Evolution of the upturned palm

Tierney writes a brief article in the Aug. 28 NYTimes science section on thinking about ancient origins of the "can you spare me a dime" upturned palm, noting that the upturned palm is a submissive gesture:

...a “gestural byproduct” of the circuits in the brain and spinal cord that protected vertebrates hundreds of millions of years ago..Confronted with a threat, ancient lizards would instinctively bend their spine and limbs to press their bodies closer to the ground, protecting the neck and head and signaling submission to a larger animal. This crouch display is the opposite of the high-stand display, the aggressive posture of a stallion or a gorilla raising its chest and head to appear larger...The human remnant of the crouch display is a shrug of the shoulders, which lowers the head and rotates the forearms outwards so that the palms face up. Conversely, the high-stand display persists in humans as a rotation of the forearms and palms in the opposite direction, producing the domineering palm-down gesture used by a boss slapping the conference table or an orator commanding quiet from his audience.

The Emory University group (Franz de Waal et al.) have found that Chimps and Bonobos use the palm-up gesture in a much more flexible way (depending on the situation and group) that vocalizations and facial expression (more strongly tied to emotions). This leads to speculation that gestures may have served as the steppingstone for early hominid communication and, possibly, language.

fMRI feedback for pain reduction

Jason Pontin discusses Omneuron and other start-ups that propose to teach sufferers to think away their pain...and... similarly treat addiction, depression and other intractable neurological and psychological conditions (PDF here).

Prokofiev Ballade for Cello and Piano

In this video Sonny Enslen (cello) and I are doing a final rehearsal before doing this piece for two amateur music performance groups in Madison Wisconsin: Carnaval and Allegro. The piano is a Steinway B at my Twin Valley, Middleton WI, home, freshly tuned and voiced.

Calisthenics for the aging mind.

I'll pass on this reasonably written NYTimes article by Christine Larson (PDF here) about software products promising brain enhancement for those of us who fret about our aging brains.

Permanent amygdala changes in people close to 9/11 attack

I'm passing on this brief piece pointed out to me by blog reader Scott Rosenblum, from Scientific American Mind. Readers will recall that the amygdala is the part of the brain that regulates emotional intensity and creates emotional memories. One clip:

In the Cornell study, functional magnetic resonance imaging (fmri) scans showed that people within two miles of the site that day have a hyperactive amygdala as compared with people who lived 200 miles away, even though those nearby were seemingly resilient and show no signs of mental disorder. The N.Y.U. team similarly found that when asked to recall the events of 9/11, twice as many people who were near Ground Zero had elevated amygdala activity as compared with people who were five miles away in midtown Manhattan. Slow recovery of a highly active amygdala, the Cornell researchers say, could increase susceptibility to mental health problems later in life.

By the way, Scientific American Mind is issued monthly, some of the brief articles you can read, others require a digital subscription (which I have been too stingy to spring for.)

The topography of fear

Mobbs and colleagues have devised an ingenious experiment to evaluate how different neural circuits in the human brain are engaged by distal and proximal threats. From the review of this work by Maren:

Mobbs and colleagues developed a computerized virtual maze in which subjects are chased and potentially captured by an "intelligent" predator. During the task, which was conducted during high-resolution functional magnetic resonance imaging (fMRI) of cerebral blood flow (which reflects neuronal activity), subjects manipulated a keyboard in an attempt to evade the predator. Although the virtual predator appeared quite innocuous (it was a small red circle), it could cause pain (low- or high-intensity electric shock to the hand) if escape was unsuccessful. Brain activation in response to the predatory threat was assessed relative to yoked trials in which subjects mimicked the trajectories of former chases, but without a predator or the threat of an electric shock....the prefrontal cortex and lateral amygdala were strongly activated when the level of threat was low, and this activation shifted to the central amygdala and periaqueductal gray when the threat level was high.

Models of consciousness at ASSC

By now I've made a number of references to the June 22-25 meeting of the Association for the Scientific Study of Consciousness in Las Vegas. Stuart Hameroff has just offered a report (PDF here) on the conference in the Journal of Consciousness Studies. His discussion of 'local' versus 'global' connection models of consciousness is worth excerpting here:

Dennett...reiterated one key feature of his multiple drafts model, that
activity anywhere in the brain could elicit consciousness, as long as
that particular activity was more than activity in any other brain area at
that moment. When asked precisely what type of neural activity did
the trick, Dennett passed. Put both Gazzaniga and Dennett in the ‘local’
camp (apparently with Christof Koch, who took that position in
last year’s ASSC debate). The globalists came later.

