Category Archives: Animals

other animal brains and behavior compared to human

Ancient Origins – a great book

Ancient Origins – a great book

I have just read a book by Feinberg and Mallatt, The Ancient Origins of Consciousness – How the Brain Created Experience. It may turn out to be one of those classic books that cause a big change in accepted science. They tackle the ‘mystery of consciousness’ in a new way, a very biological way. The book ends with, “a satisfying and complete explanation of primary consciousness requires a confluence of points of view, necessarily including neurobiological, evolutionary, and philosophical arguments, each contributing important answers to the ‘hard question’. Perhaps one reason no one has solved it before is that it requires all three perspectives, including what happened over half a billion years ago.” I assume there will be many who find the book’s theory wanting because of they view neurobiological naturalism is impossible and believe normal science cannot explain consciousness. The authors brand of neurobiological naturalism has three postulates which the book documents:

1. “sensory consciousness can be explained by known neurobiological principles

2. “sensory consciousness is ancient and widespread in the animal kingdom, and diverse neural architectures can create it

3. “the philosophical issues of ontological subjectivity, neuroontological irreducibility, and the ‘hard problem’ can be explained by the nondissociable confluence of neurobiological and adaptive neuroevolutionary events.

The book has changed my ideas in a number of ways. First to fall was my attitude to the idea of ’emergent properties’. I have viewed it as a hedge, a cope-out, and even a way to bring dualism back in disguise. This book describes emergence in a way that makes sense. In a layered hierarchy each layer is created from the layer below but is more complex with novel elements which are labeled as emergent. But the external constraints act primarily on the top layer which constrains the layers beneath it. Thus there is both control and innovation by both bottom-up effects and top-down effects. Yes, this arrangement does need its own name and is a typical situation in living organisms. “In living systems such as the human body, cells constrain their subunits (organelles) to work together, the tissues and organs constrain their cells to cooperate, and the entire body constrains its organs to team up, all to perform the many physiological functions needed for the body to survive. If the constraints were to fail at any level, the body would disassemble and die.” A particular type of layered hierarchy, nested maps of the sensory organs such as the retina, is the basis of consciousness.

My second change of thinking was about the nature of the Cambrian explosion. It had seemed to me that the changes between geological periods were caused by changes to the environment like a meteor strikes which kill off the dominant animals and plants and allowed the others to flourish. But the book makes a case of a change to some animals being the cause and not the result of the abrupt explosion 560 – 520 million years ago. The result was new lines of animals which have populated the earth ever since. Predators appeared for the first time and this resulted in an arms race between predators and prey. There were many adaptations, and among them, improved distance sensing: vision, hearing and smell. Anthropoids and vertebrates in particular evolved high mobility and brains that improved sensory processing. A key change was image forming eyes. These allowed topographical maps of the retina. The other senses in vertebrates (except smell) re-evolved from a new cell line, on the pattern of the eye and its mapping in brain. In the resulting hierarchy of topographical maps for the senses, consciousness evolved.

I had assumed that the source of consciousness was lower in the brain than the cerebrum but was surprised by the location. The book documents it arising first in the optical tectum (superior colliculus in humans) and later extending to the thalamus and cerebrum, 220 years ago in mammals. This move not only added more layers to the existing hierarchies and put the top layer in close proximity to the sense of smell and its related memory in the cerebrum. This was a major advancement for consciousness for mammals and later for birds. Again I had to change my view as I had thought that memory and consciousness were always tightly bound.

The book also traces the evolution of affective consciousness (feelings and emotions), just as old as sensory consciousness. What was news to me was the intermingling of interoceptive bodily senses and affective limbic feelings giving three strains of consciousness.

The authors point out that the experience that the brain creates is embodied, personal, and does not include information about its creation – and therefore is wholly subjective and unique to each being. How this is done, the mechanism, is available to objective investigation. The subjective cannot see the objective and objective cannot see the subjective. There is a gap and it cannot be removed but neurobiological naturalism can ‘bridge’ it. This conclusion was not new to me as I have always been suspicious of whether the ‘hard question’ was really a question at all.

