I did it again. After 6 ECTS in a summer school course covering the brain & behavior, I took a 15 ECTS distance course covering neuroscience basics. Along the way, I documented insights which challenged my knowledge and practice in human resource management and beyond. This post consists of three parts: first, I shared the most insightful questions and answers from my course, second, you will find some of my general reflections and finally, you can find a section with recommended further resources. Enjoy!
Disclaimer: As a neuroscience professional you might find these basics mundane and simplified, if even incorrect. In case of the latter, please reach out and support me in my learning process.
A set of 12 questions & answers
What are the main neuronal features involved in information processing and how does this processing take place?
In the nervous system, we find two main types of cells – neurons (or nerve cells) as well as glia cells. Neurons are specialized in receiving and transmitting information, whereas glia cells are specialized in supporting this process. 10% of the brain’s volume are neurons and glia cells make up 90% (Garret, 2015). Dendrites and the axon are extensions from a neuron’s cell body (or soma) which receive information from other neurons and transmit information to other locations respectively. Neurons transfer information by means of electrical signaling, however, most of them are not physically connected to each other. Rather, the gap between them, called synapse, bridges the signal from the neuron before the synapse (presynaptic neuron) to the neuron after (postsynaptic neuron) with the help of neurotransmitters. To be more precise, these neurotransmitters are released from terminal boutons, the synaptic endings or branches at the end of the axon. Information processing over distance takes place through the so-called action potential. Following the all-or-nothing law, this is an abrupt change in polarization at the neurons’ membrane. This is a regenerating change, which is transferred from neuron to neuron without decreasing in strength. This makes it possible for the action potential to travel long distances.
In his book “Why we sleep” discusses Matthew Walker findings based on measurements with electrodes place on the head and the face of study participants. This method is called electroencephalograph (EEG). How does this method work and what are main differences compared to other non-invasive brain imaging such as CT or MRI?
The functional analysis of the brain is based on measuring brain activity. There are two approaches which have been shown to be especially useful, namely electrophysiological recording as well as functional brain imaging. Electroencephalography (EEG) is a non-invasive method of measuring electrical activity of the brain. Benefits compared to earlier functional mapping was that research can be executed in living humans as well as that this method does not need medical intervention. Also, no radioactivity or electrical stimulation is needed. By for example using scalp electrodes in form of a “cap”, a range of tasks can be investigated in standard laboratory settings. Downsides of this method are that only activity of neurons close to the scalp can be measured and that this activity can not be pinpointed towards specific neurons (only a general localisation is possible). Another disadvantage is that it only allows limit resolution. Compared to computerized tomography (or CT), EEG has a lower resolution but does not expose the individual to radiation. CT is able to analyse the brain in more detail and display it in a three-dimensional image, so that major brain structures can be confidently identified. As individuals have to be sedentary during the computerized tomography, the range of tasks that they can execute meanwhile is limited compared to EEG. This is one explanation why EEG is used for sleep research, as individuals usual move (=role over) during sleep. MRI or Magnetic Resonance imaging is a safe, non-invasive and versatile method to image the brain. It works (as the name suggest) based on magnetic fields and can visualize human neuroanatomy in more detail than CT. Recent developments in the field allow to move from structural analysis to functional analysis such as changes in cerebral metabolism and blood flow.
Why is it misleading to describe synaptic connections as the basic “wiring” of the brain?
The widespread saying “Neurons that fire together wire together” implies that neural signaling is solely based on electrical signaling and thus follows a computational metaphor. Neural signaling is more complex than binary information based on current either flowing or not flowing. In addition, and contrary to the fixed wiring in electrical devises, connections between neuronal cells is dynamic and constantly changing. The “wiring”-metaphor does not reflect this phenomenon of synaptic plasticity.
Is there evidence for pheromones in human sexual behaviour?
