Brain and cognitive evolution: forms of modularity and functions of mind

Genetic and neurobiological research is reviewed as related to controversy over the extent to which neocortical organization and associated cognitive functions are genetically constrained or emerge through patterns of developmental experience. An evolutionary framework that accommodates genetic constraint and experiential modification of brain organization and cognitive function is then proposed. The authors argue that 4 forms of modularity and 3 forms of neural and cognitive plasticity define the relation between genetic constraint and the influence of developmental experience. For humans, the result is the ontogenetic emergence of functional modules in the domains of folk psychology, folk biology, and folk physics. The authors present a taxonomy of these modules and review associated research relating to brain and cognitive plasticity in these domains.     

Numerosity discrimination in deep neural networks: Initial competence,developmental refinement and experience statistics

Both humans and non‐human animals exhibit sensitivity to the approximate number of items in a visual array, as indexed by their performance in numerosity discrimination tasks, and even neonates can detect changes in numerosity. These findings are often interpreted as evidence for an innate ‘number sense’. However, recent simulation work has challenged this view by showing that human‐like sensitivity to numerosity can emerge in deep neural networks that build an internal model of the sensory data. This emergentist perspective posits a central role for experience in shaping our number sense and might explain why numerical acuity progressively increases over the course of development. Here we substantiate this hypothesis by introducing a progressive unsupervised deep learning algorithm, which allows us to model the development of numerical acuity through experience. We also investigate how the statistical distribution of numerical and non‐numerical features in natural environments affects the emergence of numerosity representations in the computational model. Our simulations show that deep networks can exhibit numerosity sensitivity prior to any training, as well as a progressive developmental refinement that is modulated by the statistical structure of the learning environment. To validate our simulations, we offer a refinement to the quantitative characterization of the developmental patterns observed in human children. Overall, our findings suggest that it may not be necessary to assume that animals are endowed with a dedicated system for processing numerosity, since domain‐general learning mechanisms can capture key characteristics others have attributed to an evolutionarily specialized number system.     

Deviations in the emergence of representations: a neuroconstructivist framework for analysing developmental disorders

A common way of studying developmental disorders is to adopt a static neuropsychological deficit approach, in which the brain is characterized in terms of a normal brain with some parts or ‘modules’ impaired. In this paper we outline a neuroconstructivist approach in which developmental disorders are viewed as alternative developmental trajectories in the emergence of representations within neural networks. As a concrete instantiation of the assumptions underlying this general approach, we present a number of simulations in an artificial neural network model. The representations that emerge under different architectural, input and developmental timing conditions are then analysed within a multi‐dimensional state space. We explore alternative developmental trajectories in these simulations, demonstrating how initial differences in the same parameter can lead to very different outcomes, and conversely how different starting states can sometimes result in similar end states (phenotypes). We conclude that the assumptions of the neuroconstructivist approach are likely to be more appropriate for analysing developmental deviations in complex dynamic neural networks, such as the human brain.     

A modular neural-network model of the basal ganglia’s role in learning and selecting motor behaviours

This work presents a modular neural-network model (based on reinforcement-learning actor–critic methods) that tries to capture some of the most relevant known aspects of the role that basal ganglia play in learning and selecting motor behavior related to different goals. The model uses a mixture of experts network for the critic and a hierarchical network with two levels for the actor. Some simulations with the model show that basal ganglia select ‘chunks’ of behavior whose ‘details’ are specified by direct sensory-motor pathways, and how emergent modularity can help to deal with tasks with asynchronous multiple goals. A ‘top-down’ approach is adopted that first analyses some adaptive non-trivial interaction of a whole (simulated) organism with the environment, and its capacity to learn, and then attempts to implement these functions with neural architectures and mechanisms that have an empirical neuroanatomical and neurophysiological foundation.     

Neural reuse: a fundamental organizational principle of the brain

An emerging class of theories concerning the functional structure of the brain takes the reuse of neural circuitry for various cognitive purposes to be a central organizational principle. According to these theories, it is quite common for neural circuits established for one purpose to be exapted (exploited, recycled, redeployed) during evolution or normal development, and be put to different uses, often without losing their original functions. Neural reuse theories thus differ from the usual understanding of the role of neural plasticity (which is, after all, a kind of reuse) in brain organization along the following lines: According to neural reuse, circuits can continue to acquire new uses after an initial or original function is established; the acquisition of new uses need not involve unusual circumstances such as injury or loss of established function; and the acquisition of a new use need not involve (much) local change to circuit structure (e.g., it might involve only the establishment of functional connections to new neural partners). Thus, neural reuse theories offer a distinct perspective on several topics of general interest, such as: the evolution and development of the brain, including (for instance) the evolutionary-developmental pathway supporting primate tool use and human language; the degree of modularity in brain organization; the degree of localization of cognitive function; and the cortical parcellation problem and the prospects (and proper methods to employ) for function to structure mapping. The idea also has some practical implications in the areas of rehabilitative medicine and machine interface design.     

