Zach Yaple | Purdue University (original) (raw)

Papers by Zach Yaple

The n-back task is likely the most popular measure of working memory for functional magnetic reso... more The n-back task is likely the most popular measure of working memory for functional magnetic resonance imaging (fMRI) studies. Despite accumulating neuroimaging studies with the n-back task and children, its neural representation is still unclear. fMRI studies that used the n-back were compiled, and data from children up to 15 years (n = 260) were analyzed using activation likelihood estimation. Results show concordance in frontoparietal regions recognized for their role in working memory as well as regions not typically highlighted as part of the working memory network, such as the insula. Findings are discussed in terms of developmental methodology and potential contribution to developmental theories of cognition.

Identifying facial expressions is crucial for social interactions. Functional neuroimaging studie... more Identifying facial expressions is crucial for social interactions. Functional neuroimaging studies show that a set of brain areas, such as the fusiform gyrus and amygdala, become active when viewing emotional facial expressions. The majority of functional magnetic resonance imaging (fMRI) studies investigating face perception typically employ static images of faces. However, studies that use dynamic facial expressions (e.g., videos) are accumulating and suggest that a dynamic presentation may be more sensitive and ecologically valid for investigating faces. By using quantitative fMRI meta-analysis the present study examined concordance of brain regions associated with viewing dynamic facial expressions. We analyzed data from 216 participants that participated in 14 studies, which reported coordinates for 28 experiments. Our analysis revealed bilateral fusiform and middle temporal gyri, left amygdala, left declive of the cerebellum and the right inferior frontal gyrus. These regions are discussed in terms of their relation to models of face processing.

Performance in the attentional blink task has been demonstrated to be directly influenced by alph... more Performance in the attentional blink task has been demonstrated to be directly influenced by alpha and beta neural oscillatory activity. In two experiments we stimulated the right parietal cortex and left frontal cortex with transcranial alternating current stimulation. For the first experiment we targeted only the right parietal cortex and found a non-significant increase in performance from 20 Hz stimulation. In the second experiment we applied two stimulators to the right parietal and left frontal cortex and found a significant increase in performance from 20 Hz tACS with a phase difference of 180°. Since low intensity stimulation has been shown to inhibit cortical excitability, and anti-phasic stimulation has been hypothesized to decrease presynaptic activation in one region and drive postsynaptic spikes in the other, we suggest that low intensity anti-phasic 20 Hz stimulation inhibited the parietal cortex, thereby disinhibiting the frontal cortex. This visual attention mechanism supposedly reduces processing of distractor stimuli and enhances processing of target stimuli. This study reveals that the frontal-parietal visual attention network may be modulated with low intensity 20 Hz anti-phase tACS.

A phenomenon termed negative priming is defined as an increase in reaction time and/or decrease i... more A phenomenon termed negative priming is
defined as an increase in reaction time and/or decrease in
performance during instances in which current target stimuli
are employed as distractor stimuli in the previous trial.
A recent qualitative review on negative priming reported
neural regions of interest underlined by activity within the
right middle frontal gyrus and left middle temporal gyrus;
however, these areas of interest have not been tested and
supported by using coordinate-based, quantitative metaanalysis.
We compiled functional magnetic resonance imaging
studies that examined neural correlates of priming tasks
using perceptual, conceptual and lexical primes. Effect-size
signed differential mapping was used to perform a neuroimaging
meta-analysis on the negative priming effect. Results
from fourteen studies (245 participants; 85 foci) show concordance
across studies in the right middle frontal gyrus
and the left superior temporal gyrus, as suggested by the
previous review; however, results also yielded concordance
within the anterior cingulate cortex. Our data support the
extant hypothesis and offer new insights into the neural
mechanisms of the negative priming effect.

In this study, we investigated the effect of transcranial alternating current stimulation (tACS) ... more In this study, we investigated the effect of transcranial alternating current stimulation (tACS) on voluntary risky decision making and executive control in humans. Stimulation was delivered online at 5 Hz (), 10 Hz (), 20 Hz (), and 40 Hz () on the left and right frontal area while participants performed a modified risky decision-making task. This task allowed participants to voluntarily select between risky and certain decisions associated with potential gains or losses, while simultaneously measuring the cognitive control component (voluntary switching) of decision making. The purpose of this experimental design was to test whether voluntary risky decision making and executive control can be modulated with tACS in a frequency-specific manner. Our results revealed a robust effect of a 20-Hz stimulation over the left prefrontal area that significantly increased voluntary risky decision making, which may suggest a possible link between risky decision making and reward processing, underlined by-oscillatory activity.

Top-down processing is a mechanism in which memory, context and expectation are used to perceive ... more Top-down processing is a mechanism in which memory, context and expectation are used to perceive stimuli. For this study we investigated how emotion content, induced by music mood, influences perception of happy and sad emoticons. Using single pulse TMS we stimulated right occipital face area (rOFA), primary visual cortex (V1) and vertex while subjects performed a face-detection task and listened to happy and sad music. At baseline, incongruent audiovisual pairings decreased performance, demonstrating dependence of emotion while perceiving ambiguous faces. However, performance of face identification decreased during rOFA stimulation regardless of emotional content. No effects were found between Cz and V1 stimulation. These results suggest that while rOFA is important for processing faces regardless of emotion, V1 stimulation had no effect. Our findings suggest that early visual cortex activity may not integrate emotional auditory information with visual information during emotion top-down modulation of faces.

This article addresses contemporary definitions of the self in both philosophical and cognitive n... more This article addresses contemporary definitions of the self in both philosophical and cognitive neuroscience literature. In this article, I attempt to operationally define the self by amalgamating Gallagher’s model of the narrative and minimal self with evidence from both psychological and cognitive neuroscience. Gallagher defines the narrative self as reflecting on past experiences and future endeavors. The narrative self shapes our expectations, beliefs, thoughts, feelings and actions and is susceptible to these beliefs, thoughts, feelings and actions when making decisions. Using this definition, Gallagher describes the narrative self as an ensemble of selves, a forever changing entity, contingent on mood, state and motivation. On the other hand, the minimal self is simply the self in the present objective state, irrespective of a person’s memories or future decisions. As Gallagher had described it, the minimal self is composed of the sense of ownership and the sense of agency. The sense of ownership is the acknowledgment of one’s own sense of self, which can be understood as a separate entity from non self objects. The sense of agency, however, is the understanding that the individual is the source of an action. In the next section, I discuss the operational definition of the self within the cognitive neuroscience literature. Using these philosophical definitions, I offer a bridge between these perspectives by comparing Gallagher’s narrative self with the default mode network.