Category: Inside the Brain

A gentleman from Utah has a condition which is baffling brain scientists. The left side of his brain is shrinking, although the right-hand side seems fine.

He is currently being investigated by neurologists at the University of Utah, Brain Institute.

His brain scan is shown in the picture on the left.

NB: brain scans done by radiologists have left and right reversed, as they label their scans as if they were looking at the patient as they lie on their backs in the scanner, so the patient’s left is on the viewer’s right.

Link to news story from ksl.com
Link to coverage from Daily Times.

A research team led by neurologist Nicholas Schiff has recently published a brain scanning study on two patients who may show evidence of an internal mental life, despite being in a coma-like “minimally conscious state”.

MCS usually occurs after severe brain damage and is a condition where patients seem to be unconscious, but show intermittent awareness of the self or the environment, although they are not able to communicate or maintain this awareness for pronlonged periods of time.

It is thought to be ‘less severe’ than coma, where patients are entirely unresposive, or persistent vegetative state, where patients are unconscious but may show simple automatic functions such as the sleep-wake cycle or eye-tracking.

Schiff’s study found that an area of the temporal lobe, known to be involved in language comprehension, was activated when the two unconscious patients were played recordings of a friend or relative recounting a familiar event.

These responses were remarkably similar to the responses recorded from healthy participants used as controls. This surprised the researchers, who expected far less brain activity in the MCS patients.

One further result they describe as “haunting” was finding activity in the patients’ occipital lobe. The researchers speculate that activity in these areas may reflect memories and mental images triggered by the recordings and the sound of their family member’s voice.

Little is known about the functioning of the brain during these coma-like or miminally conscious states, and medical science is often surprised by the recovery of function even after prolonged periods of unconsciousness.

Terry Wallis, the subject of a recent Channel 4 documentary, regained consciousness after a record 19 years in a coma.

Link to abstract of Schiff study.
Link to news story about the study from Yahoo News.
Link to information on Terry Wallis, his recovery and the documentary about him (“The Man Who Slept for 19 Years”).

A news story about a recent meeting on bioethics in neuroscience reports that brain abnormalities are, well, not that abnormal:

Judy Illes, a senior research scholar at the Stanford Center for Biomedical Ethics, said that she and others have found that 18 percent of healthy volunteers had some kind of brain anamoly. While only 2 percent to 8 percent have required clinical follow-up, these incidental findings have raised concerns among scientists who are using the newest technology to unravel the mysteries of the brain.

Ethical issues in neuroscience and neuroimaging research (often called ‘neuroethics’) are becoming increasingly important as previously expensive and exclusive scientific tools (such as fMRI) are becoming widely used.

One important issue of debate is the ethics of informing someone if a brain abnormality is detected, when they have volunteered to take part in a research study as a healthy participant.

Link to story from newsday.com
Link to recent article on neuroethics from Trends in Cognitive Sciences.

Recently published results report the first reliable link between brain activity and levels of sexual desire. Yoram Vardi from Rambam Hospital in Israel has reported an association between an electrical brain signal (known as P300) and libido.

The fact that such a straightforward link is both important and newsworthy may be surprising for people who aren’t aware of the state of scientific research into the neuroscience of sex.

Considering that sex is one of the most important human activities, and the current findings have been thrilling to say the least, why is it that we know so little about how the brain handles sex ?

Continue reading “On orgasms, epilepsy and the lack of sexual neuroscience”

Reports (eg) of genetic evidence that the human brain evolved usually fast may be exaggerated – see this very thorough post at language log (thanks to Cosma for the heads up).

This quote seems pretty typical of the media reports:

Humans went into evolutionary overdrive as their brains developed, sending them on a path that set them apart from other animals, scientists believe

And you can understand the general yearning for signs of human uniqueness. Despite this there is no structure, or chemical, in the human brain that isn’t found in other species – and, it seems, even the pace of genetic change associated with human brain evolution isn’t unprecentedly fast (languagelog cites a cell adhesion protein in the zebrafish, and the SARS virus as just a couple examples of higher rates of change).