It’s a great book.

 

 

Time travel is not uniquely human

There are constantly statements about what abilities humans have that are unique. One of these is mental time travel. Decades ago Tulving put forward the notion of episodic memory and at the same time stated his opinion that it was unique to humans and that animals do not have episodic memory or a conscious experience of remembering. Suddendorf and Corballis put forward the notion of mental time travel: “the human ability to travel mentally in time constitutes a discontinuity between ourselves and other animals”. Lately Corballis has changed his mind: “Mental time travel has neurophysiology underpinnings that go far back in evolution, and may not be as some (including myself) have claimed, unique to humans.” Other animals may experience remembering specific events and may experience the planning of future events. In fact, I would find it difficult to explain their behavior if they did not have these abilities.

Imaging the old grandmother elephant leading her family to the bones of dead relatives, where they can touch and look at bones of specific dead loved ones. We know elephants are conscious even self-conscious, have theory of mind, have long memories, know and can navigate huge territories and know individual elephants that are not part of their group. I find it very difficult to imagine that when they touch the bones they have come to visit, they are not experiencing vivid memories of their dead relatives.

Time travel has been indicated in rats, pigeons, jays and dolphins but without convincing all critics. Now another study is even more convincing. (Gema Martin-Ordas, Dorthe Berntsen, Josep Call; Memory for Distant Past Events in Chimpanzees and Orangutans; Current Biology, Volume 23, Issue 15, p1438–1441, 2013) Here is the abstract:

Determining the memory systems that support nonhuman animals’ capacity to remember distant past events is currently the focus an intense research effort and a lively debate. Comparative psychology has largely adopted Tulving’s framework by focusing on whether animals remember what-where-when something happened (i.e., episodic-like memory). However, apes have also been reported to recall other episodic components after single-trial exposures. Using a new experimental paradigm we show that chimpanzees and orangutans recalled a tool-finding event that happened four times 3 years earlier (experiment 1) and a tool-finding unique event that happened once 2 weeks earlier (experiment 2). Subjects were able to distinguish these events from other tool-finding events, which indicates binding of relevant temporal-spatial components. Like in human involuntary autobiographical memory, a cued, associative retrieval process triggered apes’ memories: when presented with a particular setup, subjects instantaneously remembered not only where to search for the tools (experiment 1), but also the location of the tool seen only once (experiment 2). The complex nature of the events retrieved, the unexpected and fast retrieval, the long retention intervals involved, and the detection of binding strongly suggest that chimpanzees and orangutans’ memories for past events mirror some of the features of human autobiographical memory.

It seems unscientific to assume the answer before asking the question. Why was it assumed that animals did not feel? Then why assume that they did not think? Then, anyway they were not conscious, right? And now that they cannot consciously remember personal events? There was tool using, then tool making, and then serial tool use, all disproved. The only thing that has come close is that animals have no language ability. Even that may be over turned by whales. This drive to find human uniqueness and the stubbornness in defending it, is unbecoming to science. It is not creationism – but somehow it has a tiny bit of the same odour. Science should be looking at why animals (including humans) have a episodic memory, how it helps them think, plan, react and not whether it has some mystical ‘autonoetic’ insight to its conscious experience in humans but not other animals.

Beta waves

Judith Copithorne image

Judith Copithorne image

Brain waves are measured for many reasons and they have been linked to various brain activities. But very little is known about how they arise. Are they the result or the cause of the activities they are associated with? How exactly are they produced at a cellular or network level? We know little about these waves.

One type of wave, beta waves (18-25 Hz) are associated with consciousness and alertness. In the motor cortex they are found when muscle contractions are isotonic (contractions that do not produce movement) but are absent just prior and during movement. They are increased during sensory feedback to static motor control and when movement is resisted or voluntarily suppressed. In the frontal cortex the beta waves are found during attention to cognitive tasks directed to the outside world. They are found in alert attentive states, problem solving, judgment, decision making, and concentration. The more involved the cognitive activity the faster the beta waves.

ScienceDaily reports a press release from Brown University on the work of Stephanie Jones and team, who are attempting to understand how beta waves arise. (here) Three types of study are used: MEG recordings, computer models, and implanted electrodes in animals.

