Communication as the Origin of Consciousness

Since the middle of the 20th century, more and more data have appeared on the limited role of consciousness in determining human behavior. In this opinion paper, we hypothesize that the basis of consciousness is precisely the communicative function, and discuss relations of consciousness to other cognitive processes such sensory detection, decision-making and emotions. Within the framework of the hypothesis, consciousness is considered as a highly specialized function of the brain, which ensures encoding of personal information as communication messages. On a subjective level, mental representation just means the state of information to be shared in a human group. Accordingly, consciousness affects only those components of human behavior that are associated with the transmission of messages. Sensory detection, decision-making, emotions and other processes are only projected into consciousness during the encoding of information of them. The communication hypothesis assumes that consciousness is an adaptation that increases the efficiency of a collective way of life, and the emergence of consciousness is inextricably linked with the development of language in human culture. In the future, our view of consciousness provides an opportunity for an objective analysis of subjective phenomena by means of a directed study of the formation of messages both at the level of brain processes and at the level of interactions between individuals.

Diffusion MRI Connections in the Octopus Brain

Using high angle resolution diffusion magnetic resonance imaging (HARDI) with fiber tractography analysis we map out a meso-scale connectome of the Octopus bimaculoides brain. The brain of this cephalopod has a qualitatively different organization than that of vertebrates, yet it exhibits complex behavior, an elaborate sensory system and high cognitive abilities. Over the last 60 years wide ranging and detailed studies of octopus brain anatomy have been undertaken, including classical histological sectioning/staining, electron microscopy and neuronal tract tracing with injected dyes. These studies have elucidated many neuronal connections within and among anatomical structures. Diffusion MRI based tractography utilizes a qualitatively different method of tracing connections within the brain and offers facile three-dimensional images of anatomy and connections that can be quantitatively analyzed. Twenty-five separate lobes of the brain were segmented in the 3D MR images of each of three samples, including all five sub-structures in the vertical lobe. These parcellations were used to assay fiber tracings between lobes. The connectivity matrix constructed from diffusion MRI data was largely in agreement with that assembled from earlier studies. The one major difference was that connections between the vertical lobe and more basal supra-esophageal structures present in the literature were not found by MRI. In all, 92 connections between the 25 different lobes were noted by diffusion MRI: 53 between supra-esophageal lobes and 26 between the optic lobes and other structures. These represent the beginnings of a mesoscale connectome of the octopus brain.

Potential evidence of peripheral learning and memory in the arms of dwarf cuttlefish, Sepia bandensis

CREB (cAMP response element-binding) transcription factors are conserved markers of memory formation in the brain and peripheral circuits. We provide immunohistochemical evidence of CREB phosphorylation in the dwarf cuttlefish, Sepia bandensis, following the inaccessible prey (IP) memory experiment. During the IP experiment, cuttlefish are shown prey enclosed in a transparent tube, and tentacle strikes against the tube decrease over time as the cuttlefish learns the prey is inaccessible. The cues driving IP learning are unclear but may include sensory inputs from arms touching the tube. The neural activity marker, anti-phospho-CREB (anti-pCREB) was used to determine whether IP training stimulated cuttlefish arm sensory neurons. pCREB immunoreactivity occurred along the oral surface of the arms, including the suckers and epithelial folds surrounding the suckers. pCREB increased in the epithelial folds and suckers of trained cuttlefish. We found differential pCREB immunoreactivity along the distal-proximal axis of trained arms, with pCREB concentrated distally. Unequal CREB phosphorylation occurred among the 4 trained arm pairs, with arm pairs 1 and 2 containing more pCREB. The resulting patterns of pCREB in trained arms suggest that the arms obtain cues that may be salient for learning and memory of the IP experiment.