Koch (ASSC’s scientific compass) and most neuroscientists
assume axonal firings, or spikes are the bit-like currency underlying
the NCC. Gamma synchrony (coherent 30 to 90 Hz EEG, a.k.a.
‘coherent 40 Hz’) and other EEG are generated not by spikes, but by
dendritic local field potentials (LFPs), a distinction addressed in two
excellent posters from David Leopold’s NIMH group. Recording both
spikes and LFPs in monkey cortex and thalamus, they found that subjective
awareness correlates with dendritic LFPs rather than axonal
spikes.

Are dendrites and gamma synchrony outside ASSC’s narrow
focus? After Singer discovered gamma correlations with consciousness
in the 1980s, Francis Crick and Christof Koch helped launch the
gamma synchrony NCC bandwagon. But they later jumped ship,
along with many others, related to an influential analysis by Shadlen
and Movshon which rejected gamma synchrony. Gamma synchrony
was rejected not because it doesn’t correlate with consciousness — it
clearly does — but because it doesn’t jive with axonal spikes, the
anointed currency of the NCC. Gamma synchrony EEG derives from
LFPs, in turn derived from post-synaptic dendritic potentials. Forced
to choose between dendritic synchrony and axonal spikes as the NCC,
Shadlen and Movshon, Crick and Koch and many others chose spikes,
and ASSC followed. Too bad.

LFPs and gamma synchrony occur both locally and globally,
compatible with both local origin theories, and global/hierarchical
views like Global Workspace (GW) and HOT. With GW guru Bernie
Baars in the house, global hierarchies surfaced in the superb session
‘Cortical Networks and Conscious Awareness’ with Alumit Ishai
(Zurich), Rafael Malach (Israel) and Giulio Tononi (Wisconsin).

Tononi, more suave than even Koch, claimed that effective connectivity
(measurable through EEG/LFPs) in thalamocortical circuits
correlates with consciousness. Tononi used transcranial magnetic
stimulation on himself, among others, to see how it disrupted normal
sleep. (What an interesting college roommate he could have been!)
Put Tononi in the globalist camp.

Alumit Ishai used fMRI to study face recognition. She found
activity in a feed-forward (posterior to frontal) hierarchical network,
including posterior visual, limbic/emotional and frontal cortex. Put
Ishai in the globalist camp (along with Koch — now in both camps —
whose tutorial covered ‘top-down’, frontal to posterior, attention
mechanisms).

So … does consciousness require hierarchical organization as the
globalists and HOT proponents advocate? Or are the localists correct
in that consciousness can erupt in any sufficiently active brain region?
Rafael Malach from the Weizman Institute in Israel addressed this
issue. He studied continuous fMRI in subjects watching Sergio
Leone’s epic spaghetti Western The Good, the Bad and the Ugly,correlating
specific fMRI activity with precise movie scenes and frames.
While viewing the film, all above-baseline fMRI activity remained
posterior in the subjects’ visual cortical areas, with occasional snippets
of activity in sensory cortex. Malach showed that the appearance
of faces in the film (Clint Eastwood, Lee van Cleef, Eli Wallach) corresponded
with activity in viewers’ posterior visual cortex face
regions. Activity in the ‘hand’ area of sensory homunculi occurred
precisely during scenes/frames showing characters’ hands gripping a
gun, cigar or dealing cards.

Without posterior-frontal connections, Malach suggested lateral
links among basal dendrites of layer 5 pyramidal cells and cortical
interneurons worked in a distributed, rather than hierarchical,
LFP-friendly architecture to produce conscious experience. Put
Malach in his own camp — not local but not necessarily global. Call it
lateral/distributed.

Could local, global and/or lateral/distributed neuronal organizations
each support different modes of consciousness in different circumstances?
When we are passively engrossed in a film, brain activity
remains posterior, e.g. in Malach’s lateral/distributed scheme. When
we become introspective or engage in command-and-control modes,
frontal cortex kicks in and more global GW/HOT networks take over.
Very localized activity could also result in consciousness (e.g. Zeki’s
famous colour consciousness in isolated V4 activity, or Damasio’s or
Panksepp’s emotional core suggestions).

So the question becomes not so much where, but precisely what
type of neural activity distinguishes consciousness from unconscious
processes. The evidence points to synchronized dendritic LFPs rather
than axonal spikes. And if Block and Kouider are correct, neural
activities supporting unconscious processes must be further divided
into (at least) two sub-types: non-conscious and pre-conscious/
access. There’s plenty of need for lower level subtlety.

