Pioneers of sight

 Watching a hawk circle the canyon overhead starts out as packets of light or ‘photons’ striking my retina. How these photons strike the retina and which pathways they activate in the brain tell me what I’m seeing. Photons landing in a specific orientation will travel pathways that construct its’ form (bird). When they hit adjacent areas in succession I’m informed of its’ motion and direction. And the length of time between hits tells me its’ speed. None of this was known before 1968 when David Hubel and Torten Wiesel first announced their research findings. And it wasn’t until 1981 that it was generally accepted and they earned the Nobel Prize in Neurophysiology and Medicine.

false memory

“Memory is not a passive record of things past. It's more like an ongoing construction-site, integrating and revising the past with events from the present and predictions about the future.”  [link]

How to plant a false memory by Dr. Susumu Tonegawa [link]: I’m skeptical. How is it possible to know what’s going on inside the head of a mouse ..let alone tell whether it’s true or not. I’m also intrigued. They say the fabric of memory is pliable and self-serving. It can be revised by the simple act of re-hashing things. Psychologist Elizabeth Loftus used to demonstrate this with eyewitness testimony. Neuroscientists have now replicated it with mice in a maze. Here’s how:

1. They narrow down a set of brain cells that get activated whenever a mouse enters a new location. Unfamiliar territory evokes a ‘neo-phobic’ response, which adds staying power to novel experience.
2. Then they create a new memory by stimulating the same set of cells and delivering an unpleasant jolt when the mouse enters a neutral part of the maze. The mouse ‘re-lives’ the experience of being in the location it explored before and couples it with the jolt. How do they know? The mouse avoids the location like never before.

They say memory serves as a road map to the future. However humans can play pretty loose with it .. reminiscing or ruminating about things ..which may make us more prone to revising the past. I don’t know if this has anything to do with it but I often recollect scenes from movies I enjoy. Lately I’ve been watching a lot of French films with the actress Audrey Tautou ..who I just adore. I also saw her in the movie ‘Da Vinci Code’ last night. This morning when Audrey Tautou popped into my head ..I mistook her for the character she plays in the movie. A character of potentially game-changing consequence to humanity. It felt eerie. It was just a flash but I’m wondering if this isn’t also some kind of false memory. Perhaps I’m overthinking it. I often blur the distinction between fantasy and reality. I know I confuse scenes from the movies with episodes from my past.

PTS prevention study

What makes some people less susceptible to PTS ..? Nociceptin receptors in the amygdala. Nociceptin (NOP) is a compound found at the synapse that acts like an analgesic. Nociceptin receptors are part of the amygdala involved in conditioned fear. According to neuroscientist Raul Andero Gali, we can prevent PTSD-like symptoms from developing.

Animal model of PTS

Traumatic   ~>    Fear-Response   ~>   Extinction
   Event                 Conditioning              Training  

During extinction training, some animals unlearn fear response (freezing) more rapidly than others. Persistence of fear in absence of danger is a characteristic of PTS. So, what makes some animals less susceptible to PTS ..?

Study 1 – naturalistic observation

Study found that those who unlearn the fastest were those whose Nociceptin receptors were most active. Nociceptin is a natural occurring opiate in the brain that’s thought to dampen consolidation of fearful memories 

Study 2 – experimental method

Animals that received a drug during conditioning that activates Nociceptin receptors  quickly learned to stop fearing the tone during extinction training. NOP receptors may interfere with fear memory consolidation, with implications for prevention of PTSD after a traumatic event [link] [link].

Sexual development

“The onset of puberty is determined by a mix of genetic and environmental factors coming to bear on the hypothalamus of the brain.”  Margaret M McCarthy, Piece in the puzzle of puberty, Nature, February 2013.

Somatosensory awareness

Mindfulness starts with the body: Meditation has been practiced for over two millennia in Asian Buddhist traditions. It is said to involve the cultivation of experiential awareness of the present moment. This present-moment focus is thought to improve well-being by allowing individuals to become aware of sensations, emotions and thoughts that arise in the mind without judgment or reactivity. Over the last two decades, mindfulness-related treatments have become an increasingly common component of the healthcare system. A common set of mindfulness exercises have been shown to reduce distress in chronic pain and decrease risk of depression relapse. These practices require attending to breath and body sensations. Here, we offer a novel view. Somatic focus helps modulate 7–14 Hz alpha rhythms (brain waves) that play a key role in filtering inputs to primary sensory neocortex and organizing the flow of sensory information in the brain. In support of the framework, we describe our previous finding that meditation enhances attention in the primary somatosensory cortex. The framework allows us to make several predictions. In chronic pain, we predict somatic attention “de-biases” neuro activity, freeing up pain-focused resources. In depression relapse, we predict somatic attention competes with internally focused rumination, as internally focused cognitive processes (including working memory) rely on alpha filtering of sensory input. Somatic focus sensitizes practitioners to better detect and regulate when the mind wanders from its somatic focus. Enhanced regulation of somatic mind-wandering may be an important early stage of mindfulness training that leads to enhanced cognitive regulation and metacognition

From Frontiers in Neuroscience [ link ]

Buddhist parable

“I am going to give you big secret of the fountain of youth that will save you much money on cosmetics and plastic surgery: In stillness we do not age as quickly as those whose minds are constantly battling to hold their personalities together.”  ◊  Wing

Psychologists have reached the same conclusion. A large amount of mental activity is spent to making sure that what we say conforms to our personality. In a study titled Cognitive demand and self-presentation [link] they asked participants about a specific event. Participants often answered with an average case that best represented the image they were trying to maintain. That's a lot of work. Far easier to report an actual experience than compute an average.