Pheromones are airborne chemicals released by animals that have effects on other animals of the same species. Those pheromones are detected by the vomeronasal organ as a cluster of receptors located in the nasal cavity. Researchers today believe that in humans, this function has been suppressed by the processing complexity needed for colour vision so that humans increasingly relied on visual cues for sexual signals. In sum, pheromones do not seem to be as impactful on human behaviour as they are for animal behaviour. Research on pheromones has been criticised for small sample sizes and statistical reliability (besides others) and by their results, which can be summarised in terms that no human secretion has yet been determined as pheromone and although secretions have physiological effects, so do plant odours.
What are mirror motor neurons?
Mirror motor neurons are a subset of neurons which is not only activated in preparation for movements but also when a movement is observed. This means that these premotor neurons fire in a similar fashion independently of if the same movement is self-initiated of observed in somebody else. Interestingly, suppression of firing of these neurons has been observed in trials, even if these neurons would be active during self-initiated movement. As far as research results can explain today, the mirror motor system has a role in encoding the intention of a specific movement based on observing others executing a relevant action. Mirror neurons where first discovered in monkeys reaching for food. They showed neuronal activity even when they only observed the researcher reaching for food or picking up food. Similar correlations have been observed in other brain areas, for example those involved in emotions. When being presented with a person’s face expression, this activates emotional areas in the brain and the activation is dependent on how much empathy we have. This system is still highly debated and researched, with the full scope of contribution to complex behaviours still to be eluded.
In more neuro-scientifically elaborated ways, what did Walter Cannon mean when he said that the visceral motor system would prepare humans to fight or flight?
Looking at the two divisions of the visceral motor system, it is the neuronal activity of the sympathetic division which prepares humans to fight or fly. Besides others, this division is responsible for accelerating the heartbeat, constricting blood vessels, dilating pupils and inhibiting digestion. By doing so, humans can channel all available energy in specific situations to reach maximum resources, specifically from a metabolic perspective. However, the “fight or flight” metaphor is a bit too simplistic to illustrate what is going on in an active sympathetic division from a neuronal perspective. Particularly important to keep in mind is that the sympathetic division is constantly tonically active to maintain sympathetic functions at an appropriate level. This means that this division is not just active in specific situations but at all times in human live. Secondly, various organ functions can be controlled independently. This emphasises the characteristic of the sympathetic division, that is does not respond in an all-or-nothing way. The different sympathetic reflexes can indeed operate independently.
Why is it strictly seen incorrect to describe brain regions devoted to language as specialised for heard and spoken language?
First of all, there are several major brain areas involved in the comprehension and production of language. These are Broca’s and Wernicke’s area, as well as the primary motor cortex, the primary somatosensory cortex, the primary auditory cortex and the primary visual cortex. There as been a heated debate about lateralization as well as single responsible brain areas involved in the production of human behaviour. It is safe to say that every brain region is efficiently used for important information processing all the time. Also, language production and understanding happens in the left hemisphere for most people, not for all. The right hemisphere contributes with fulfilling richness of everyday language. Language localization can vary dramatically from patient to patient. Interestingly enough, research on brain activity during a number of language related tasks reveal that bilingual patients to not necessarily activate the same bit of cortex for storing the names of the same thing in different languages. It seems that certain language aspects are organized in categories rather then in the meaning of the individual word. Underlying the foregoing part of this answer is the assumption that we are assessing heard and spoken language. However, research in brain-impaired death patients using sign language have shown that left-hemisphere lesions led to sign production and comprehension difficulty whereas right-hemisphere lesions led to showed impaired emotional tone in signing. As a result, the language regions describe above seem to be broadly organized for processing symbols for social communication rather than that they are solely devoted to heard and spoken language.
What justifies the emphasis of the amygdala in the process of expressing emotions as well as the relationship between stimulus and behavioural response?
The amygdala is a part of the limbic system and more specifically lies within the anterior-medial part of the temporal lobe rostral to the hippocampus. It is also called amygdaloid complex and is divided into three functionally and anatomically different sections, the medial group of subnuclei, the basolateral group of subnuclei as well as the central and anterior group of subnuclei. The amygdala functions as the connection between cortical areas that process sensory information and hypothalamic and brainstem effector systems. Degeneration in the amygdala has shown to result in changes to the experience of fear. Also, the connection between the amygdala, the prefrontal cortex and the basal ganglia are likely to affect behaviour choice and initiation with the aim to receive rewards and to avoid punishment. Finally, research has shown the likelihood of the connection between the amygdala, the neocortex and related subcortical circuits being responsible for the subjectivity of emotions, meaning that the same emotions can be interpreted differently in individuals.
