Elena's Legacy. Texts written by Elena, excerpts from texts she liked, her artworks.

Friday, February 9, 2018

Self-Control and Ego-Depletion

An important topic in psychology is self-control or willpower, the implications of which are tremendous to both individuals and societies. An interesting psychological theory involves ego-depletion, stating that inner resources can get used up in tasks necessitating self-control. For example, if one has to exercise self-control on task A, it may be more difficult to exercise self-control on task B at a later time.

Ego-depletion refers to the theorem that self-control and self-regulation tap into a limited resource, which gets depleted overtime. Thus, if you use you willpower on something, you have less of it left for other tasks. Some paradigms propose that the mechanism has to do with glucose. Inzlicht and Schmeichel (2012) also found that self-control on a first task, resulted in less self-control in performance on a second task. Proposed explanations cover shifts of motivation from self-regulation to self-gratification and shifts in attention from control to rewards.

Romantic Read-head. Illustration: Elena

To add to the ego-depletion discussion, limited internal resources used for making choices, tolerating disagreeable situations, choosing healthier foods despite tastier alternatives, controlling one’s internal urges, aggressive or otherwise, all stem from the idea that self-control and willpower get used up. However, it seems that beliefs about willpower as an unlimited resource moderates the effect. Therefore, if you do not believe that your motivation to self-regulate will be lower with additional demands it may not be.

In addition, slacking off may be rationalized self-indulgence or decreased motivation to self-regulate. Alternatively, when self-control fails, it may be attributed to strong impulse, weak control or a combination of these factors. Moreover, psychology has many limitations. For example psychologists examine people who exert self-control on eating. Then, subsequently these same people tend to overeat. Psychologists may ask the question of whether this was due to depletion of internal resources, or of allowing the self to indulge as a reward for having worked hard. The problem is that the third alternative, that the participants are simply hungrier, fails to be discussed.

Neuroscientific Comics

Entertainment is defined as something amusing, enjoyable, as well as denoting the activities surrounding receiving guests. Neuroscience is incredibly insightful, while comics are entertaining. Psychology fields: Experimental, cognitive, social, personality, abnormal, developmental, computational, evolutionary, positive, cultural, biological and mathematical.

The following section aims at coordinating the two.

One could argue that neuroscience began to emerge in Ancient Egypt, where the brain was removed post-mortem (during mummification). While close to nothing was known about the cortex at the time, interest in mental constructs, such as intelligence, was well under way. Image: Copyright Elena

Traditional neuroscience. Although traditionally considered a branch of biology, neuroscience is an interdisciplinary field, combining elements from other disciplines, such as computer science, chemistry, mathematics, physics, linguistics, philosophy, psychology, medicine and engineering. Image: Copyright © Elena

Due to lack of photoreceptors (rods and cones), a blind spot is formed where the optic nerve leaves the eye. The brain fills in the missing information, which explains perceptive unawareness. Image: Copyright © Elena

Stellate neurons get their name because they are shaped like stars. The inhibitory aspiny stellate cells, the inhibitory interneurons and the excitatory spiny stellate interneurons, represent the three types most commonly mentioned. Image: Copyright ©Elena

Neuroscience & Fear

The essay discussed the neural correlates of fear, and psychology. Fear, as a phenomenon, is omnipresent. The statement could be easily verified by how common doomsday predictions, fear mongering, and conspiracy theories are. Social events such as Steven Colbert’s Rally to Keep Fear Alive are only some of the evidence. Further, many believe that subliminal messages embedded in media somehow influence the human mind. While that seems exaggerated, it is scientifically plausible to show something for such a short time that the brain registers it, but without any conscious awareness of what has been seen. Regardless, such far fetched suggestions are far beyond the topic of the present short essay, the purpose of which is to outline fear conditioning and extinction as documented in the academic literature.

Japan is renown, aside from electronics, anime and other elements, for its shockingly scary movies, a premiere of one of them allegedly being so scary that it had to be banned from show, due to heart attacks at the premiere. Film festivals such as Fantasia center on such thematic motion pictures. Moreover, fear is a strong motivator, and to judge by the horror movie genre and amusement parks popularity, actually a feeling many seek out.

Wall of fear. Photo by Elena

From a neuroscience perspective, the brain structure mostly associated with the emotion is the amygdala (Wilensky et al., 2006; Pare et al., 2004). Interestingly, anxiety differs from fear in that anxiety is fright of something unconfirmed, whereas fear relates to something certain (i.e. if there is a lion in one’s room and one is afraid, then that constitutes fear, but if one thinks there might be a monster under one’s bed, then that represents anxiety). Naturally, fear and anxiety are very important for anxiety disorders and other troubles related to abnormal psychology. Perhaps, the most obvious example of such ailments is GAD (Generalized Anxiety Disorder, characterized by chronic and excessive worry about almost everything).

Further, classical conditioning refers to the technique pioneered by Ivan Pavlov at the beginning of the 20th century. Fear conditioning works in a similar way. A famous story is that of little Albert, who was thus conditioned to fear white fluffy animals. So, fear conditioning works in the same way as classical conditioning. An initially neutral stimulus is repeatedly paired with one that elicits fear, and eventually, the neutral stimulus comes to be experienced as frightening.

Widely used in the treatment of phobias (irrational fears, such as acrophobia: fear of heights, arachnophobia: fear of spiders, agoraphobia with or without panic attack: fear of crowded places, claustrophobia: fear of enclosed spaces, and so on). Individuals suffering from these afflictions, often realize that their worries are unsubstantiated, but simply cannot do much about them. Fear extinction takes advantage of the reverse mechanism to treat phobias. For example, in desensitization, a scary stimulus is presented gradually in a safe environment (i.e. supervised by a mental health professional), and in time, the person gets more and more confortable and can potentially get rid of the fear all together.