Navigating memory

“Here we propose that mechanisms of memory and planning have evolved from mechanisms of navigation in the physical world and hypothesize that the neuronal algorithms underlying navigation in mental space are fundamentally the same as those that underlie navigation in  physical space.”

From: Memory navigation and theta rhythm in the hippocampus [link]

György Buzsáki and Edvard I Moser

Puzzle Box

A fun way to learn to relax

Puzzlebox Orbit relies on EEG hardware from NeuroSky to capture brainwaves that signal attention and meditation. The more relaxed the player ..the higher and more controlled the helicopter goes [ link ].

Decision making

Decisions are mostly intuitive, logical explanations
catch-up milliseconds later ~ Robert Sapolsky [ link ]

GABA

GABA is the chief inhibitory neurotransmitter of the central nervous system. It is responsible for lowering excessive activity in the brain. Sedatives and tranquilizers act by enhancing the effects of GABA. When the potency of GABA is elevated for reasons unknown ..it results in a condition called hypersomnia or around-the-clock sleep, which can be very disruptive. It renders people unable to work or maintain relationships. Dr. David Rye found that a drug called flumazenil counteracts both tranquilizers and GABA in patients suffering hypersomnia. Furthermore it targets only people with high sensitivity to GABA while leaving people with normal GABA response alone ..meaning it gets closer to the root of the problem [ link ].

Neuro news

Neuroscientists have documented the functional neuro-anatomy of the hippocampus and amygdala. They’ve deciphered the role of the hippocampus ..showing how it works to transfer and consolidate information during long-term storage. They have also seen how the amygdala acts to adjust our threshold to threat and assign emotional-value to information transfer. “..what’s unclear however is the way the two regions connect ..and it’s the inter-connectivity that enables complex behavior that occurs so seamlessly.” 

Neuro feedback:  Real-time ‘visual feedback’ showing activity in the brain that’s linked to pain gives patients the ability to adjust and relieve instances of pain. Activity is displayed as a ‘flame’ ..which they can be taught to lower ..thereby reducing the activity and relieving the pain 

Depression :  Anti-depressants have been shown to work by lowering activity in a part of the prefrontal cortex called Broadmann's area 25 [ link ]. According to Neuroscientists “ ..area 25 is a key conduit of neural traffic between the “thinking” frontal cortex and the phylogenetically older limbic region that gives rise to emotion .. area 25 appears overactive in depressed people, like it opens the floodgates and allows negative emotions to overwhelm thinking and mood.” My question is - if they can treat depression in this area with anti-depressants and deep brain stimulation  ....couldn’t they also treat it with neurofeedback training ..?

Predictions in social perception

Research has shown that perception is an active process. The brain is constantly making predictions about the outcome of sensory events and revising predictions in response to feedback. Discrepancies naturally occur between expected and actual events resulting in ‘prediction errors’ that the brain actively works to resolve. Although prediction errors are transient in nature, they can be observed and measured during tests of sense-function. The longer they persist, the more disruptive they are to tasks involving high-speed sense-discrimination such as speech and reading comprehension. The principles of “predictive brain” are well established in the field of neuro-cognition. This study suggests they apply to the field of social-cognition as well ..and error analysis could be a useful measure of disruptions in social perception that characterize delusions of mental-illness [link].

Neural basis of stuttering

The neural basis of stuttering has to do with the integration of auditory information with speech-production commands. Previous studies show that stutterers’ produce a weaker-than-normal compensatory response while processing auditory feedback during speech. In this study they manipulated auditory feedback in order to see if weak compensatory responses are due to problems hearing feedback or using feedback. What they found is that stutterers’ have no difficulty hearing feedback, which narrows it down to functional areas responsible for using feedback ..or those areas responsible for translating performance-to-target feedback into corrective speech-action commands [link]

Refreshing the mind

EEG recordings from the visual cortex show that conscious experience is ‘periodically refreshed’ rather than ‘continuously updated’. Sensory memory persists long enough to bridge the gap [ link ]

The feeling of discourse

An MRI study reveals that emotion, not fact-sharing, promotes social interaction and facilitates interpersonal understanding. What researchers discovered is that emotions ‘synchronize mental networks’ between individuals. Synchronized network activity focuses attention on shared experience and produces a common framework for understanding. Sharing other people’s emotional state during discourse enables us to perceive, experience and interpret what others say in a like manner ..without separation [ link ].

