March 29, 2011

Being rejected a real pain, brain images show

From CBC News:

The pain of rejection is more than just a figure of speech: regions of the brain that respond to physical pain overlap with those that react to social rejection, a brain imaging study shows.

The study used brain imaging on people involved in romantic breakups.

“These results give new meaning to the idea that rejection ‘hurts,”‘ wrote psychology professor Ethan Kross of the University of Michigan and his colleagues. Their findings are reported in Tuesday’s edition of Proceedings of the National Academy of Sciences.

Co-author Edward Smith of Columbia University explained that the research shows that psychological or social events can affect regions of the brain that scientists thought were dedicated to physical pain.

Click here to read the rest of the article.

Click here for full access to the study published in Proceedings of the National Academy of Sciences.

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January 11, 2011

Neuroscientist, VS Ramachandran: The neurons that Shaped Civilization

Enjoy this short video:

From: Ted.com

Neuroscientist Vilayanur Ramachandran outlines the fascinating functions of mirror neurons. Only recently discovered, these neurons allow us to learn complex social behaviors, some of which formed the foundations of human civilization as we know it.

Comments:

Hans Bauer

Jun 24 2010: Any species of comparable level in evolution may attain mirror neurons or something equivalent one day. May even be that this is already happening without our notice. It will hardly happen within a few days. As we heard it took hundreds of thousands of years for us.

May be that some species will develop culture and civilization one day – that is if mankind will not interfere.

By the way – my tom cat sometimes pees standing on two legs. Who knows how he learned it? :)

Watch the video, and read more

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December 23, 2010

A Prescription for Abdominal Pain: Due Diligence

From: NYTimes.com: “For some reason people respect headaches,” said Dr. Carlo Di Lorenzo, a leading pediatric gastroenterologist and a professor of clinical pediatrics at Ohio State. “I’ve never seen a parent or a pediatrician tell a child complaining of a headache, ‘You don’t have a headache — it’s not real.’ Bellyache is just as real as headache.”

Indeed it is. And recurrent abdominal pain in children is common, frustrating and often hard to explain.

Consider a girl who came to the clinic for her 10-year physical exam. She gets these bellyaches, she told me. Had a bad one that week, but her stomach wasn’t hurting right at the moment.

She’d been treated for constipation; she’d been tested for celiac disease and other problems. Every blood and stool test over the two years since the pain began was completely normal. One night the bellyache was so bad she went to the emergency room — and her abdominal X-rays were normal as well.

The diagnostic term for this common and perplexing condition is “functional abdominal pain”: recurrent stomachaches, as the American Academy of Pediatrics put it in 2005, with no “anatomic, metabolic, infectious, inflammatory or neoplastic disorder” to explain them.

When I was a resident, we often smirked when we spoke of functional abdominal pain, treating it as a code for a troublesome patient, dubious symptoms or an anxious family. But recent research suggests we were too biomedically narrow in our thinking.

Scientists are coming to understand that abdominal pain is transmitted by a specialized nervous system that may be hypersensitive or hyperactive in some children. Studies in which researchers inflated balloons in children’s intestines suggested that those with functional abdominal pain might be unusually sensitive to any distension on the inside.

Click here for the entire article

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February 16, 2009

When Your Gain is My Pain and Your Pain is My Gain: Neural Correlates of Envy and Schadenfreude

We often make social comparisons to evaluate others and ourselves.  In a recent study in Science, Takahashi and colleagues investigated the neurocognitive mechanisms of envy and schadenfreude (pleasure at another’s misfortune) using fMRI.  The researchers found that envy and schadenfreude are associated with different parts of the brain.  Whereas envy was associated with the dorsal anterior cingulate cortex, schadenfreude was associated with the ventral striatum. The dorsal anterior cingulate is involved in the processing of cognitive conflicts; envy-related activation in this region was greater when the envied person had superior and more self-relevant characteristics.  The ventral striatum is involved in processing reward and the schadenfreude-related activity in this region was stronger when misfortune befell an envied person more so than a neutral person.  Additionally, envy-related activity in the anterior cingulate predicted schadenfreude-related activity in the ventral striatum.  Takahashi and colleagues suggest that their findings document mechanisms of painful emotion, envy, and a rewarding reaction, schadenfreude.