The MEG recordings from the somatosensory cortex (sense of touch) and the inferior frontal cortex (higher cognition) showed a very distinct form for the beta waves, “they lasted at most a mere 150 milliseconds and had a characteristic wave shape, featuring a large, steep valley in the middle of the wave.” This wave form was recreated in a computer model of the layers of the cortex. “They found that they could closely replicate the shape of the beta waves in the model by delivering two kinds of excitatory synaptic stimulation to distinct layers in the cortical columns of cells: one that was weak and broad in duration to the lower layers, contacting spiny dendrites on the pyramidal neurons close to the cell body; and another that was stronger and briefer, lasting 50 milliseconds (i.e., one beta period), to the upper layers, contacting dendrites farther away from the cell body. The strong distal drive created the valley in the waveform that determined the beta frequency. Meanwhile they tried to model other hypotheses about how beta waves emerge, but found those unsuccessful.” The model was tested in mice and rhesus monkeys with implanted electrodes and was supported.

Where do the signals come from that drive the pyramidal neurons? The thalamus is a reasonable guess at the source. Thalamo-cortex-thalamus feedback loop makes those very contacts of the thalamus axons within the cortex layers. The thalamus is known to have signals with 50 millisecond duration. All of the sensory and motor information that enters the cortex (except smell) comes though the thalamus. It regulates consciousness, alertness and sleep. It is involved in processing sensory input and voluntary motor control. It has a hand in language and some types of memory.

The team is continuing their study. “With a new biophysical theory of how the waves emerge, the researchers hope the field can now investigate beta rhythms affect or merely reflect behavior and disease. Jones’s team in collaboration with Professor of neuroscience Christopher Moore at Brown is now testing predictions from the theory that beta may decrease sensory or motor information processing functions in the brain. New hypotheses are that the inputs that create beta may also stimulate inhibitory neurons in the top layers of the cortex, or that they may may saturate the activity of the pyramidal neurons, thereby reducing their ability to process information; or that the thalamic bursts that give rise to beta occupy the thalamus to the point where it doesn’t pass information along to the cortex.

It seems very clear that understanding of overall brain function will depend on understanding the events at a cellular/circuit level; and that those processes in the cortex will not be understood without including other regions like the thalamus in the models.

Fish integrate their senses

Judith Copithorne image

Judith Copithorne image

Consciousness seems to have at its foundation the melding of information from all the senses into a integrated model of the world (and ourselves in it). It would be impossible to meld a sound with a sight, for example, without having a common framework of space and of time. And without the different senses informing one another, they would lose much of their usefulness. Therefore when we see melding of sensory information into a model, we can guess that there is a good probability that some level of consciousness exists. Two recent papers on fish show this sort of hint.

The first paper (Thompson, Vanwalleghem, Heap, Scott; Functional Profiles of Visual-, Auditory-, and Water Flow-Responsive Neurons in the Zebrafish Tectum; Current Biology 2016) shows that the tectum integrates sense information in a similar way to the human superior colliculus. “In order to function efficiently, fish and humans need a unified sensory view of the external world contributed to by multiple senses”, says Ethan Scott.

Using calcium imaging in transparent zebrafish, the dynamics of visual processing were shown to replicate previous studies. When sound or waterflow stimuli were used, a small number of cells in the tectum responded, similarly to the visual response but not showing the same cells. The visual response was somewhat less when other signals were present at the same time. This was similar to processes in the mammalian superior colliculus – information from various senses is integrated there.

The second paper (Schumacher, de Perera, Thenert, von der Emde; Cross-modal object recognition and dynamic weighting of sensory inputs in a fish; Proceedings of the National Academy of Sciences 2016) showed that fish can switch between senses as do monkeys, dophins, rats and humans.

The elephantnose fish explores objects in its surroundings by using its eyes or its electrical sense – sometimes both together. The skin contains numerous sensor organs that perceive objects in the water by means of the changed electrical field. “This is a case of active electrolocation, in principle the same as the active echolocation of bats, which use ultrasound to perceive a three- dimensional image of their environment.” Electrolocation is more useful at close range and vision is better at longer distances. The fish can, in effect, turn off one of the senses if the information from the other sense is more reliable.

