Sarit Ashkenazi

Using executive control training to suppress amygdala reactivity to aversive information

The ability to regulate emotions is essential for adaptive behavior. This ability is suggested to be mediated by the connectivity between prefrontal brain regions and the amygdala. Yet, it is still unknown whether the ability to regulate emotions can be trained by using a non-emotional procedure, such as the recruitment of executive control (EC). Participants who were trained using a high-frequent executive control (EC) task (80% incongruent trials) showed reduced amygdala reactivity and behavioral interference of aversive pictures. These effects were observed only following multiple-session training and not following one training session. In addition, they were not observed for participants exposed to low-frequent EC training (20% incongruent trials). Resting-state functional connectivity analysis revealed a marginally significant interaction between training group and change in the connectivity between the amygdala and the right inferior frontal gyrus (IFG). Amygdala-IFG connectivity was significantly increased following the training only in the high-frequent EC training group. These findings are the first to show that non-emotional training can induce changes in amygdala reactivity to aversive information and alter amygdala-prefrontal connectivity.

Domain-specific and domain-general effects on strategy selection in complex arithmetic: Evidences from ADHD and normally developed college students

Abstract The solution of multi-digit addition problems involves numerous strategies (e.g., retrieval or backup strategies). Here, we investigated the role of domain specific factors related to math ability, versus domain general factors such as executive functions on strategy selection and accuracy in complex addition problems. In order to examine the role of domain general processing, typically developed college students were compared to Attention-Deficit Hyperactivity Disorder (ADHD) students due to the ADHD deficits in executive function and sustained attention. We discovered that both domain specific factors and domain general factors play a significant role in the strategy selection process and accuracy. Importantly, domain specific and domain general abilities uniquely impact the complex arithmetical condition (carry over; e.g., 59+63) but not the simple arithmetical condition (non-carry; e.g., 52+63). Hence, the present finding suggests that superior executive function or superior sustained attention abilities can serve as a compensatory mechanism to low approximate number system acuity.

Visuospatial Attention Deficits in Developmental Dyslexia: Evidence from Visual and Mental Number Line Bisection Tasks

Previous research has shown that individuals with DD (developmental dyslexia) demonstrated a left mini neglect on visual line (VL) bisection tasks, which has been commonly referred to as right parietal dysfunction. However, insufficient reading experience characterizes dyslexia and may call into question the validity of this interpretation, since the VL bisection task has been found to be influenced by reading habits. The current study investigated whether altered performance of individuals with DD on bisection tasks may be attributed to impaired attentional mechanisms or to insufficient reading exposure. DD and control groups performed visual and mental number line bisection tasks, which have been shown to be modulated differently by reading habits. In both tasks, the magnitude of left bisection errors was significantly larger in the DD group compared with controls. This finding suggests attentional mechanisms act differently in dyslexia and supports evidence linking dyslexia to decreased function of the left hemisphere.

Automatic numerical-spatial association in synaesthesia: An fMRI investigation

ABSTRACT A horizontal mental number line (MNL) is used to describe how quantities are represented across space. In humans, the neural correlates associated with such a representation are found in different areas of the posterior parietal cortex, especially, the intraparietal sulcus (IPS). In a phenomenon known as number‐space synaesthesia, individuals visualise numbers in specific spatial locations. The experience of a MNL for number‐space synaesthetes is explicit, idiosyncratic, and highly stable over time. It remains an open question whether the mechanisms underlying numerical‐spatial association are shared by synaesthetes and nonsynaesthetes. We address the neural correlates of number‐space association by examining the brain response in a number‐space synaestheste (MkM) whose MNL differs dramatically in its ordinality and direction from that of a control group. MkM and 15 nonsynaesthetes compared the physical size of two numbers, while ignoring their numerical value, during an event‐related functional magnetic resonance imaging session (fMRI). Two factors were analysed: the numerical distance effect (NDE; e.g., 2−4 small distance vs. 1−6 large distance), and the size congruity effect (e.g., 2−8 congruent vs. 2−8 incongruent). Only for MkM, the NDE elicited significant activity in the left and right IPS, supramarginal gyrus (bilateral), and in the left angular gyrus. These results strongly support the role of the parietal cortex in the automatic coding of space and quantity in number‐space synaesthesia, even when numerical values are task‐irrelevant. HIGHLIGHTSNumber‐space synaesthetes visualise number in specific spatial locations.We addressed the neural correlates of such representation using fMRI.A synaesthete (MkM) and controls reported the physical size of numbers.Only for the synaesthete task‐irrelevant numbers elicited parietal activity.Results implicate the parietal cortex in the automatic coding of space and numbers.

The role of mathematical anxiety and working memory on the performance of different types of arithmetic tasks

Abstract Introduction Goal of the current study was to compare the respective roles of domain general cognitive skills with domain specific quantitative understanding, as well as the effect of math anxiety, on the performance of different types of arithmetic tasks. Methods Fifty-eight adults performed a battery of tests. Results We found dissociations between domain general abilities that supported verbally or spatially mediated arithmetic tasks. The verbally mediated tasks were supported by the verbal central executive component of working memory, while the spatially mediated task, number line knowledge, was supported by the spatial central executive component of working memory. Conclusions Different tasks had differential relationships with math anxiety: math anxiety effected school-like math tasks more than verbally mediated tasks and number line task. Math anxiety was negatively influenced by the spatial central executive component of working memory, indicating that spatial working memory can be a source of vulnerability to math anxiety.

