Basic functions of brain regions collectively known as the limbic system—the brain’s “police station” that assures cognitive functions and behavioral response that are most beneficial for the organism and the propagation of the species. The limbic system controls emotion and communicates interactively with higher processing levels of the cortex, particularly the prefrontal regions, relating everything the brain perceives and plans to the needs of the organism and vice versa. In higher species, the coherent operational mode of the cortico-limbic interplay gives rise to consciousness. The human brain is able to map and coor- dinate this interplay at an even higher level, which leads to self-consciousness. After Roederer (1995). 

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Context 1

... changes of relevance to the organism. To accomplish its integrative function, the animal brain evolved in a way quite different from the development of most other organs. Separate layers appeared, with distinct functions, overgrowing the older structures but not replacing them, thus preserving “older functions”. Subcortical structures such as the “limbic system” are phylogenetically old parts of the brain carrying information acquired during the evolution of the species. The outermost layer of the brain, or neocortex, executes all higher order cognitive operations, based on sensory information acquired during the lifetime of the organism. We thus have two neural information-processing systems that coexist and cooperate, working with two fundamentally distinct sources and types of information—genetic and acquired in real time. To understand the cognitive mechanisms in music perception it is important to examine in more detail how the various levels of sensory information processing and representation operate in the brain. For that purpose, we turn again to the visual system, with which the readers may be more familiar, pointing out those processing aspects that operate similarly in the auditory system (see the oversimplified sketch in Fig. 2 ; Roederer, 2000). The neural circuitry in the periphery and afferent pathways up to and including the so-called primary sensory receiving area of the cortex carries out some basic preprocessing operations mostly related to feature detection (e.g., detection of edges and motion in vision, spectral pitch and transients in hearing—see preceding section). The next stage is feature integration or binding , needed to sort out from an incredibly complex input those features that belong to one and the same spatial or temporal object (i.e., binding those edges together that define the boundary of the object; or in the auditory system, complex tone discrimination, i.e., sorting out those resonance regions on the basilar membrane that belong to the same musical tone). At this stage the brain “knows” that it is dealing with an object (or tone), but it does not yet know what the object is. This requires a complex process of comparison with existing, previously acquired information. The recognition process can be “automatic” by associative recall, or require a further analysis of the full sensory input in the prefrontal cortex. As one moves up the stages of Fig. 2 , the information processing becomes less automatic and more centrally controlled; in particular, more motivation-controlled actions and decisions are necessary, and increasingly the previously stored (learned) information will influence the outcome. A fundamental fact is that the paths shown in Fig. 2 can also operate in reverse : there is experimental evidence now that the memory recall (or, in humans, also the imagination) of a given object, triggers those specific neural activity distributions at lower levels that would occur if the object was actually seen. In the auditory system, “internal hearing” operates on this basis: the imagination of a melody or the recall of an entire musical piece is the result of the activation, or “replay”, of neural activity triggered somewhere in the prefrontal cortical areas (depending on the specific recall process), which then feed the appropriate information back down the line of the auditory processing stages creating sensory sensations without any sound whatsoever entering our ears. The motivational control of these processes deserves special attention. As mentioned above, one of the phylogenetically old parts of the vertebrate brain is the so-called limbic system , which works on the basis of genetic information represented in mostly prewired (inherited) networks. We use this term as a short-hand for several deep interconnected subcortical structures which, in conjunction with the cingulate cortex and the hypothalamus, construct neural representations of the information on the state of the organism, evaluate sensory input according to phylogenetic experiences, selectively direct memory storage according to the relevance or value of the information, and mobilize motor output ( Fig. 3 ; for a recent review see Dolan [2002]). Emotion (controlled by the deep structures) and motivation (controlled by the anterior cingulate) are integral manifestations of the limbic system's function. It constantly challenges the brain to find solutions to alternatives, to probe the environment, to overcome aversion and difficulty in the desire to achieve a goal, and to perform certain actions even if not