I agree with the view expressed in the target article that the early structural organization of the mammalian neocortex (the primordial neocortical organization) is different from its final one and resembles the more primitive organization of reptilian cortex. During the early development of the neocortex, a distinctly mammalian multilayered pyramidal-cell plate is introduced within a more primitive reptilian-like cortex, establishing simultaneously layer I (marginal zone) above it and layer VII (subplate zone) below it. This multilayered pyramidal-cell plate represents (...) a recent mammalian innovation in the evolution of the cerebral cortex of vertebrates. Hence, the term neocortex is preferable to isocortex. (shrink)

Episodic memories are shaped by the representational format of their contents. These formats are not only determined by medial temporal lobe areas, but essentially also by the neocortical regions which these areas control. The representational formats of medial temporal lobe and neocortex are sufficient to determine both, memory contents and subjective memory qualities, without the further need for an attribution system.

Disregard of primary-process consciousness is endemic in mind science. Most neuroscientists subscribe to ruthless reductionism whereby mental qualities are discarded in preference for neuronal functions. Such ideas often lead to envisioning other animals, and all too often other humans, as unfeeling zombies. Merker correctly highlights how the roots of consciousness exist in ancient neural territories we share, remarkably homologously, with all the other vertebrates. (Published Online May 1 2007).

As bridges or brains become bigger or smaller, the changes pose problems of design thatneed to be solved. Larger brains could have larger or more neurons, or both. With largerneurons, it becomes difficult to maintain conduction times over longer axons andelectrical cable properties over longer dendrites. With more neurons, it becomes difficultfor each neuron to maintain its proportion of connections with other neurons. Theseproblems are addressed by making brains more modular, thereby reducing the lengths ofmany connections, and by altering functions. (...) Smaller brains may not have enoughneurons for all circuits, and they may lose modules and functions. Mammals with moreneocortex tend to have more cortical areas and more columns and types of columnswithin the larger areas. (shrink)

This paper reviews the fate of the central ideas behind the complementary learning systems (CLS) framework as originally articulated in McClelland, McNaughton, and O’Reilly (1995). This framework explains why the brain requires two differentially specialized learning and memory systems, and it nicely specifies their central properties (i.e., the hippocampus as a sparse, pattern-separated system for rapidly learning episodic memories, and the neocortex as a distributed, overlapping system for gradually integrating across episodes to extract latent semantic structure). We review the (...) application of the CLS framework to a range of important topics, including the following: the basic neural processes of hippocampal memory encoding and recall, conjunctive encoding, human recognition memory, consolidation of initial hippocampal learning in cortex, dynamic modulation of encoding versus recall, and the synergistic interactions between hippocampus and neocortex. Overall, the CLS framework remains a vital theoretical force in the field, with the empirical data over the past 15 years generally confirming its key principles. (shrink)

This paper examines social network size in contemporary Western society based on the exchange of Christmas cards. Maximum network size averaged 153.5 individuals, with a mean network size of 124.9 for those individuals explicitly contacted; these values are remarkably close to the group size of 150 predicted for humans on the basis of the size of their neocortex. Age, household type, and the relationship to the individual influence network structure, although the proportion of kin remained relatively constant at around (...) 21%. Frequency of contact between network members was primarily determined by two classes of variable: passive factors (distance, work colleague, overseas) and active factors (emotional closeness, genetic relatedness). Controlling for the influence of passive factors on contact rates allowed the hierarchical structure of human social groups to be delimited. These findings suggest that there may be cognitive constraints on network size. (shrink)

Brain evolution is a complex weave of species similarities and differences, bound by diverse rules and principles. This book is a detailed examination of these principles, using data from a wide array of vertebrates but minimizing technical details and terminology. It is written for advanced undergraduates, graduate students, and more senior scientists who already know something about “the brain,” but want a deeper understanding of how diverse brains evolved. The book's central theme is that evolutionary changes in absolute brain size (...) tend to correlate with many other aspects of brain structure and function, including the proportional size of individual brain regions, their complexity, and their neuronal connections. To explain these correlations, the book delves into rules of brain development and asks how changes in brain structure impact function and behavior. Two chapters focus specifically on how mammal brains diverged from other brains and how Homo sapiens evolved a very large and “special” brain. Key Words: basal ganglia; cladistics; development; hippocampus; homology; lamination; mammal; neocortex; neuromere; parcellation; primate. (shrink)