Finally, Silverstein et al. (2011) explain that fear is processed at different levels in the brain. Thus, there appear to be cortical and subcortical pathways in the brain’s interpretation of aversive stimuli. Using neuroimaging techniques, the authors confirmed the involvement of the amygdala, but also of the thalamus, visual cortex, orbitofrontal cortex (OFC) and prefrontal cortex (PFC). Thus, the paper discusses the neuronal substrates of fear, and psychology.

References:

Pare, D., Quirk, G. L. and LeDoux, J. E. (2004). New vistas on amygdala networks in conditioned fear. Journal of Neurophysiology, 92: 117-33.
Silverstein, D., Lansner, A., Ingvar, M. and Ohman, A. (2011). A neural model of human fear pathways based on anatomical and neuroimaging data. BMC Neuroscience, 12, P241-2. From the Twentieth Annual Computational Neuroscience Meeting: Stockholm, Sweden.
Wilensky, A. E., Schafe, G. E., Kristensen, M. P. and LeDoux, J. E. (2006). Rethinking the fear circuit: The central nucleus of the amygdala is required for the acquisition, consolidation, and expression of Pavlovian fear conditioning. Journal of Neuroscience, 26: 12387-96.

Neurons

Neuroscience is the study of the nervous system, or the CNS – central nervous system and PNS – peripheral nervous system. The CNS contains the brain and the spinal cord, while the PNS represents cranial nerves and ganglia. Neurons are brain cells. Several different types of neural and glial cells exist: oligodendrocytes, astrocytes, pyramidal cells, stellate spiny neurons, Schwann cells.

A neuron consists of a nucleus, the cell body or soma, an axon and dendrites ending in terminal buttons. Neurotransmitters are discharged into the synaptic cleft, the space between neurons. The are several billions neurons in the brain, some comparing the number to the amount of stars in the Milky Way galaxy.

Brain stimulation. An artist’s impression of stained neurons. As can be seen from the picture, image: Public Domain

Loud noise or sound can cause hair cell trauma and, consequently, noise-induced hearing loss (NIHL). Fryatt et al. (2011) explain that this is often due to damage to spiral ganglions, the afferent neurons innervating the cochlear neuronal components. Other apoptosis is due to chemical and other trauma, potentially resulting in other auditory conditions such as tinnitus and hyperacusis.

Neuron can also refer to the neural simulation software, used by neuroscientists in research, such as Varela and colleagues (2011) in their study on PFC (prefrontal cortex) neurons, stress and plasticity. Many models of neuroplasticity have been proposed (Brito & Gerstner, 2011), such as the concepts: ICA (independent component plasticity), STDP (spike timing dependent plasticity), and non-linear Hebbian rule as related to BCM theory.

References:

Brito, C. SN & Gerstner, W. (2011). General conditions for spiking neurons and plasticity rules to perform independent component analysis. BMC Neuroscience, 12 (1): 124.
Fryatt, A. G., Mulheran, M., Egerton, J., Gunthorpe, M. J. & Grubb, B. D. (2011). Ototrauma induces sodium channel plasticity in auditory afferent neurons. Molecular and Cellular Neuroscience, 48 (1): 51-61.
Varela, J. A., Wang, J., Varnell, A. L. & Cooper, D. C. (2011). Control over stress induces plasticity of individual prefrontal cortical neurons: A conductance-based neural simulation. Nature Proceedings: Neuroscience, 1-2.

Neuroregeneration

Lesion studies have shed immense light on diverse neuroscientific subjects. An important topic in neuroscience is neuroregeneration, or cell repair and regrowth (neurogenesis refers to new cell growth). While the process differs between the CNS and PNS, generally in the CNS (which comprises the brain) damaged cells are doomed.

Neurodegeneration is the exact opposite, with many neurodegenerative disorders discusses in the literature (including Alzheimer’s, Multiple Sclerosis and various forms of dementia). From biology, one knows that there are internal cell mechanisms that cause it to undergo apoptosis in certain (traumatic) cases. For example, the process is triggered in auditory receptors (hair cells) in response to very loud noises. The old joke of a person going deaf after listening to too much loud music may have some background after all…

Fan and Fan (2006) explored the neuroregenerative process in Huntington’s disease (HD). The authors attest that precursor cells may start the process. Exploring the neurogenic mechanisms in mice, they noticed that NSCs (Neural Stem Cells) exhibit enhanced self-renewal potential shortly after the onset of HD. Further, the capability is inherited by subsequent cell generations, suggesting epigenetic changes.

Enciu et al. (2011) likewise look at the mechanism by which neurons come back to life after significant trauma. Thus, as hinted at above, they confirm that neuroregeneration takes place with the proliferation of endogenous, or implantation of exogenous NSCs, which in turn differentiate and successfully adapt. What’s more, the colleagues explain that neuroregeneration may be perceived as a neulogism, involving all the following events: neuroplasticity, neurogenesis and neurorestoration.

References:

Enciu, A. M., Nicolescu, M. I., Manole, C. G., Muresanu, D. F., Popescu, L. M. & Popescu, B. O. (2011). Neuroregeneration in neuroregenerative disorders. BMC Neurology, 11 (75): 1-7.
Fan, M. M. Y. & Fan, J. (2006). Proliferating neural precursor cells as first step toward neuroregeneration in Huntington’s disease? The Journal of Neuroscience, 26 (52): 13411-2.