Continue reading “No uniqueness in the speed of the brain’s evolution?”

Electronic voice phenomena or EVP is the appearance of mysterious voices on tapes or recordings. They are usually hard to make out, ambiguous and hidden among the static, although some claim they are voices of spirits trying to communicate with the living.

Others claim this is a result of apophenia, a psychological tendency to see meaning in noise where there is none.

There’s been quite a bit of interest in this lately, probably spurred by the upcoming release of the movie White Noise, which has EVP recordings as its major plot device.

The Scotsman has an article exploring the phenomena from several angles, including quotes from a psychologist and parapsychologist on approaches to understanding these puzzling communications.

This is a hack which never made it into the book, but we thought it worth sharing. At this point, to get the most out of this hack, look at this figure (in a pop-up window) quickly before reading on. It’s not important to try and work out what it is, but have a good look. Seen it? Now, without further ado…

Hack #102: Alter Input With Expectation

The balance between feed-forward and feed-back connections in the brain gives a clue to the balance between raw sensation and expectations in constructing experience.

Feedback is ubiquitous in the brain. The brain is not just massively parallel [Hack #52], it is also massively interconnected- an awesomely complex cybernetic system.

Continue reading “Hack #102 : Alter Input With Expectations”

Controversy has erupted over Michael Persinger’s findings that applying weak complex magnetic fields over the temporal lobes can induce unusual experiences, particularly the experience ‘sensing a presence’ in the room, which Persinger has linked to religious belief and spiritual experience.

This work was part of a larger project in which Persinger and his colleagues have reported strong links between temporal lobe disturbance and anomalous beliefs and experiences throughout the population.

However, a group of Swedish neuroscientists led by Pehr Granqvist have reported that they’ve failed to replicate Persinger’s results with magnetic stimulation when they used a double blind approach to running their experiments (where neither the experimentor nor the participant knows whether they are getting magnetic stimulation).

Persinger has replied by stating that the Swedish study was not an accurate replication.

Link to story on nature.com

The second part of a three part neuroscience tutorial has just been published on kuro5hin.org. While the first part covered the basic physiology of the neuron and how signals are generated and propogate within them, the second part deals with how signals are passed between neurons, over the synapse.

The synapse is the principal part of the neuron where neurotransmitters are released. Because of this, it is where most psychoactive drugs have their effect, which often work by mimicking or altering the normal function of neurotransmitters as they communicate signals throughout the brain and other parts of the nervous system.

A study investigating the number of left-handed people in tribal societies has found that the more violent the society, the higher the number of left-handers in the population. The researchers speculate that this is due to left-handers having an advantage in hand-to-hand combat, as shown by the higher number of left-handed champions in sports like boxing and fencing.

Some researchers have linked left-handedness to neurobiological stress during the early stages of brain development, so it has been a puzzle why left-handedness remains a common trait in the population, when this sort of biological stress has been linked to other, less advantageous traits, such as higher rates of nervous system and immune system disorders.

The advantage in combat may be one way (among, potentially, many others, including better non-verbal intelligence) in which left-handers have an edge on their right-handed peers.

Link to story on nature.com

“So, I’m not really comfortable with the fact that my mind is actually something physical.” — at Daily Dinosaur Comics [via introvert.net]. Hey that freaks me out too, knowing that the thought “that freaks me out,” is not just accompanied by but actually is some kind of arrangement of the actual physical stuff in my head, which represents (in this context) “that freaks me out.”

There’s a lot to say here, on the philosophical aspects, but I refuse to be drawn into discussion on the nature of representation, emergence, and where “self” is stored by a cartoon T. Rex stomping on a house. Forgive me.

There are little men inside my head that tell me what to do.

No.

Really.

Here’s one of them:

The little man is a model according to a sketch of the human body on the surface of our brain.

Continue reading “Little men and their discontinuities”