A Neural Signature of Self-Control

From Brass and Haggard, in a recent issue of the Journal of Neuroscience (PDF here):

Voluntary action is fundamental to human existence. Recent research suggests that volition involves a specific network of brain activity, centered on the fronto-median cortex. An important but neglected aspect of intentional action involves the decision whether to act or not. This decision process is crucial in daily life because it allows us to form intentions without necessarily implementing them. In the present study, we investigate the neural correlates of intentionally inhibiting actions using functional magnetic resonance imaging. Our data show that a specific area of the fronto-median cortex is more strongly activated when people prepare manual actions but then intentionally cancel them, compared with when they prepare and then complete the same actions. Our results suggest that the human brain network for intentional action includes a control structure for self-initiated inhibition or withholding of intended actions. The mental control of action has an enduring scientific interest, linked to the philosophical concept of "free will." Our results identify a candidate brain area that reflects the crucial decision to do or not to do.

Figure: A, Activation in the dFMC for the contrast of inhibition versus action trials. The z-map is thresholded at z > 3.09 (p <>

Nature's revenge - Cicadas crashing the internet

Because any interruption of my internet connection leaves me feeling as if one of my limbs had been severed, I notice small articles like this from the Aug. 30 Nature Magazine. A clip:

A cicada known as the kumazemi is descending on Japan en masse...cutting households off from their Internet. Apparently mistaking fibre-optic cables for withered branches, they have been punching their one-millimetre-diameter ovipositors into the cables and laying eggs. In at least 1,000 cases over the past two years, the cicadas have either severed the cable or opened up a hole, allowing water to seep in. The Osaka-based Nippon Telephone and Telegraph West Corporation has responded by creating new cables that lack the grooves that the cicadas target with their ovipositors ...

Sexual orientation in women - brain correlates

Ponseti et al. suggest that they can observe a brain correlate of prenatal androgenization in homosexual women - they have less grey matter in their perirhinal cortex than heterosexual women. The article starts with a useful review of the controversial literature on previously suggested brain differences between homosexual and heterosexual individuals of the same sex. Here is their abstract and two figures:

Is sexual orientation associated with structural differences in the brain? To address this question, 80 homosexual and heterosexual men and women (16 homosexual men and 15 homosexual women) underwent structural MRI. We used voxel-based morphometry to test for differences in grey matter concentration associated with gender and sexual orientation. Compared with heterosexual women, homosexual women displayed less grey matter bilaterally in the temporo-basal cortex, ventral cerebellum, and left ventral premotor cortex. The relative decrease in grey matter was most prominent in the left perirhinal cortex. The left perirhinal area also showed less grey matter in heterosexual men than in heterosexual women. Thus, in homosexual women, the perirhinal cortex grey matter displayed a more male-like structural pattern. This is in accordance with previous research that revealed signs of sex-atypical prenatal androgenization in homosexual women, but not in homosexual men. The relevance of the perirhinal area for high order multimodal (olfactory and visual) object, social, and sexual processing is discussed.

Figure 1. Areas of increased GM concentration in heterosexual women compared to homosexual women. Coronal sections from y = 8 to y = −6 (p<0.05;>homosexual) was implicit masked with the contrast heterosexual (women>men). That way the intersection of significant voxels of both contrasts was gathered. As a result we found one cluster that matches both comparisons. That is, this brain area showed both, a lower GM concentration in heterosexual men compared to heterosexual women and a lower GM concentration in homosexual women relative to heterosexual women.

Figure 2. Heterosexual men and homosexual women compared to heterosexual women.
Areas of decreased GM concentration in heterosexual men are shown in blue and areas of decreased GM concentration in homosexual women are shown in yellow. Reduced GM concentration of homosexual women (relative to heterosexual women) is located within a sex dimorphic brain area.

A mouse model for OCD?

An interesting article from Welch et. al. reports finding a mutation that causes mice to display obsessive-compulsive behaviors. From the review of this work by Hyman:

Roughly 2% of humans suffer from obsessive compulsive disorder, but a lack of animal models has impeded research into this condition. Could a genetically engineered mouse model provide an exciting lead?

The mice studied by Welch et al. showed excessive grooming, which resulted in hair loss and skin injuries, as well as anxiety-like traits. These mice lack the gene encoding SAPAP3 — a scaffolding protein that is found in excitatory, glutamate-responsive synapses and is highly expressed only in the striatum region of the brain. The behavioural abnormalities in these mice were reversed by local expression of Sapap3 in the striatal region, which indicates that loss of this gene is responsible for the observed behavioural abnormalities.