Is consciousness based in prefrontal circuits involved in cognitive processes like thought, reasoning, and memory or, alternatively, is it based in sensory areas in the back of the neocortex? The no-report paradigm has been crucial to this debate because it aims to separate the neural basis of the cognitive processes underlying post-perceptual decision and report from the neural basis of conscious perception itself. However, the no-report paradigm is problematic because, even in the absence of report, subjects might engage in (...) post-perceptual cognitive processing. Therefore, to isolate the neural basis of consciousness, a no-cognition paradigm is needed. Here, I describe a no-cognition approach to binocular rivalry and outline how this approach can help resolve debates about the neural basis of consciousness. (shrink)

Opponents to consciousness in fish argue that fish do not feel pain because they do not have a neocortex, which is a necessary condition for feeling pain. A common counter-argument appeals to the multiple realizability of pain: while a neocortex might be necessary for feeling pain in humans, pain might be realized differently in fish. This paper argues, first, that it is impossible to find a criterion allowing us to demarcate between plausible and implausible cases of multiple realization (...) of pain without running into a circular argument. Second, opponents to consciousness in fish cannot be provided with reasons to believe in the multiple realizability of pain. I conclude that the debate on the existence of pain in fish is impossible to settle by relying on the multiple realization argument. (shrink)

Some proponents of the Integrated Information Theory of consciousness profess strong views on the Neural Correlates of Consciousness, namely that large swathes of the neocortex, the cerebellum, at least some sensory cortices, and the so-called limbic system are all not essential for any form of conscious experiences. We argue that this connection is not incidental. Conflation between strong and weak versions of the theory has led these researchers to adopt definitions of NCC that are inconsistent with their own previous (...) definitions, inadvertently betraying the promises of an otherwise fruitful empirical endeavour. (shrink)

Dunbar's idea that neocortex size limits the number of relationships beings may be able to maintain is an engaging hypothesis for cognitive psychologists interested in a limited capacity model. It is suggested that the thesis would have been enhanced had the author considered the concept of peers as part of an information processing scheme.

How do minds emerge from developing brains? According to the representational features of cortex are built from the dynamic interaction between neural growth mechanisms and environmentally derived neural activity. Contrary to popular selectionist models that emphasize regressive mechanisms, the neurobiological evidence suggests that this growth is a progressive increase in the representational properties of cortex. The interaction between the environment and neural growth results in a flexible type of learning: minimizes the need for prespecification in accordance with recent neurobiological evidence (...) that the developing cerebral cortex is largely free of domain-specific structure. Instead, the representational properties of cortex are built by the nature of the problem domain confronting it. This uniquely powerful and general learning strategy undermines the central assumption of classical learnability theory, that the learning properties of a system can be deduced from a fixed computational architecture. Neural constructivism suggests that the evolutionary emergence of neocortex in mammals is a progression toward more flexible representational structures, in contrast to the popular view of cortical evolution as an increase in innate, specialized circuits. Human cortical postnatal development is also more extensive and protracted than generally supposed, suggesting that cortex has evolved so as to maximize the capacity of environmental structure to shape its structure and function through constructive learning. (shrink)

This paper begins by calling attention to a puzzling feature of our deep past: an apparent mis-match between morphological evolution in our lineage, including the expansion of our brain and neocortex, and changes in material culture. Three ideas might explain this mis-match. The apparent mis-match is an illusion: change in material culture is indeed driven by biological evolution, but of a kind difficult to identify in the fossil record; the mismatch is caused by the fact that material culture is (...) sensitive to the social and demographic environment, not just the native cognitive capacities of individual agents. Innovation and its uptake is more reliable in larger social worlds. The mis-match is made possible by adaptive phenotypic plasticity; in particular, cognitive plasticity. Just as material culture evolves through cumulative cultural learning, so too do cognitive skills, including ones which make innovations in, and the transmission of, material culture more efficient. This paper is targeted on the second of these ideas, and distinguishes three different versions of the view that increases in social scale support increases in the complexity of material culture. Those are: cultural selection is more efficient in larger social worlds; larger social worlds support more specialisation, which in turn supports a more complex material culture; cultural learning is more efficient in larger social worlds. The paper argues that the first two of these pathways are probably more important than the third in explaining otherwise puzzling features of the archaeological and ethnographic record. (shrink)

