When an animal attracts a mate or declares its ownership of a territory, it has to advertise. Signals used in communication usually have clearly defined functions, and signalling behaviour is sometimes associated with clear specialisations within the nervous system. Not only does the animal that sends signals need to make the meaning of its signals clear, but also the animals for which the signals are intended need to be able to capture, interpret and respond appropriately to those signals. So, during evolution, the motor signals that individuals of a species use to create signals need to be matched by appropriate sensory filters to recognise the same signals. For these and other reasons, communication is a fruitful area for investigation by neuroethologists.

In this chapter, we shall describe three different groups of animals that specialise in making and receiving particular types of signal. Two of these, crickets and song birds, use songs – extended patterned sounds – for communication. The other group are electric fish, which broadcast waves or pulses of electrical voltage in the water rather than audible sounds. The function of these electrical signals is not only to communicate with each other, but also to investigate their nearby surroundings. Sound and electric signals share the advantage that they can be used in conditions when sight is of limited use, such as at night or in undergrowth.

One of the most important and intriguing aspects of animal behaviour is that it continually changes. As they move around actively exploring their surroundings, animals rarely behave in completely predictable ways. That is evident just by observing flies walking on a table top: they rarely take more than a few steps in one direction, but often turn and stop for short times as they walk. Animals are programmed to change their behaviour when their environment alters, which is an efficient strategy that enables them to react appropriately to a wide variety of possible situations. Some of the changes are elements of the processes of development and maturation while others allow an animal to learn about alterations in its environment so it can make and modify predictions based on experience, for example to predict that a particular action will be followed by a rewarding or an aversive event. Sometimes learning particular features only happens during restricted time periods of an animal's life history, or critical periods. These are part of a programme of the normal development of behaviour – for example an owl develops its auditory map most easily during the first few weeks after hatching (Chapter 6), and a young song bird needs to hear the songs of adults during the first few weeks of its life so that when it matures it sings a song that is effective in attracting a mate (Chapter 9).

Individual neurons receive and transmit information in the form of small electrical signals. Most significantly, they also integrate the signals they receive, combining inputs from different sources and over time to determine their own outputs. Integration enables neurons to work together and form networks that perform the kinds of operations needed to control behaviour, such as sensory filtering or motor pattern generation. In this chapter we first provide the information about how neurons work that is needed to understand the later chapters in the book, starting with a description of how a simple sense organ works. We then illustrate the ways in which neurons receive and integrate signals in simple behavioural responses in two different animals: a mammal, and an insect. Sometimes these movements are called reflexes; they are almost automatic reactions to simple stimuli that affect a limited part of the body, and involve pathways of only a few neurons. They illustrate very well the basic principles of neuronal physiology.

The shortest neuronal pathways in arthropods and vertebrates include just two connected neurons: a sensory receptor, and a motor neuron. Sensory receptors are cells specialised to receive a particular form of environmental stimulus – such as light energy, mechanical movement, or chemical molecules in an odour – and to respond with an electrical signal. Some sensory receptors provide information about positions or movements of an animal's body parts, and receptors that do this are called proprioceptors.

Imagine a damp forest floor with a toad sitting motionless by a log. An insect scuttles from under the log, moving too fast to identify, and immediately the toad lunges towards the insect, flicking its tongue towards it. The toad misses its meal this time and the insect swivels away from the lunge of the toad and runs for cover; it was a cockroach (Fig. 3.1). These two behaviours, prey capture by toads and escape running by cockroaches, are excellent case studies in neuroethology because both show how it is possible to identify the roles played by individual nerve cells in recognising significant stimuli and triggering appropriate behavioural responses. In these cases, the stimuli require immediate action on the part of the animal. A toad will in fact try to catch and eat any small animal that moves along the ground in front of it; it probably does not hunt for cockroaches in particular. Likewise a cockroach will turn and run away from rapidly accelerating air currents, such as those produced by the sudden strike of any predator including a toad. Toads and cockroaches are not specifically adapted to detect each other, but natural selection has shaped the evolution of effective neuronal mechanisms that enable toads to recognise scuttling insects as a potential meal and cockroaches to escape from predatory assaults. In each behaviour, the animal needs to assimilate sensory information rapidly and to organise its motor response appropriately.