Naming with proper names: the left temporal pole theory

Existing empirical data on proper names processing are critically reviewed in trying to understand which tasks may involve the left temporal pole, which proper name related functions are supported by this structure and eventually offer some speculations about why these functions might have developed in this location in the course of human evolution. While clinical group studies support the idea that proper name processing takes place in the left temporal pole, single case studies of selective proper name anomia or sparing, as well as neuroimaging studies, suggest the involvement of a larger neural network. Within this network, an important role may be played by the ventro-medial prefrontal cortex, including areas critical in social interaction. The differentiation in the brain of proper name processing from common names processing could in part be due to social pressure, favouring a neural system able to more efficiently and unambiguously sustain designating categories or designating individual entities. The activation of the left temporal pole in proper name processing is shown to increase with age. Longer social interaction may thus contribute to convey proper names processing toward areas closer to those supporting social cognition.     

Evidence of Common Timing Processes in the Control of Manual,Orofacial, and Speech Movements

Recent investigations of timing in motor control have been interpreted as support for the concept of brain modularity. According to this concept, the brain is organized into functional modules that contain mechanisms responsible for general processes. Keele and colleagues (Keele & Hawkins, 1982; Keele & Ivry, 1987; Keele, Ivry, & Pokorny, 1987; Keele, Pokorny, Corcos, & Ivry, 1985) demonstrated that the within-subject variability in. cycle duration of repetitive movements is correlated across finger, forearm, and foot movements, providing evidence in support of a general timing module. The present study examines the notion of timing modularity of speech and nonspeech movements of the oral motor system as well as the manual motor system. Subjects produced repetitive movements with the finger, forearm, and jaw. In addition, a fourth task involved the repetition of a syllable. All tasks were to be produced with a 400-ms cycle duration; target duration was established with a pacing tone, which then was removed. For each task, the within-subject variability of the cycle duration was computed for the unpaced movements over 20 trials. Significant correlations were found between each pair of effectors and tasks. The present results provide evidence that common timing processes are involved not only in movements of the limbs, but also in speech and nonspeech movements of oral structures.     

Evidence of Common Timing Processes in the Control of Manual,Orofacial, and Speech Movements

Recent investigations of timing in motor control have been interpreted as support for the concept of brain modularity. According to this concept, the brain is organized into functional modules that contain mechanisms responsible for general processes. Keele and colleagues (Keele & Hawkins, 1982; Keele & Ivry, 1987; Keele, Ivry, & Pokorny, 1987; Keele, Pokorny, Corcos, & Ivry, 1985) demonstrated that the within-subject variability in cycle duration of repetitive movements is correlated across finger, forearm, and foot movements, providing evidence in support of a general timing module. The present study examines the notion of timing modularity of speech and nonspeech movements of the oral motor system as well as the manual motor system. Subjects produced repetitive movements with the finger, forearm, and jaw. In addition, a fourth task involved the repetition of a syllable. All tasks were to be produced with a 400-ms cycle duration; target duration was established with a pacing tone, which then was removed. For each task, the within-subject variability of the cycle duration was computed for the unpaced movements over 20 trials. Significant correlations were found between each pair of effectors and tasks. The present results provide evidence that common timing processes are involved not only in movements of the limbs, but also in speech and nonspeech movements of oral structures.     

Syntactic structure building in the anterior temporal lobe during natural story listening

The neural basis of syntax is a matter of substantial debate. In particular, the inferior frontal gyrus (IFG), or Broca’s area, has been prominently linked to syntactic processing, but the anterior temporal lobe has been reported to be activated instead of IFG when manipulating the presence of syntactic structure. These findings are difficult to reconcile because they rely on different laboratory tasks which tap into distinct computations, and may only indirectly relate to natural sentence processing. Here we assessed neural correlates of syntactic structure building in natural language comprehension, free from artificial task demands. Subjects passively listened to Alice in Wonderland during functional magnetic resonance imaging and we correlated brain activity with a word-by-word measure of the amount syntactic structure analyzed. Syntactic structure building correlated with activity in the left anterior temporal lobe, but there was no evidence for a correlation between syntactic structure building and activity in inferior frontal areas. Our results suggest that the anterior temporal lobe computes syntactic structure under natural conditions.     