It is traditionally believed that cerebral activation (the presence of low voltage fast electrical activity in the neocortex and rhythmical slow activity in the hippocampus) is correlated with arousal, while deactivation (the presence of large amplitude irregular slow waves or spindles in both the neocortex and the hippocampus) is correlated with sleep or coma. However, since there are many exceptions, these generalizations have only limited validity. Activated patterns occur in normal sleep (active or paradoxical sleep) and during states (...) of anesthesia and coma. Deactivated patterns occur, at times, during normal waking, or during behavior in awake animals treated with atropinic drugs. Also, the fact that patterns characteristic of sleep, arousal, and waking behavior continue in decorticate animals indicates that reticulo-cortical mechanisms are not essential for these aspects of behavior. (shrink)

Grant Gillett argues that it is consciousness which makes a human or other being the 'locus of ethical value'. Since cortical functioning is, in Gillett's view, necessary for conscious activity, an individual whose neocortex is permanently non-functional is no longer a locus of ethical value and cannot be benefited or harmed in a morally relevant sense. This means that there is no obligation to continue treating those who have suffered neocortical death.

Creativity is the hallmark of human intelligence. Roli et al. (Frontiers in Ecology and Evolution 9:806283, 2022) state that algorithms cannot achieve human creativity. This paper analyzes cooperation between humans and intelligent algorithmic tools to compensate for algorithms’ limited creativity. The intelligent tools have functionality from the neocortex, the brain’s center for learning, reasoning, planning, and language. The analysis provides four key insights about human-tool cooperation to solve challenging problems. First, no neocortex-based tool without feelings can achieve human (...) creativity. Second, an interactive tool exploring users’ feeling-guided creativity enhances the ability to solve complex problems. Third, user-led abductive reasoning incorporating human creativity is essential to human-tool cooperative problem-solving. Fourth, although stakeholders must take moral responsibility for the adverse impact of tool answers, it is still essential to teach tools moral values to generate trustworthy answers. The analysis concludes that the scientific community should create neocortex-based tools to augment human creativity and enhance problem-solving rather than creating autonomous algorithmic entities with independent but less creative problem-solving. (shrink)

The processes whereby our brains continue to learn about a changing world in a stable fashion throughout life are proposed to lead to conscious experiences. These processes include the learning of top-down expectations, the matching of these expectations against bottom-up data, the focusing of attention upon the expected clusters of information, and the development of resonant states between bottom-up and top-down processes as they reach an attentive consensus between what is expected and what is there in the outside world. It (...) is suggested that all conscious states in the brain are resonant states and that these resonant states trigger learning of sensory and cognitive representations. The models which summarize these concepts are therefore called Adaptive Resonance Theory, or ART, models. Psychophysical and neurobiological data in support of ART are presented from early vision, visual object recognition, auditory streaming, variable-rate speech perception, somatosensory perception, and cognitive-emotional interactions, among others. It is noted that ART mechanisms seem to be operative at all levels of the visual system, and it is proposed how these mechanisms are realized by known laminar circuits of visual cortex. It is predicted that the same circuit realization of ART mechanisms will be found in the laminar circuits of all sensory and cognitive neocortex. Concepts and data are summarized concerning how some visual percepts may be visibly, or modally, perceived, whereas amodal percepts may be consciously recognized even though they are perceptually invisible. It is also suggested that sensory and cognitive processing in the What processing stream of the brain obey top-down matching and learning laws that are often complementary to those used for spatial and motor processing in the brain's Where processing stream. This enables our sensory and cognitive representations to maintain their stability as we learn more about the world, while allowing spatial and motor representations to forget learned maps and gains that are no longer appropriate as our bodies develop and grow from infanthood to adulthood. Procedural memories are proposed to be unconscious because the inhibitory matching process that supports these spatial and motor processes cannot lead to resonance. (shrink)