needed by the organism at that moment. For the purpose of this article (see following sections), the most important examples of the latter are animal play and, for human beings, paying attention to music! In all its tasks, the limbic system communicates interactively with the cortex, particularly the prefrontal regions, relating everything the brain perceives and plans to the organism and vice versa ( Fig. 3 ). In short, the aim of this system is to ensure a behavioral response that is most beneficial to the organism and the propagation of the species according to genetically acquired information—the so called instincts and drives . To carry out its functions, the limbic system works in a curious way by dispensing sensations of reward or punishment; pleasure or pain; love or anger; happiness or sadness, anxiety and fear. Of course, only human beings can report to each other on these feelings , but on the basis of behavioral and neurophysiological studies we have every reason to believe that higher vertebrates also experience them. What kind of evolutionary advantage was there to this mode of operation? Why does an open wound hurt? Why do we feel pleasure scratching a mosquito bite, listening to Bach or having sex? How would we program similar reactions into a robot? Obviously this has much to do with evoking the anticipation of pain or pleasure whenever certain constellations of environmental events are expected to lead to something detrimental or favorable according to genetic experience, respectively. Since such anticipation comes before any actual harm or benefit could arise, it helps guide the organism's response into the direction of maximum chance of survival. In short, feelings direct a brain to want to survive and to find out the best way of doing so given unexpected, genetically unprogrammable, external circumstances. Plants cannot respond quickly and plants do not exhibit emotions; their defenses (spines, poisons) or insect-attracting charms (colors, scents) developed through the slow process of evolution. Reactions of non- vertebrate animals are neural-controlled but “automatic”—there is no interplay between two distinct neural information processing systems and there are no feelings guiding behavioral response. It is important to emphasize that the specific neural activity in cognitive acts is not limited to just one brain processing center, but that it involves much of the cortex and many underlying nuclei at the same time. What characterizes the neural activity distribution is that, even if many well- defined processing levels are involved, there is monolithic coherence and synchronism (von der Marlsburg, 1997), and consistent specificity with each cognitive act, feeling or motor output. While no doubt many subservient programs or “subroutines” are involved which do not reach consciousness but control very specific information-processing operations in highly localized “modules” (think of listening to music while driving!), there is only one “main program” (or “operating system”) which leads to unity of perception and behavior and represents the basic conscious state of the animal or human brain (close but not equal to what has been called “core consciousness” (Damasio, 1999)). There are fundamental operational and evolutionary reasons for having a single state of consciousness. First of all, if several “main programs” with different emotional states were to run at the same time, there could be no coherence between the many subsystems, and simultaneous but conflicting orders would ensue: the brain would fall into a sort of epileptic state. Second, the instantaneous state of brain activity as represented by a specific neural activity distribution must spread over processing networks that are responsible for memory recall in all modalities, in order to be able to trigger an appropriate behavioral response. And, finally, the specific neural activity must be intimately coupled to the limbic system, to be able to implement the dictates of the latter for the benefit of the organism (see Fig. 3 ). Without the guiding mechanism of a limbic “control station”, animal intelligence could not have evolved. This should also be true for animal-like intelligences elsewhere. Without instincts and drives the survival of a complex, mobile organism would be highly improbable. Without the drive to acquire information even if not needed at the moment, a repertoire of environmental information and appropriate responses thereto could not be built up in the memory. Without a coherent, cooperative mode of two distinct information processing systems, a cognitive one (mainly handling recent information) and an instinctive one (mainly working with genetic information and values), that is, without the single “main program” we call consciousness, animal-like intelligence would not be possible. From the neurophysiological and neuroanatomical points of view the human brain is not particularly different from that of a chimpanzee. It does have a cortex with more neurons (a total of 10 10 – 10 11 ) and some of the intercortical fasciculae have more fibers, but this difference is of barely one order of magnitude. More significant is the number of synapses in the adult brain, which for humans is several orders of magnitude larger (about 10 14 ). Is the difference in information processing capabilities only one of quantity ...

