Biology subjects

Lingnau, A.

Publications and source records attributed to Lingnau, A..

3 recordsLinked to original sources

bioRxiv2019

The representational space of observed actions

Categorizing and understanding other peoples actions is a key human capability. Whereas there exists a growing literature regarding the organization of objects, the representational space underlying the organization of observed actions remain largely unexplored. Here we examined the organizing principles of a large set of actions and the corresponding neural representations. Using multiple-regression representational similarity analysis of fMRI data, in which we accounted for variability due to major action-related features (body parts, scenes, movements, objects), we found that the semantic dissimilarity structure was best captured by patterns of activation in the lateral occipitotemporal cortex (LOTC) and the left posterior inferior parietal lobe (IPL). Together, our results demonstrate that the organization of observed actions in the LOTC and the IPL resembles the organizing principles used by participants to classify actions behaviorally, in line with the view that these regions are crucial for accessing the meaning of actions.

neuroscience↗

bioRxiv2019

Practiced naming of objects and actions: An fMRI study

Word retrieval deficits are a common problem in patients with stroke-induced brain damage. While complete recovery of language in chronic aphasia is rare, patients naming ability can be significantly improved by speech therapy. A growing number of neuroimaging studies have tried to pinpoint the neural changes associated with successful outcome of naming treatment. However, the mechanisms supporting naming practice in the healthy brain have received little attention. Yet, understanding these mechanisms is crucial for teasing them apart from functional reorganization following brain damage. To address this issue, we trained a group of healthy monolingual Italian speakers on naming pictured objects and actions for ten consecutive days and scanned them before and after training. Although activity during object vs. action naming dissociated in several regions (lateral occipitotemporal, parietal and left inferior frontal cortices), training effects for the two word classes were similar and included activation decreases in classical language regions of the left hemisphere (posterior inferior frontal gyrus, anterior insula), potentially due to decreased lexical selection demands. Additionally, MVPA revealed training-related activation changes in the left parietal and temporal cortices associated with the retrieval of knowledge from episodic memory (precuneus, angular gyrus) and facilitated access to phonological word forms (posterior superior temporal sulcus).

neuroscience↗

bioRxiv2019

Identifying cortical substrates underlying the phenomenology of stereopsis and realness: A pilot fMRI study

Viewing a real scene or a stereoscopic image (e.g., 3D movies) with both eyes yields a vivid subjective impression of object solidity, tangibility, immersive negative space and sense of realness; something that is not experienced when viewing single pictures of 3D scenes normally with both eyes. This phenomenology, sometimes referred to as stereopsis, is conventionally ascribed to the derivation of depth from the differences in the two eyes images (binocular disparity). Here we report on a pilot study designed to explore if dissociable neural activity associated with the phenomenology of realness can be localised in the cortex. In order to dissociate subjective impression from disparity processing, we capitalised on the finding that the impression of realness associated with stereoscopic viewing can also be generated when viewing a single picture of a 3D scene with one eye through an aperture. Under a blocked fMRI design, subjects viewed intact and scrambled images of natural 3-D objects and scenes under three viewing conditions: (1) single pictures viewed normally with both eyes (binocular) (2) single pictures viewed with one eye through an aperture (monocular-aperture); (3) stereoscopic anaglyph images of the same scenes viewed with both eyes (binocular stereopsis). Fixed-effects GLM contrasts aimed at isolating the phenomenology of stereopsis demonstrated a selective recruitment of similar posterior parietal regions for both monocular and binocular stereopsis conditions. Our findings provide preliminary evidence that the cortical processing underlying the subjective impression of realness may be dissociable and distinct from the derivation of depth from disparity.

neuroscience↗