Sound mind

It’s well known that the brain receives information from the ears in an orderly fashion. Signals for different frequencies arrive in tonotopic order along the auditory cortex. This means high tones are processed at one end of the auditory cortex while low tones are processed toward the other end. The location where these signals arrive determines our perception of pitch [ link ]. What’s interesting is that this type of organization applies to other properties of sound as well. Synapses that quickly release transmitters provide us with information about the onset of sound, like the beat, while synapses that release neurotransmitters more slowly provide information on qualities like timbre that persist over the duration of a sound. What’s new? Researchers have found that the pathways carrying these different synapse types are not grouped randomly. Instead, like orchestra musicians sitting in their own sections, they are bundled together by the property of sound that they convey. Tonotopic organization is preserved here as well. This means that beat and timbre have their own locations in the brain contributing to the perception of sound and music  [ link ].

Expectation-based perception

The journal Nature reports that expectation of a sensory event can increase the speed and accuracy we perceive it [ link ]. “Animals are not passive spectators of the sensory world in which they live. In natural conditions they often sense objects on the bases of expectations initiated by predictive cues. Expectation profoundly modulates neural activity by altering the background state of cortical networks and modulating sensory processing” [ link ].

Expectations alter perception ..I know this from my own practice. Expectations amplify and channel speech perception. Listeners have to take a moment to adjust when speakers say something that defies expectation. This study shows that the same holds true for taste. In one sense experiences arrive one by one, always fresh and new, but over time they become familiar re-enactments of prior experience. For instance I like yogurt for breakfast ..so I say it’s good and look forward to it when I get up in the morning. Good is a property I supply as something I experienced so long ago I don’t remember. It’s no longer fresh and new but an experience that my expectations enhance.

Heartbreak beat

       

Heartbreak Beat~Psychedelic Furs

Most children I see with dyslexia don’t have problems with vision. What they have is a slight gap somewhere in their auditory system, or sense of hearing. They cannot translate the word they see on the page to the sound of a word in memory. Until they can do that .. it’s hard for them to recognize the word as something they’ve heard before. I have a theory. I believe that the first language we learn is the sound of our mother’s heart beat. It serves as an internal metronome ..setting the tempo that helps us follow the sound of speech. It marks the onset of phonemes and syllables, which then helps us identify words and sentences. Dr Oliver tells me that his stroke patients who lose their ability to speak can still sing. When they begin putting their words into a melody ..they can express themselves fluently. My friend Levi has MS. He uses music as a prosthesis. He my not be able to walk the same as he used to, but he can dance every bit as good. He thanks his early years spent at Grateful Dead concerts for that. What this suggests to me is that ‘keeping the beat’ may be a more fundamental process than learning to read or understand speech. So I’ve been pushing the envelope of my heartbeat theory ..to the annoyance of those around me. I’ve come to believe that the heartbeat we hear in the womb sets up an internal rhythm that helps us follow events for the rest of our lives. Without it ..everything we hear and see would simply appear as though they were coming out of nowhere ..then vanish into nowhere ..without coherence ..nothing helping us string them together.

Anti-anxiety

The complaint I most frequently hear from former pot smokers of my generation (those who came-of-age during the 60’s and 70’s) ..is that smoking marijuana makes them feel nervous. Some describe it as so intense, it borders on paranoia. Consequently they quit and never came back. In the day, little was known about cultivating for the psychoactive effects of marijuana.

The times they are a’ changing. A new breed of cultivator has revolutionized the field. They can grow sophisticated varietals with a range of psychoactive properties. “The THC component is the same ..it is the mixture of other elements that play a vital role in changing the psychoactive effect.” Two decades ago, most marijuana smokers bought whatever their dealer had. It was illegal even for research purposes. Consequently nothing was known about marijuana other than its THC content.

One of these newly found elements is a compound called Cannabidoil or CBD. It’s responsible for the calming and pain relieving effects found in medicinal marijuana. Takes the buzz off THC so to speak. CBD is also helpful in treating a range of problems, including arthritis, the side effects of chemotherapy, asthma, sleep disorders and post-traumatic stress disorder [ link ]. CBD is measured in grams. Your local dispensary should carry varieties containing different amounts of CBD .. 0.35 grams being considered ‘good’.

The bell jar

Conscious experience is a bell jar shaped by historical and environmental forces. What we call ‘ordinary experience’ is fashioned by exposure during early childhood and a sensory-network that has evolved over eons of earthly habitation. Recent findings published in the journal Proceeding of the Academy of Sciences help support my bell jar theory. They show that the sensory world is tuned by exposure early in life. Children growing up in cultures where their diets don’t offer much in the way of sugar, eventually lose the taste-receptor for it [ link ]. In the same way, children growing up in cultures where their language doesn’t include sounds found in other cultures eventually lose the receptor sites for them [ link ]. The neuro-pathways for discerning phonemes that are not available in the child’s early environment get ‘pruned away’. For example, children in Asian cultures that don’t have phonemes for the English ‘L’ and ‘R’ lose the ability to hear any difference between them.