thoughts on thoughts

My holiday from posting is over (I did not get moved though – now end of March date). I did notice some interesting things in January and include five of them below. Also went through the million visits mark mid-Jan.

One:

Deric Bownds (here) had this: Nakano and others, Blink-related momentary activation of the default mode network while viewing videos, in Jan 2013 PNAS.

It remains unknown why we generate spontaneous eyeblinks every few seconds, more often than necessary for ocular lubrication. Because eyeblinks tend to occur at implicit breakpoints while viewing videos, we hypothesized that eyeblinks are actively involved in the release of attention. We show that while viewing videos, cortical activity momentarily decreases in the dorsal attention network after blink onset but increases in the default-mode network implicated in internal processing. In contrast, physical blackouts of the video do not elicit such reciprocal changes in brain networks. The results suggest that eyeblinks are actively involved in the process of attentional disengagement during a cognitive behavior by momentarily activating the default-mode network while deactivating the dorsal attention network.

This fits with the idea that blinks mark the small divisions of memory, the bits which are strung together in chronological order to make a memory. It also fits with the finding that people blink in unison when watching a film. As blinks can be plainly seen and can also be recorded with electrodes, they could be useful in studies to mark the divisions of attention, thought and memory.

Two:

I have never been a fan of personality types since in first encountered them seriously over 50 years ago. They just never rang true for explaning me or people I knew well. There are schemes that have seemed true and basic that have turned out to be just surface similarities (for example the elements of air, water, fire and earth). I have noticed that there is not much evidence for personality types in physiology or genetics. There is still some disagreement among believers on how many and what archetypes to use. But, for some reason I cannot understand, they are still held to be important universal parameters by many. So I note – surprise, surprise – they may not be universal. ScienceDaily has an item (here) on a paper by M. Gurven and others, How Universal Is the Big Five? Testing the Five-Factor Model of Personality Variation Among Forager–Farmers in the Bolivian Amazon, Journal of Personality and Social Psychology, 2012.

Five personality traits widely thought to be universal across cultures might not be, according to a study of an isolated Bolivian society. Researchers who spent two years looking at 1,062 members of the Tsimane culture found that they didn’t necessarily exhibit the five broad dimensions of personality — openness, conscientiousness, extraversion, agreeableness and neuroticism — also known as the “Big Five.” … these researchers discovered more evidence of a Tsimane “Big Two:” socially beneficial behavior, also known as prosociality, and industriousness. These Big Two combine elements of the traditional Big Five, and may represent unique aspects of highly social, subsistence societies. … Other recent research has shown the existence of Big Five personality traits may be lacking in some developing cultures, particularly in Asia and Africa. … Despite its popularity, there is no good theory that explains why the Big Five takes the form it does.

Three:

ScienceDaily has an item (here) on a paper about dopamine that might change the interpretation of a number of studies – J. Salamone and M. Correa, The Mysterious Motivational Functions of Mesolimbic Dopamine. Neuron, 2012.

The widespread belief that dopamine regulates pleasure could go down in history with the latest research results on the role of this neurotransmitter. Researchers have proved that it regulates motivation, causing individuals to initiate and persevere to obtain something either positive or negative. … (This) poses a major paradigm shift with applications in diseases related to lack of motivation and mental fatigue and depression, Parkinson’s, multiple sclerosis, fibromyalgia, etc. and diseases where there is excessive motivation and persistence as in the case of addictions. … It was believed that dopamine regulated pleasure and reward and that we release it when we obtain something that satisfies us, but in fact the latest scientific evidence shows that this neurotransmitter acts before that, it actually encourages us to act. In other words, dopamine is released in order to achieve something good or to avoid something evil. … Studies had shown that dopamine is released by pleasurable sensations but also by stress, pain or loss. These research results however had been skewed to only highlight the positive influence.

There may, even probably, be a reward (and/or a punishment) system in the brain, but if there is, it is not identical to the supply of dopamine.

Four:

ScienceDaily had an item (here) by A Schindler and A Bartels; Parietal Cortx Codes for Egocentric Space beyond the Field of View; Current Biology 2012. Vision and the concept of the world from our personal viewpoint seem to be the same, but physically they are different projections. Here is the abstract:

Our subjective experience links covert visual and egocentric spatial attention seamlessly. However, the latter can extend beyond the visual field, covering all directions relative to our body. In contrast to visual representations, little is known about unseen egocentric representations in the healthy brain. Parietal cortex appears to be involved in both, because lesions in it can lead to deficits in visual attention, but also to a disorder of egocentric spatial awareness, known as hemispatial neglect. Here, we used a novel virtual reality paradigm to probe our participants’ egocentric surrounding during fMRI recordings. We found that egocentric unseen space was represented by patterns of voxel activity in parietal cortex, independent of visual information. Intriguingly, the best decoding performances corresponded to brain areas associated with visual covert attention and reaching, as well as to lesion sites associated with spatial neglect.

Five:

Deric Bownds had a post on intuition (here) from a paper: Wan and others; Developing Intuition: Neural Correlates of Cognitive-Skill Learning in Caudate Nucleus; The Journal of Neuroscience 2012 . It showed that the ability of experts to make decisions very quickly and accurately without consciously considering the situation is due to training the involves part of the basal ganglia, the caudate head. This part of unconscious cognition does not even appear to be primarily in the neocortex. Here is the abstract:

The superior capability of cognitive experts largely depends on automatic, quick information processing, which is often referred to as intuition. Intuition develops following extensive long-term training. There are many cognitive models on intuition development, but its neural basis is not known. Here we trained novices for 15 weeks to learn a simple board game and measured their brain activities in early and end phases of the training while they quickly generated the best next-move to a given board pattern. We found that the activation in the head of caudate nucleus developed over the course of training, in parallel to the development of the capability to quickly generate the best next-move, and the magnitude of the caudate activity was correlated with the subject’s performance. In contrast, cortical activations, which already appeared in the early phase of training, did not further change. Thus, neural activation in the caudate head, but not those in cortical areas, tracked the development of capability to quickly generate the best next-move, indicating that circuitries including the caudate head may automate cognitive computations.