Biology subjects

Dicke, P. W.

Publications and source records attributed to Dicke, P. W..

6 recordsLinked to original sources

bioRxiv2024

Minimally invasive electrocorticography (ECoG) recording in common marmosets

Electrocorticography (ECoG) enables high spatio-temporal resolution recordings of brain activity with excellent signal quality, making it essential for pre-surgical mapping in epilepsy patients and increasingly useful in neuroscience research, including the development of brain-machine interfaces. The relatively minimal cortical convolution in non-human primate (NHP) brains facilitates ECoG recordings, in particular in the common marmoset (Callithrix jacchus), whose lissencephalic (unfolded) brain surface provides broad cortical access. One of the key advantages of ECoG recordings is the ability to study interactions between distant brain regions. The standard approach is the usage of large electrode arrays, which, however, require extended trepanations and a trade-off between size and electrode spacing. This study introduces an alternative ECoG approach for examining interactions between multiple distant cortical areas in marmosets, combining the advantages of circumscribed trepanations with high-density electrode arrays at specific sites of interest. Two adult marmosets underwent ECoG implantation across frontal, temporal, and parietal regions of interest, assessed by circumscribed trepanations to position individual high density electrode arrays. Postoperative monitoring showed rapid recovery and no long-term complications. The animals remained healthy, and stable neural recordings were successfully obtained during behavioral tasks, highlighting the methods effectiveness for long-term cortical monitoring.

neuroscience↗

bioRxiv2024

Gaze and Arrows: does the Gaze Following Patch in the posterior temporal cortex differentiate social and symbolic spatial cues?

The Gaze Following Patch (GFP) is located in the posterior temporal cortex and has been described as a cortical module dedicated to processing other peoples gaze direction in a domain-specific manner. Thus, it appears to be the neural correlate of Baron-Cohens Eye-Direction Detector (EDD) which is one of the core modules in his Mindreading System - a neurocognitive model for the Theory of Mind concept. Inspired by Jerry Fodors ideas on the modularity of the mind, Baron-Cohen proposed that, among other things, the individual modules are domain-specific. In the case of the EDD this means that it exclusively processes eye-like stimuli to extract gaze direction and that other stimuli, that may carry directional information as well, are processed elsewhere. If the GFP is indeed EDDs neural correlate it must meet this expectation. To test this, we compared the GFPs BOLD activity during gaze-direction following with the activity during arrow-direction following. Contrary to the expectation based on the assumption of domain specificity we did not find a differentiation between gaze and arrow-direction following. In fact, we were not able to reproduce the GFP as presented in previous studies. A possible explanation is that in the present study - unlike previous work -, the gaze stimuli did not contain an obvious change of direction that represented a visual motion. Hence, the critical stimulus component responsible for the identification of the GFP in previous experiments might have been visual motion.

neuroscience↗

bioRxiv2023

Is there a brain area dedicated to socially guided spatial attention?

Where we look lets others know what we are interested in and allows them to join our focus of attention. In several studies our group investigated the neuronal basis of gaze following behavior in primates and described a gaze following patch (GFP) as the underlying functional unit. This makes the GFP a promising neurobiological correlate of Simon Baron-Cohens eye direction detector (EDD), an integral part of his mindreading system. With the latter, Baron-Cohen proposed a set of domain-specific neurocognitive modules implementing a Theory of Mind - the attribution of mental states to others. The tenet of domain-specificity requires that the EDD processes exclusively eye-like stimuli. In this preregistered fMRI study, we aimed to critically test if the GFP fulfills this criterion. Contrary to previous studies, we found that this was not the case and that it functionally and anatomically overlapped with the MT+ complex, putting the plausibility of Baron-Cohens mindreading model as a set of domain-specific modules into question. TeaserThe presented results demonstrate that a brain area previously thought to be a domain-specific cortical module specialized in processing other peoples focus of visual attention is, in fact, domain-general. More specifically, we show that it is indistinguishable from cortical areas involved in the processing of visual motion. These findings add to a growing body of evidence arguing against domain-specific accounts in social neuroscience which posit that the functional building blocks of social behaviors are facilitated by dedicated neurocognitive modules.

neuroscience↗

bioRxiv2021

A prosocial character of head-gaze aversion in common marmosets

Gaze aversion is a behavior adopted by several mammalian and non-mammalian species in response to eye contact and usually interpreted as reaction to perceived threat. Unlike many other primates, common marmosets (Callithrix jacchus) are thought to have high tolerance for direct gaze, barely exhibiting gaze avoidance towards conspecifics and humans. Here we show that this does not hold for marmosets interacting with a familiar experimenter who suddenly establishes eye contact in a playful interaction ("peek-a-boo"). In video footage synchronously recorded from the two agents, we found that our monkeys consistently alternated between eye contact and head-gaze aversion. The striking similarity with the gaze aversions dynamics exhibited by human infants interacting with their caregivers suggests a shared behavioral strategy to disengage temporarily from overwhelming social stimulation, in order to prepare for a new round of rewarding, affiliative face-to-face interaction. The potential of our finding for a marmoset model of autism is discussed.

animal behavior and cognition↗

bioRxiv2019

Reflexive gaze following in common marmoset monkeys

The ability to extract the direction of the others gaze allows us to shift our attention to an object of interest to the other and to establish joint attention. By mapping ones own expectations, desires and intentions on the object of joint attention, humans develop a Theory of (the others) Mind (TOM), a functional sequence possibly disrupted in autism. Although old world monkeys probably do not possess a TOM, they follow the others gaze and they establish joint attention. Gaze following of both humans and old world monkeys fulfills Fodors criteria of a domain specific function and is orchestrated by very similar cortical architectures, strongly suggesting homology. Also new world monkeys, a primate suborder that split from the old world monkey line about 35 million years ago, have complex social structures. One member of this group, the common marmoset (Callithrix jacchus), has received increasing interest as a potential model in studies of normal and disturbed human social cognition. Marmosets are known to follow human head-gaze. However, the question is if they use gaze following to establish joint attention with conspecifics. Here we show that this is indeed the case. In a free choice task, head-restrained marmosets prefer objects gazed at by a conspecific and, moreover, they exhibit considerably shorter choice reaction times for the same objects. These findings support the assumption of an evolutionary old domain specific faculty shared within the primate order and they underline the potential value of marmosets in studies of normal and disturbed joint attention.\n\nHIGHLIGHTSO_LICommon marmosets follow the head gaze of conspecifics in order to establish joint attention.\nC_LIO_LIBrief exposures to head gaze are sufficient to reallocate an animals attention.\nC_LIO_LIThe tendency to follow the others gaze competes with the attractional binding of the conspecifics face\nC_LI

animal behavior and cognition↗

bioRxiv2019

A fronto-temporo-parietal network disambiguates potential objects of joint attention

We use the others gaze direction to identify her/his object of interest and to shift our attention to the same object, i.e. to establish joint attention. However, gaze direction may not be sufficient to unambiguously identify the object of interest as the others gaze may hit more than one object. In this case, the observer must use a priori information to disambiguate the object choice. Using fMRI, we suggest that the disambiguation is based on a 3-component network. A first component, the well-known gaze following patch in the posterior STS is activated by gaze following per se. BOLD activity here is determined exclusively by the usage of gaze direction and is independent of the need to disambiguate the relevant object. On the other hand, BOLD activity revealing a priori information for the disambiguation and starting early enough to this end is confined to a patch of cortex at the inferior frontal junction. Finally, BOLD activity reflecting the convergence of both, a priori information and gaze direction, needed to shift attention to a particular object location is confined to the posterior parietal cortex.

neuroscience↗