it is easy to understand, and has a short administration. However, it has important limitations. First, the underlying EFs articulated during the task are...

Early access to categorical visual information plays an important role in real-world behaviour. Under fixed-gaze conditions, there are well-established electrophysiological signatures of categorical processing like the N170 EEG component. Here we aimed to study how the sensitivity to category information extends to a free viewing paradigm and consi...

Finding objects is essential for almost any daily-life visual task. Saliency models have been useful to predict fixation locations in natural images during a free-exploring task. However, it is still challenging to predict the sequence of fixations during visual search. Bayesian observer models are particularly suited for this task because they rep...

Different interventions have shown effectiveness in modifying cognitive performance on cognitive control demanding tasks in children from poor homes. However, little is known about the influence of cognitive interventions on children’s brain functioning and how individual variability modulates the impact of those interventions. In the present study...

Surface electroencephalography is a standard and noninvasive way to measure electrical brain activity. Recent advances in artificial intelligence led to significant improvements in the automatic detection of brain patterns, allowing increasingly faster, more reliable and accessible Brain-Computer Interfaces. Different paradigms have been used to en...

Visual search is an essential part of almost any everyday human goal-directed interaction with the environment. Nowadays, several algorithms are able to predict gaze positions during simple observation, but few models attempt to simulate human behavior during visual search in natural scenes. Furthermore, these models vary widely in their design and...

Modern Natural Language Processing (NLP) models can achieve great results resolving different types of linguistic tasks. This is possible thanks to a high volume of internal parametersthat are optimized during the training phase. They allow to model high-level linguistic properties. For example, LSTM-based language models have the ability to find l...

The Trail Making Test (TMT) is one of the most popular neuropsychological tests in the clinical assessment of executive functions (EF) and research in a wide range of clinical conditions. In addition to its sensitivity to executive dysfunction, the TMT presents several strengths: it is simple and intuitive, it is easy to understand for patients, an...

With the arrival of the pandemic in Argentina in March 2020, a working group of scientists from two institutes belonging to the Faculty of Exact and Natural Sciences of the University of Buenos Aires and CONICET, together with colleagues from different academic institutions in the country, decided to put forth our experience and knowledge in data s...

Surface electroencephalography is a standard and noninvasive way to measure electrical brain activity. Recent advances in artificial intelligence led to significant improvements in the automatic detection of brain patterns, allowing increasingly faster, more reliable and accessible Brain-Computer Interfaces. Different paradigms have been used to en...

Finding objects is essential for almost any daily-life visual task. Saliency models have been useful to predict fixation locations in natural images, but are static, i.e., they provide no information about the time-sequence of fixations. Nowadays, one of the biggest challenges in the field is to go beyond saliency maps to predict a sequence of fixa...

When we read printed text, we are continuously predicting upcoming words to integrate information and guide future eye movements. Thus, the Predictability of a given word has become one of the most important variables when explaining human behaviour and information processing during reading. In parallel, the Natural Language Processing (NLP) field...

Las implicaturas conversacionales generalizadas (ICG) son un tipo de inferencia pragmática que se caracteriza por una derivación que sigue ciertas regularidades y que es relativamente independiente del contexto de situación (Grice, 1989). Existen dos modelos de procesamiento sobre este fenómeno desde una perspectiva cognitiva (Noveck & Reboul, 2008...

A conversational implicature arises when there is a gap between the syntactically and semantically encoded meaning of a sentence and the pragmatic meaning that is inferred in an actual communicative situation. Several experimental studies have approached the processing of implicatures and examined the extent to which the derivation of the pragmatic...

Predictions of future events play an important role in daily activities, such as visual search, listening, or reading. They allow us to plan future actions and to anticipate their outcomes. Reading, a natural, commonly studied behavior, could shed light over the brain processes that underlie those prediction mechanisms. We hypothesized that differe...

The use of human neuroimaging technology provides knowledge about several emotional and cognitive processes at the neural level of organization. In particular, electroencephalographic (EEG) techniques allow researchers to explore high-temporal resolution of the neural activity that underlie the dynamics of cognitive processes. Although EEG research...