Aquarium Tank Design Is Integral to the Elimination of Mantle Abrasion in the Captive Curled Octopus (Eledone cirrhosa): A Case Study at Macduff Marine Aquarium

Macduff Marine Aquarium is a native species aquarium situated on the Moray Firth coastline and houses the curled octopus, Eledone cirrhosa, for public display. Historically, the designated octopus display tank has been in-keeping with the overall theme of the aquarium, consisting of artificially created rock work mimicking the local rocky coastline, within an angular glass tank. This tank was not originally designed for housing octopus and as a consequence, if individuals on display exhibited jetting behavior mantle abrasion occurred. In 2016, a new bespoke octopus tank was designed and installed. Since then 14 different octopuses have been individually housed and maintained within the tank, with none having experienced mantle abrasion. This paper highlights the importance of aquarium design for the ethical maintenance of an intelligent and challenging species.

Bigfin reef squid demonstrate capacity for conditional discrimination and projected future carbon dioxide levels have no effect on learning capabilities

Anthropogenic carbon dioxide (CO₂) emissions are being absorbed by the oceans, a process known as ocean acidification, and risks adversely affecting a variety of behaviours in a range of marine species, including inhibited learning in some fishes. However, the effects of elevated CO₂ on learning in advanced invertebrates such as cephalopods are unknown. Any impacts to the learning abilities of cephalopods could have far-reaching consequences for their populations and the communities they inhabit. Cephalopods have some of the most advanced cognitive abilities among invertebrates and are one of the few invertebrate taxa in which conditional discrimination has been demonstrated, though the trait has not been demonstrated in any species of squid. Here, we tested for the first time the capacity for conditional discrimination in a squid species (Sepioteuthis lessoniana). Furthermore, we investigated the effects of projected future CO₂ levels (1,084 µatm) on conditional discrimination and learning more generally. A three-task experiment within a two-choice arena was used to test learning and conditional discrimination. Learning was measured by improvements in task completion in repeated trials over time and the number of trials required to pass each task. Squid exhibited significant learning capabilities, with an increase in correct choices over successive trials and a decrease in the number of trials needed to complete the successive tasks. Six of the 12 squid tested successfully passed all three tasks indicating a capacity for conditional discrimination in the species. Elevated CO₂ had no effect on learning or on the capacity for conditional discrimination in squid. This study highlights the remarkable cognitive abilities of S. lessoniana, demonstrated by their capacity for conditional discrimination, and suggests that ocean acidification will not compromise learning abilities. However, other behavioural traits in the species have been shown to be altered at comparable elevated CO₂ conditions. It is not clear why some ecologically important behaviours are altered by elevated CO₂ whereas others are unaffected. Future research should focus on the physiological mechanism responsible for altered behaviours in squid at elevated CO₂.

Validity of Cognitive Tests for Non-human Animals: Pitfalls and Prospects

Comparative psychology assesses cognitive abilities and capacities of non-human animals and humans. Based on performance differences and similarities in various species in cognitive tests, it is inferred how their minds work and reconstructed how cognition might have evolved. Critically, such species comparisons are only valid and meaningful if the tasks truly capture individual and inter-specific variation in cognitive abilities rather than contextual variables that might affect task performance. Unlike in human test psychology, however, cognitive tasks for non-human primates (and most other animals) have been rarely evaluated regarding their measurement validity. We review recent studies that address how non-cognitive factors affect performance in a set of commonly used cognitive tasks, and if cognitive tests truly measure individual variation in cognitive abilities. We find that individual differences in emotional and motivational factors primarily affect performance via attention. Hence, it is crucial to systematically control for attention during cognitive tasks to obtain valid and reliable results. Aspects of test design, however, can also have a substantial effect on cognitive performance. We conclude that non-cognitive factors are a minor source of measurement error if acknowledged and properly controlled for. It is essential, however, to validate and eventually re-design several primate cognition tasks in order to ascertain that they capture the cognitive abilities they were designed to measure. This will provide a more solid base for future cognitive comparisons within primates but also across a wider range of non-human animal species.

Evidence of learning and memory in the juvenile dwarf cuttlefish Sepia bandensis

Measuring behavior in the form of numerical data is difficult, especially for studies involving complex actions. DanioVision is a closed-chamber system that utilizes subject tracking to comprehensively record behavior, while also mitigating the influence of environmental conditions. We used DanioVision to record activity of juvenile dwarf cuttlefish (Sepia bandensis) during the inaccessible prey (IP) procedure, a memory experiment in which cuttlefish learn to inhibit capture attempts towards inaccessible prey. By quantifying total movement and orientation of the body, we found that cuttlefish show memory by selectively inhibiting tentacle strikes without reducing total movement, or orientation towards the prey. We show that DanioVision can be used to assess multiple components of dynamic responses that are not measurable by direct observation alone and provide new evidence that strike inhibition is the product of learning, and not motor fatigue.

