neuropsyc

agnosia

not able to recognize/ without knowledge

neuropsychology

how the brain supports cognition, emotion, behavior

ventral

stomach

dorsal

back

front

anterior

back

posterior

unilateral

one sided

bilateral

both sided

ipsilateral

same sidecont

contralateral

on the opposite side

Central Nervous System

brain & spinal cord

peripheral nervous system

neurons outside of the CNS

neurons

signaling units of the nervous system

glia

the support cells

astrocytes

creates the Blood Brain Barrier between the central nervous system and the blood   

oligodendrocytes

connect axons of neurons

form myelin sheath by wrapping their cell membrane around the axon

microglia

immune cells, phagocytes (wrap around & digest other cells)

ependymal cells

line the ventricles of the brain & spinal cord

gyrus

bumps

sulci

valleys

white matter

myelinated axons & glia cells

grey matter

mainly cell bodies & synapses

corpus callosum

white matter tract that connects 2 hemispheres 

• lesion here causes split brain

protecting the brain

• CSF

• 3 meninges

• skull (bone)

  • ventricles cushioning the brain

Circle of Willis

base of brain - cerebral arteries connect in a ring

traumatic brain injury

injury by external force; mechanic temperature

non-traumatic acquired brain injury

internal cause, stroke

Open TBI

object penetrates the skull

diffused or focal

Phineas Gauge

open TBI 1848

metal rod through skull

personality change —> more aggressive

prefrontal cortex impact

Closed TBI

blunt force, not penetrating 

can be diffused or focal

skull can protect the brain 

• brain can bump into the skull —> blood vessels are injured

Acceleration

moving object impacts a stationary head

Deceleration

moving head impacts a stationary object

Closed rotation

brain twists inside skull

closed compression

change in shape of

closed deformation

skull causes injury

closed coup

side of impact damage, obviously

closed contrecoup

damage, rebound might be less obvious

Concussion

diffuse, closed TBI

mostly in young individuals

loss of consciousness

headaches, neck aches, dizziness, nausea

recover 1-3 months, can have long term consequences

CTE

multiple repeated trauma to head

accumulation of phosphorylated tau (p-tau)

only confirmed postmortem

CTE stage progression

Stage 1: headache, impaired attention and concentration

Stage 2: depression, explosivity short term memory loss

Stage 3: executive dysfunction, cognitive impairment

Stage 4: dementia, word-finding difficulty, aggression

Diffuse axonal injury (DAI)

axons are injured/ compressed

hard to detect/ diagnose

symptoms: confusion, headache, nausea, drowsiness, loss of balance, changes in memory

Focal Injuries

hematomas: localized (often clotted) collection of blood outside of a blood vessel

hemorrhage: active, ongoing process of bleeding from a ruptured/ damaged blood vessel

stroke

insufficient blood flow to the brain

ischemic stroke

blockage causing the stroke

hemorrhagic stroke

ruptured blood vessel

high blood pressure 

deadliest type of stroke ~50% death rate 

emergency surgery required

hypoxia

deprivation of oxygen

caused by stroke / other

brain, liver, and other organs start to be damaged a few minutes after symptoms

hypoxemia

low oxygen in blood

hypoxia

low oxygen in your tissues (includes brain)

anoxic

complete lack of oxygen to the brain results in cell death after about 4 minutes

hypoxic brain injury

insufficient oxygen to the brain results in gradual cell death

• caused by strokes, heart attacks, anemia, toxins, breathing problems/ suffocation

• full recovery from a severe injury is rare

• can be diffuse or focal

ways to acquire brain damage

• TBI

• strokes

• infections

• toxins

• tumors

• neurosurgery 

cognitive jigsaw

looking for what is intact/ damaged

relies on assumption of subtractivity

subtractivity

assumption that the brain-damaged system is the same as the unimpaired system except with some pieces missing

• possible to take one thing away & the rest of the system will remain intact

single case lesion

examine the effects on brain lesions in individual patients 

valuable insight into brain function

may/ may not be for generalization

considerations for single case lesion

pre-injury function

difference in brain anatomy

time since lesion acquisition

secondary effects (depression)