Summary

The striatum is a subcortical structure thought to be important for higher motor functions and reward processing. It is part of a larger system called the basal ganglia (BG) and composed of multiple subregions thought to be functionally heterogeneous. This review provides information and evidence for the role of the striatum in implementing the fixed action pattern of the grooming chain in the rat. The support for the involvement of the dorsolateral striatal subregion involved in the production of this movement sequence is described, and the general functional significance of implementation by striatal circuitry is discussed. Implementation is meant to refer to the ability of local processing within striatal circuits to enable motor action plans to be completed without distraction from competing sensory or motor demands. The idea that the striatum is involved in more than motor functions is developed and evidence for detailed processing of reward outcomes is presented. We introduce the possibility that the general nature of striatal function of “implementing” chains of information crosses different functional boundaries between movement and reward information. For movement plans, the implementation includes enabling motor sequences for appropriate output and for reward plans, the implementation includes enabling reward incentive hierarchies for appropriate outcome choices. These types of functions could rely upon cross-talk among striatal subregions and reveal a possible shared integrative function for the different “loops” of the BG circuitry.

Explaining grammar as meaningful

In the previous chapter I presented linguistic studies that concentrated on the integration of syntax and conceptual semantics. Chomsky (1957) proposed several varieties of formal structure descriptions originally based on standard frameworks of traditional grammar. Jackendoff (1983) demonstrated that an appropriate integration of phonological, syntactic and semantic phenomena requires a reorganization, in which each of the different domains determines its own principles of formal structure description. We have seen that this insight led to three stages in which the domain’s structure descriptions were represented independently but systematically integrated by means of interface relations. The previous chapter finished with a radical revision: The foundations of different domains and their integration should no longer be represented as phenomena in the body external world, that is, the world of things. Instead the external world should be pushed into the mind/brain/body that organizes the ranges of internal feelings and externally oriented perception, action and objective thought.

The reader may ask why many modern schools of linguistics had widely accepted logical formats as guidelines for descriptive representations. He should recall that antiquity and the middle ages already understood grammar and logic as related disciplines. All other disciplines had to be understood in domain-appropriate conception frameworks following schematic knowledge of grammar and logic. Accounting for the enormous progress of mathematics and logic linguistics also aimed at correspondingly improved formats and theories that nevertheless should be adapted to the characteristics of natural languages. Without abandoning the formalist techniques, theoretical linguistics should clearly circumscribe and define the basic properties that distinguish ordinary language from other notational systems, say of computer science, the genetic code, the “language” of bees etc. or from other knowledge frames defined for the sciences physics, genetics, formal information theory, computer theory etc.

Summary

We explore the possibility that self-grooming in response to the odors or presence of another animal plays a role in olfactory communication. For some animals, the substances released by self-grooming may make groomers more easily detected, more attractive, and/or less threatening to conspecifics that are in close proximity to them. The fact that animals self-groom at different rates when they encounter different individuals suggests that they can target particular conspecifics for purposes of communicating with them. Given that voles and other animals generally spend more time grooming in response to reproductively active, opposite-sex conspecifics than to reproductively quiescent opposite-sex conspecifics, self-grooming may be involved in attracting potential mates and is associated with the behaviors that surround reproduction. Studies have shown that conditions such as endocrine state, diet, age, and familiarity and relatedness of both the groomer and the scent donor affect the amount of time that individuals self-groom when they are exposed to the odors of opposite-sex conspecifics. Consequently, self-grooming in response to the odors of opposite-sex conspecifics may be akin to scent marking in that animals are transmitting odiferous substances into the environment that honestly signal features of their quality and condition to potential mates and competitors.

Introduction

As many terrestrial animals move about their home ranges they are surrounded by scent marks, some are their own and some are those of conspecifics. Animals investigating these scent marks can often determine many features about the individual that deposited them such as its sex, age, reproductive condition, diet, etc.

Grooming and related behaviors

Behavioral and pharmacological research continues to play a crucial role in modern neuroscience, often spearheading new and innovative techniques and models that further our understanding of the intricate workings of the nervous system. This is particularly evident in the arena of mental health research where, with the help of animal models and novel genetic or pharmacological treatments, new insights and theories are evolving to conceptualize more accurately common brain disorders such as anxiety, depression, obsessive–compulsive disorder (OCD), and schizophrenia.

These advances are allowing for an unprecedented examination of the heritable and environmental factors that contribute to disease pathogenesis. However, although there has been marked progress, the biological substrates of many of these disorders remain unclear. To establish a more concrete understanding of these disorders, a careful dissection of experimental phenotypes must be pursued. In this way, every aspect of behavior is a potentially fruitful source of experimental data that can provide clues to the contributing mechanisms.

