Posts Tagged ‘amygdala’

Project H.M. & Clive Wearing’s Diaries

26/11/2009 2 comments

Project H.M.

H.M. is considered to be one of the most famous cases in neuropsychology. His dense amnesia contributed significantly to our understanding of human memory. On December 2nd, exactly a year after his death, anyone interested will have the chance to watch the dissection of his brain. I’m really looking forward to this (that sounds a bit weird).

According to the Project H.M. official blog:

“On December 2nd, 2009 we will begin slicing the brain of the amnesic patient H.M. into giant histological sections. The brain specimen is going to be frozen and sectioned whole during one continuous session that we expect will last approximately 30 hours”

If you’re interested in finding more about the project and the next phase, visit the Project H.M. website

Clive Wearin’s Diaries @ Wellcome Trust Exhibition

A few months ago I wrote a post on Clive Wearing, another case of amnesia. If you’re lucky enough to live in London, you’d be interested to know that the Wellcome Trust’s new collection, titled “Identity: Eight Rooms, Nine Lives” hosts Wearing’s famous diaries in the Samuel Pepy’s room. The exhibition will be on from today until April and it’s a part of The Identity Project (Pressure Drop could also be interesting). Oh, and it’s free.  For more information visit the exhibition’s website. They have a special section on Clive Wearing including a number of interesting videos.


image: Salvador Dali’s – the disintegration of the persistence of memory


Music Listening, Emotion and Reward Systems

31/10/2009 5 comments

brain_musicMusic is an important part of most people’s lives. Recently, many studies are focused on music and especially its relationship with emotion and the reward system. Here are a few interesting ones:

1.Salimpoor et al (2009), found that the rewarding aspects of music listening are related to the degree of emotional arousal. Here’s the abstract from their interesting study:

Background: Listening to music is amongst the most rewarding experiences for humans. Music has no functional
resemblance to other rewarding stimuli, and has no demonstrated biological value, yet individuals continue listening to
music for pleasure. It has been suggested that the pleasurable aspects of music listening are related to a change in
emotional arousal, although this link has not been directly investigated. In this study, using methods of high temporal
sensitivity we investigated whether there is a systematic relationship between dynamic increases in pleasure states and
physiological indicators of emotional arousal, including changes in heart rate, respiration, electrodermal activity, body
temperature, and blood volume pulse.

Methodology: Twenty-six participants listened to self-selected intensely pleasurable music and ‘‘neutral’’ music that was
individually selected for them based on low pleasure ratings they provided on other participants’ music. The ‘‘chills’’
phenomenon was used to index intensely pleasurable responses to music. During music listening, continuous real-time
recordings of subjective pleasure states and simultaneous recordings of sympathetic nervous system activity, an objective
measure of emotional arousal, were obtained.

Principal Findings: Results revealed a strong positive correlation between ratings of pleasure and emotional arousal.
Importantly, a dissociation was revealed as individuals who did not experience pleasure also showed no significant increases
in emotional arousal.

Conclusions/Significance: These results have broader implications by demonstrating that strongly felt emotions could be
rewarding in themselves in the absence of a physically tangible reward or a specific functional goal.”

2. Activation in brain regions implicated in reward and emotion was also found in an earlier study by Blood & Zatorre (2001). Using PET they found cerebral blood flow increases and decreases in brain regions that are thought to be involved in reward/motivation, emotion, and arousal such as the ventral striatum, midbrain, amygdala, orbitofrontal cortex, and ventral medial prefrontal cortex. These structures are known from previous studies to be active in response to other euphoria-inducing stimuli, such as food, sex, and drugs of abuse.

3. Menon & Levitin (2005) also found that:

“listening to music strongly modulates activity in a network of mesolimbic structures involved in reward processing including the nucleus accumbens (NAc) and the ventral tegmental area (VTA), as well as the hypothalamus and insula, which are thought to be involved in regulating autonomic and physiological responses to rewarding and emotional stimuli.”

4. For more information on the neural correlates of music perception, you can read the reviews by Limb (2006) and Koelsch (2006).

(picture: part of Guilherme Marconi’s collection – My Schizophrenic Brain)

Does time really slow down during frightening events?

Overestimation of time duration is often reported during brief, dangerous or possibly life threatening events, like car accidents, robberies or attacks. Observers mention that time feels like slowing down and everything seems to move in slow motion. Does time resolution really increase during the event or is it all an illusion?

Chess Stetson, Matthew P. Fiesta and David M. Eagleman (2007) decided to test this hypothesis. Using a hand-held device to measure speed of visual perception, they made volunteers free fall for 31 m before landing safely in a net. This device displayed a series of digits in high speed, so that they couldn’t be read by the  by the participants. The idea was that if time really slows down while we experience a frightening event (free falling), the participants could successfully read some or all of the digits displayed on the device’s screen. In addition to that, after landing they were asked to make duration judgements about their fall and the fall of others.

Although the participants  free-falling from 50 meters experienced a duration expansion,  no evidence of increased temporal resolution was found. Contrary to the initial hypothesis, they failed to read the digits that were displayed on the hand-held device. The results of this study don’t support the hypothesis that subjective time as a whole runs in slow motion during frightening events. The researchers suggest that the slowing of time that’s reported is a function of our recollection and not perception:

“The involvement of the amygdala in emotional memory may lead to dilated
duration judgments retrospectively, due to a richer, and perhaps
secondary encoding of the memories. Upon later readout,
such highly salient events may be erroneously interpreted to have
spanned a greater period of time.”

You can read the original study here.

Further Reading:

Changing Time and Emotions – Pierre-Yves Geoffard & Stéphane Luchini (2007)
Time and the Brain: How Subjective Time Relates to Neural Time – David M. Eagleman, Peter U. Tse, Dean Buonomano, Peter Janssen, Anna Christina Nobre & Alex O. Holcombe (2005)

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