Why Do Humans Cry? Scientist Says Tears Served as a Means of Communication Before the Evolution of Language

Leading expert in neurology Michael Trimble, British professor at the Institute of Neurology in London, says that there must have been a time in human evolution when tears represented something greater than their simple function of lubricating the eye.

In his new book, Why Humans Like To Cry, Trimble tries to explain the mystery of why humans are the only species in the animal kingdom to shed tears in response to an emotional state. In his book, Trimble examines the physiology and the evolutionary past of emotional crying.

Trimble explains that biologically, tears are important to protect the eye.  They keep the eyeball moist, flush out irritants and contain certain proteins and substances that keep the eye healthy and fight infections. He explains that in every other animal on planet Earth, tears seem to only serve these biological purposes.

However, in humans, crying or sobbing, bawling or weeping seems to serve another purpose: communicating emotion. Humans cry for many reasons- out of joy, grief, anger, relief and a variety of other emotions. However, our tears are most frequently shed out of sadness. Trimble said that it was this specific communicative nature of human crying that piqued his interest.

"Humans cry for many reasons," he told Scientific American. "But crying for emotional reasons and crying in response to aesthetic experiences are unique to us."

"The former is most associated with loss and bereavement, and the art forms that are most associated with tears are music, literature and poetry," he said. "There are very few people who cry looking at paintings, sculptures or lovely buildings. But we also have tears of joy the associated feelings of which last a shorter time than crying in the other circumstances."

Pioneering research helps to unravel the brain’s vision secrets

A new study led by scientists at the Universities of York and Bradford has identified the two areas of the brain responsible for our perception of orientation and shape.

Using sophisticated imaging equipment at York Neuroimaging Centre (YNiC), the research found that the two neighbouring areas of the cortex — each about the size of a 5p coin and known as human visual field maps — process the different types of visual information independently.

The scientists, from the Department of Psychology at York and the Bradford School of Optometry & Vision Science established how the two areas worked by subjecting them to magnetic fields for a short period which disrupted their normal brain activity. The research which is reported in Nature Neuroscience represents an important step forward in understanding how the brain processes visual information.

Attention now switches to a further four areas of the extra-striate cortex which are also responsible for visual function but whose specific individual roles are unknown.

The study was designed by Professor Tony Morland, of York’s Department of Psychology and the Hull York Medical School, and Dr Declan McKeefry, of the Bradford School of Optometry and Vision Science at the University of Bradford. It was undertaken as part of a PhD by Edward Silson at York.

Researchers used functional magnetic resonance imaging (fMRI) equipment at YNiC to pinpoint the two brain areas, which they subsequently targeted with magnetic fields that temporarily disrupt neural activity. They found that one area had a specialised and causal role in processing orientation while neural activity in the other underpinned the processing of shape defined by differences in curvature.

(Photo: Image courtesy of Brian A. Wandell, Serge O. Dumoulin and Alyssa A. Brewer)

BNA 2013: FESTIVAL OF NEUROSCIENCE

The British Neuroscience Association’s biennial meeting in 2013 will be a unique event. Eighteen learned societies with a neuroscience interest - both clinical and non-clinical - have contributed one or more symposia to the programme, creating a meeting with 56 scientific sessions and 8 plenary lectures involving more than 240 speakers, over 80 from outside the U.K.

The hottest topics in neuroscience research will be covered under 8 themes, Development, Molecular, Cellular and Synaptic Mechanisms, Sensory and Motor Systems, Cognition, Circadian, Homeostatic and Neuroendocrine Mechanisms, Nervous System Disorders, Methods and Techniques and Public Awareness and Societal Impacts. Over 900 abstracts representing all aspects of the subject have been submitted.

As the venue for the BNA2013 meeting is the Barbican Centre - one of London’s leading entertainment venues - a major public engagement programme will form part of the Festival of Neuroscience - enabling members of the public to interact with scientists, carers, charities, funders, policy-makers…and some well-known celebrities with experience of mental health issues…to learn more about the brain and the importance of a multi-disciplinary approach to research.

Propping Open the Door to the Blood Brain Barrier

The treatment of central nervous system (CNS) diseases can be particularly challenging because many of the therapeutic agents such as recombinant proteins and gene medicines are not easily transported across the blood-brain barrier (BBB). Focused ultrasound can be used to “open the door” of the blood brain barrier. However, finding a way to “prop the door open” to allow therapeutics to reach diseased tissue without damaging normal brain tissue is the focus of a new study by a team of researchers at the Institute of Biomedical Engineering at National Taiwan University presenting at the 57th Annual Meeting of the Biophysical Society (BPS), held Feb. 2-6, 2013, in Philadelphia, Pa.