Using darkness to force electrolocation and electrically transparent objects to force vision, the researchers could study the switching of the senses. They found that the fish could remember, find and recognize shapes experienced with one sense when using the other sense. They form a model of the space which could be used by either or both senses.

It seems that fish form a model of the their environment that all their senses can contribute to in an integrated way.

To see others as we see ourselves

In psychology there is a theory about the ‘fundamental attribution error’, the error in how we attribute causes to actions. When we look at our own actions, they are caused by our cognition in the circumstances in which we are deciding what to do. When we look at the actions of others, they are caused by their personality or character traits. So we do not really take into consideration the circumstances of others when we judge their actions. Nor do we consider the fixed patterns of our own behavior that do not enter into our conscious thoughts when we judge our own actions. We just do what is reasonable at the time and they just do what they always do. I can be too busy to help while they can be too thoughtless. This is a problem for us but at least we can understand the problem and occasionally overcome it. (My way to deal with it is to just assume that people are intelligent and well-meaning most of the time. If they do something that seems dumb or nasty, I look at the circumstances to see if there is a reasonable explanation. There very often is. I realize that this view of my own behaviour is somewhat ironic in its internal attribution – well nothing is perfect.)

But this problem with attribution is much greater than human social interaction. We do the same thing with animals. Elephants were tested for self recognition with the mirror test. If they recognize a black spot appearing on their forehead then it is clear that they know it is their forehead. Elephants failed the test and so they were said to not have a sense of self. It turned out that the mirrors used were too small. The elephants could not make out that it was an elephant in the mirror let alone themselves. If we start out underestimating an animals intelligence, and either not test that assumption or test it in a way that is inappropriate for the animal – then we are making a big attribution error.

There is an assumption on the part of many that vertebrate brains are quite different in the various sorts of vertebrates. This is not true! All animals with a spine have the same brain pattern with the same regions. All vertebrates have seven parts and no more or less: accessory olfactory bulb; cerebellum; cerebral hemispheres; medulla oblongata; olfactory bulb; optic tectum; and pituitary gland. There are differences in size, details and subdivisions, but there are no missing parts. (R.G. Northcutt; Understanding Vertebrate Brain Evolution; Integr. Comp. Biol. 2002 42(4) 743-756). There is every reason to believe that the brain works in fundamentally the same way in mammals, birds, reptiles, amphibians and fish. And by and large, this same pattern of brain has the same functions – to move, find/eat food, escape enemies and so on. It is obvious that animals have motor control and sensory perception.

What evidence is there that other animals have emotions, memory, or consciousness? Can they be automatons with no mental life? The reports trickle in year after year that add to the evidence that animals have a mental life similar to ours.

Reptiles probably dream. Most animal species sleep, from invertebrates to primates. However, neuroscientists have until now only actively recorded the sleeping brains of birds and mammals. Shein-Idelson et al. now describe the electrophysiological hallmarks of sleep in reptiles. Recordings from the brains of Australian dragons revealed the typical features of slow-wave sleep and rapid eye movement (REM) sleep. These findings indicate that the brainstem circuits responsible for slow-wave and REM sleep are not only very ancient but were already involved in sleep dynamics in reptiles.(Shein-Idelson, Ondracek, Liaw, Reiter, Laurent; Slow waves, sharp waves, ripples, and REM in sleeping dragons; Science 2016 Vol 352 (6285) 590-596) These wave types in sleep also are evidence for a memory system similar to ours.

