Biology subjects

Cornelissen, P.

Publications and source records attributed to Cornelissen, P..

3 recordsLinked to original sources

bioRxiv2025

Diverse ways of holding verbal information in mind revealed with functional Magnetic Resonance Imaging and Transcranial Magnetic Stimulation: Individual differences in left anterior parietal cortex

Cognitive neuroscience has identified brain systems that reliably underpin specific abilities, including verbal short-term memory. However, there is no simple mapping between anatomy and function; moreover, brains are differently organised across people. In two functional magnetic resonance imaging studies, and using transcranial magnetic brain stimulation to test causality, we characterised differences in the neural processes supporting verbal short-term memory in healthy participants who varied in their use of semantic information. In group analyses, left anterior inferior parietal cortex showed the expected pattern for a "phonological buffer" -- this site was responsive to phonological tasks and verbal short-term memory for meaningless items. However, the functions of this site differed across the sample; individuals with the strongest "semantic reliance" in short-term memory (showing higher imageability effects and poorer nonword performance) showed weaker phonological responses. They also showed more activation when maintaining meaningful word sequences in short-term memory, compared with nonwords. In these semantically-reliant participants, left anterior inferior parietal cortex showed stronger functional connectivity to limbic and default mode regions during nonword rehearsal. While inhibitory stimulation to phonologically responsive regions disrupted nonwords more than words in people with good phonological short-term memory, these effects were reversed when verbal short-term memory was more semantically reliant. These findings show that left anterior inferior parietal cortex supports the maintenance of different kinds of verbal information across individuals.

neuroscience↗

bioRxiv2024

Interactions between weather, ungulates and geese create opportunities for wood-pasture cycles

Managing nature reserves to achieve coexistence of ungulate species and vegetation heterogeneity is challenging in small reserves. A central question is whether spatial heterogeneity is maintained or restored through occasional natural disturbances. This is the premise of the wood-pasture hypothesis, which asserts that natural disturbances, such as winter severity, are sufficiently significant to sustain the long-term coexistence of ungulate species and provide opportunities for the establishment of shrubs and trees, thereby enhancing vegetation heterogeneity. Testing the wood-pasture hypothesis under field conditions necessitates long-term time series of both vegetation and herbivore dynamics. Therefore, we employed a modeling approach to test this hypothesis. The study area was the Oostvaardersplassen, a nature reserve in the Netherlands characterized by rich and productive clay soil. This area hosts an assemblage of Heck cattle, Konik horses, and red deer. Additionally, large numbers of geese frequent this reserve, competing for the same food resources. The Oostvaardersplassen is one of the few areas in Europe where neither the populations of coexisting herbivore species nor the vegetation have been managed and its development was monitored for several decades. This provides unique insights into natural herbivore-vegetation interactions that can be applied to the management of other nature reserves. The results indicate that weather variability and the presence of both geese and large ungulates are essential factors in creating a heterogeneous landscape. The general pattern is that weather variability induces fluctuations in ungulate numbers, and geese reduce the numbers of ungulates. Coexistence of the three ungulate species remains possible regardless of weather variability and the presence of geese. However, the presence of the largest ungulate, cattle, is threatened when weather is highly variable and geese numbers are high. The vegetation is likely evolving towards a predominantly open landscape with occasional opportunities for the establishment of spiny shrub species. Nature reserves managed with an assemblage of ungulate species, which numbers are controlled by food supply, winter severity and competition, should thus focus on the substantial presence of a few species ("biomassality," e.g., for migratory birds) rather than achieving the highest species diversity in a small area ("biodiversity").

ecology↗

bioRxiv2017

Dynamic semantic cognition: Characterising coherent and controlled conceptual retrieval through time using magnetoencephalography and chronometric transcranial magnetic stimulation

Distinct neural processes are thought to support the retrieval of semantic information that is (i) coherent with strongly-encoded aspects of knowledge, and (ii) non-dominant yet relevant for the current task or context. While the brain regions that support coherent and controlled patterns of semantic retrieval are relatively well-characterised, the temporal dynamics of these processes are not well-understood. This study used magnetoencephalography (MEG) and dual-pulse chronometric transcranial magnetic stimulation (cTMS) in two separate experiments to examine temporal dynamics within the temporal lobe during the retrieval of strong and weak associations. MEG results revealed a dissociation within left temporal cortex: anterior temporal lobe (ATL) showed greater oscillatory response for strong than weak associations, while posterior middle temporal gyrus (pMTG) showed the reverse pattern. In the cTMS experiment, stimulation of ATL at ~150ms disrupted the efficient retrieval of strong associations, indicating a necessary role for ATL in coherent conceptual activations. Stimulation of pMTG at the onset of the second word disrupted the retrieval of weak associations, suggesting this site may maintain information about semantic context from the first word, allowing engagement of semantic control. Together these studies provide converging evidence for a functional dissociation within the temporal lobe, across both tasks and time.

neuroscience↗