The influence of adverse environmental conditions on the organization and reorganization of the brain structure and function involves distinct neural systems at different levels of organization. Electroencephalographic (EEG) measures provide precise evidence on the temporal sequence in which relevant cognitive processes occur. Here, we offer a syst...

En el marco de un proyecto de intervención, orientado a optimizar el desempeño cognitivo a través de actividades de juego para madres y sus hijos, este estudio presenta los resultados de un análisis de asociación entre factores (a) individuales (i.e. cortisol; actividad electroencefalográfica; lenguaje; y salud), y (b) contextuales (i.e. caracterís...

Sensorimotor synchronization (SMS) is a form of referential behavior in which an action is coordinated with a predictable external stimulus. The neural bases of the synchronization ability remain unknown, even in the simpler, paradigmatic task of finger tapping to a metronome. In this task the subject is instructed to tap in synchrony with a period...

When a word is read more than once, reading time generally decreases in the successive occurrences. This Repetition Effect has been used to study word encoding and memory processes in a variety of experimental measures. We studied naturally occurring repetitions of words within normal texts (stories of around 3000 words). Using Linear Mixed Models...

We study the dynamics of objective and subjective measures of visibility and choice in brief presentations occurring within a fixation during free eye-movements. We show that brief presentations yield homogeneous levels of performance in a window that extends almost throughout the entire fixation. Instead, confidence judgments vary for presentation...

Despite the compelling contribution of the study of event related potentials (ERPs) and eye movements to cognitive neuroscience, these two approaches have largely evolved independently. We designed an eye-movement visual search paradigm that allowed us to concurrently record EEG and eye movements while subjects were asked to find a hidden target fa...

Cognitive psychologists have relied on dual-task interference experiments to understand the low-capacity and serial nature of conscious mental operations. Two widely studied paradigms, the Attentional Blink (AB) and the Psychological Refractory Period (PRP) have demonstrated a first-come first-served policy; processing a stimulus either impedes con...

In recent years, Independent Component Analysis (ICA) has become a standard to identify relevant dimensions of the data in neuroscience. ICA is a very reliable method to analyze data but it is, computationally, very costly. The use of ICA for online analysis of the data, used in brain computing interfaces, results are almost completely prohibitive....

We report a study of concurrent eye movements and electroencephalographic (EEG) recordings while subjects freely explored a search array looking for hidden targets. We describe a sequence of fixation-event related potentials (fERPs) that unfolds during ∼ 400 ms following each fixation. This sequence highly resembles the event-related responses in a...

Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) share DSM-IV criteria in adults and cause problems in decision-making. Nevertheless, no previous report has assessed a decision-making task that includes the examination of the neural correlates of reward and gambling in adults with ADHD and those with BD. We used the Iowa ga...

When presented with a sequence of visual stimuli in rapid succession, participants often fail to detect a second salient target, a phenomenon referred as the attentional blink (AB; Raymond, Shapiro, & Arnell, 1992; Shapiro, Raymond, & Arnell, 1997). On the basis of a vast corpus of experiments, several cognitive theories suggest that the blink resu...

The operations and processes that the human brain employs to achieve fast visual categorization remain a matter of debate. A first issue concerns the timing and place of rapid visual categorization and to what extent it can be performed with an early feed-forward pass of information through the visual system. A second issue involves the categorizat...

Does extensive practice reduce or eliminate central interference in dual-task processing? We explored the reorganization of task architecture with practice by combining interference analysis (delays in dual-task experiment) and random-walk models of decision making (measuring the decision and non-decision contributions to RT). The main delay observ...

Derivation of the equation to fit distribution of error rates (0.09 MB DOC)

When two tasks are presented within a short interval, a delay in the execution of the second task has been systematically observed. Psychological theorizing has argued that while sensory and motor operations can proceed in parallel, the coordination between these modules establishes a processing bottleneck. This model predicts that the timing but n...

Neurogenesis in the dentate gyrus of the hippocampus follows a unique temporal pattern that begins during embryonic development, peaks during the early postnatal stages and persists through adult life. We have recently shown that dentate granule cells born in early postnatal and adult mice acquire a remarkably similar afferent connectivity and firi...