Resolving emotional conflict

Dissociated responses in the amygdala and orbitofrontal cortex to bottom-up and top-down components of emotional evaluation.
Wright P, Albarracin D, Brown RD, Li H, He G, Liu Y.
Neuroimage. 2007 Sep 19

Background: Although emotional responses to stimuli may be automatic, explicit evaluation of emotion is a voluntary act. These bottom-up and top-down processes may be supported by distinct neural systems. Previous studies reported bottom-up responses in the amygdala, top-down responses in the orbital and ventromedial prefrontal cortices, and top-down modulation of the amygdalar response.

Methods: The current study used event-related fMRI on fifteen healthy males to examine these responses in the absence of stimulus anticipation or task repetition. Factorial analysis distinguished bottom-up responses in the amygdala from top-down responses in the orbitofrontal cortex.

Results: Activation of ventromedial prefrontal cortex and modulation of amygdalar response were not observed, and future studies may investigate whether these effects are contingent upon anticipation or cognitive set.

Sleep loss linked to psychiatric disorders

The human emotional brain without sleep — a prefrontal amygdala disconnect
Yoo SS, Gujar N, Hu P, Jolesz FA & Walker MP.
Current Biology 2007; 17(20): 877-878.

It has long been assumed that sleep deprivation can play havoc with our emotions.

Sleep deprivation is known to impair a range of functions, including immune regulation and metabolic control, as well as neurocognitive processes, such as learning and memory. But evidence for the role of sleep in regulating our emotional brain-state is surprisingly scarce, and while the dysregulation of affective stability following sleep loss has received subjective documentation, any neural examination remains absent. Clinical evidence suggests that sleep and emotion interact; nearly all psychiatric and neurological disorders expressing sleep disruption display corresponding symptoms of affective imbalance. Independent of sleep, knowledge of the basic neural and cognitive mechanisms regulating emotion is remarkably advanced. The amygdala has a well-documented role in the processing of emotionally salient information, particularly aversive stimuli. The extent of amygdala engagement can also be influenced by a variety of connected systems, particularly the medial-prefrontal cortex (MPFC); the MPFC is proposed to exert an inhibitory, top-down control of amygdala function, resulting in contextually appropriate emotional responses [5, 6]. We have focused on this network and using functional magnetic resonance image (fMRI) have obtained evidence, reported here, that a lack of sleep inappropriately modulates the human emotional brain response to negative aversive stimuli.

Negative emotion

How Negative Emotion Enhances the Visual Specificity of a Memory
Elizabeth A. Kensinger, Rachel J. Garoff-Eaton and Daniel L. Schacter
Journal of Cognitive Neuroscience, 19, 1872-1887

Background: Some studies have suggested that emotion primarily increases memory for "gist," and does not enhance memory for detail. There are, however, some instances in which negative objects (e.g., snake, grenade) are remembered with more visual detail than neutral objects (e.g., barometer, blender).

Methods: In the present functional magnetic resonance imaging (fMRI) study, we examined the encoding processes that lead a person to remember the exact visual details of negative and neutral objects, and to remember which of two decisions were made about the objects (a size decision or an animacy decision).

Results: The enhancement in memory for a negative item's visual details appeared to result from enhanced visual processing: The right fusiform gyrus, a region known to be critical for processing exemplar-specific details, showed a greater extent and magnitude of activity during the successful encoding of negative objects. Activity in the right amygdala also corresponded with memory for visual detail, although it did not relate to memory for the task performed with the item.

Conclusions: These data provide strong evidence that engagement of some amygdalar regions can correspond with enhanced memory for certain types of details, but does not ensure successful encoding of all contextual details.

The Power of Birth Order

Excellent article in the latest TIME magazine by Dan Cray.

"Of all the things that shape who we are, few seem more arbitrary than the sequence in which we and our siblings pop out of the womb. Maybe it's your genes that make you a gifted athlete, your training that makes you an accomplished actress, an accident of brain chemistry that makes you a drunk instead of a President. But in family after family, case study after case study, the simple roll of the birth-date dice has an odd and arbitrary power all its own.

The importance of birth order has been known—or at least suspected—for years. But increasingly, there's hard evidence of its impact."

Link to Time article 'The Power of Birth Order'.

10 Unsolved Mysteries Of The Brain

The Mind & Brain section of Discover magazine had a fantastic article on the mysteries of brain by David Eagleman.

"What we know—and don’t know—about how we think."

1. How is information coded in neural activity?
Neurons, the specialized cells of the brain, can produce brief spikes of voltage in their outer membranes. These electrical pulses travel along specialized extensions called axons to cause the release of chemical signals elsewhere in the brain.

2. How are memories stored and retrieved?
When you learn a new fact, like someone’s name, there are physical changes in the structure of your brain. But we don’t yet comprehend exactly what those changes are, how they are orchestrated across vast seas of synapses and neurons, how they embody knowledge, or how they are read out decades later for retrieval.

3. What does the baseline activity in the brain represent?
Neuroscientists have mostly studied changes in brain activity that correlate with stimuli we can present in the laboratory, such as a picture, a touch, or a sound. But the activity of the brain at rest—its “baseline” activity—may prove to be the most important aspect of our mental lives. The awake, resting brain uses 20 percent of the body’s total oxygen, even though it makes up only 2 percent of the body’s mass.

4. How do brains simulate the future?
The awake state may be essentially the same as the dreaming state. In this view, your conscious life is an awake dream.

5. What are emotions?
We often talk about brains as information-processing systems, but any account of the brain that lacks an account of emotions, motivations, fears, and hopes is incomplete.