Recent research in cognitive and computational neuroscience portrays the neocortex as a hierarchically structured prediction machine. Several theorists have drawn on this research to challenge the traditional distinction between perception and cognition – specifically, to challenge the very idea that perception and cognition constitute useful kinds from the perspective of cognitive neuroscience. In place of this traditional taxonomy, such theorists advocate a unified inferential hierarchy subject to substantial bi-directional message passing. I outline the nature of this challenge and then (...) raise two objections to the cognitive architecture it proposes as a replacement: first, standard ways of characterising this inferential hierarchy are in tension with the representational reach of conceptual thought; second, there is compelling evidence that commonsense reasoning is structured around highly domain-specific intuitive theories that are difficult to situate within a single hierarchy. (shrink)

A tacit assumption since the 19th Century has been that the neocortex serves as the "seat of consciousness." An unexpected challenge to that assumption arose in 1949 with the discovery that high-frequency EEG activation associated with an alert state requires the intactness of the brainstem reticular formation. This discovery became the impetus for nearly three decades of research on what came to be known as the reticular activating system. By the 1970s, however, methodological and philosophical controversies led to general (...) abandonment of subcortical theories of attention and consciousness, with a return to an almost exclusive focus upon the cortex. With recent advances in the neurosciences the focus is shifting once more, this time to the unique contributions of cortical, thalmic, and brainstem structures in mediating selective attention and perceptual awareness. This paper offers a nontechnical review of the history of these developments up to contemporary interest in the putative role of oscillatory EEG patterns in the integration of perceptual features of experience. It puts forward the thesis that a key to understanding attention and consciousness is an appreciation of contributions of the thalmus to these cognitive processes. (shrink)

Abstract The language of consciousness and that of brain function seem vastly different and incommensurable ways of approaching human mental life. If we look at what we mean by consciousness we find that it has a great deal to do with the sensitivity and responsiveness shown by a subject toward things that happen. Philosophically, we can understnd ascriptions of consciousness best by looking at the conditions which make it true for thinkers who share the concept to say that one of (...) them is conscious. This depends on consciousness being manifest. When we also note that manifest, flexible and exploratory responses to one's environment are the basis of concept use, an a priori link between concepts and consciousness is forged. The brain structures subserving such responses are complex but crucially involve the multi?tracked and cross?linked information processing to be found in the neocortex. This function draws on the motivational and orienting activity arising in lower brain systems but orchestrates that into an articulated structure of behaviour control. The conclusion is that human consciousness is an umbrella term for complex and animated mental activity which makes extensive use of many different perceptual systems and also of the social milieu within which human cognition develops. (shrink)

Quartz (2002) argues that some recent findings about the evolution of the brain (Finlay & Darlington, 1995) are inconsistent with evolutionary psychologists’ massive modularity hypothesis. In substance, Quartz contends that since the volume of the neocortex evolved in a concerted manner, natural selection did not act on neocortical systems independently of each other, which is a necessary condition for the massive modularity of our cognition to be true. I argue however that Quartz’s argument fails to undermine the massive modularity (...) hypothesis. (shrink)

How certain neural mechanisms momentarily endow with the subjective awareness percepts and affects represented elsewhere is more likely to be clarified when structures essential to Mc are identified. The loss of C with bilateral thalmic lesions involving the intralaminar nuclei contrasts with retention of C after large cortical ablations depriving C of specific contents. A role of ILN in the perception of primitive sensations is suggested by their afference of directly ascending pathways. A role for ILN in awareness of cortical (...) activity is suggested by their widespread afference from cortex, a property shared with striatum. A role for ILN in volition is suggested by their heavy projection to striatum. Unlike striatum, ILN also project widely to almost all neocortex, enabling an effect on ideation; this last property is in common with other structures but none of them has the same direct cortical afference. And passage through the reticular nucleus of ILN efferents to cortex could impact the attention-selective action of nRt. It is suggested that the quickest route to a better understanding of C involves more intensive study of ILN. No other structure seems, in the light of our current knowledge, a more likely site for Mc. (shrink)