Why do we dream?
Dreaming is typically associated with the REM sleep stage and defined as a specific state of awareness, where the experience of dreams is not related to perception from external stimuli but rather comparable to hallucination and features of memory. The purpose of dreaming is still poorly understood from a scientific perspective. Dreams indeed often reflect events or conflicts which happened during the day and could play a role in memory consolidation. Another perspective of dreams is, that they provide a safe environment to replay otherwise emotionally unbearable experience and thus preventing those experience to affect an individual in the awake state. A third perspective is highly critical towards the purpose of dreams, indicating that dreams might have no purpose at all. Specific sleep deprivation experiments have shown that humans can get along without REM sleep but not without non-REM sleep. These results mark the importance of seeing sleep as a construct of different stages and their importance as opposed to simplifying sleep as a single construct.
What is consciousness?
Being awake and being conscious are two separate cortical states, although being awake is essential for being conscious. Consciousness refers to a state where one is aware of oneself and the world around. This builds on a physiological perspective as a brain state we connect with wakefulness as well as on a more subjective perspective as a brain state connected to a subjective awareness of the world. The underlying challenge in consciousness research is that the former perspective can be harmonized with conventional models in neurobiology and neuroscience, however the latter perspective builds on additional frameworks generally to be found in philosophy. Also, being aware and being self-aware are not necessarily the same thing. The neuronal basis of awareness is activity of cortical neurons in association cortices which can process relevant stimuli and integrate results with other information. However, this neuronal basis is only necessary and not enough as a prerequisite for awareness. The question of consciousness and specifically “What is consciousness?” has been particularly present during the recent rise of interest in Artificial Intelligence. To move forward in this matter, Zarkadakis (2015) proposes four empirical propositions necessary to investigate if machines can be made intelligent (p. 152). Dualism must be rejected, we must accept that there is only matter, intelligence is a purely biological phenomenon and the brain can be conscious. If these propositions are accepted, it is theoretically possible that another object can also be conscious.
What is the neurobiological definition of learning and memory? How are these two concepts interlinked?
The most important complex function of the brain is to store new information and to retrieve information when needed. A challenge when it comes to defining learning and memory are the underlying complexity and interdisciplinary approaches towards those concepts. In general, research agrees on the so-called engram, that is the physical embodiment of any memory in the neuronal system and that it depends on changes in synaptic connection efficacy and/or actual growth and reordering of these connections. In other words, plasticity on cellular and molecular level is assumed to be the basis for learning and learning comprises all processes which lead to the nervous system acquiring new information. From this perspective, memory formation is a learning process. The existence of memory has been made evident since experience can be brought into consciousness retrospectively as well as that behaviours change based on experience. In neuroscience, memory research is most prevalent for declarative memory, as is it compromised by specific bran region impairment and there are different ways of investigating the information transfer from immediate and short-term memory to long-term memory.
Which are the three ways memories can change?
There are three ways of changing memories, namely extinction, forgetting and reconsolidation. It is easy to assume that once memories have been consolidated, they are there to stay. Indeed, a memory must be stable to be useful but also open to adjustments based on additional external stimuli and internal feedback. Extinction refers to behavioural changes involved in learned reactions to a stimulus. The memory of this stimulus is not gone, rather is this a forgetting process. You get used to a stimulus and your reaction to it and if this stimulus is paired with a second stimulus it is enough to present the second stimulus to elicit the initial reaction. This reaction fades ones the fist stimulus is no longer paired with the second one and this describes extinction, which involves new learning. If memories are not used frequently, they dissipate at least to some extent, a process referred to as forgetting. Research findings indicate, that the brain has established activities to remove unused information to prevent synaptic overload. This indicates the importance for remembering and forgetting for efficient memory. Finally, the third way how memories can change is called reconsolidation. Each time a memory is retrieved, it undergoes the delicate time of reconsolidation, making it even more vulnerable. This delicate time has advantages and disadvantages. The advantages are that – besides the fact that this period leads to strengthened memories – the memory can be refined, errors can be corrected as well as emotional responses can be modified so that there exists a potential therapeutic usefulness. On the other hand, reopening a memory opens for the introduction of new errors, for example the reconstruction of memories over time, especially when remembering childhood experience.
