SPECIFIC FUNCTIONS OF THE BRAIN: PAPERS

 

Spontaneous activity of the brain displays lower information entropy than task-related activities

Tozzi A, Zare M, Benasich AA.  2016.  New Perspectives on Spontaneous Brain Activity: Dynamic Networks and Energy Matter.  Front Hum Neurosci. 10:247. doi: 10.3389/fnhum.2016.00247.

Spontaneous activity of the brain is generated in the absence of an explicit task and hence frequently associated to resting-state or default-network functions.  Despite its recent discovery has shed new light on questions concerning the structural and functional architecture of the brain and how they are related to “mind”, several issues still need to be assessed.  In this review, we focus on the scarcely explored energetic requirements and constraints of spontaneous activity, taking into account both thermodynamical and informational standpoints.  At first, we argue that the “classical” definitions of spontaneous activity do not take into account an important feature. Indeed, spontaneous brain activity is equipped with slower oscillations compared with the evoked, task-related one, hence it exhibits lower levels of enthalpy and free-energy.   Therefore, noteworthy thermodynamic energetic differences occur between spontaneous and evoked brain activities.  It means that the brain functions traditionally associated with spontaneous activity, such as mind wandering and so on, require less energy that other nervous activities.  We also review recent empirical observations in neuroscience, in an attempt to capture how spontaneous brain dynamics and mental function can be embedded in a non-linear dynamical framework, which talks about nervous activity in terms of phase spaces, particle trajectories, random walks, attractors and/or paths at the edge of the chaos.  This takes us from the thermodynamic free-energy to the realm of variational free-energy, a theoretical construct pertaining to probability and information theory and able to explain several unexplored features of spontaneous.

 

A neuroscientific account of syntax and semantics in the brain says that the first Wittgenstein was right 

Tozzi A, Peters JF, Fingelkurts A, Fingelkurts A, Perlovsky L.  2018. Syntax meets semantics during brain logical computations.  Progr Biophys Mol Biol, 140: 133-141.  https://doi.org/10.1016/j.pbiomolbio.2018.05.010. 

The discrepancy between syntax and semantics is a painstaking issue that hinders a better comprehension of the underlying neuronal processes in the human brain.  In order to tackle the issue, we at first describe a striking correlation between Wittgenstein’s Tractatus, that assesses the syntactic relationships between language and world, and Perlovsky’s joint language-cognitive computational model, that assesses the semantic relationships between emotions and “knowledge instinct”.  Once established a correlation between a purely logical approach to the language and computable psychological activities, we aim to find the neural correlates of syntax and semantics in the human brain.  Starting from topological arguments, we suggest that the semantic properties of a proposition are processed in higher brain’s functional dimensions than the syntactic ones.  In a fully reversible process, the syntactic elements embedded in Broca’s area project into multiple scattered semantic cortical zones. The presence of higher functional dimensions gives rise to the increase in informational content that takes place in semantic expressions.  Therefore, diverse features of human language and cognitive world can be assessed in terms of both the logic armor described by the Tractatus, and the neurocomputational techniques at hand.  One of our motivations is to build a neuro-computational framework able to provide a feasible explanation for brain’s semantic processing, in preparation for novel computers with nodes built into higher dimensionsPDF

 

Einstein’s special relativity and thoughts: an imagined object is stretched in jour mind

Tozzi A. 2018.  Einstein and the physics of the mind: Comment on “Physics of mind: experimental confirmations of theoretical predictions” by Felix Schoeller et al.Phys Life Rev, https://doi.org/10.1016/j.plrev.2018.01.009.

In touch with the Authors’ strong physicalist claims, we take a step further: to encompass the dynamics described by the Queen of physics, i.e., special relativity, into the fruitful framework of dynamic logic. Indeed, the subjective perception of time could be assessed through the objective reference frame described by Einstein’s four-dimensional spacetime in special relativity.  PDF

 

Tozzi A.  2018.  When Einstein’s relativity meets neuroscience.  PsyArXiv,  10.31234/osf.io/3n6c8. 