This target article presents a plausible evolutionary scenario for the emergence of the neural preconditions for language in the hominid lineage. In pleistocene primate lineages there was a paired evolutionary expansion of frontal and parietal neocortex (through certain well-documented adaptive changes associated with manipulative behaviors) resulting, in ancestral hominids, in an incipient Broca's region and in a configurationally unique junction of the parietal, occipital, and temporal lobes of the brain (the POT). On our view, the development of the POT (...) in our ancestors resulted in the neuroanatomical substrate consistent with the ability for representations in modality-neutral association cortex and, as a result of structure-imposing interaction with Broca's area, the hierarchically structured Evidence from paleoneurology and comparative primate neuroanatomy is used to argue that Homo habilis (2.5–2 million years ago) was the first hominid to have the appropriate gross neuroanatomical configuration to support conceptual structure. We thus suggest that the neural preconditions for language are met in H. habilis. Finally, we advocate a theory of language acquisition that uses conceptual structure as input to the learning procedures, thus bridging the gap between it and language. (shrink)

We argue that prediction success maximization is a basic objective of cognition and cortex, that it is compatible with but distinct from prediction error minimization, that neither objective requires subtractive coding, that there is clear neurobiological evidence for the amplification of predicted signals, and that we are unconvinced by evidence proposed in support of subtractive coding. We outline recent discoveries showing that pyramidal cells on which our cognitive capabilities depend usually transmit information about input to their basal dendrites and amplify (...) that transmission when input to their distal apical dendrites provides a context that agrees with the feedforward basal input in that both are depolarizing, i.e., both are excitatory rather than inhibitory. Though these intracellular discoveries require a level of technical expertise that is beyond the current abilities of most neuroscience labs, they are not controversial and acclaimed as groundbreaking. We note that this cellular cooperative context-sensitivity greatly enhances the cognitive capabilities of the mammalian neocortex, and that much remains to be discovered concerning its evolution, development, and pathology. (shrink)

In 1981, David Hubel and Torsten Wiesel received the Nobel Prize for their research on cortical columns—vertical bands of neurons with similar functional properties. This success led to the view that “cortical column” refers to the basic building block of the mammalian neocortex. Since the 1990s, however, critics questioned this building block picture of “cortical column” and debated whether this concept is useless and should be replaced with successor concepts. This paper inquires which experimental results after 1981 challenged the (...) building block picture and whether these challenges warrant the elimination “cortical column” from neuroscientific discourse. I argue that the proliferation of experimental techniques led to a patchwork of locally adapted uses of the column concept. Each use refers to a different kind of cortical structure, rather than a neocortical building block. Once we acknowledge this diverse-kinds picture of “cortical column”, the elimination of column concept becomes unnecessary. Rather, I suggest that “cortical column” has reached conceptual retirement: although it cannot be used to identify a neocortical building block, column research is still useful as a guide and cautionary tale for ongoing research. At the same time, neuroscientists should search for alternative concepts when studying the functional architecture of the neocortex. keywords: Cortical column, conceptual development, history of neuroscience, patchwork, eliminativism, conceptual retirement. (shrink)

We propose that rapid eye movement (REM) and slow-wave sleep contribute differently to the formation of episodic memories. REM sleep is important for building up invariant object representations that eventually recur to gamma-band oscillations in the neocortex. In contrast, slow-wave sleep is more directly involved in the consolidation of episodic memories through replay of sequential neural activity in hippocampal place cells.