Fish don’t make noise or wave their fins to show emotion but that does not mean they don’t have emotions. “Whether fishes are sentient beings remains an unresolved and controversial question. Among characteristics thought to reflect a low level of sentience in fishes is an inability to show stress-induced hyperthermia (SIH), a transient rise in body temperature shown in response to a variety of stressors. This is a real fever response, so is often referred to as ‘emotional fever’. It has been suggested that the capacity for emotional fever evolved only in amniotes (mammals, birds and reptiles), in association with the evolution of consciousness in these groups. According to this view, lack of emotional fever in fishes reflects a lack of consciousness. We report here on a study in which six zebrafish groups with access to a temperature gradient were either left as undisturbed controls or subjected to a short period of confinement. The results were striking: compared to controls, stressed zebrafish spent significantly more time at higher temperatures, achieving an estimated rise in body temperature of about 2–48C. Thus, zebrafish clearly have the capacity to show emotional fever. While the link between emotion and consciousness is still debated, this finding removes a key argument for lack of consciousness in fishes.” (Rey, Huntingford, Boltana, Vargas, Knowles, Mackenzie; Fish can show emotional fever: stress-induced hyperthermia in zebrafish; 2015 Proc. R. Soc. B 282: 20152266)

One of the problems with comparing the brains of different vertebrates is that they have been named differently. When development is followed through the embryos, many differently named regions should really have a single name. Parts of the tectum are the same as our superior colliculus and they have been found to act in the same way. They integrate sensory stimuli from various senses. They can register whether events are simultaneous. For example in tadpoles the tectum can tell if a sight and vibration stimulus are simultaneous. That is the same function with the same development in the same part of the brain in an amphibian and a mammal. (Felch, Khakhalin, Aizenmen; Multisensory integration in the developing tectum is constrained by the balance of excitation and inhibition. 2016 eLife 5)

We should be assuming that other vertebrates think like we do to a large extent – just as we should assume that other people do – and try to understand their actions without an attribution error.

A sense of rhythm

In a recent scientific press release, the opening sentence is, “A sense of rhythm is a uniquely human characteristic.” I am used to this sort of thing in opening sentences; I think to myself that they definitely have no evidence for that statement; they have not studied most animals, done a literature search or watched the videos of parrots dancing on the back of chairs. Never mind, it is an opener, just read on.

But the next paragraph starts, “What most people call the sense of rhythm — the mechanism that enables us to clap along or dance to music — is an intangible ability that is exclusive to human beings.” So it is not just the usual unexamined opener. And to top it off, the third paragraph starts with, “Human beings are the only species that recognise these patterns and scientists suspect that an evolutionary development is at the root of it.” Well I am not convinced that they have even thought much about these statements.

I find it very difficult to believe that anything is really, purely, uniquely human. The first assumption until proven false should be that our anatomy, genome, behavior etc. is part of the general characteristics of mammals. There will be other examples, or very similar examples, or the un-elaborated roots of any human ability to be found in some other animals. That is an assumption that is almost forced on us by the nature of evolution. But so many resist this approach and assume uniqueness without evidence of it.

Having a sense of rhythm would be very useful to many animals in their ordinary lives. And rhythms of many kinds occur in all living bodies. Movement in particular is rhythmic (perhaps particularly for swinging through trees). It would be something of a miracle if being able to entrain to a beat was not found in any other animal – just unbelievable.

And this reminds me of how annoying it is to still run across the rule against being anthropomorphic. It is not that we should assume that animals are like us in their mental lives without testing the idea. But it is also wrong to assume the opposite without testing. If it looks like a duck, and walks like a duck and quacks like a duck, hey, it just maybe is a duck. If the only way I can understand and predict the actions of my dog is to assume she has emotions similar to mine; then my tentative assumption is that she has those emotions. The rule against seeing similarities between ourselves and other animals shows a level of misunderstanding of both.

The need to see ourselves as unique and as fundamentally different from other animals is a left-over from the old beliefs in there being a hierarchy of life with man at the pinnacle. It is about time we got over this notion, just like we had to get over being the center of the universe. Our biggest differences from the rest of the animal world is the extent of our culture, not our basic biology. Other animals have consciousness, memory, emotion and intelligence, just like us. We are all different (each unique in their own way) but as variations of a theme – the fundamental plan of vertebrates is the starting point for all vertebrates. And I would bet money that a sense of rhythm is part of that basic plan.

