primary visual cortex

maybe in another life

Steve/Tony, MCU, post-Infinity War, major angst.
Warnings for character death and mental illness.


When Steve thought back to that day, he memories felt unreal, as if he were watching a movie about someone else’s life.

He’d seen Thanos grab Tony by the neck. He heard the tortured wrenching of the armor even over the sounds of the battle. Thanos had looked down at Tony with a distasteful grimace and tossed him aside with no more consideration than if he were swatting a fly.

Steve had seen Tony flying through the air, impacting a concrete wall hard enough to smash it, heard the sickening screech as rubble and debris rained down on top of him.

He vaguely remembered sprinting towards the pile, throwing chunks of concrete and metal aside, digging until his knuckles bled and stuck to the inside of his gloves.

But mostly he remembered that when he found Tony, his armor was split by deep, ugly gashes and the ground beneath his body was stained crimson.

The arc reactor had sputtered and gone dim, and when he ripped the faceplate off the suit, Tony’s eyes were blank and vacant, staring at nothing. He wasn’t breathing.

He’d heard someone yelling, then realized it was him. The sounds of battle faded into the background as he stared in horror at the crushed shell of Tony’s armor lying in a pool of blood.

It might have been hours later that he felt a hand on his shoulder. The streets around them were quiet and it was dark. “Steve,” Natasha said, wiping her eyes on her sleeve, “He’s gone, Steve.”

No, Steve decided. No, he would not accept this. Not when they had finally managed to mend the rift between them, to start trusting each other and working together again. Not when they had only just found their way back to each other.

He was going to save Tony. He was Captain America, and saving people was what he did.

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Vision in the brain!

Continuation of this post

So there’s this vague… misunderstanding that what you see in your left eye is processed on the right side of the brain and vice versa… which is… incorrect. Essentially, both eyes are processed with both sides. But the RIGHT side of both eyes goes RIGHT, and the LEFT side of both eyes go LEFT. The optic chiasm is where these paths cross

There are lots of areas in the brain involved with vision, but it seems the one that constitutes the vision in the most conscious sense is the Primary Visual Cortex (V1) located in the backity back of the occipital lobe. Not only is this where vision occurs, but it’s also where dreams and imagination occurs (oooooo), literally. If you are told to imagine something (um? a dog?), your visual cortex will do the same thing as if you were looking at the actual dog! So it seems to be responsible for the conscious experience of “seeing”. It’s also important for  static and moving objects, edge detection, and pattern recognition

Damage to this area not only makes you blind, but you can no longer have visual dreams, hallucinations, or imagine images. It takes away all possible senses of vision in the most broad sense of the term. The weird thing is, your eyes aren’t done doing their jobs. If you tell someone with V1 blindness to point to something, they do it with a surprising amount of accuracy for someone who is blind. They can predict the color, movement, and shape of objects as well. It’s difficult to determine if this is the result of incomplete damage to V1 or if the eyes are communicating with other areas…

Identification of images seems to take 2 streams from the V1 area, the ventral and the dorsal stream, also known as the what and where pathways. The ventral stream travels through the temporal lobe, which has areas of identification (some are vague like… “oh it’s kinda round and fluffy?”, some are “this is a motherfucking face”-fusiform gyrus). The Dorsal stream travels up through the parietal lobe, which deciphers basically… where the image is coming from

Also can we talk about my professor’s “helpful study tip” for this? because it’s fucking adorable

Damage to the inferior temporal lobe may result in visual agnosia. Y’all heard that pretentious “Ceci n’est pas une pipe” or whatever… It’s (not based on but eerily similar to) this, and it’s meant to call out the concept of perception. They handed a pipe to a guy with visual agnosia and he was like “umm??? it’s? it gets longer… it starts out thin, seems to curve into a rounded, hollow end? But I for the life of me don’t know what this is!” and the doctor was like “it’s a pipe” and the guy was like “huh. I suppose it is…” Then the doctor said “what if I told you it wasn’t a pipe?” and the guy was like “well then I’d have to believe you.” so he sees the image clearly and can identify its features, but he can’t… identify it.

(for the record, ceci n’est pas une pipe means that a painting of a pipe is technically not a pipe… I like the neuroscience version better)

Also worth noting is the V4 region, which is important for color perception. If you see something that’s green in a room with red lighting, you can still figure out that it’s green, even though it looks different from what green looks like in other contexts. That’s because of your V4 region keeping its shit together.

FINALLY there’s the V5 area, also known as the MT area (Middle temporal), which is again, motion oriented. Different areas of the MT area respond selectively to specific speeds and directions. They’re the reason you can tell a man is running in a picture, even when he isn’t moving. Your brain makes assumptions based on context clues. Next to the MT area is the MST area (medial-superior temporal cortex). which kinda… lowkey… helps with depth perception and movement? Part of it is the trick where you see a road getting narrower in an image indicating that it’s getting further away? The MST area is the part that makes that assumption

Citation:

Kalat, J. (2016). Biological Psychology. Australia South-Western. 12E

Brain MRI 

A: L - Ventral Posterior Thalamus (relays sensory information) 
B: Caudate 
C: Genu of Internal Capsule
D: Posterior limb of Internal Capsule
E: Primary Visual Cortex 
F: Corpus Callosum 
G: Putamen
H: Brocas area (frontal cortex) - Speech center 

Remember: the left side of the MRI is the patients right side and visa versa. 