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... where it triggers a contraction. Later, neural networks evolved that could analyze and discriminate different types of input signals and send appropriate orders to different effectors. Finally, memory circuits emerged that could store relevant information for later use. The culmination of this evolutionary process is the animal brain as a central processor, coupling information stored in genes and ontogenic memory, as well as real-time information on body and environment, with behavioral motor output. We must assume that elsewhere in the Universe animal-like intelligence, a necessary precursor of human- like intelligence, also would require the evolution of an information gathering and processing system working on two basic time scales: a genetic one, and one dictated by the pace of real-time environmental changes of relevance to the organism. To accomplish its integrative function, the animal brain evolved in a way quite different from the development of most other organs. Separate layers appeared, with distinct functions, overgrowing the older structures but not replacing them, thus preserving “older functions”. Subcortical structures such as the “limbic system” are phylogenetically old parts of the brain carrying information acquired during the evolution of the species. The outermost layer of the brain, or neocortex, executes all higher order cognitive operations, based on sensory information acquired during the lifetime of the organism. We thus have two neural information-processing systems that coexist and cooperate, working with two fundamentally distinct sources and types of information—genetic and acquired in real time. To understand the cognitive mechanisms in music perception it is important to examine in more detail how the various levels of sensory information processing and representation operate in the brain. For that purpose, we turn again to the visual system, with which the readers may be more familiar, pointing out those processing aspects that operate similarly in the auditory system (see the oversimplified sketch in Fig. 2 ; Roederer, 2000). The neural circuitry in the periphery and afferent pathways up to and including the so-called primary sensory receiving area of the cortex carries out some basic preprocessing operations mostly related to feature detection (e.g., detection of edges and motion in vision, spectral pitch and transients in hearing—see preceding section). The next stage is feature integration or binding , needed to sort out from an incredibly complex input those features that belong to one and the same spatial or temporal object (i.e., binding those edges together that define the boundary of the object; or in the auditory system, complex tone discrimination, i.e., sorting out those resonance regions on the basilar membrane that belong to the same musical tone). At this stage the brain “knows” that it is dealing with an object (or tone), but it does not yet know what the object is. This requires a complex process of comparison with existing, previously acquired information. The recognition process can be “automatic” by associative recall, or require a further analysis of the full sensory input in the prefrontal cortex. As one moves up the stages of Fig. 2 , the information processing becomes less automatic and more centrally controlled; in particular, more motivation-controlled actions and decisions are necessary, and increasingly the previously stored (learned) information will influence the outcome. A fundamental fact is that the paths shown in Fig. 2 can also operate in reverse : there is experimental evidence now that the memory recall (or, in humans, also the imagination) of a given object, triggers those specific neural activity distributions at lower levels that would occur if the object was actually seen. In the auditory system, “internal hearing” operates on this basis: the imagination of a melody or the recall of an entire musical piece is the result of the activation, or “replay”, of neural activity triggered somewhere in the prefrontal cortical areas (depending on the specific recall process), which then feed the appropriate information back down the line of the auditory processing stages creating sensory sensations without any sound whatsoever entering our ears. The motivational control of these processes deserves special attention. As mentioned above, one of the phylogenetically old parts of the vertebrate brain is the so-called limbic system , which works on the basis of genetic information represented in mostly prewired (inherited) networks. We use this term as a short-hand for several deep interconnected subcortical structures which, in conjunction with the cingulate cortex and the hypothalamus, construct neural representations of the information on the state of the organism, evaluate sensory input according to phylogenetic experiences, selectively direct memory storage according to the relevance or value of the information, and mobilize motor output ( Fig. 3 ; for a recent review see Dolan [2002]). Emotion (controlled by the deep structures) and motivation (controlled by the anterior cingulate) are integral manifestations of the limbic system's function. It constantly challenges the brain to find solutions to alternatives, to probe the environment, to overcome aversion and difficulty in the desire to achieve a goal, and to perform certain actions even if not needed by the organism at that moment. For the purpose of this article (see following sections), the most important examples of the latter are animal play and, for human beings, paying attention to music! In all its tasks, the limbic system communicates interactively with the cortex, particularly the prefrontal regions, relating everything the brain perceives and plans to the organism and vice versa ( Fig. 3 ). In short, the aim of this system is to ensure a behavioral response that is most beneficial to the organism and the propagation of the species according to genetically acquired information—the so called instincts and drives . To carry out its functions, the limbic system works in a curious way by dispensing sensations of reward or punishment; pleasure or pain; love or anger; happiness or sadness, anxiety and fear. Of course, only human beings can report to each other on these feelings , but on the basis of behavioral and neurophysiological studies we have every reason to believe that higher vertebrates also experience them. What kind of evolutionary advantage was there to this mode of operation? Why does an open wound hurt? Why do we feel pleasure scratching a mosquito bite, listening to