When perceived by the human mind, an object might encompass diverse content according to different observers.  Further, subjectively experienced time is encoded in the later entorhinal cortex.  Starting from these two observations concerning mental perception of space and time, and considering Einstein’s accounts, we show how, in terms of special relativity, imagination’s content is not stationary and fixed, rather depends on the observer’s standpoint.  We elucidate how the subjective phenomenon of time (perceived by our mind as static) might give rise to changes in quantifiable content between the real and the imagined object.  We describe how to correlate the quantifiable content of the sensed object embedded in the environment with the corresponding internal thought (subjective percept).  In particular, based on recent neuroscientific literature, we show how changes in our mental time windows are able to squeeze the information content of the subjective percepts, compared with their matching environmental objects.  Further, we elucidate how this novel framework could be able to confirm or reject a recently raised hypothesis, which suggests that the brain activity takes place in functional dimensions higher than our usual four-dimensional spacetime.   PDF

 

Topologically-framed theory of knowledge.  Starring: Richard Avenarius

Tozzi A, Peters JF.  2017.  Towards Topological Mechanisms Underlying Experience Acquisition and Transmission in the Human Brain.  Integr Psychol Behav Sci. 51(2), 303–323.  doi: 10.1007/s12124-017-9380-z.

Experience is a process of awareness and mastery of facts or events, gained through actual observation or second-hand knowledge.  Recent findings reinforce the idea that a naturalized epistemological approach is needed to further advance our understanding of the nervous mechanisms underlying experience.  This essay is an effort to build a coherent topological-based framework able to elucidate particular aspects of experience, e.g., how it is acquired by a single individual, transmitted to others and collectively stored in form of general ideas.  Taking into account concepts from neuroscience, algebraic topology and Richard Avenarius’ philosophical analytical approach, we provide a scheme which is cast in an empirically testable fashion.  In particular, we emphasize the foremost role of variants of the Borsuk-Ulam theorem, which tells us that, when a pair of opposite (antipodal) points on a sphere are mapped onto a single point in Euclidean space, the projection provides a description of both antipodal points.   These antipodes stand for nervous functions and activities of the brain correlated with the mechanisms of acquisition and transmission of experience.  PDF

 

Multisensory integration & Borsuk-Ulam theorem: when visual and auditory stimuli topologically melt

Tozzi A, Peters JF. 2017.  A Symmetric Approach Elucidates Multisensory Information Integration.  Information 8,1.  doi: 10.3390/info8010004. 

Recent advances in neuronal multisensory integration suggest that the five senses do not exist in isolation of each other. Perception, cognition and action are integrated at very early levels of central processing, in a densely-coupled system equipped with multisensory interactions occurring at all temporal and spatial stages. In such a novel framework, a concept from the far-flung branch of topology, namely the Borsuk-Ulam theorem, comes into play. The theorem states that when two opposite points on a sphere are projected onto a circumference, they give rise to a single point containing their matching description. Here we show that the theorem applies also to multisensory integration: two environmental stimuli from different sensory modalities display similar features when mapped into cortical neurons. Topological tools not only shed new light on questions concerning the functional architecture of mind and the nature of mental states, but also provide an empirically assessable methodology. We argue that the Borsuk-Ulam theorem is a general principle underlying nervous multisensory integration, resulting in a framework that has the potential to be operationalized.   

 

Gibson 4.0:  a topological account of the ecological theory of vision

Tozzi A, Peters JF. 2019.  Topology of Human Perception.  Preprints, 2019030235.

During the exploration of the surrounding environment, the brain links together external inputs, giving rise to perception of a persisting object.  During imaginative processes, the same object can be recalled in mind even if it is out of sight.   Here, topological theory of shape provides a mathematical foundation for the notion of persistence perception.  In particular, we focus on ecological theories of perception, that account for our knowledge of world objects by borrowing a concept of invariance in topology.  We show how a series of transformations can be gradually applied to a pattern, in particular to the shape of an object, without affecting its invariant properties, such as boundedness of parts of a visual scene. High-level representations of objects in our environment are mapped to simplified views (our interpretations) of the objects, in order to construct a symbolic representation of the environment. The representations can be projected continuously to an environmental object that we have seen and continue to see, thanks to the mapping from shapes in our memory to shapes in Euclidean space.  PDF