This patient presented with decreased sensation over the right side of his face and body. The area most like effected given this image would be A, the thalamus

General sensory information relays to the thalamus: 
- From the C/L body: VPL (Ventral Posterolateral nucleus) 
- From the C/L face: VPM (Ventral Posteromedial nucleus)

Brodmann areas & Lesions
  • Areas 3, 1 & 2: Primary Somatosensory Cortex; impairment of all somatic sensations of CL body
  • Area 4: Primary Motor Cortex; spastic paresis of CL body
  • Area 5 & 7: Somatosensory Association Cortex; apraxia, astereognosia
  • Area 6: Premotor cortex and Supplementary Motor Cortex; apraxia
  • Area 8: Includes Frontal eye fields; CL horizontal gaze palzy
  • Area 9 & 10: Dorsolateral & Anterior Prefrontal cortex; frontal lobe sd
  • Area 17: Primary visual cortex; unilateral lesion- CL homonymus hemianopsia w/ macular sparing, bilateral lesion- cortical blindness w/ intact PLR (pupillary light reflex)
  • Area 18 & 19: Associative visual cortex; deficit in perceiving visual motion
  • Area 20 & 21: Inferior & Middle temporal gyrus, part of Associative visual cortex; visual agnosia, achromatopsia, prosopagnosia.
  • Area 22: Superior temporal gyrus, the caudal part contains the Wernicke's area, Auditory Association Cortex;
  • Area 39: Angular gyrus, considered to be part of Wernicke's area
  • Area 40: Supramarginal gyrus, part of Wernicke's area; Lesion of Wernicke's area result in aphasia and alexia.
  • Areas 41& 42: Primary Auditory cortex; unilateral lesion- CL slight hearing loss and difficulty localizing sounds, bilateral lesion- deafness
  • Area 43: Primary gustatory cortex
  • Area 44 & 45: Pars opercularis & Pars triangularis, part of the inferior frontal gyrus and part of Broca's area; lesion results in aphasia and agraphia
Brain Regions of PTSD Patients Show Differences During Fear Responses

Regions of the brain function differently among people with post-traumatic stress disorder, causing them to generalize non-threatening events as if they were the original trauma, according to new research from Duke Medicine and the Durham VA Medical Center.

Using functional MRI, the researchers detected unusual activity in several regions of the brain when people with PTSD were shown images that were only vaguely similar to the trauma underlying the disorder. The findings, reported in the Dec. 15, 2015, issue of the journal Translational Psychiatry, suggest that exposure-based PTSD treatment strategies might be improved by focusing on tangential triggers to the initial event.

“We know that PTSD patients tend to generalize their fear in response to cues that merely resemble the feared object but are still distinct from it,” said Rajendra A. Morey, M.D., an associate professor in the Department of Psychiatry and Behavioral Sciences at Duke and director of the Neuroimaging Lab at the Durham VA Medical Center. “This generalization process leads to a proliferation of symptoms over time as patients generalize to a variety of new triggers. Our research maps this in the brain, identifying the regions of the brain involved with these behavioral changes.”

Morey and colleagues enrolled 67 military veterans who had been deployed to conflict zones in Iraq or Afghanistan after Sept. 11, 2001, and who had been involved in traumatic events. Thirty-two were diagnosed with PTSD and 35 did not have the disorder.

All patients were showed a series of five facial images, depicting a range of emotions from neutral to frightened, while undergoing a functional MRI. The scans showed no dissimilarities between those with PTSD and those unaffected.

Outside the MRI, the participants were shown the images again and given a mild electrical shock when viewing the middle image – the face showing moderate fear.  

The patients then underwent another MRI scan as they viewed all five faces. People with PTSD showed heightened brain activity when they saw the most fearful face and associated it with the electric shock, even though they had actually experienced shocks when the middle, less fearful face appeared. Brain activity was heightened for the non-PTSD group when participants saw the correctly associated middle face.

“The PTSD patients remembered incorrectly and generalized their anxiety to the image showing the most fearful expression,” Morey said. “This phenomenon was captured in MRI scans, showing where the PTSD group had heightened activity.

“The amygdala, which is an important region in responding to threat, did not show a bias in activation to any particular face,” Morey said. “But there was a definite bias of heightened activity in response to the most frightened expression in brain regions such as the fusiform gyrus, insula, primary visual cortex, locus coeruleus and thalamus.”

Morey said the visual cortex was significant because it is not only doing visual processing, but also assessing threats. He said the locus coeruleus is responsible for triggering the release of adrenaline during stress or serious threat.

These functional brain differences provide a neurobiological model for fear generalization in which PTSD symptoms are triggered by things that merely resemble the source of original trauma.

“People with posttraumatic stress disorder grow anxious based on reminders of past trauma, and generalize that fear to a variety of triggers that resemble the initial trauma,” Morey said. “Current fear conditioning therapies are limited by repeated use of the same cue to trigger the initial trauma, but they might be enhanced by including cues that resemble, but are not identical to, cues in the original trauma.”

The Blind Woman Who Sees Rain, But Not Her Daughter’s Smile

Imagine a world that is completely black. You can’t see a thing — unless something happens to move. You can see the rain falling from the sky, the steam coming from your coffee cup, a car passing by on the street.

This was the world that Milena Channing claimed to see, back in 2000, shortly after she was blinded by a stroke at 29 years old. But when she told her doctors about these strange apparitions, they looked at her brain scans (the stroke had destroyed basically her entire primary visual cortex – the receiving station of visual information to the brain), and told her she must be hallucinating. “You’re blind and that’s it,” Channing remembers them saying to her.

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The Blind Woman Who Saw Rain

Posting our new video again for the late crowd: A story of love, loss and neuroscience.