Multiple Skills Underlie Arithmetic Performance: A Large-Scale Structural Equation Modeling Analysis

Current theoretical approaches point to the importance of several cognitive skills not specific to mathematics for the etiology of mathematics disorders (MD). In the current study, we examined the role of many of these skills, specifically: rapid automatized naming, attention, reading, and visual perception, on mathematics performance among a large group of college students (N = 1,322) with a wide range of arithmetic proficiency. Using factor analysis, we discovered that our data clustered to four latent variables 1) mathematics, 2) perception speed, 3) attention and 4) reading. In subsequent structural equation modeling, we found that the latent variable perception speed had a strong and meaningful effect on mathematics performance. Moreover, sustained attention, independent from the effect of the latent variable perception speed, had a meaningful, direct effect on arithmetic fact retrieval and procedural knowledge. The latent variable reading had a modest effect on mathematics performance. Specifically, reading comprehension, independent from the effect of the latent variable reading, had a meaningful direct effect on mathematics, and particularly on number line knowledge. Attention, tested by the attention network test, had no effect on mathematics, reading or perception speed. These results indicate that multiple factors can affect mathematics performance supporting a heterogeneous approach to mathematics. These results have meaningful implications for the diagnosis and intervention of pure and comorbid learning disorders.

Non-adaptive strategy selection in adults with high mathematical anxiety

Participants with mathematical anxiety (MA) tend to show particular difficulty in mathematical operations with high working memory (WM) demands compared to operations with lower WM demands. Accordingly, we examined strategy selection to test the cognitive mechanism underlying the observed weakness of high MA participants in mathematical operations with high WM demands. We compared two groups of college students with high or low MA, in the solution of simple non-carry addition problems (e.g., 54 + 63) and complex carryover addition problems (e.g., 59 + 63). The results indicated that high MA participants showed particular difficulty in the harder carry condition. Testing the strategy selection mechanism among high MA participants, we found in the carry condition 1) they used the common strategy less often compared to low MA participants and 2) employed unusual strategies more often compared to low MA participants. Therefore, high MA participants were less efficient in their strategy selection, which may be due to weaker spatial representations, numerical difficulties, or less experience solving complex problems. These primitive representations are not adaptive, and can negatively impact performance in math tasks with high WM demands.

Intentional and automatic processing of numerical information in mathematical anxiety: testing the influence of emotional priming

ABSTRACT Current theoretical approaches suggest that mathematical anxiety (MA) manifests itself as a weakness in quantity manipulations. This study is the first to examine automatic versus intentional processing of numerical information using the numerical Stroop paradigm in participants with high MA. To manipulate anxiety levels, we combined the numerical Stroop task with an affective priming paradigm. We took a group of college students with high MA and compared their performance to a group of participants with low MA. Under low anxiety conditions (neutral priming), participants with high MA showed relatively intact number processing abilities. However, under high anxiety conditions (mathematical priming), participants with high MA showed (1) higher processing of the non-numerical irrelevant information, which aligns with the theoretical view regarding deficits in selective attention in anxiety and (2) an abnormal numerical distance effect. These results demonstrate that abnormal, basic numerical processing in MA is context related.

Number line estimation under working memory load: Dissociations between working memory subsystems

Abstract Introduction The preverbal representation of quantity has been shown to associate with space, as quantities are spatially mapped on a mental number line. One traditional method to test this association is the number line estimation task that asks participants to locate a number on a number line. However, current approaches suggest that number line estimation task performance involves verbally mediated strategies such as reliance on reference points, questioning the nature of the task as a measurement of pure quantitative or spatial skills. Methods To resolve this conflict, in the current study participants performed the number line estimation task in three dual task conditions under phonological, spatial or visual working memory (WM) loads. Results We found that phonological WM load and spatial WM load affected performance, while visual WM load did not. Model fits indicated that number line estimation task performance was based on the usage of reference points. Conclusions Number line estimation task involved phonological WM and spatial WM which are required for the understanding of symbols and the spatial relation between them.

The Cognitive Estimation Task Is Nonunitary: Evidence for Multiple Magnitude Representation Mechanisms Among Normative and ADHD College Students

There is a current debate on whether the cognitive system has a shared representation for all magnitudes or whether there are unique representations. To investigate this question, we used the Biber cognitive estimation task. In this task, participants were asked to provide estimates for questions such as, “How many sticks of spaghetti are in a package?” The task uses different estimation categories (e.g., time, numerical quantity, distance, and weight) to look at real-life magnitude representations. Experiment 1 assessed (N = 95) a Hebrew version of the Biber Cognitive Estimation Task and found that different estimation categories had different relations, for example, weight, time, and distance shared variance, but numerical estimation did not. We suggest that numerical estimation does not require the use of measurement in units, hence, it represents a more “pure” numerical estimation. Experiment 2 found that different factors explain individual abilities in different estimation categories. For example, numerical estimation was predicted by preverbal innate quantity understanding (approximate number sense) and working memory, whereas time estimations were supported by IQ. These results demonstrate that cognitive estimation is not a unified construct.