In defense of experience-coding nonarbitrary temporal neural activity patterns

Various neurophysiological experiments have revealed remarkable correlations between cortical neuronal activity and subjective experiences. However, the mere presence of neuronal electrical activity does not appear to be sufficient to produce these experiences. It has been suggested that the explanation for the neural basis of consciousness might lie in understanding the reason that some types of neuronal activity possess subjective correlates and others do not. Here I propose and develop the idea that this difference may be caused by the existence of an elementary nonarbitrary linkage between temporal or spatiotemporal patterns of neuronal activity and their subjective attributes. I also show how cortical neural circuits capable of generating experience-coding patterns could emerge during evolution and brain development, due to the presence of spontaneous stochastic neuronal activity and activity-dependent synaptic plasticity. This hypothesis leads to several testable predictions, principal among which is the idea that the neural correlates of consciousness are essentially innate and universal.     

On the possibility of universal neural coding of subjective experience

Various neurophysiological experiments have revealed remarkable correlations between cortical neuronal activity and subjective experiences. However, the mere presence of neuronal electrical activity does not appear to be sufficient to produce these experiences. It has been suggested that the explanation for the neural basis of consciousness might lie in understanding the reason that some types of neuronal activity possess subjective correlates and others do not. Here I propose and develop the idea that this difference may be caused by the existence of an elementary nonarbitrary linkage between temporal or spatiotemporal patterns of neuronal activity and their subjective attributes. I also show how cortical neural circuits capable of generating experience-coding patterns could emerge during evolution and brain development, due to the presence of spontaneous stochastic neuronal activity and activity-dependent synaptic plasticity. This hypothesis leads to several testable predictions, principal among which is the idea that the neural correlates of consciousness are essentially innate and universal.     

Through neural stimulation to behavior manipulation: a novel method for analyzing dynamical cognitive models

The dynamical systems' approach to cognition (Dynamicism) promises computational models that effectively embed cognitive processing within its more natural behavioral context. Dynamical cognitive models also pose difficult, analytical challenges, which motivate the development of new analytical methodology. We start by illustrating the challenge by applying two conventional analytical methods to a well-known Dynamicist model of categorical perception. We then introduce our own analysis, which works by analogy with neural stimulation methods, and which yields some novel insights into the way the model works. We then extend and apply the method to a second Dynamicist model, which captures the key psychophysical trends that emerge when humans and animals compare two numbers. The results of the analysis-which reveals units with tuning functions that are monotonically related to the magnitudes of the numbers that the agents must compare-offer a clear contribution to the contentious debate concerning the way number information is encoded in the brain.     

社会互动视角下人际公平形成的脑机制

最后通牒博弈任务被广泛用以探究公平行为, 以往研究大多集中于对博弈中某一方决策行为和神经机制的探讨, 但是人际公平可能是互动双方重复博弈的结果。因此只考察单个大脑活动, 并不足以揭示由互动双方共同完成的社会认知活动的脑机制。因此, 本研究结合修改版的最后通牒博弈任务和基于fNIRS的超扫描技术, 从群体脑水平上考察人际公平形成的脑机制。行为结果显示, 相比无惩罚条件, 惩罚下提议者的分配金额更高, 且惩罚力度越强, 分配越趋近公平分配。fNIRS的结果显示, 惩罚下右侧背外侧前额叶皮层、顶下小叶和颞-顶联合区的脑间活动同步性显著强于无惩罚条件, 而且两条件的分配金额差异越大, 右侧顶下小叶的脑间活动同步性差异也越大。综上, 脑间活动同步性可以作为惩罚下人际公平形成的客观脑指标, 研究为探讨人际公平的内在机制提供了新的视角。     

Dissociable neural systems support retrieval of how and why action knowledge

In everyday discourse, people typically represent actions in one of two ways: how they are performed or why they are performed. In the present study, we determined the neural systems that support these natural modes of representing actions. Participants underwent functional magnetic resonance imaging while identifying how and why people perform various familiar actions. Identifying how actions are performed produced activity in premotor areas that support the execution of actions and in higher-order visual areas that support the perception of action-related objects; this finding supports an embodied view of action knowledge. However, identifying why actions are performed preferentially engaged areas of the brain associated with representing and reasoning about mental states; these areas were right temporoparietal junction, precuneus, dorsomedial prefrontal cortex, and posterior superior temporal sulcus. Our results suggest that why action knowledge is not sufficiently constituted by information in motor and visual systems, but requires a system for representing states of mind, which do not have reliable motor correlates or visual appearance.     