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October 19, 2008

Pain, dissociation and subliminal self-representations

conscious states,pain — alice @ 3:09 am

Petr Bob
Review article in Consciousness and Cognition

Abstract:
According to recent evidence, neurophysiological processes coupled to pain are closely related to the mechanisms of consciousness. This evidence is in accordance with findings that changes in states of consciousness during hypnosis or traumatic dissociation strongly affect conscious perception and experience of pain, and markedly influence brain functions. Past research indicates that painful experience may induce dissociated state and information about the experience may be stored or processed unconsciously. Reported findings suggest common neurophysiological mechanisms of pain and dissociation and point to a hypothesis of dissociation as a defense mechanism against psychological and physical pain that substantially influences functions of consciousness. The hypothesis is also supported by findings that information can be represented in the mind/brain without the subject’s awareness. The findings of unconsciously present information suggest possible binding between conscious contents and self-functions that constitute self-representational dimensions of consciousness. The self-representation means that certain inner states of own body are interpreted as mental and somatic identity, while other bodily signals, currently not accessible to the dominant interpreter’s access are dissociated and may be defined as subliminal self-representations. In conclusion, the neurophysiological aspects of consciousness and its integrative role in the therapy of painful traumatic memories are discussed.

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November 18, 2007

Measuring pain

brain imaging,pain — thomasr @ 8:33 am

Nature News features an article about a recent study relating pain intensity and EEG signals.

Recordings from electrodes in the human brain may offer the first objective way to measure the intensity of pain. Researchers say that they have found a neural signal that correlates with the amount of pain that an individual feels. The signal could be used to refine pain-relief techniques that involve stimulating the brain with electricity, they say.

Single cells have previously been identified in the human brain that are active in pain, but their response is binary, signalling either pain or no pain. Now, Morten Kringelbach of the psychiatry department at the University of Oxford, UK, and his colleagues have identified low-frequency brain waves that emanate from two regions buried deep within the brain when a patient is in pain. The more pain that is experienced, the longer the waves last.

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October 30, 2007

The neuropathic pain triad: neurons, immune cells and glia

pain — thomasr @ 10:05 am

Joachim Scholz and Clifford J Woolf have a nice article in Nature Neuroscience on the biological causes of neuropathic pain. This includes (as the title goes) neurons, as well as immune cells and glia cells.

Abstract:

Nociceptive pain results from the detection of intense or noxious stimuli by specialized high-threshold sensory neurons (nociceptors), a transfer of action potentials to the spinal cord, and onward transmission of the warning signal to the brain. In contrast, clinical pain such as pain after nerve injury (neuropathic pain) is characterized by pain in the absence of a stimulus and reduced nociceptive thresholds so that normally innocuous stimuli produce pain.

The development of neuropathic pain involves not only neuronal pathways, but also Schwann cells, satellite cells in the dorsal root ganglia, components of the peripheral immune system, spinal microglia and astrocytes.

As we increasingly appreciate that neuropathic pain has many features of a neuroimmune disorder, immunosuppression and blockade of the reciprocal signaling pathways between neuronal and non-neuronal cells offer new opportunities for disease modification and more successful management of pain.

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October 22, 2007

Empathy for Pain and Touch in the Human Somatosensory Cortex

empathicpain.jpegAlthough feeling pain and touch has long been considered inherently private, recent neuroimaging and neurophysiological studies hint at the social implications of this experience. Here we used somatosensory-evoked potentials (SEPs) to investigate whether mere observation of painful and tactile stimuli delivered to a model would modulate neural activity in the somatic system of an onlooker.