The authors also found that a drug from the SSRI class — which selectively enhance serotonin-mediated neurotransmission throughout the brain — that is used to treat OCD in humans decreases both grooming and anxiety in these mice. This is interesting because a condition responsive to an enhancer of serotonin neurotransmission does not signify a primary defect in serotonin-mediated signalling; instead, the defect is in glutamate-responsive synapses. So alterations in serotonin seem to modulate glutamate action. These findings are also noteworthy because Welsh and colleagues have generated a possible mouse model of OCD. Moreover, these observations add to the accumulating, if circumstantial, evidence that OCD and its associated disorders result from abnormalities in neural circuits spanning the frontal, striatal and thalamic regions of the brain.

And, a word of caution:

Even if we can gain assurance with additional research that the behaviours observed in Sapap3-deficient mice reflect abnormalities in circuits that produce human symptoms, we cannot assume that OCD-related conditions in humans involve variations in this gene. These disorders, like other major psychiatric diseases, seem to be heterogeneous with complex underpinnings — probably involving several genes — that, in interaction with developmental and environmental factors, could lead to abnormalities in frontal–striatal–thalamic circuits.

An enzyme that keeps old memories alive

Greg Miller writes a brief review of work by Shema et al. :

Many substances interfere with memory, as any hung-over partygoer can attest. But although booze and drugs can disrupt the making of new memories (such as the embarrassing antics at last night's party), they leave older memories intact. Neuroscientists think this is because, after a time, memories become wired into the brain in a way that makes them harder to wipe out: Long-term memories, in the generally accepted view, are maintained by structural changes to the synaptic connections between neurons.

The study [by Shama et al.] adds to other recent evidence that may challenge, or at least complicate, this view. A team of neuroscientists reports that injecting a drug that blocks an enzyme called protein kinase Mzeta (PKMzeta) into the cerebral cortex of rats makes the animals forget a meal that made them sick weeks earlier. The findings suggest that the continuing activity of PKMzeta is somehow necessary to maintain long-term memory, something that's not predicted by most current hypotheses on the mechanisms of memory. The work also hints at the possibility of future drugs that could tinker with memory--for therapeutic uses or for boosting brainpower.

"This is a somewhat mind-blowing conclusion," says David Glanzman, a neuroscientist at the University of California, Los Angeles. Enzymes similar to PKMzeta are known to be important in early stages of memory formation, Glanzman says, but most researchers had thought that these compounds were not needed to sustain memory once synaptic changes--such as the growth of new synapses or the strengthening of existing ones--had occurred.

...Going forward, it will be important to figure out how specific ZIP's memory-erasing effects are, says Lynn Nadel, a neuroscientist at the University of Arizona in Tucson. "It's possible that ZIP erases all learning, no matter how old," Nadel says. But if the drug works more selectively, it could one day have clinical applications, he says. For example, researchers and clinicians have been looking for compounds capable of eliminating the painful memories of trauma survivors (Science, 2 April 2004, p. 34). The flip side is cognitive enhancement, adds Richard Morris, a neuroscientist at the University of Edinburgh, U.K. "The next step might be to find out whether augmenting the action of PKMzeta can help sustain memories for longer than occurs normally."

Pruning of nerve connections during development.

As we grow from infancy to adulthood, specific connections (synapses) between nerve cells are formed, and excess connections pruned away. Approximately 40% of the connections (synapses) between nerve cells in our brains disappear during development. How does a nerve cell decide which synapses to destroy? Din et al., studying the nematode Caenorhabditis elegans provide evidence that the creation of adult synapses triggers the destruction of developmentally transient synapses forged by the same neuron. David Miller offers a summary figure in his review showing the molecular details of how a primary synapse region matures while a secondary synapse region is eliminated.


Disconnections (Click to enlarge). (Top) The developing HSNL motor neuron initially forms synapses with vulval muscles and motor neurons in two locations. (Bottom) The protein SYG-1 blocks proteolysis of synaptic proteins at primary synapses but allows destruction of secondary synapses. E2, E2 ubiquitin conjugating enzyme; RBX, Ring finger protein.