Sort out your neighbourhood

Axelrod (The evolution of cooperation, 1984) and others explain how cooperation can emerge in repeated 2-person prisoner’s dilemmas. But in public good games with anonymous contributions, we expect a breakdown of cooperation because direct reciprocity fails. However, if agents are situated in a social network determining which agents interact, and if they can influence the network, then cooperation can be a viable strategy. Social networks are modelled as graphs. Agents play public good games with their neighbours. After each game, they can terminate connections to others, and new connections are created. Cooperative agents do well because they manage to cluster with cooperators and avoid defectors. Computer simulations demonstrate that group formation and exclusion are powerful mechanisms to promote cooperation in dilemma situations. This explains why social dilemmas can often be solved if agents can choose with whom they interact.     

Connectionist models of development

How have connectionist models informed the study of development? This paper considers three contributions from specific models. First, connectionist models have proven useful for exploring nonlinear dynamics and emergent properties, and their role in nonlinear developmental trajectories, critical periods and developmental disorders. Second, connectionist models have informed the study of the representations that lead to behavioral dissociations. Third, connectionist models have provided insight into neural mechanisms, and why different brain regions are specialized for different functions. Connectionist and dynamic systems approaches to development have differed, with connectionist approaches focused on learning processes and representations in cognitive tasks, and dynamic systems approaches focused on mathematical characterizations of physical elements of the system and their interactions with the environment. The two approaches also share much in common, such as their emphasis on continuous, nonlinear processes and their broad application to a range of behaviors.     

Lexical access and the brain: anatomical constraints on cognitive models of word recognition.

Recent studies in the cognitive psychology of reading and many other skilled performances have been dominated by models inspired by neural connectivity (e.g., McClelland & Rumelhart, 1986). Such models have not yet begun to consider the accumulating evidence of considerable anatomical localization of component cognitive operations in the human brain (e.g., Posner, Petersen, Fox, & Raichle, 1988). In this article we apply anatomical findings to the job of building computational models of visual word recognition. Brain imaging studies already provide important constraints on how lexical access should be defined in terms of isolable encoding operations that compute the visual form, phonology, and semantics of words. Brain imaging studies also speak to issues of modularity versus interaction between these encoding operations, distribution versus localization of processing within the operations, and orchestration of operations to accomplish different word processing tasks. We conclude that a combined cognitive and anatomical analysis may be of considerable benefit in developing more adequate models of human information processing.     

Cognitive architecture of a mini-brain: the honeybee

Honeybees have small brains, but their behavioural repertoire is impressive. In this article we focus on the extent to which adaptive behaviour in honeybees exceeds elementary forms of learning. We use the concept of modularity of cognitive functions to characterize levels of complexity in the honeybee brain. We show that behavioural complexity in the honeybee cannot be explained by independent functions of vertically arranged, domain-specific processing modules, but requires horizontal integration in a central state, and we identify neural mechanisms that may underlie domain-specific processing and central integration. The honeybee may serve as a useful model for the study of intermediate levels of complexity in cognitive functions and the search for their neural substrates.     

自我控制资源与认知资源相互影响的机制:整合模型

尽管有学者认为自我控制资源和认知资源应该是两种独立的资源,但近期的研究却表明两种资源是互相影响的.以往研究从执行控制的角度解释两种资源为什么相互影响,但却没有指出两种资源如何影响执行控制,以及缺乏考虑神经机制和自我控制资源调节变量在其中的作用.为更系统地解释两种资源相互影响的机制,作者提出了一个整合模型,该模型指出:(1)两种资源相互影响的主要原因是两者都受到执行控制和前额叶皮层的影响;(2)个体进行自我控制或认知加工会消耗能量,产生心理疲劳,降低执行任务的动机,表现为前额叶皮层激活水平下降;(3)前额叶皮层激活不足进一步限制了执行控制在随后的自我控制和认知加工任务中的作用,因而影响后续自我控制或认知加工任务的表现;(4)自我控制资源调节变量通过提高个体对疲劳的耐受性、补充能量和提高动机等方法,使前额叶皮层和执行控制在完成前一阶段任务后仍然能够正常发挥作用,从而维持个体在后续自我控制或认知加工任务上的表现.未来的研究可考察自我控制资源与其他认知加工的关系;用动态的认知神经研究方法,建立前额叶皮层激活水平在前后两阶段任务之间的中介作用模型,以及研究自我控制资源调节变量的神经机制.