Counting crows

It is getting to be common knowledge that some birds can count. Recent research (citation below) has shown some of the details of how crows handle numbers. They have a different brain architecture from mammals but in some ways show similar functions to our neo-cortex in their endbrain association area. This points to possible convergent evolution.

Ditz and Nieder planted electrodes in the endbrain of crows and recorded activity of NLC (nidopallium caudolaterale) neurons. The birds were shown groups of items and the NCL neurons shown activity to specific numbers of items. The activity of a particular neuron peaked at a particular number.

Here is the abstract: “It is unknown whether anatomical specializations in the endbrains of different vertebrates determine the neuronal code to represent numerical quantity. Therefore, we recorded single-neuron activity from the endbrain of crows trained to judge the number of items in displays. Many neurons were tuned for numerosities irrespective of the physical appearance of the items, and their activity correlated with performance outcome. Comparison of both behavioral and neuronal representations of numerosity revealed that the data are best described by a logarithmically compressed scaling of numerical information, as postulated by the Weber–Fechner law. The behavioral and neuronal numerosity representations in the crow reflect surprisingly well those found in the primate association cortex. This finding suggests that distantly related vertebrates with independently developed endbrains adopted similar neuronal solutions to process quantity.

It is interesting, and confirms other bird studies, that:

  • they can put items in categories in order to count them,
  • they can make a set of the items in a particular category,
  • they can assess the quantity on a logarithmic scale (like 1, 2, 3, 4, 6ish, 9ish, 15ish etc),
  • this is an abstract quantity and does not depend on the arrangement, size etc. of the items.

Citation: Helen M. Ditz and Andreas Nieder. Neurons selective to the number of visual items in the corvid songbird endbrain. PNAS, June 2015 DOI: 10.1073/pnas.1504245112

 

Gibbon calls

There is some interesting news on gibbons. But first, what are gibbons? They are apes, called lesser apes but definitely in our group with chimps, gorillas, and orangs and not with monkeys. The Chinese used to call them “gentlemen of the forest” to separate them from troublesome monkeys. Our lineage split from theirs about 18 million years ago. For context, the separation with orangs was 14, gorillas 7, and chimps 5 mya.

They are the fastest travelers through forest canopy, clocked at 55 km/hr, swinging from branch to branch. They have ball and socket wrists on their long and powerful arms. When they are forced to the ground they walk upright (more upright than chimps can manage). Gibbons are social, territorial and pair bond for life. And they sing with very powerful voices due to reverberating throat sacs. They sing duets, and family choir performances. But they also whisper or “hoo”. There have been some studies of their song but the Clarke paper (citation below) is the first study of the softer hoos.

This is important to the inquiry into the history of human language. There are two approaches to looking at our language: one is to look at what is unique and separates us from our nearest cousins; the other is to look a what is similar and forms a continuum with our relatives. We can read many articles on the uniqueness but only recently have there been articles on the similarities.

Although language is a uniquely human behaviour, it is likely to have evolved from precursors in the primate lineage, some of which may still be detectable in the vocal behaviour of extant primates. One important candidate for such a precursor is the ability to produce context-specific calls, a prerequisite to referential communication during which an actor refers a recipient’s attention to an external event. … More recently, functionally referential calling behaviour also has been described for other species of monkeys, apes, dogs, dolphins, and birds such as fowl, jays and chickadees.

Overall, context-specific calling behaviour appears to be widespread in animal communication, presumably because the selection pressure to attend to and understand context-specific calls is very strong, especially in evolutionarily urgent situations. In addition, there is good evidence for call comprehension between different species of primates, between primates and birds and between primates and other mammals, suggesting that such phenomena are driven by a generalised cognitive mechanism that is widely available to animals. Whether or not such abilities are relevant for understanding language evolution has triggered much debate with no real consensus. Nevertheless, the comparative study of animal communication, especially across non-human primates, is one of the most useful tools to make progress and address open questions about human language evolution.

Although gibbon hoos sound much the same to human observers, when they are recorded and analyzed for highest pitch, lowest pitch, pitch delta, duration, volume, interval between calls, it is possible to see the difference between hoo calls in different situations. The distinct situations noted included: tiger, leopard, raptor, encounter with another group, feeding, and introduction to duet song.