The group is investigating the feasibility of using heparin, a common anticoagulant, to enhance the delivery of therapeutic macromolecules using ultrasound into the brain. Heparin could be employed to increase treatment efficacy in patients with different types of CNS diseases under the guidance of medical imaging system providing new hope in these challenging cases. Initial results show that heparin does have the potential to optimize therapeutic delivery with ultrasound, acting as a “doorstop,” allowing drugs to better permeate the BBB and enhancing treatment success.

“A higher acoustic pressure and longer sonication, and/or a higher dose of microbubbles may increase the delivery of drugs or tracers into the sonicated brain tissue,” explains Kuo-Wei Lu, a member of the research team, “but side-effects, such as microhemorrhage, can also increase dramatically. The results of this study indicate that heparin may offer a safer way can to enhance the delivery of therapeutics to patients with CNS diseases.”

With these encouraging results, the next step for the team is to develop a focused ultrasound system with Magnetic Resonance Imaging (MRI) guidance to establish suitable parameters needed for patient clinical trials. “Focused ultrasound sonication is a noninvasive technology capable of localized and transient BBB opening for the delivery of CNS therapeutics,” Lu states. “We hope by developing suitable parameters and using chemical enhancers like heparin, this can be a valuable tool in the treatment of patients with CNS diseases, opening the door to better patient outcomes.”

(Image: Ben Brahim Mohammed)

City Life Changes How Our Brains Deal With Distractions

City life requires a lot of attention. Navigating a busy sidewalk while processing loud storefronts and avoiding rogue pigeons may feel like second-nature at times, but it’s actually quite a bit of work for the human brain. Psychologists do know that quick walks through the park can restore our focus, but they’re still getting a handle on just what urbanization means for human cognition.

A new series of behavioral studies offers some of the richest evidence to date on the mental exhaustion of urban living. In an upcoming issue of the Journal of Experimental Psychology: Human Perception and Performance, a group of British psychologists reports that people who live in cities show diminished powers of general attention compared to people from remote areas. With so much going on around them, urbanites don’t pay much attention to surroundings unless they’re highly engaging.

Kynurenines in the CNS: recent advances and new questions

Various pathologies of the central nervous system (CNS) are accompanied by alterations in tryptophan metabolism. The main metabolic route of tryptophan degradation is the kynurenine pathway; its metabolites are responsible for a broad spectrum of effects, including the endogenous regulation of neuronal excitability and the initiation of immune tolerance. This Review highlights the involvement of the kynurenine system in the pathology of neurodegenerative disorders, pain syndromes and autoimmune diseases through a detailed discussion of its potential implications in Huntington’s disease, migraine and multiple sclerosis. The most effective preclinical drug candidates are discussed and attention is paid to currently under-investigated roles of the kynurenine pathway in the CNS, where modulation of kynurenine metabolism might be of therapeutic value.

Even the brains of people with anxiety states can get used to fear

Fear is a protective function against possible dangers that is designed to save our lives. Where there are problems with this fear mechanism, its positive effects are cancelled out: patients who have a social phobia become afraid of perfectly normal, everyday social situations because they are worried about behaving inappropriately or being thought of as stupid by other people. Scientists from the Centre for Medical Physics and Biomedical Technology and the University Department of Psychiatry and Psychotherapy at the MedUni Vienna have now discovered that this fear circuit can be deactivated, at least in part.

In a study by Ronald Sladky, led by Christian Windischberger (Centre for Medical Physics and Biomedical Technology), which has recently been published in the magazine PLOS One, functional magnetic resonance tomography was used to measure the changes in the brain activity of socially phobic patients and healthy test subjects while they were looking at faces. This experiment simulates social confrontation with other people without actually placing the individual in an intolerable situation of anxiety.

Permanent confrontation has a diminishing effect on anxiety
“The study demonstrated that people with social phobia initially exhibit greater activity in the amygdala and in the medial, prefrontal cortex of the brain, however after a few faces this activity recedes,” says Sladky. This contradicts the assumption made thus far that the emotional circuit of socially phobic individuals is unable to adapt adequately to this stress-inducing situation.

Permanent confrontation with the test task not only led to a solution to the “problem” being found more quickly among the patients with anxiety, but also to some areas of the brain being bypassed which otherwise were over-stimulated, a characteristic typical of anxiety. Says Sladky: “We therefore concluded that there are functional control strategies even in the emotional circuits of people with social phobia, although the mechanisms take longer to take effect in these individuals. The misregulation of these parts of the brain can therefore be compensated to a degree.”

These findings could, according to Sladky, provide a starting point for the development of personalised training programmes that will help affected individuals to conquer unpleasant situations in their everyday lives more effectively. In Austria, around 200,000 people a year are affected by some form of social phobia. The number of people who suffer this condition without seeking help for it is likely to be very high, since many affected individuals fail to seek assistance or do so only too late as a result of their anxiety.