Your Brain Is Not an Onion With a Tiny Reptile Inside

A widespread misconception in much of psychology is that (a) as vertebrate animals evolved, “newer” brain structures were added over existing “older” brain structures, and (b) these newer, more complex structures endowed animals with newer and more complex psychological functions, behavioral flexibility, and language. This belief, although widely shared in introductory psychology textbooks, has long been discredited among neurobiologists and stands in contrast to the clear and unanimous agreement on these issues among those studying nervous-system evolution. We bring psychologists up to date on this issue by describing the more accurate model of neural evolution, and we provide examples of how this inaccurate view may have impeded progress in psychology. We urge psychologists to abandon this mistaken view of human brains.

Sensorial Hierarchy in Octopus vulgaris's Food Choice: Chemical vs. Visual

Simple Summary

Coleoids are cephalopods endowed with a highly sophisticated nervous system with keen sense organs and an exceptionally large brain that includes more than 30 differentiated lobes. Within this group, Octopus vulgaris, well known as an intelligent soft-bodied animal, has a significant number of lobes in the nervous system dedicated to decoding and integrating visual, tactile, and chemosensory perceptions. In this study, we aimed to understand the key role of chemical and visual cues during food selection in O. vulgaris. We first defined the preferred food, and subsequently, we set up five different problem-solving tasks, in which the animal’s choice is guided by visual and chemosensory signals, either alone or together, to evaluate whether individual O. vulgaris uses a sensorial hierarchy. Our behavioural experiments show that this species does integrate different sensory information from chemical and visual cues during food selection; however, our results indicate that chemical perception provides accurate and faster information leading to food choice. This research opens new perspectives on O. vulgaris’ predation strategies.

Abstract

Octopus vulgaris possesses highly sophisticated sense organs, processed by the nervous system to generate appropriate behaviours such as finding food, avoiding predators, identifying conspecifics, and locating suitable habitat. Octopus uses multiple sensory modalities during the searching and selection of food, in particular, the chemosensory and visual cues. Here, we examined food choice in O. vulgaris in two ways: (1) We tested octopus’s food preference among three different kinds of food, and established anchovy as the preferred choice (66.67%, Friedman test p < 0.05); (2) We exposed octopus to a set of five behavioural experiments in order to establish the sensorial hierarchy in food choice, and to evaluate the performance based on the visual and chemical cues, alone or together. Our data show that O. vulgaris integrates sensory information from chemical and visual cues during food choice. Nevertheless, food choice resulted in being more dependent on chemical cues than visual ones (88.9%, Friedman test p < 0.05), with a consistent decrease of the time spent identifying the preferred food. These results define the role played by the senses with a sensorial hierarchy in food choice, opening new perspectives on the O. vulgaris’ predation strategies in the wild, which until today were considered to rely mainly on visual cues.

Electrophysiological and Motor Responses to Chemosensory Stimuli in Isolated Cephalopod Arms

While there is behavioral and anatomical evidence that coleoid cephalopods use their arms to "taste" substances in the environment, the neurophysiology of chemosensation has been largely unexamined. The range and sensitivity of detectable chemosensory stimuli, and the processing of chemosensory information, are unknown. To begin to address these issues, we developed a technique for recording neurophysiological responses from isolated arms, allowing us to test responses to biologically relevant stimuli. We tested arms from both a pelagic species (Doryteuthis pealeii) and a benthic species (Octopus bimaculoides) by attaching a suction electrode to the axial nerve cord to record neural activity in response to chemical stimuli. Doryteuthis pealeii arms showed anecdotal responses to some stimuli but generally did not tolerate the preparation; tissue was nonviable within minutes ex vivo. Octopus bimaculoides arms were used successfully, with tissue remaining healthy and responsive for several hours. Arms responded strongly to fish skin extract, glycine, methionine, and conspecific skin extract but not to cephalopod ink or seawater controls. Motor responses were also observed in response to detected stimuli. These results suggest that chemosensory receptor cells on O. bimaculoides arms were able to detect environmentally relevant chemicals and drive local motor responses within the arm. Further exploration of potential chemical stimuli for O. bimaculoides arms, as well as investigations into the neural processing within the arm, could enhance our understanding of how this species uses its arms to explore its environment. While not successful in D. pealeii, this technique could be attempted with other cephalopod species, as comparative questions remain of interest.

