Subcortical DisordersSubcortical Disorders

Thomas G. Bowers, Ph.D.Thomas G. Bowers, Ph.D.

Karen Quinland CaseKaren Quinland Case

Pathology SamplePathology Sample

Kinney, Korein, Panigraphy et al.(1994)

Pathology sample Pathology sample indicated prominent indicated prominent subcortical damagesubcortical damage

Especially in the Especially in the thalamusthalamus

However, there is also However, there is also evidence of evidence of considerable cortical considerable cortical damagedamage

835 grams835 grams

Karen QuinlandKaren Quinland

Anthony Bland CaseAnthony Bland Case

At age 18 suffered cerebral anoxia At age 18 suffered cerebral anoxia secondary to crushing injuries.secondary to crushing injuries.

Brain weighed 1007 grams (average Brain weighed 1007 grams (average ~1300 grams).~1300 grams).

Narrowed gyri, cerebral atrophyNarrowed gyri, cerebral atrophy

AB Pathology SampleAB Pathology Sample

Jarmulowicz (1995), Catholic Medical Quarterly

AB Pathology SampleAB Pathology Sample

Cingulate Gyrus

Hippocampus

FornixMamimilary

Bodies

Hypothalamus

AnteriorThalamus

The Circuit of Papez: An Early Model of Neural Substrates of Emotion

White Matter in Cognition White Matter in Cognition

Three types of white matter fibersThree types of white matter fibers– 1. Association fibers1. Association fibers

Connect different regionsConnect different regions

– 2. Commissural fibers 2. Commissural fibers Connect corresponding hemispheresConnect corresponding hemispheres

– 3. Projection fibers3. Projection fibersUp-downUp-down

White Matter Changes in AgingWhite Matter Changes in Aging

LeukoaraisosisLeukoaraisosis– No mass effect, does not enhanceNo mass effect, does not enhance

Periventricular sourcesPeriventricular sources– Glio cell lossGlio cell loss– Small vessel infarctSmall vessel infarct– ArteriosclerosisArteriosclerosis– Infection/inflammationInfection/inflammation– DemyelinationDemyelination– VasculitidesVasculitides

MRI Characteristics MRI Characteristics

Patchy, diffuse hyperdensityPatchy, diffuse hyperdensity Pencil thin linesPencil thin lines

Cognitive CharacteristicsCognitive Characteristics

Attentional processesAttentional processes Working memory (not span)Working memory (not span) Encoding and retrievalEncoding and retrieval Spatial rotationSpatial rotation Discourse comprehensionDiscourse comprehension

Disease ProcessesDisease Processes

1. Infection and autoimmune 1. Infection and autoimmune disordersdisorders

2. Vasculitis2. Vasculitis 3. Multiple sclerosis (MS)3. Multiple sclerosis (MS) 4. HIV4. HIV 5. Neurotoxic 5. Neurotoxic 6. Gliomas6. Gliomas

Infection and AutoimmuneInfection and Autoimmune

Systemic lupusSystemic lupus– 1. cognitive impairment fluctuates1. cognitive impairment fluctuates– 2. Can appear manic2. Can appear manic– 3. Deficits in retrieval, delayed recall3. Deficits in retrieval, delayed recall– 4. Problems in cognitive speed and 4. Problems in cognitive speed and

flexibilityflexibility VasculitisVasculitis

– Inflammation of blood vessels Inflammation of blood vessels

Multiple Sclerosis (MS)Multiple Sclerosis (MS)

Variable lesions in white matter and Variable lesions in white matter and corpus callosumcorpus callosum

Many different clinical coursesMany different clinical courses Periventricular changesPeriventricular changes Very impaired on divided attention Very impaired on divided attention

taskstasks

Multiple Sclerosis (MS)Multiple Sclerosis (MS)

Problems in reading comprehension, Problems in reading comprehension, visual memory retrieval, verbal visual memory retrieval, verbal memory, motor slowingmemory, motor slowing

Executive dysfunction Executive dysfunction – Negative recency effect noted Negative recency effect noted – Possible loss of temporal codesPossible loss of temporal codes

Do well on STM tasksDo well on STM tasks

HIVHIV

Patchy white matter changesPatchy white matter changes Atrophy in later stagesAtrophy in later stages Prodromal stage (up to 2 years)Prodromal stage (up to 2 years)