Bach or having sex? How would we program similar reactions into a robot? Obviously this has much to do with evoking the anticipation of pain or pleasure whenever certain constellations of environmental events are expected to lead to something detrimental or favorable according to genetic experience, respectively. Since such anticipation comes before any actual harm or benefit could arise, it helps guide the organism's response into the direction of maximum chance of survival. In short, feelings direct a brain to want to survive and to find out the best way of doing so given unexpected, genetically unprogrammable, external circumstances. Plants cannot respond quickly and plants do not exhibit emotions; their defenses (spines, poisons) or insect-attracting charms (colors, scents) developed through the slow process of evolution. Reactions of non- vertebrate animals are neural-controlled but “automatic”—there is no interplay between two distinct neural information processing systems and there are no feelings guiding behavioral response. It is important to emphasize that the specific neural activity in cognitive acts is not limited to just one brain processing center, but that it involves much of the cortex and many underlying nuclei at the same time. What characterizes the neural activity distribution is that, even if many well- defined processing levels are involved, there is monolithic coherence and synchronism (von der Marlsburg, 1997), and consistent specificity with each cognitive act, feeling or motor output. While no doubt many subservient programs or “subroutines” are involved which do not reach consciousness but control very specific information-processing operations in highly localized “modules” (think of listening to music while driving!), there is only one “main program” (or “operating system”) which leads to unity of perception and behavior and represents the basic conscious state of the animal or human brain (close but not equal to what has been called “core consciousness” (Damasio, 1999)). There are fundamental operational and evolutionary reasons for having a single state of consciousness. First of all, if several “main programs” with different emotional states were to run at the same time, there could be no coherence between the many subsystems, and simultaneous but conflicting orders would ensue: the brain would fall into a sort of epileptic state. Second, the instantaneous state of brain activity as represented by a specific neural activity distribution must spread over processing networks that are responsible for memory recall in all modalities, in order to be able to trigger an appropriate behavioral response. And, finally, the specific neural activity must be intimately coupled to the limbic system, to be able to implement the dictates of the latter for the benefit of the organism (see Fig. 3 ). Without the guiding mechanism of a limbic “control station”, animal intelligence could not have evolved. This should also be true for animal-like intelligences elsewhere. Without instincts and drives the survival of a complex, mobile organism would be highly improbable. Without the drive to acquire information even if not needed at the moment, a repertoire of environmental information and appropriate responses thereto could not be built up in the memory. Without a coherent, cooperative mode of ...

Context 3

... works on the basis of genetic information represented in mostly prewired (inherited) networks. We use this term as a short-hand for several deep interconnected subcortical structures which, in conjunction with the cingulate cortex and the hypothalamus, construct neural representations of the information on the state of the organism, evaluate sensory input according to phylogenetic experiences, selectively direct memory storage according to the relevance or value of the information, and mobilize motor output ( Fig. 3 ; for a recent review see Dolan [2002]). Emotion (controlled by the deep structures) and motivation (controlled by the anterior cingulate) are integral manifestations of the limbic system's function. It constantly challenges the brain to find solutions to alternatives, to probe the environment, to overcome aversion and difficulty in the desire to achieve a goal, and to perform certain actions even if not needed by the organism at that moment. For the purpose of this article (see following sections), the most important examples of the latter are animal play and, for human beings, paying attention to music! In all its tasks, the limbic system communicates interactively with the cortex, particularly the prefrontal regions, relating everything the brain perceives and plans to the organism and vice versa ( Fig. 3 ). In short, the aim of this system is to ensure a behavioral response that is most beneficial to the organism and the propagation of the species according to genetically acquired information—the so called instincts and drives . To carry out its functions, the limbic system works in a curious way by dispensing sensations of reward or punishment; pleasure or pain; love or anger; happiness or sadness, anxiety and fear. Of course, only human beings can report to each other on these feelings , but on the basis of behavioral and neurophysiological studies we have every reason to believe that higher vertebrates also experience them. What kind of evolutionary advantage was there to this mode of operation? Why does an open wound hurt? Why do we feel pleasure scratching a mosquito bite, listening to Bach or having sex? How would we program similar reactions into a robot? Obviously this has much to do with evoking the anticipation of pain or pleasure whenever certain constellations of environmental events are expected to lead to something detrimental or favorable according to genetic experience, respectively. Since such anticipation comes before any actual harm or benefit could arise, it helps guide the organism's response into the direction of maximum chance of survival. In short, feelings direct a brain to want to survive and to find out the best way of doing so given unexpected, genetically unprogrammable, external circumstances. Plants cannot respond quickly and plants do not exhibit emotions; their defenses (spines, poisons) or insect-attracting charms (colors, scents) developed through the slow process of evolution. Reactions of non- vertebrate animals are neural-controlled but “automatic”—there is no interplay between two distinct neural information processing systems and there are no feelings guiding behavioral response. It is important to emphasize that the specific neural activity in cognitive acts is not limited to just one