P. Kuhnke: The Neural Bases of Conceptual Knowledge Retrieval

Date

Feb 22, 2023

Time

12:30 PM - 1:30 PM

Speaker

Dr. Philipp Kuhnke

Affiliation

Wilhelm Wundt Institute for Psychology, Leipzig University & Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig

Language

en

Main Topic

Psychologie

Other Topics

Psychologie

Description

The Neural Bases of Conceptual Knowledge Retrieval

Short abstract
Conceptual knowledge is central to human cognition. Previous research indicates that concepts consist of perceptual and motor features represented in modality-specific perceptual-motor brain regions. In addition, cross-modal convergence zones integrate modality-specific features into more abstract conceptual representations. However, several questions remain open: First, to what extent does the retrieval of perceptual-motor features depend on the concurrent task? Second, how do modality-specific and cross-modal regions interact during conceptual knowledge retrieval? Third, which brain regions are causally relevant for conceptually-guided behavior? Here, I will present three studies that addressed these key issues using functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) in the healthy human brain. The results of these studies indicate that conceptual knowledge retrieval involves both modality-specific and cross-modal regions in a task-dependent fashion. We propose a new model of the conceptual system, according to which conceptual processing relies on a flexible multi-level neural architecture from modality-specific to multimodal up to amodal brain regions.

Full abstract
Conceptual knowledge is central to human cognition. Previous research indicates that concepts consist of perceptual and motor features represented in modality-specific perceptual-motor brain regions. In addition, cross-modal convergence zones integrate modality-specific features into more abstract conceptual representations.

However, several questions remain open: First, to what extent does the retrieval of perceptual-motor features depend on the concurrent task? Second, how do modality-specific and cross-modal regions interact during conceptual knowledge retrieval? Third, which brain regions are causally relevant for conceptually-guided behavior? Here, I will present three studies that addressed these key issues using functional magnetic resonance imaging (fMRI) and transcranial magnetic stimulation (TMS) in the healthy human brain.

            Study 1—an fMRI activation study—tested to what extent the retrieval of sound and action features of concepts depend on the task (Kuhnke et al. 2020 Cerebral Cortex). 40 participants performed three different tasks—lexical decision, sound judgment, and action judgment—on words with a high or low association to sounds and actions. We found that modality-specific regions selectively respond to task-relevant features. Surprisingly, several regions (e.g. the left posterior inferior parietal lobe; pIPL) exhibited a task-dependent response to both sound and action features. We propose these regions to be “multimodal” convergence zones which retain modality-specific information.

            Study 2—an fMRI connectivity study—investigated the functional interaction between modality-specific and multimodal areas during conceptual knowledge retrieval (Kuhnke et al. 2021 Cerebral Cortex). We asked (1) whether modality-specific and multimodal regions are functionally coupled during sound and action feature retrieval, (2) whether their coupling depends on the task, (3) whether information flows bottom-up, top-down, or bidirectionally, and (4) whether their coupling is behaviorally relevant. We found that functional coupling between multimodal and modality-specific areas is task-dependent, bidirectional, and relevant for conceptually-guided behavior.

            Study 3—a TMS study—tested the causal relevance of left pIPL for sound and action feature retrieval (Kuhnke et al. 2020 NeuroImage). We found that TMS over left pIPL selectively impaired action judgments. Computational simulations of the TMS-induced electrical field revealed that stronger stimulation of left pIPL was associated with worse performance on action, but not sound, judgments. These results suggest that left pIPL is specialized for action knowledge, challenging the view of left pIPL as a multimodal conceptual hub.

            Overall, our studies support “hybrid theories” which assume that conceptual processing involves both modality-specific perceptual-motor regions and cross-modal convergence zones. In our new model of the conceptual system, we propose conceptual processing to rely on a flexible representational hierarchy from modality-specific to multimodal up to amodal brain regions.

Links

• Termindetails auf den Webseiten der TU Dresden (https://tu-dresden.de)

Last modified: Feb 22, 2023, 7:38:18 AM