Temporal Profile of Brain Gene Expression After Prey Catching Conditioning in an Anuran Amphibian

A key goal in modern neurobiology is to understand the mechanisms underlying learning and memory. To that end, it is essential to identify the patterns of gene expression and the temporal sequence of molecular events associated with learning and memory processes. It is also important to ascertain if and how these molecular events vary between organisms. In vertebrates, learning and memory processes are characterized by distinct phases of molecular activity involving gene transcription, structural change, and long-term maintenance of such structural change in the nervous system. Utilizing next generation sequencing techniques, we profiled the temporal expression patterns of genes in the brain of the fire-bellied toad Bombina orientalis after prey catching conditioning. The fire-bellied toad is a basal tetrapod whose neural architecture and molecular pathways may help us understand the ancestral state of learning and memory mechanisms in tetrapods. Differential gene expression following conditioning revealed activity in molecular pathways related to immediate early genes (IEG), cytoskeletal modification, axon guidance activity, and apoptotic processes. Conditioning induced early IEG activity coinciding with transcriptional activity and neuron structural modification, followed by axon guidance and cell adhesion activity, and late neuronal pruning. While some of these gene expression patterns are similar to those found in mammals submitted to conditioning, some interesting divergent expression profiles were seen, and differential expression of some well-known learning-related mammalian genes is missing altogether. These results highlight the importance of using a comparative approach in the study of the mechanisms of leaning and memory and provide molecular resources for a novel vertebrate model in the relatively poorly studied Amphibia.

Need for speed: Short lifespan selects for increased learning ability

It is generally assumed that an investment into cognitive abilities and their associated cost is particularly beneficial for long-lived species, as a prolonged lifespan allows to recoup the initial investment. However, ephemeral organisms possess astonishing cognitive abilities too. Invertebrates, for example, are capable of simple associative learning, reversal learning, and planning. How can this discrepancy between theory and evidence be explained? Using a simulation, we show that short lives can actually select for an increase in learning abilities. The rationale behind this is that when learning is needed to exploit otherwise inaccessible resources, one needs to learn fast in order to utilize the resources when constrained by short lifespans. And thus, increased cognitive abilities may evolve, not despite short lifespan, but because of it.

Genetic structure of Octopus minor around Chinese waters as indicated by nuclear DNA variations (Mollusca, Cephalopoda)

Octopus minor is an economically important resource commonly found in Chinese coastal waters. The nuclear gene (RD and ODH) approach of investigation has not reported in this species. Rhodopsin (RD) and octopine dehydrogenase (ODH) genes were used to elaborate the genetic structure collected from eight localities ranging from the northern to the southern coast of China. In total, 118 individuals for the RD gene and 108 for the ODH were sequenced. Overall (RD and ODH) genes resulted in high (0.741±0.032; 0.805±0.038) haplotype and low nucleotide (0.01261±0.00165; 0.00747±0.00086) diversity. Molecular variance displayed higher values among the populations and lower values within the population where the fixation index FST denoted 0.880 and 0.584 in RD and ODH genes respectively. The Dongshan population clustered separately in a phylogenetic tree as in the haplotype networking assessment. The current data suggests that the Dongshan population needs separate management.

The Current State of Cephalopod Science and Perspectives on the Most Critical Challenges Ahead From Three Early-Career Researchers

Here, three researchers who have recently embarked on careers in cephalopod biology discuss the current state of the field and offer their hopes for the future. Seven major topics are explored: genetics, aquaculture, climate change, welfare, behavior, cognition, and neurobiology. Recent developments in each of these fields are reviewed and the potential of emerging technologies to address specific gaps in knowledge about cephalopods are discussed. Throughout, the authors highlight specific challenges that merit particular focus in the near-term. This review and prospectus is also intended to suggest some concrete near-term goals to cephalopod researchers and inspire those working outside the field to consider the revelatory potential of these remarkable creatures.