One important example of such a behavior is grooming. Grooming is a very highly represented behavior in many animals, comprising a large proportion of their waking time. It serves an incredibly diverse range of purposes in the life of the animal from chemocommunication to basic hygiene. It is a natural behavior, yet it can be induced as part of an experimental procedure and has been shown to be sensitive to stress and bidirectionally sensitive to anxiolytic and anxiogenic drugs in rodents, making it an ideal focal point for high-throughput behavioral studies.

The integrated mind/brain/body: a new version of pushing “the world” into the mind/brain/body of a person

The previous chapter finished by emphasizing the importance of archetypes, mentioning also that Langacker’s dominant archetypes belong to the range of objective events. He acknowledged that archetypes in the range of emotions, feelings and self-experience and of other self-experience would transcend his collection of externally observable and objectively analysable facts. In this limited framework important aspects of internal human experience are excluded.

Jackendoff presents a number of arguments for a fundamental extension in which language, thought, perceived things and events in the world are organized in our mind/brain/bodies (Jackendoff 2002, p. 272–273, 305–306). The available structures of the world do not exist independently of our mind/brain/body’s organization generated in mutual cooperation and communication among social groups of people. This is even true for science; theories and measurement techniques are invented, developed, applied and checked in scientific communities. Though there is continuous search for progress, scientific knowledge also is never completed. I agree with Jackendoff that in view of extending our perspective we must go deeper into psychology and neuropsychology of neural assemblies for storing and processing conceptual structures in terms of neural assemblies. They interact with other organization systems, thus generating the interplay and integration of perception, action, attention, selectivity, emotions, feelings and self-awareness and mentalizing the psychology and functional neuropsychology of others. The complete system is in continuous mental and communicative contact with the normal community.

Summary

Electrical stimulation of the midline cerebellum and striatum elicits grooming in rats. Lesioning methods with either surgery or genetic mutations indicate that these brain regions contribute to grooming behaviors. Grid2Lc mutant mice with selective cerebellar atrophy and Girk2Wv mutants with combined cerebellar and substantia nigra atrophy display different effects on grooming. While Grid2Lc mutants were affected in grooming completion but not serial ordering, the reverse was true in Girk2Wv mutants. Our results implicate cerebello–neocortical pathways in the completion of grooming chains, and a striato–pallido–neocortical pathway in the serial ordering of grooming chains.

Introduction and methodological considerations

The role of the cerebellum and basal ganglia on grooming is of some importance considering that grooming implies movement. It is therefore expected that part of the neural circuitry underlying grooming involves some aspect of motor function. In view of the importance of the cerebellum and basal ganglia in balance and posture (Lalonde and Strazielle 2007a), there is a special challenge in interpreting lesion effects of these brain regions on grooming. This is achievable by measuring serial ordering of grooming sequences. It is well established that rodents groom in a cephalocaudal order, anterior before posterior body parts (Richmond and Sachs 1980; Sachs 1988). Different types of grooming components may also be measured, such as face washing; licking of forelimbs, abdomen, back, and hindlimbs; as well as body shaking and scratching (Vanderwolf et al. 1978). Lesions may selectively affect some grooming components in a fashion inexplainable by motor deficits.

Summary

Abnormal phospholipid metabolism has been implicated in the pathogenesis of schizophrenia, and phospholipase C (PLC) β1 was shown to be reduced in specific brain areas of patients with schizophrenia. However, the causal relationship of the PLCβ1 gene with the behavioral symptoms of schizophrenia remains unclear. Recent studies with the knockout (KO) mice for the PLCβ1 gene have revealed an array of interesting phenotypes, which along with other previous information makes the PLCβ1-KO mouse a good candidate for an animal model for schizophrenia. This also suggests that the PLCβ1-linked signaling pathways may be involved in the neural system whose function is disrupted in the pathogenesis of schizophrenia. In this chapter we will introduce various studies relevant to this issue, highlighting the social withdrawal phenotypes of the mutant, such as the lack of barbering behaviors.

Introduction

An animal model for a disease is expected to display endophenotypes, which are quantifiable phenotypes relevant to symptoms of the disease to be modeled (Braff and Freedman 2002; Gould and Gottesman 2006; van den Buuse et al. 2005). The endophenotypes currently pursued in schizophrenia models are: locomotive hyperactivity, sensorimotor gating deficit, deficits in social interaction, and cognitive deficits (e.g., learning and memory). Genetically modified mice targeted on candidate susceptibility genes have so far been generated as animal models for schizophrenia.