brain processing center, but that it involves much of the cortex and many underlying nuclei at the same time. What characterizes the neural activity distribution is that, even if many well- defined processing levels are involved, there is monolithic coherence and synchronism (von der Marlsburg, 1997), and consistent specificity with each cognitive act, feeling or motor output. While no doubt many subservient programs or “subroutines” are involved which do not reach consciousness but control very specific information-processing operations in highly localized “modules” (think of listening to music while driving!), there is only one “main program” (or “operating system”) which leads to unity of perception and behavior and represents the basic conscious state of the animal or human brain (close but not equal to what has been called “core consciousness” (Damasio, 1999)). There are fundamental operational and evolutionary reasons for having a single state of consciousness. First of all, if several “main programs” with different emotional states were to run at the same time, there could be no coherence between the many subsystems, and simultaneous but conflicting orders would ensue: the brain would fall into a sort of epileptic state. Second, the instantaneous state of brain activity as represented by a specific neural activity distribution must spread over processing networks that are responsible for memory recall in all modalities, in order to be able to trigger an appropriate behavioral response. And, finally, the specific neural activity must be intimately coupled to the limbic system, to be able to implement the dictates of the latter for the benefit of the organism (see Fig. 3 ). Without the guiding mechanism of a limbic “control station”, animal intelligence could not have evolved. This should also be true for animal-like intelligences elsewhere. Without instincts and drives the survival of a complex, mobile organism would be highly improbable. Without the drive to acquire information even if not needed at the moment, a repertoire of environmental information and appropriate responses thereto could not be built up in the memory. Without a coherent, cooperative mode of two distinct information processing systems, a cognitive one (mainly handling recent information) and an instinctive one (mainly working with genetic information and values), that is, without the single “main program” we call consciousness, animal-like intelligence would not be possible. From the neurophysiological and neuroanatomical points of view the human brain is not particularly different from that of a chimpanzee. It does have a cortex with more neurons (a total of 10 10 – 10 11 ) and some of the intercortical fasciculae have more fibers, but this difference is of barely one order of magnitude. More significant is the number of synapses in the adult brain, which for humans is several orders of magnitude larger (about 10 14 ). Is the difference in information processing capabilities only one of quantity but not one of substance? Aristotle already recognized that “animals have memory and are able of instruction, but no other animal except man can recall the past at will”. More specifically, the most fundamentally distinct operation that the human, and only the human, brain can perform is to recall stored information as images or representations, manipulate them, and re-store modified or amended versions thereof without any concurrent external sensory input (Roederer, 1978). In other words, the human brain has internal control over the feedback information flow depicted in Fig. 2 ; in animal brains, that feedback can only be triggered by real-time somatic and sensorial input. The acts of information recall, alteration and re-storage without any external input represent the human thinking process or reasoning . More recently, J. Z. Young (1987) stated this in the following terms: “Humans have capacity to rearrange the ‘facts’ that have been learned so as to show their relations and relevance to many aspects of events in the world with which they seem at first to have no connection”. And Bickerton (1995) writes: “...only humans can assemble fragments of information to form a pattern that they can later act upon without having to wait on ... experience”. This had vast consequences in human evolution. The capability of re-examining, rearranging and altering images led to the discovery of previously overlooked cause-and-effect relationships (creation of new information), to a quantitative concept of elapsed time, and to the awareness of future time . Along this came the possibility of long-term prediction and planning (“information about the future”; Squires, 1990; Roederer, 2000), i.e., the mental representation of things or events that have not yet happened (this should not be confused with the capacity of higher vertebrates to anticipate the course of current events on a short-term basis of seconds or, at most, a few minutes). Concomitantly with this came the postponement of behavioral goals and, more generally, the capacity to overrule the dictates of the limbic system (think of a diet) and also to willfully stimulate the limbic system , without external input (think of sexual self-arousal). The body started serving the brain instead of the other way around! Mental images and emotional feelings could thus be created that had no relationship with momentary sensory input—the human brain can go “off-line”, as expressed by Bickerton (1995). Abstract thinking and artistic creativity began; the capacity to predict also brought the development of beliefs (unverifiable long-term predictions) and values (societally adopted priorities). Concurrently with this development came the ability to encode complex mental images into simple acoustic signals and the emergence of human language. This was of such decisive importance for the development of human intelligence that certain parts of the auditory and motor cortices began to specialize in verbal image coding and decoding, and the human thinking process began to be influenced and sometimes controlled by the language networks (this does not mean that we always think in words!). Finally, though much later in human evolution, there came the deliberate storage of information in the environment; this externalization of memory led to the documentation of events and feelings through visual symbols and written language, music scores, visual artistic expression, and science—to human culture as such. And it was only very recently that human beings started creating artifacts capable of processing information and entertaining information-based interactions with the ...