Woodpeckers and Diamonds: Some Aspects of Evolutionary Convergence in Astrobiology

Jared Diamond's argument against extraterrestrial intelligence from evolutionary contingency is subjected to critical scrutiny. As with the earlier arguments of George Gaylord Simpson, it contains critical loopholes that lead to its unraveling. From the point of view of the contemporary debates about biological evolution, perhaps the most contentious aspect of such arguments is their atemporal and gradualist usage of the space of all possible biological forms (morphospace). Such usage enables the translation of the adaptive value of a trait into the probability of its evolving. This procedure, it is argued, is dangerously misleading. Contra Diamond, there are reasons to believe that convergence not only plays an important role in the history of life, but also profoundly improves the prospects for search for extraterrestrial intelligence success. Some further considerations about the role of observation selection effects and our scaling of complexity in the great debate about contingency and convergence are given. Taken together, these considerations militate against the pessimism of Diamond's conclusion, and suggest that the search for traces and manifestations of extraterrestrial intelligences is far from forlorn. Key Words: Astrobiology-Evolution-Contingency-Convergence-Complex life-SETI-Major evolutionary transitions-Selection effects-Jared Diamond. Astrobiology 18, 491-502.

Molecular clocks indicate turnover and diversification of modern coleoid cephalopods during the Mesozoic Marine Revolution

Coleoid cephalopod molluscs comprise squid, cuttlefish and octopuses, and represent nearly the entire diversity of modern cephalopods. Sophisticated adaptations such as the use of colour for camouflage and communication, jet propulsion and the ink sac highlight the unique nature of the group. Despite these striking adaptations, there are clear parallels in ecology between coleoids and bony fishes. The coleoid fossil record is limited, however, hindering confident analysis of the tempo and pattern of their evolution. Here we use a molecular dataset (180 genes, approx. 36 000 amino acids) of 26 cephalopod species to explore the phylogeny and timing of cephalopod evolution. We show that crown cephalopods diverged in the Silurian-Devonian, while crown coleoids had origins in the latest Palaeozoic. While the deep-sea vampire squid and dumbo octopuses have ancient origins extending to the Early Mesozoic Era, 242 ± 38 Ma, incirrate octopuses and the decabrachian coleoids (10-armed squid) diversified in the Jurassic Period. These divergence estimates highlight the modern diversity of coleoid cephalopods emerging in the Mesozoic Marine Revolution, a period that also witnessed the radiation of most ray-finned fish groups in addition to several other marine vertebrates. This suggests that that the origin of modern cephalopod biodiversity was contingent on ecological competition with marine vertebrates.

Reconsideration of Serial Visual Reversal Learning in Octopus (Octopus vulgaris) from a Methodological Perspective

Octopuses (Octopus vulgaris) are generally considered to possess extraordinary cognitive abilities including the ability to successfully perform in a serial reversal learning task. During reversal learning, an animal is presented with a discrimination problem and after reaching a learning criterion, the signs of the stimuli are reversed: the former positive becomes the negative stimulus and vice versa. If an animal improves its performance over reversals, it is ascribed advanced cognitive abilities. Reversal learning has been tested in octopus in a number of studies. However, the experimental procedures adopted in these studies involved pre-training on the new positive stimulus after a reversal, strong negative reinforcement or might have enabled secondary cueing by the experimenter. These procedures could have all affected the outcome of reversal learning. Thus, in this study, serial visual reversal learning was revisited in octopus. We trained four common octopuses (O. vulgaris) to discriminate between 2-dimensional stimuli presented on a monitor in a simultaneous visual discrimination task and reversed the signs of the stimuli each time the animals reached the learning criterion of ≥80% in two consecutive sessions. The animals were trained using operant conditioning techniques including a secondary reinforcer, a rod that was pushed up and down the feeding tube, which signaled the correctness of a response and preceded the subsequent primary reinforcement of food. The experimental protocol did not involve negative reinforcement. One animal completed four reversals and showed progressive improvement, i.e., it decreased its errors to criterion the more reversals it experienced. This animal developed a generalized response strategy. In contrast, another animal completed only one reversal, whereas two animals did not learn to reverse during the first reversal. In conclusion, some octopus individuals can learn to reverse in a visual task demonstrating behavioral flexibility even with a refined methodology.