In the past two decades, reinforcement learning has become a popular framework for understanding brain function. A key component of RL models, prediction error, has been associated with neural signals throughout the brain, including subcortical nuclei, primary sensory cortices, and prefrontal cortex. Depending on the location in which activity is observed, the functional interpretation of prediction error may change: Prediction errors may reflect a discrepancy in the anticipated and actual value of reward, a signal indicating the salience or novelty of (...) a stimulus, and many other interpretations. Anterior cingulate cortex has long been recognized as a region involved in processing behavioral error, and recent computational models of the region have expanded this interpretation to include a more general role for the region in predicting likely events, broadly construed, and signaling deviations between expected and observed events. Ongoing modeling work investigating the interaction between ACC and additional regions involved in cognitive control suggests an even broader role for cingulate in computing a hierarchically structured surprise signal critical for learning models of the environment. The result is a predictive coding model of the frontal lobes, suggesting that predictive coding may be a unifying computational principle across the neocortex. (shrink)

Part I of this two-part paper provided a broad overview of clinical and experimental findings bearing on the neural correlates of conscious processes. It was argued that several neurocognitive models related to: orienting to the outer world, dream sleep, and the integration of sensory-motor representations, converge upon a core ‘conscious system’, dubbed the extended reticular-thalamic activating system . The functions of the ERTAS, which shares extensive projections with the cerebral cortex, are mostly ‘implicit’, in contrast to the explicit representation of (...) conscious content within the neocortex. Part II expands this ERTAS model to encompass: the generation of coherent patterns of EEG activation, the integration of distributed cortical processes into a stream of unified percepts , and selective attention, as well as links between the ERTAS and systems providing the neural substrates for episodic memory and volition. (shrink)

The goal of computational cognitive neuroscience is to understand how the brain embodies the mind by using biologically based computational models comprised of networks of neuronlike units. This text, based on a course taught by Randall O'Reilly and Yuko Munakata over the past several years, provides an in-depth introduction to the main ideas in the field. The neural units in the simulations use equations based directly on the ion channels that govern the behavior of real neurons and the neural networks (...) incorporate anatomical and physiological properties of the neocortex. Thus the text provides the student with knowledge of the basic biology of the brain as well as the computational skills needed to simulate large-scale cognitive phenomena. (shrink)

This Element provides a comprehensive introduction to philosophy of neuroscience. It covers such topics as how neuroscientists procure knowledge, including not just research techniques but the use of various model organisms. It presents examples of knowledge acquired in neuroscience that are then employed to discuss more philosophical topics such as the nature of explanations developed in neuroscience, the different conception of levels employed in discussions of neuroscience, and the invocation of representations in neuroscience explanations. The text emphasizes the importance of (...) brain processes beyond those in the neocortex and then explores what makes processing in neocortex different. It consider the view that the nervous system consists of control mechanisms and considers arguments for hierarchical vs. heterarchical organization of control mechanisms. It concludes by considering implications of findings in neuroscience for how humans conceive of themselves and practices such as embracing norms. (shrink)

The paper gives a comparison of Durkheim´s sociogenetic approach, according to which the specific character of human knowledge consists in its being commonly created, culturally transmitted and transgeneratively communicated, with the biological approach, which considers the culture to be a continuation of biological nature. As an example the author uses the famous case study of Phine Gage, who as a consequence of a brain damage suffered from a serious personality disorder. This and other similar cases are interpreted as an evidence (...) of a specific inborn module of social thinking and decision making. More adequate is, according to the author, to consider this disorder as a disorder of the ability to integrate the rational and emotional regulations. Her argument is, that it is impossible to explain the human thinking and acting as a consequence of biological regulation - otherwise the controlling function of the neocortex looses it evolutionary importance. (shrink)