This communication based calling, that is fairly common in non-solitary animals, differs from human language to the extent that the calls are relatively fixed to particular situations and are small in number for most animals (dolphins and whales may have a surprising number and it is not known whether they are fixed). Some would say that animal calls are automatic and do not involve any decision to call; it is difficult to measure this and in any case does not seem to apply to the more intelligent animals. The exchange of information is clearly involved in animal communication – communication and exchange of information are almost synonymous. The idea that our communication is based on affecting one another’s attention, metaphorically pointing at concepts, objects, actions etc. fits nicely with animal referential communication.

Here is the paper’s abstract:

Background: Close range calls are produced by many animals during intra-specific interactions, such as during home range defence, playing, begging for food, and directing others. In this study, we investigated the most common close range vocalisation of lar gibbons (Hylobates lar), the ‘hoo’ call. Gibbons and siamangs (family Hylobatidae) are known for their conspicuous and elaborate songs, while quieter, close range vocalisations have received almost no empirical attention, perhaps due to the difficult observation conditions in their natural forest habitats.

Results: We found that ‘hoo’ calls were emitted by both sexes in a variety of contexts, including feeding, separation from group members, encountering predators, interacting with neighbours, or as part of duet songs by the mated pair. Acoustic analyses revealed that ‘hoo’ calls varied in a number of spectral parameters as a function of the different contexts. Males’ and females’ ‘hoo’ calls showed similar variation in these context-specific parameter differences, although there were also consistent sex differences in frequency across contexts.

Conclusions: Our study provides evidence that lar gibbons are able to generate significant, context-dependent acoustic variation within their main social call, which potentially allows recipients to make inferences about the external events experienced by the caller. Communicating about different events by producing subtle acoustic variation within some call types appears to be a general feature of primate communication, which can increase the expressive power of vocal signals within the constraints of limited vocal tract flexibility that is typical for all non-human primates. In this sense, this study is of direct relevance for the on-going debate about the nature and origins of vocally-based referential communication and the evolution of human speech.”
ResearchBlogging.org

Clarke, E., Reichard, U., & Zuberbühler, K. (2015). Context-specific close-range “hoo” calls in wild gibbons (Hylobates lar) BMC Evolutionary Biology, 15 (1) DOI: 10.1186/s12862-015-0332-2

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Curious sponge behaviour

In a little tidy-up of old files, I ran across a paper on sneezing sponges. This is not an April Fool’s joke – today is the 2nd of April. When we sneeze, we fill our lungs and then hold the air in while increasing the pressure on the lung. When we open up and let the air out, it rushes out, moving particles, mucous and irritants as it rushes. Sponges take in water all over their surface but the water exits through one hole. In order to rid themselves of particles and irritants, they close that single hole while continuing to take in water. When the exit is opened, the water inside comes out with some force.

Sponges are such primitive animals that they have no muscles and no nervous system. Until recently it was believed that they also lacked sense organs. But they do have a sense organ and that is how they are able to organize a sneeze. The exit hole (osculum) is lined with cells that have little hairs (cilia) protruding into the water stream. These cilia can sense grit and changes in flow. The cilia are of a type called ‘primary’; they cannot move but can sense being moved. Primary cilia are found in a number of sensory organs in other animals; for example, in our ears and the lateral line of fishes. The general molecular structure of primary cilia is more or less conserved over multicellular animals.

In the same way that the molecules needed for neurons and synapses are seen in organisms that have no nervous systems, this is another component of our nervous system that has a very ancient lineage.

Here is the abstract of the paper ( D. Ludeman, N. Farrar, A. Riesgo, J. Paps, S. Leys; Evolutionary origins of sensation in metazoans: functional evidence for a new sensory organ in sponges. BMC Evolutionary Biology, 2014; 14 (1): 3 ):

Background: One of the hallmarks of multicellular organisms is the ability of their cells to trigger responses to the environment in a coordinated manner. In recent years primary cilia have been shown to be present as ‘antennae’ on almost all animal cells, and are involved in cell-to-cell signaling in development and tissue homeostasis; how this sophisticated sensory system arose has been little-studied and its evolution is key to understanding how sensation arose in the Animal Kingdom. Sponges (Porifera), one of the earliest evolving phyla, lack conventional muscles and nerves and yet sense and respond to changes in their fluid environment. Here we demonstrate the presence of non-motile cilia in sponges and studied their role as flow sensors.