– May be only mildly symptomaticMay be only mildly symptomatic Attention deficitsAttention deficits Memory deficitsMemory deficits Slowed processingSlowed processing Impaired conceptual processingImpaired conceptual processing Impaired self monitoringImpaired self monitoring

Neurotoxic InjuryNeurotoxic Injury

SolventsSolvents– Acute and late developing effectsAcute and late developing effects– Headaches, dizziness, mild depression, Headaches, dizziness, mild depression,

impaired behavioral controlimpaired behavioral control– Problems in attention, self-monitoringProblems in attention, self-monitoring

Chronic CO exposureChronic CO exposure

GliomasGliomas

Astrocytomas (glioblastoma Astrocytomas (glioblastoma multiforme)multiforme)

Ischemic Vascular DementiaIschemic Vascular Dementia

LeukencephalopathyLeukencephalopathy– 1. Arteriosclerosis1. Arteriosclerosis– 2. Spasm2. Spasm– 3. Transitant ischemia3. Transitant ischemia

Severity related to brain tissue lossSeverity related to brain tissue loss– 1. decreased processing efficiency1. decreased processing efficiency– 2. retrieval failures2. retrieval failures– 3. problems with semantic access3. problems with semantic access– 4. spatial rotation impairment4. spatial rotation impairment– 5. selective executive dysfunction5. selective executive dysfunction

Progressive gliosisProgressive gliosis

Also progressive subcortical gliosisAlso progressive subcortical gliosis Often may cause frontal problemsOften may cause frontal problems

Frontal Lobe DementiaFrontal Lobe Dementia

Changes in eating habitsChanges in eating habits Sleep disturbanceSleep disturbance Somatic complaintsSomatic complaints Mute, empty behaviorsMute, empty behaviors Not amnesic, but fail to use memoryNot amnesic, but fail to use memory

Diffuse Axonal InjuryDiffuse Axonal Injury

Acceleration/deceleration rotational Acceleration/deceleration rotational forcesforces

Yields shearingYields shearing Mechanical forces lead to neuronal Mechanical forces lead to neuronal

segmentation, small hemorrhages, segmentation, small hemorrhages, edemaedema

Diffuse Axonal InjuryDiffuse Axonal Injury

Povlishock workPovlishock work– Shearing due to axonal swelling, not Shearing due to axonal swelling, not

mechanical tearingmechanical tearing– Wallerian degeneration ensuesWallerian degeneration ensues– Evolves in 6-24 hoursEvolves in 6-24 hours– Affects more distal axonsAffects more distal axons– No disruption of myelin, of cellNo disruption of myelin, of cell– ““retraction ball” forms retraction ball” forms

Radiation Injury to BrainRadiation Injury to Brain

Acute effectsAcute effects– Edema, elevated ICPEdema, elevated ICP– Early delayed effects, inhibition f myelin Early delayed effects, inhibition f myelin

synthesis synthesis – Late delayed effects, damage to myelin, Late delayed effects, damage to myelin,

vascular damage, immune processesvascular damage, immune processes– Nausea, headache, drowsiness, anorexiaNausea, headache, drowsiness, anorexia– Verbal semantic LTM retrieval problemsVerbal semantic LTM retrieval problems– Memory/motor dysfunctionMemory/motor dysfunction

Radiation Injury to BrainRadiation Injury to Brain

Dementia can occur and lead to Dementia can occur and lead to deathdeath

More likely memory decline, gradual More likely memory decline, gradual recoveryrecovery

SummarySummary

White matter difficulty yields White matter difficulty yields problems in complex cognitive problems in complex cognitive processingprocessing– Problems in processing speedProblems in processing speed– Difficulties with high cognitive demandsDifficulties with high cognitive demands– Problems with complex stimulus Problems with complex stimulus

demands, as rotationsdemands, as rotations– Problems with attentional monitoringProblems with attentional monitoring– Impairment with multiple associations Impairment with multiple associations

SummarySummary

Object recognition is unimpaired, Object recognition is unimpaired, knowledge in unimpairedknowledge in unimpaired

No single modality of input is No single modality of input is impaired, but multiple input is impaired, but multiple input is impairedimpaired