Lesion patients

Phineas Gauge, HM, “tan”

causal inference, establish the necessity of a region

• sufficiency is never the case for the brain

averaging single case lesion patients

can mask critical differences

single dissociation

impaired performance task A but not on task B

• deficit on A = B is still intact

prosopagnosia

unable to recognize faces (A) but can recognize objects (B)

• dissociated 2 cognitive functions from one another

  • single dissociation

double dissociation

at least two patients with opposing patterns of cognitive functions

• both patients perform within normal limits on at least one of the two tasks and poorly on the second task

weak double dissociation

P1 and P2 both performing sub-normally on tasks A and B

visual object agnosia

one or more patients show impairment in recognizing objects but not faces = double dissociation

Patient KF

motorcycle accident at age 19

brain damage & epilepsy

impairment in verbal short term memory 

intact visual short term memory intact

KF performance

more than one type of working memory

working memory/ short term memory & long term memory are 2 separate systems

KF single dissociation

impaired short term memory, intact long term memory

double dissociation: KF and HM

evidence of independent processes, relying on neural resources 

commissurotomy/ callosotomy

surgical procedure —> split brain patients

• cutting the corpus callosum & anterior commissure

• MINIMAL effects on everyday behavior

• each hemisphere receives sensory input from all sensory systems, can control body’s muscles but no longer communicate with one another

corpus callosum

connects the two hemispheres with millions of heavily myelinated connected fibers

Right visual field information processed in the 

left hemisphere

left visual field information processed in the

right hemisphere

language is in the left hemisphere

left laterized

intact corpus callosum (language)

verbalize what was presented in left visual field

partial split patients (language)

enough transfer of information they can get to verbalization

complete split brain patients (language)

report not seeing anything

Case NG

right - cup shown (and correctly reported), left - spoon (touch only, finds and hold up spoon, might not name it)

key presented to left visual field

processed in the right, left hand pick object

ring presented to right visual field

processed in the left, says ring aloud, can use right hand to pick ring

right hemisphere processes FACES

top- down, general perception

left hemisphere processes more detail LANGUAGE

bottom up, minor details, specifics

interpreter hypothesis

left hemisphere tries to make sense of the world

consciousness

hemispheres 2 independently conscious minds within one body

patient JW

right handed man, epilepsy for 7 years

nonverbal plays asked who was nicer

right finger (left hemisphere) —> chose at random

left finger (right hemisphere) —> based on intent not outcome

commissurotomy/ callosotomy has 

minimal effects on everyday life BUT profound effects in a lab setting

phantom limb sensation

feeling that the amputated limb is still present

phantom limb pain PLP

perception of pain/ discomfort in a limb that is no longer attached

can be short-lasting/ rare or constant/ excruciating

can be immediate or after years onset

telescoping

shortening of phantom limb sensation 

lower intensity of PLP

related to cortical reorganization following amputation 

treatment: pharmacologic therapy 

residual limb pain (stump pain)

perception of pain or discomfort in the existing site of the amputated limb

neuromas

when a limb is severed, a terminal swelling/ ‘endbulb’ is formed and axonal sprouting occurs

• generate ectopic discharges

• spontaneous abnormal nerve signals

  • contributes to phantom limb pain

cortical reorganization

subset of people with PLS can find somatotopic map of missing limb on another part of their body

• internally consistent within patients

  • not same across patients

neighboring body areas invade the missing limb’s region in S1 and M1

mirror therapy

restore sensory feedback & motor congruence commands

doesn’t always work

disrupted integration of visual, proprioceptive, and somatosensory signals

PLS and PLP are common in

adult amputees

asymmetry of inputs

genes for cortical organization (brain and body work together) is strong

binding problem

scientific/ philosophical questions about how we perceive objects as single entities

object constancy

assumption that an object is the same even when it’s viewed differently

• from different angles, lighting, distances away from the viewer

Proximity - Gestalt grouping principles

• visual elements are more likely to be grouped if they are closer together

Similarity Gestalt grouping principles

• share visual attributes (color/ shape)

Good continuation Gestalt grouping principles

edges are grouped together to avoid changes/ interruptions

closure Gestalt grouping principles

missing parts are “filled in”

common fate - Gestalt grouping principles

elements that move together tend to be grouped together

object recognition steps

color/ shape/ movement

grouping - perception 

visual representation / meaning 

accessing a name 

final output