Viewing video clips showing pain and tactile stimuli delivered to others, respectively, increased and decreased the amplitude of the P45 SEP component that reflects the activity of the primary somatosensory cortex (S1). These modulations correlated with the intensity but not with the unpleasantness of the pain and touch ascribed to the model or the aversion induced in the onlooker by the video clips. Thus, modulation of S1 activity contingent upon observation of others’ pain and touch may reflect the mapping of sensory qualities of observed painful and tactile stimuli.

Results indicate that the S1 is not only involved in the actual perception of pain and touch but also plays an important role in extracting somatic features from social interactions.

Bufalari et al. in Cerebral Cortex

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February 8, 2007

Pain in the brain

EEG,brain imaging,fMRI,pain,perception — thomasr @ 5:21 am

index_pain.gifPain is one of the most prominent examples of the problem of consciousness: from a subjective point of view we know the experience of pain all too well. Seen from the objective side of pain, the neural processes related to pain are becoming unravelled. But the essential relationship between neural processes going on from the sensation to the experience are much less known.

In a study by Christmann and colleagues, a combination of EEG and fMRI demonstrates how regional brain areas make different contributions — and at different times — to the experience of pain.

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December 29, 2006

Genetic Mechanism Helps Explain Chronic Pain Disorders

genetics,pain,perception — thomasr @ 7:09 am

painbrain.jpegResearchers at the University of North Carolina at Chapel Hill have discovered that commonly occurring variations of a gene trigger a domino effect in chronic pain disorders. The finding might lead to more effective treatments for temporomandibular joint disorder (TMJD) and other chronic pain conditions.

Catechol-O-methyltransferase (COMT), an enzyme that metabolizes neurotransmitters such as epinephrine, norepinephrine and dopamine and that has been implicated in the modulation of persistent pain, as well as cognition and mood, is regulated by a gene, also called COMT. Previous UNC-led research showed that common genetic variants of this gene are associated with increased pain sensitivity and the likelihood of developing TMJD.

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December 17, 2006

The mutation that takes away pain

genetics,pain,perception — thomasr @ 4:34 pm

headache.jpgImagine being unable to feel any pain at all. For a tiny handful of people, that is the reality — and medical researchers have now pinpointed the mutation that removes their ability to perceive painful sensations.The study began when doctors in northern Pakistan examined a remarkable group of related families in which several individuals seem entirely unaffected by pain. Their attention was first attracted by one member of the clan, a locally famous boy who performed street theatre involving walking on burning coals and stabbing his arms with knives.Although it sounds like a party trick, the condition is devastating, as sufferers don’t learn to know their limits. The street-performing boy killed himself on his fourteenth birthday after jumping off a house roof. The researchers studied six of his relatives, aged between 4 and 14 years. All had suffered many cuts and bruises, and injuries to lips and tongue caused by biting themselves; several had fractured bones without noticing.

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October 6, 2006

Neuropathic pain review

pain,perception — thomasr @ 2:41 am

neuropain.jpgThe last issue of Neuron features a nice review of the mechanisms behind neuropathic pain. Here is the abstract:

Mechanisms of Neuropathic Pain

Campbell et al
Neuron
Volume 52, Issue 1 , 5 October 2006, Pages 77-92

Neuropathic pain refers to pain that originates from pathology of the nervous system. Diabetes, infection (herpes zoster), nerve compression, nerve trauma, “channelopathies,” and autoimmune disease are examples of diseases that may cause neuropathic pain. The development of both animal models and newer pharmacological strategies has led to an explosion of interest in the underlying mechanisms. Neuropathic pain reflects both peripheral and central sensitization mechanisms. Abnormal signals arise not only from injured axons but also from the intact nociceptors that share the innervation territory of the injured nerve. This review focuses on how both human studies and animal models are helping to elucidate the mechanisms underlying these surprisingly common disorders. The rapid gain in knowledge about abnormal signaling promises breakthroughs in the treatment of these often debilitating disorders.

ScienceDirect

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