Domains of generality

We argue that general intelligence, as presented in the target article, generates multiple distinct and non-equivalent characterisations. Clarifying this central concept is necessary for assessing Burkart et al.'s proposal that the cultural intelligence hypothesis is the best explanation for the evolution of general intelligence. We assess this claim by considering two characterisations of general intelligence presented in the article.

Effects of Visual Cues of a Moving Model Predator on Body Patterns in Cuttlefish Sepia pharaonis

We examined the effects of predator-prey distance (PPD) and trajectory of the predator on the body patterns that the pharaoh cuttlefish, Sepia pharaonis, shows in response to a predator. A model predator moving in three different trajectories was presented to the cuttlefish: T1, approached the cuttlefish but bypassed above; T2, approached directly toward the cuttlefish; T3, bypassed the cuttlefish both vertically and horizontally. We divided the body patterns that the cuttlefish expressed into seven categories, i.e., "uniform light", "disruptive", "center circle", "dark square", "vertical stripe", "all dark" and "eyespots". In T1, the number of individuals that showed "dark square" increased as the model approached the cuttlefish, whereas the number of individuals that showed "disruptive" decreased. In T2, the number of individuals that showed "all dark" and "eyespots" increased as the model approached the cuttlefish. In T3, the number of individuals that showed "dark square" and "vertical stripe" increased as the model approached the cuttlefish, and it tended to decrease as the model receded from the cuttlefish. These results demonstrate that S. pharaonis changes its body patterns according to PPD and the trajectory of the predator, which would affect predation risk and/or predator perception.

Orientation-Dependent Changes in Single Motor Neuron Activity during Adaptive Soft-Bodied Locomotion

Recent major advances in understanding the organizational principles underlying motor control have focused on a small number of animal species with stiff articulated skeletons. These model systems have the advantage of easily quantifiable mechanics, but the neural codes underlying different movements are difficult to characterize because they typically involve a large population of neurons controlling each muscle. As a result, studying how neural codes drive adaptive changes in behavior is extremely challenging. This problem is highly simplified in the tobacco hawkmoth Manduca sexta, which, in its larval stage (caterpillar), is predominantly soft-bodied. Since each M. sexta muscle is innervated by one, occasionally two, excitatory motor neurons, the electrical activity generated by each muscle can be mapped to individual motor neurons. In the present study, muscle activation patterns were converted into motor neuron frequency patterns by identifying single excitatory junction potentials within recorded electromyographic traces. This conversion was carried out with single motor neuron resolution thanks to the high signal selectivity of newly developed flexible microelectrode arrays, which were specifically designed to record from M. sexta muscles. It was discovered that the timing of motor neuron activity and gait kinematics depend on the orientation of the plane of motion during locomotion. We report that, during climbing, the motor neurons monitored in the present study shift their activity to correlate with movements in the animal's more anterior segments. This orientation-dependent shift in motor activity is in agreement with the expected shift in the propulsive forces required for climbing. Our results suggest that, contrary to what has been previously hypothesized, M.sexta uses central command timing for adaptive load compensation.

Unveiling the morphology of the acetabulum in octopus suckers and its role in attachment

In recent years, the attachment mechanism of the octopus sucker has attracted the interest of scientists from different research areas, including biology, engineering, medicine and robotics. From a technological perspective, the main goal is to identify the underlying mechanisms involved in sucker attachment for use in the development of new generations of artificial devices and materials. Recently, the understanding of the morphology of the sucker has been significantly improved; however, the mechanisms that allow attachment remain largely unknown. In this work, we present new anatomical findings: specifically, a protuberance in the acetabular roof in five different octopus species; previously, this protuberance was identified by the authors in Octopus vulgaris. Moreover, we discuss the role of the protuberance and other anatomical structures in attachment with minimal energy consumption.