Biology subjects

Weisholtz, D. S.

Publications and source records attributed to Weisholtz, D. S..

4 recordsLinked to original sources

bioRxiv2022

Category-specific fMRI Correlates of Picture Naming: a study with Arabs and Filipinos

Cross cultural neuroimaging work has demonstrated differences in neural correlates of some cognitive processes between individuals from different cultures, often comparing American and Chinese subjects. In contrast, a limited number of studies examined Arab and/or Filipino participants. This fMRI study aimed to demonstrate neural activations during animal and tool picture naming by 18 healthy Arabs and 18 healthy Filipino participants. In animal naming contrasted with tool naming, Arabs preferentially activated regions in the right lateral occipital and fusiform cortices, whereas Filipinos recruited bilateral visual areas. Cross-group comparisons of animal naming revealed that Arabs recruited right visual areas more than Filipinos, who in turn recruited the cerebellum more than Arabs. In tool naming, Arabs preferentially activated a predominantly left frontoparietal network, whereas no regions were identified in Filipinos, and no differences in activation between groups were found. Using a low-demand picture-naming task, this study revealed category-specific neural activations during picture naming by Arabs and Filipinos, as well as between-group differences in animal naming. The results suggest that Arabs and Filipinos may have culture-specific differences in processing animate and inanimate pictures, and caution against generalizing findings from the more commonly studied populations, especially in verbal tasks such as picture naming. HIGHLIGHTS{blacksquare} The neural correlates of animal and tool picture naming in Arabs and Filipinos are category specific. {blacksquare}Animal naming by Arabs tended to preferentially activate the nondominant ventral visual stream. {blacksquare}Animal naming by Filipinos activated bilateral visual areas, and the cerebellum. {blacksquare}Tool naming by Arabs activated dominant frontoparietal areas related to praxis. {blacksquare}Results suggest that Arabs and Filipinos have culture-specific differences in visual processing.

neuroscience↗

bioRxiv2021

Impact of stimulation location relative to grey and white matter on single pulse electrical stimulation responses in the human brain

BackgroundElectrical neuromodulation is an increasingly common therapy for a wide variety of neuropsychiatric diseases. Unfortunately, therapeutic efficacy is inconsistent, possibly a result of our limited understanding of the mechanisms and the massive stimulation parameter space. Objective/HypothesisTo better understand the role different parameters play in inducing a response, we systematically examined single pulse-induced cortico-cortico evoked potentials (CCEP) as a function of stimulation amplitude, duration and location in the brain and relative to grey and white matter. MethodsWe measured voltage peak amplitudes and area under the curve of intracranially recorded stimulation responses as a function of distance from the stimulation site, pulse width, current injected, location relative to grey and white matter, and brain region stimulated (N=52, n=719 stimulation sites). ResultsIncreasing stimulation pulse width increased response values near the stimulation location. Increasing stimulation amplitude (current) increased responses nonlinearly. Locally (<15 mm from the stimulation site), stimulation closer to the grey matter-white matter boundary induced larger responses. In contrast, for distant sites (>15 mm), white matter stimulation consistently produced larger responses than stimulation in or near grey matter. These relationships were different between cingulate, lateral prefrontal, and lateral temporal cortical stimulation. ConclusionThese results demonstrate the importance of location and stimulation parameters in inducing a specific output and indicate that a stronger local response may require stimulation in the grey-white boundary while stimulation in the white matter may be needed for network activation, suggesting that stimulation location can be tailored for a specific outcome, key to informed neuromodulatory therapy. HighlightsO_LIIntracranial single pulse electrical stimulation (SPES) response increases with increased pulse duration mostly near the stimulation site C_LIO_LISPES response varies nonlinearly with injected current with an effect of distance from the stimulation site. C_LIO_LISPES near the grey-white boundary and 90{degrees} to the nearest cortical axis induces larger local responses, but white matter stimulation produces larger distant responses. C_LIO_LIThe relationship between SPES location and responses depends on brain region stimulated C_LI

neuroscience↗

bioRxiv2020

Closed loop enhancement and neural decoding of human cognitive control

Cognitive control is the ability to withhold a default, prepotent response in favor of a more adaptive choice. Control deficits are common across mental disorders, including depression, anxiety, and addiction. Thus, a method for improving cognitive control could be broadly useful in disorders with few effective treatments. Here, we demonstrate closed-loop enhancement of one aspect of cognitive control by direct brain stimulation in humans. We stimulated internal capsule/striatum in participants undergoing intracranial epilepsy monitoring as they performed a cognitive control/conflict task. Stimulation enhanced performance, with the strongest effects from dorsal capsule/striatum stimulation. We then developed a framework to detect control lapses and stimulate in response. This closed-loop approach produced larger behavioral changes than open-loop stimulation, with a slight improvement in performance change per unit of energy delivered. Finally, we decoded task performance directly from activity on a small number of electrodes, using features compatible with existing closed-loop brain implants. Our findings are proof of concept for a new approach to treating severe mental disorders, based on directly remediating underlying cognitive deficits.

bioengineering↗

bioRxiv2019

Bidirectional modulation of human emotional conflict resolution using intracranial stimulation

The ability to regulate emotions in the service of meeting ongoing goals and task demands is a key aspect of adaptive human behavior in our volatile social world. Consequently, difficulties in processing and responding to emotional stimuli underlie many psychiatric diseases ranging from depression to anxiety, the common thread being effects on behavior. Behavior, which is made up of shifting, difficult to measure hidden states such as attention and emotion reactivity, is a product of integrating external input and latent mental processes. Directly measuring, and differentiating, separable hidden cognitive, emotional, and attentional states contributing to emotion conflict resolution, however, is challenging, particularly when only using task-relevant behavioral measures such as reaction time. State-space representations are a powerful method for investigating hidden states underlying complex systems. Using state-space modeling of behavior, we identified relevant hidden cognitive states and predicted behavior in a standardized emotion regulation task. After identifying and validating models which best fit the behavior and narrowing our focus to one model, we used targeted intracranial stimulation of the emotion regulation-relevant neurocircuitry, including prefrontal structures and the amygdala, to causally modulate separable states. Finally, we focused on this one validated state-space model to perform real-time, bidirectional closed-loop adaptive stimulation in a subset of participants. These approaches enable an improved understanding of how to sample and understand emotional processing in a way which could be leveraged in neuromodulatory therapy for disorders of emotional regulation.

neuroscience↗