Results: Demosponges excrete wastes from their body with a stereotypic series of whole-body contractions using a structure called the osculum to regulate the water-flow through the body. In this study we show that short cilia line the inner epithelium of the sponge osculum. Ultrastructure of the cilia shows an absence of a central pair of microtubules and high speed imaging shows they are non-motile, suggesting they are not involved in generating flow. In other animals non-motile, ‘primary’, cilia are involved in sensation. Here we show that molecules known to block cationic ion channels in primary cilia and which inhibit sensory function in other organisms reduce or eliminate sponge contractions. Removal of the cilia using chloral hydrate, or removal of the whole osculum, also stops the contractions; in all instances the effect is reversible, suggesting that the cilia are involved in sensation. An analysis of sponge transcriptomes shows the presence of several transient receptor potential (TRP) channels including PKD channels known to be involved in sensing changes in flow in other animals. Together these data suggest that cilia in sponge oscula are involved in flow sensation and coordination of simple behaviour.

Conclusions: This is the first evidence of arrays of non-motile cilia in sponge oscula. Our findings provide support for the hypothesis that the cilia are sensory, and if true, the osculum may be considered a sensory organ that is used to coordinate whole animal responses in sponges. Arrays of primary cilia like these could represent the first step in the evolution of sensory and coordination systems in metazoans. ”

Music affects on the brain

A recent paper identified genes that changed their expression as a result of music performance in trained musicians. (see citation below). There were a surprising number of affected genes, 51 genes had increased and 22 had decreased expression, compared to controls who were also trained musicians but were not involved in making or listening to music for the same time period. It is also impressive that this set of 73 genes has a very broad range of presumed functions and effects in the brain.

musictableAnother interesting aspect is the overlap of a number of these genes with some that have been identified in song birds. This implies that the music/sophisticated sound perception and production has been conserved from a common ancestor of birds and mammals.

It has been known for some time that musical training has a positive effect on intelligence and outlook – that it assists learning. Musical training changes the structure of the brain. Now scientists are starting to trace the biology of music’s effects. Isn’t it about time that education stopped treating music (and other arts for that matter) as unimportant frills? It should not be the first thing to go when money or teaching time is short.

Here is the Abstract:

Music performance by professional musicians involves a wide-spectrum of cognitive and multi-sensory motor skills, whose biological basis is unknown. Several neuroscientific studies have demonstrated that the brains of professional musicians and non-musicians differ structurally and functionally and that musical training enhances cognition. However, the molecules and molecular mechanisms involved in music performance remain largely unexplored. Here, we investigated the effect of music performance on the genome-wide peripheral blood transcriptome of professional musicians by analyzing the transcriptional responses after a 2-hr concert performance and after a ‘music-free’ control session. The up-regulated genes were found to affect dopaminergic neurotransmission, motor behavior, neuronal plasticity, and neurocognitive functions including learning and memory. Particularly, candidate genes such as SNCA, FOS and DUSP1 that are involved in song perception and production in songbirds, were identified, suggesting an evolutionary conservation in biological processes related to sound perception/production. Additionally, modulation of genes related to calcium ion homeostasis, iron ion homeostasis, glutathione metabolism, and several neuropsychiatric and neurodegenerative diseases implied that music performance may affect the biological pathways that are otherwise essential for the proper maintenance of neuronal function and survival. For the first time, this study provides evidence for the candidate genes and molecular mechanisms underlying music performance.”

ResearchBlogging.org

Kanduri, C., Kuusi, T., Ahvenainen, M., Philips, A., Lähdesmäki, H., & Järvelä, I. (2015). The effect of music performance on the transcriptome of professional musicians Scientific Reports, 5 DOI: 10.1038/srep09506

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