Dramatic out of body demonstrations in normal subjects

I've done several posts (for example here, here, and here) on how underlying brain processes might explain what have been taken to be paranormal experiences, particularly assuming part or all of one's body to be projected out into surrounding space. By now the evidence is overwhelming that our sense of of the location of our physical body can be projected in space wherever we wish. Sandra Blakeslee now comments (PDF here) on several recent very effective demonstrations of body projection in space reported in Science Magazine (here and here). You really should watch this video of one of the experiments from Blanke's group:

Steven Fry's secret life of the manic-depressive

A friend pointed out this video to me. Fascinating. This is part I, which at its end links you on to the subsequent installments in the series.

More on magic at Las Vegas

I've done several postings on this already, but want to pass on George Johnson's excellent article in the Aug. 21 Science Section of the NYTimes about a session I attended given by Las Vegas Magicians for the recent meeting of the Association for the Scientific Study of Consciousness (PDF here).

The four ages of functional neuroimaging

An essay offered by Brad Buchsbaum on his blog.

Really weird...

Passing this on from MindHacks: an unknown man with a brain tattooed on the top of his head, revealed by a picture of a peeled back tuna can.

Changes in brain control circuits during human development

A collaboration at Washington University between Fair, Raichle, and others has offered a fascinating glimpse at how brain networks controlling our behavior develop from childhood through adolescence to adulthood. Here is their abstract, followed by two figures from the paper (PDF is here).

Human attentional control is unrivaled. We recently proposed that adults depend on distinct frontoparietal and cinguloopercular networks for adaptive online task control versus more stable set control, respectively. During development, both experience-dependent evoked activity and spontaneous waves of synchronized cortical activity are thought to support the formation and maintenance of neural networks. Such mechanisms may encourage tighter "integration" of some regions into networks over time while "segregating" other sets of regions into separate networks. Here we use resting state functional connectivity MRI, which measures correlations in spontaneous blood oxygenation level-dependent signal fluctuations between brain regions to compare previously identified control networks between children and adults. We find that development of the proposed adult control networks involves both segregation (i.e., decreased short-range connections) and integration (i.e., increased long-range connections) of the brain regions that comprise them. Delay/disruption in the developmental processes of segregation and integration may play a role in disorders of control, such as autism, attention deficit hyperactivity disorder, and Tourette's syndrome.

Fig. 2. (click to enlarge) Graphs formed from putative task-control regions in children, adolescents, and adults. ROI (regions of interest) locations are drawn to correspond to topographic brain locations. Right-sided ROIs are displayed on the right and anterior ROIs at the top of each graph. (A) rs-fcMRI revealed two separate control networks in adults as previously described (6). (B) The top 75 connections in adolescents revealed a similar two-component system as seen in adults; however, the dACC/msFC region was incorporated into the frontoparietal network. (C) The top 75 connections in children revealed a significant deviation from the adult architecture. The two networks were connected by a bridge connection (aPFC–dlPFC). The dACC/msFC region was incorporated into the frontoparietal network. Children lacked connections from the dlPFC to IPS and IPL. (D) Fit LOWESS curves of connection strength (r) versus age. As connection strength between the dACC/msFC region and the dF cortex decreased with age, correlation strength increased between the dACC/msFC and aI/fO regions. The aPFC region also decreased its connection strength with the dlPFC region with age but was already strongly connected to the aI/fO region in children. The strength of the aI/fO–aPFC connection was maintained into adulthood.

Fig. 3. (click to enlarge) Increased long-range and decreased short-range connectivity with age. Direct comparisons of all possible connections between adults and children were performed to test the statistical reliability of between-group differences. Both left- and right-hemisphere regions are placed on a transparent brain to aid with visualization. Red and blue lines highlight significant between-group differences for connections with an r ≥ 0.1 in either children or adults (i.e., absolute difference). Light blue and pink lines highlight connections present in both children and adults (r ≥ 0.1) that differed significantly in connection strength between groups (relative difference; P ≤ 0.05). (A) The segregation of the dACC/msFC region from the frontoparietal network (Fig. 2) was statistically significant, as was the disconnection of the aPFC from the dlPFC region (P ≤ 0.05). Most of the connections that "grew down" with age constituted short-range connections. Connections that "grew up" with age are faded to highlight this observation. (B) Connections between the dACC/msFC region and the cinguloopercular network that grew stronger with age were statistically significant (P ≤ 0.05). The connections of left dlPFC to left IPS and left frontal to left IPS were already present in children but significantly increased in strength with age. Most of the connections that "grew up" with age constituted long-range connections. Connections that "grew down" with age are faded to highlight this observation. Selected LOWESS curves are presented in A and B.

Live Longer - Don't Worry

Check out the Worriers Anonymous site and its several mellow out options such as this, this, or this.