Cognitive deficits were produced in rats by different methods of damaging the brain: chronic ingestion of alcohol, causing widespread damage to diffuse cholinergic and aminergic projection systems; lesions (by local injection of the excitotoxins, ibotenate, quisqualate, and AMPA) of the nuclei of origin of the forebrain cholinergic projection system (FCPS), which innervates the neocortex and hippocampal formation; transient cerebral ischaemia, producing focal damage especially in the CA1 pyramidal cells of the dorsal hippocampus; and lesions (by local injection of the (...) neurotoxin, colchicine) of the granule cells of the dentate gyrus. Following chronic alcohol or lesions of the FCPS, transplants of cholinergically rich fetal brain tissue into the terminal areas (neocortex and/or hippocampus) restored performance almost to control levels, with a time course consistent with growth of the transplants and integration with host tissue; transplants of cholinergically poor fetal tissue (hippocampus) were without effect, as were transplants of cholinergically rich tissue into the region containing the nuclei of origin of the FCPS. Grafts of primary cells enriched in glia and cultured neuroblastoma cells into the terminal areas of the FCPS were equally effective, suggesting that there are multiple mechanisms by which neural transplants can restore cognitive function following diffuse cholinergic damage. In contrast, after ischaemia- or neurotoxin-induced damage to CA1 or dentate granule cells respectively, cholinergically rich fetal transplants into the damaged hippocampal formation were ineffective in restoring performance. After ischaemic damage, however, performance was restored by suspension grafts of CA1 cells but not by transplants containing CA3 pyramidal cells or granule cells; and after colchicine damage it was restored by solid grafts containing granule but not CA1 pyramidal cells. Furthermore, electrophysiological evidence has demonstrated functional, graft type-specific host-graft functional neuronal connectivity. Thus, restoration of cognitive function by neural transplants is possible after damage to either diffuse (cholinergic) or point-to-point (intrahippocampal) forebrain systems, but the transplant must be appropriate to the damage to be repaired. Because the different types of brain damage studied provide analogues of human alcoholic dementia, Alzheimer's disease, and heart attack, these results are encouraging with regard to the eventual application of neural transplant surgery to the treatment of cognitive deficits in humans. (shrink)

A complex brain network, centered on the hippocampus, supports episodic memories throughout their lifetimes. Classically, upon memory encoding during active behavior, hippocampal activity is dominated by theta oscillations (6-10Hz). During inactivity, hippocampal neurons burst synchronously, constituting sharp waves, which can propagate to other structures, theoretically supporting memory consolidation. This 'two-stage' model has been updated by new data from high-density electrophysiological recordings in animals that shed light on how information is encoded and exchanged between hippocampus, neocortex and subcortical structures such (...) as the striatum. Cell assemblies (tightly related groups of cells) discharge together and synchronize across brain structures orchestrated by theta, sharp waves and slow oscillations, to encode information. This evolving dynamical schema is key to extending our understanding of memory processes. (shrink)

This paper argues that humans possess unique cognitive abilities due to the presence of a functional system that exists in the human brain that is absent in the non-human brain. This system, the frontal feedback system, was born in the hominin brain when the great phylogenetic expansion of the prefrontal cortex relative to posterior sensory regions surpassed a critical threshold. Surpassing that threshold effectively reversed the preferred direction of information flow in the highest association regions of the neocortex, producing (...) the frontal feedback system. This reversal was from the caudo-rostral bias characteristic of non-human, or pre-human, brain dynamics to a rostro-caudal bias characteristic of modern human brain dynamics. The frontal feedback system works through frontal motor routines, or action schemes, manipulating the release and reconstruction of stored sensory memories in posterior sensory areas. As an obligatory feature of frontal feedback, a central character, or self, emerges within this cortical network that manifests itself as agent in these reconstructions as well as in the experience of sensory perceptions. Dynamical-systems modeling of cortical interactions is combined in the paper with recent neuroimaging studies of “resting-state” brain activity to bridge the gap between microscopic and macroscopic levels of cortical behavior. This synthesis is used to support the proposal of an information flow reversal occurring in the hominin brain and also to explain how such a reversal generates the wide variety of cognitive and experiential phenomena that many consider to be uniquely human. (shrink)

Insight is a cognitive feature that is usually regarded as being generated by the neocortex and being present only in humans and possibly some closely related primates. In this essay we show that especially corvids display behavioral skills within the domains of object permanence, episodic memory, theory of mind, and tool use/causal reasoning that are insightful. These similarities between humans and corvids at the behavioral level are probably the result of a convergent evolution. Similarly, the telencephalic structures involved in (...) higher cognitive functions in both species show a high degree of similarity, although the forebrain of birds has no cortex-like lamination. The neural substrate for insight-related cognitive functions in mammals and birds is thus not necessarily based on a laminated cortical structure but can be generated by differently organized forebrains. Hence, neither is insight restricted to mammals, as predicted from a “scala naturae”, nor is the laminated cortex a prerequisite for the highest cognitive functions. (shrink)