Neurons that fire together wire together – the challenge with metaphors
In his book „How we learn“, Benedict Carey describes the challenge with methaphors. I touch upon several of them in my questions and aswers above because I have heard these in professional contexts. On the one hand, they simplify phenomena and make them easier to grasp. On the other hand, metaphors give the impression that complex problems have easy solutions. (Academic) research is continously evolving and often contradictory – an ongoing heated debate some would say. It is tempting (and more satisfying) to say „Yes“ instead of „It depends“ and sell metaphors instead of multifacetted perspectives. Another challenge in neuroscience which adds to the complexity is described in Tood Rose’s „The end of average“ – scientific studies often create an average of brain activity of all subjects participating in a study. Sometimes this leads to astonishing research results. Or as Rose puts it: „Not only was each person’s brain different from the average, they were all different from each other.“ (Rose, 2016, p. 21) We need to be careful in drawing conclusions from averages on brain activity, as well as in simplifying cause and effect.
Good leaders need to lead based on neuroscience – the challenge of translating research into behaviours
Metaphors can (but do not have to) easily translate into myth and simplified recipes for – for example – good learning & development interventions or leadership strategies. I have long thought about what it actually is that bothers me with such myths until Dr. Alexander Klier put it out there in his blog series on „Lerndogmen und Bildungsmythen“. From my perspective, the key challenge with myth is when interventions that are based on missinterpretations, simplifictions or myths are systematically inflicted on others. In the organizational context, this could be organizing leadership trainings were participants have to run over embers, or base their leadership behaviors on non-scientific approaches. In the learning & development context, this could be trainers who are instructed to base their course offer on the 70/20/10 model or adapt to individual learning styles. In this structured and systematic approach in organizational contexts, myth lead to a waste of resources because they do not generate results. Luckily, a recent research paper indicates, that my concerns might be unfounded and that neursocience myths actually might be irrelevant for successful work practises.
Predicting where Dr. Shepard will operate next – the challenge of not turning into a besserwisser
Especially in my first neuroscience (mini) course, studying the different areas and parts of the brain was an essential part of the curriculum. For me it was a painfull experience and I vividly remember coloring all the study resource sheets and not remembering much after all. When I started the second course it felt like I had never heard of the basic brain structures before. Which was really frustrating, considering the time I had spent learning them. By accident, I studied for the second neuroscience course at the same time as deciding to re-watch Grey’s Anatomy. Somewhere in Staffel 2, my happy moment was when I could predict where Dr. Shepard would do surgery on a patient after explaining that „We are going to do surgery in an area of the brain responsible for movement and speech.“ I burst out (in very un-neuroscientific terms): „Left side in the middle.“ Which was technically correct but in reality a bit too vague if poor Dr. Shepard was to rely on my instructions. I don’t have a party trick yet – maybe this could become one? Another of these eureka moments came when listening to a the lyrics „Hit me hard – hit me right between the eyes. I wanna see the stars“ and realising that you would see that stars only when you (after having beeing hit) would hit the floor with your back of the head (where the brain area responsible for vision is located). I don’t know, rather than a party trick this might quickly evolve into somekind of besserwisser.
Carey, B. 2015. How we learn. Reprint edition.
Garret, B. 2015. Brain & Behavior. Fourth Edition.
Howard-Jones, P. 2018. Evolution of the Learning Brain.
Purves, D. et al. 2018. Neuroscience. Sixth Edition.
Rose, T. 2016. The end of average. First Edition.
Walker, M. 2017. Why we sleep. First Edition.
Zarkadakis, G. 2015. In Our Own Image. First Edition.