Research
“Orientation” in space, time and person
The human experience is situated in space (here), time (now) and person (self, body). Nonetheless, we can vividly imagine ourselves navigating to other locations, we can re-experience past events as well as simulate future ones and we can picture ourselves in another person’s shoes. These high-order mental abilities rely on two fundamental cognitive functions: self-projection and orientation. While the former refers to our ability to deliberately disengage from the here, now or self and “mentally travel” to a specific location, moment or perspective, the latter is defined as the tuning between ourselves and the internal representation we form of the external world. The way in which we generate these internal representations, also dubbed as “cognitive maps” or “mental models”, and their underlying characteristics has recently become a heavily researched topic. At our lab we focus our research questions on the relations between these cognitive maps and the behaving self: Is orientation in space, time and person mediated by three separate neurocognitive faculties or do they rely on a similar metric system? How is the interplay between the experiencing-self and the represented-self managed? Do the neural mechanisms supporting orientation and self-projection extend beyond the spatial, temporal and social domains? Are notable landmarks, important events and significant others represented differently than negligible ones? How do we represent different spatial and temporal scales simultaneously and alternate between them interchangeably? By means of behavioral and functional neuroimaging studies we investigate these questions, with special interest in its relevance to clinical symptoms seen in various brain disorders.
Alzheimer’s Disease
Alzheimer’s disease (AD) is an incurable, progressive degenerative neurological disorder causing immense suffering for patients and families. Accurately diagnosing the disease at an early stage is critical for intervention before extensive neuronal death takes place. We address this challenge by redefining AD as an orientation disorder (rather than a memory or general cognition disorder, as is widely accepted). An orientation test developed in our lab, which tests for orientation in the domains of space, time and person was shown to be highly sensitive for the classification of patients in different stages on the Alzheimer’s disease continuum. This test challenges the orientation brain system which highly overlaps the regions of the brain affected by the disease. A highly personal character of orientation can only now be addressed thanks to developments in AI, databases such as social media, and ML tools, which are enabled through an AI system we developed ‘Clara’ (claramind.com). Clara also enable mass-screening of preclinical population for very early diagnosis. Moreover, the test provides important scientific understanding pf the disease’s underlying neurocognitive and molecular mechanisms by demonstrating the monotonic decline of orientation in the entorhinal cortex and parallel hyperactivation of the medial temporal system in early stages, which later on decline. Our overarching goal is (1) to provide accurate, early AD-detection methods that are easy to administer to mass scanning at an early stage, and (2) to provide a clear and insightful neuroscientific basis to these methods and consequently, the nature of AD.
Agency and Ownership of cognitive maps
The concepts of agency of one’s actions and ownership of one’s experience have proven useful in relating body representations to bodily consciousness. Recently, we have applied these concepts to mental maps. Under this framework, agency is defined as ‘the sense that I am the one who is generating the experience represented on a mental map’, entailing beliefs, priors or inductions; ownership is defined as ‘the sense that I am the one who is undergoing an experience, represented on a mental map’, entailing the personal, self-referenced processing of information encountered. We endeavor to examine the roles of agency and ownership and their underlying neurocognitive and computational mechanisms.
Organizing Principles
Ecological validity and analyses. Experiments in cognitive psychology are usually applied in laboratory conditions using classical frequentist statistics. While this approach has led the field for many years, it also contributed to the reproducibility problem in psychology. Accordingly, in our research we request personalized, subject/patient-tailored design and stimuli, in the real and virtual world, complemented by analysis in the individual subject level in addition to group-level analysis. Using classifications, model-based or Bayesian tests we ensure our analyses fit such a design.
Network organization in the gray and white matter. The debate concerning the neural building blocks of cognition has fascinated the minds of cognitive neuroscientists since the field’s earliest days. The discovery of large-scale brain networks and their functional connectivity has proven to carry important explanatory power in the cognitive neuroscience. Therefore, we dedicate significant efforts to develop research tools for network organizational principles and their derivations. In addition, we have also emphasized network organization in the white matter.
Default Mode Network (DMN) A,B,x. Since its discovery in the start of the millennium, the DMN, a network of “high-order” brain regions, was associated with self-related activity. Moreover, it was also associated with various neuropsychiatric disorders, and most strongly with Alzheimer’s disease. In recent years the functional role of the DMN became more and more evident. Additionally, an intrinsic functional division within the DMN was highlighted. Our ongoing work about orientation in the domains of space, time and person showed a significant overlap with the DMN. Moreover, brain activity of orientation in the different domains showed tight conjunction to the subnetworks of the DMN in the individual subject level. The intertwining relations between the orientation brain system and the DMN plays therefore an important aspect of all our research scope, with specific focus on the individual subject/patient level.
Gradients. A cortical gradient is an axis of variance of a certain measurement of cortical activity, along which areas fall in a spatially continuous order. Gradiential arrangement is a recurrent finding in our research (e.g. body processing and organization of temporal and spatial scales). Arrangement of areas along a global gradient between primary/posterior and high-order/anterior regions is a key feature of human cortical organization, that may reflect evolutionary principles of the human brain. We explore gradients in the different domains, derive neuroscientific meanings and develop computational methods for their detection and application.