6. What is intelligence?
Intelligence comes in many forms, but it is not known what intelligence—in any of its guises—means biologically. How do billions of neurons work together to manipulate knowledge, simulate novel situations, and erase inconsequential information? What happens when two concepts “fit” together and you suddenly see a solution to a problem? What happens in your brain when it suddenly dawns on you that the killer in the movie is actually the unsuspected wife? Do intelligent people store knowledge in a way that is more distilled, more varied, or more easily retrievable?

7. How is time represented in the brain?
When it comes to awareness, the brain goes through a good deal of trouble to synchronize incoming signals that are processed at very different speeds.

8. Why do brains sleep and dream?
One of the most astonishing aspects of our lives is that we spend a third of our time in the strange world of sleep. Newborn babies spend about twice that. It is inordinately difficult to remain awake for more than a full day-night cycle. In humans, continuous wakefulness of the nervous system results in mental derangement; rats deprived of sleep for 10 days die. All mammals sleep, reptiles and birds sleep, and voluntary breathers like dolphins sleep with one brain hemisphere dormant at a time. The evolutionary trend is clear, but the function of sleep is not.

9. How do the specialized systems of the brain integrate with one another?
To the naked eye, no part of the brain’s surface looks terribly different from any other part. But when we measure activity, we find that different types of information lurk in each region of the neural territory. There is no special anatomical location in the brain where information from all the different systems converges; rather, the specialized areas all interconnect with one another, forming a network of parallel and recurring links.

10. What is consciousness?
Think back to your first kiss. The experience of it may pop into your head instantly. Where was that memory before you became conscious of it? How was it stored in your brain before and after it came into consciousness? What is the difference between those states. The mechanisms underlying consciousness could reside at any of a variety of physical levels: molecular, cellular, circuit, pathway, or some organizational level not yet described.

Click here to read the entire story.

Brain Gardening

Blocking a brain chemical in some people with mental retardation makes their neurons grow like health plants. Watch the video about MIT research work on this from Discover magazine.


NeuroPod is the neuroscience podcast from Nature, produced in association with the Dana Foundation. Each month, Kerri Smith will be delving into the latest research on the brain, from its molecular makings to the mysteries of the mind.

In the first show, Kerri Smith explores the latest neuroscience research from Nature: untangling autism, slimming down obesity, getting emotional about memories, multipurpose ion channels, and neuroeconomics. Link

Alternatively, to ensure you do not miss any further issues of NeuroPod, you can subscribe to their free RSS feed. This way it will be delivered straight to your desktop! To do this, copy and paste the following URL into a media player such as iTunes:

Caring for children with sleep problems

Ward TM, Rankin S, Lee KA.
J Pediatr Nurs 2007;22(4):283-96.

Sleep disturbances are common in infants and children. Sleep disturbances in children not only disrupt the child and family but also impact parental and child well-being, daytime functioning, and behavior. Pediatric nurses care for the individual child as well as their family members. Understanding the importance of healthy sleep habits and the implications of inadequate sleep on child behavior and family-peer interactions provides nurses an opportunity to decrease family stress and increase positive coping, adaptation, and family function. Common types of sleep problems are presented, and recommendations for screening tools are included to help nurses better assess sleep problems in children and make appropriate referrals.

Curry your Brain

A chemical in the spice turmeric, used widely in Indian food, could help ward off Alzheimer's.

SWS and recollection in recognition memory

Daurat A, Terrier P, Foret J, Tiberge M.
Conscious Cogn 2007;16(2):445-55.

Recognition memory performance reflects two distinct memory processes: a conscious process of recollection, which allows remembering specific details of a previous event, and familiarity, which emerges in the absence of any conscious information about the context in which the event occurred. Slow wave sleep (SWS) and rapid eye movement (REM) sleep are differentially involved in the consolidation of different types of memory. The study assessed the effects of SWS and REM sleep on recollection, by means of the "remember"/"know" paradigm. Subjects studied three blocks of 12 words before a 3-h retention interval filled with SWS, REM sleep or wakefulness, placed between 3 a.m. and 6 a.m. Afterwards, recognition and recollection were tested. Recollection was higher after a retention interval rich in SWS than after a retention interval rich in REM sleep or filled with wakefulness. The results suggest that SWS facilitates the process of recollection in recognition memory.

Do you think you sleep?

Graciela E. Silva,James L. Goodwin,Duane L. Sherrill,Jean L. Arnold,Richard R. Bootzin, Terry Smith, Joyce A. Walsleben,Carol M. Baldwin,Stuart F. Quan
Journal of Clinical Sleep Medicine 2007;3(6):622-630.

Background: Subjective and objective assessments of sleep may be discrepant due to sleep misperception and measurement effects, the latter of which may change the quality and quantity of a person’s usual sleep. This study compared sleep times from polysomnography (PSG) with self-reports of habitual sleep and sleep estimated on the morning after a PSG in adults.

Methods: Total sleep time and sleep onset latency obtained from unattended home PSGs were compared to sleep times obtained from a questionnaire completed before the PSG and a Morning Survey completed the morning after the PSG.

Results: A total of 2,113 subjects who were ≥ 40 years of age were included in this analysis. Subjects were 53% female, 75% Caucasian, and 38% obese. The mean habitual sleep time (HABTST), morning estimated sleep time (AMTST), and PSG total sleep times (PSGTST) were 422 min, 379 min, and 363 min, respectively. The mean habitual sleep onset latency, morning estimated sleep onset latency, and PSG sleep onset latency were 17.0 min, 21.8 min, and 16.9 min, respectively. Models adjusting for related demographic factors showed that HABTST and AMTST differ significantly from PSGTST by 61 and 18 minutes, respectively. Obese and higher educated people reported less sleep time than their counterparts. Similarly, small but significant differences were seen for sleep latency.

Conclusions: In a community population, self-reported total sleep times and sleep latencies are overestimated even on the morning following overnight PSG.