Transcript Neurology for Psychiatrists

Neuroanatomy for
Psychiatrists
Dr Rohit Shankar
MBBS, MD, MRCPsych, CCT, PGC Cl. Research
Consultant in Adult Developmental Neuropsychiatry
Why should we know any Neurology?
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Brain Behaviour connection
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Man made divide
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2000 years of togetherness
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Hippocrates (460-377BC) Humours theory and Triad of mental
illness
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Plato – divine inspired and physical inspired mental illness
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Inter canon of the yellow emperor
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Johann Christian Reil 1808
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Reintegration – biological underpinnings
Golden Rules
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Adhere to the routine
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A good History is more useful than a good examination
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Usually well practiced testing would take 20 minutes then come
back to any areas of deficits
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Don’t ‘Scan’ before you ‘Can’ physically examine
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Hoof beats are usually more likely to be from horses as opposed
to Zebras, Hemiparesis is more likely from a stroke as opposed
to an unwitnessed seizure
The Neurological Exam
Motor System –
Limb strength
spasticity, flaccidity and fasciculation
Abnormal movements – e.g.. Chorea and tremors
Reflexes –
DTRs – biceps, triceps, Quadriceps, Achilles
Pathological reflexes – Babinski, frontal release signs
Sensation –
Position, vibration, stereognosis, Pain
Cerebellar –
Finger – Nose, Heel – Toe, Rapid alternating movements, Gait
The Neurological Exam
Mental Status –
GCS, orientation, Language, higher intellectual functions (arithmetic)
Cranial Nerves –
I Smell
II Visual acuity, visual field, optic fundi
Ocular motility nerves:
III,IV,VI pupil size and reactivity, extra ocular motion
cerebello-pontine angle nerves:
V corneal reflex and facial sensation
VII upper and lower facial muscle strength, taste
VIII hearing
Others:
IX - XI articulation, palate movement, gag reflex
XII tongue movements
THE LAST SUPPER
DETAILS LIE IN BEHOLDER’S
OBSERVATIONS!
Detail of the Da Vinci's The Last Supper by Giacomo Raffaelli
Diagnostic Pathway
Be Ritualistic
The formulation:
Symptoms, Signs, Localization and Diagnosis
Localization:
Where is the lesion?
CNS, PNS or Muscles
What is the lesion?
Diffuse or Discrete
Diagnosis:
Common conditions arise commonly –
Hoof beats are usually more likely to be from horses as opposed to Zebras
Hemiparesis is more likely from a stroke as opposed to an unwitnessed
seizure
The Lobes
Job Allocation
Division of Labour
Lobe Function
Frontal Lobe Dysfunction
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The primary motor cortex
Contra lateral motor control
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The medial frontal cortex
Arousal and motivation – Abulic (Apathy & inattention)
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The orbital frontal cortex
Modulate Behaviour -Labile, euphoric, facetious, vulgar
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The left postero-inferior frontal cortex (Broca's)
Language – expressive Aphasia
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The dorsolateral frontal cortex
Working memory
Parietal Lobe Dysfunction
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The primary somatosensory cortex
Integrates somesthetic stimuli for recognition and recall of form, texture, and
weight - Contralateral astereognosis
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Posterolateral - Postcentral gyrus
visual-spatial relationships and proprioception
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Midparietal lobe (dominant)
calculation, writing, left-right orientation, and finger recognition - Gerstmann's
syndrome
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The nondominant parietal lobe
Contralateral environmental awareness, drawing – Anosognosia,
Hemiasomatognosia, spatial Apraxia
Temporal Lobe Dysfunction
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Auditory perception, receptive components of language,
visual memory, declarative (factual) memory, and emotion
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Right temporal lobe lesions - interpret nonverbal auditory
stimuli (e.g. music)
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Left temporal lobe lesions interfere greatly with the
recognition, memory, and formation of language
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medial limbic - emotional parts & TLE
Occipital Lobe Dysfunction
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Primary visual cortex and visual association areas
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Anton Babinski Syndrome
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Occipital Seizures – C/L Visual Hallucination
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Prosopagnosia - Face blindness
Conscious pain, temperature, crude touch & pressure
Lateral and an anterior tract
Thalamus (all conscious sensations) projection to areas of the cerebral cortex
This tract carries unconscious proprioception (muscle sense) to
the cerebellum which is responsible for muscle coordination
They innervate the cerebellum on the same side
Corticospinal tract cerebral cortex – Localised voluntary motor control
Two branches, the lateral and the anterior
The lateral crosses in the medulla at the ‘pyramids’
The anterior does not cross
Common signs: DTR abnormalities, Motor Paresis, Babinski
The Basal Ganglia
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Located Sub cortically
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Modulates the Corticospinal tract
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Regulates muscle tone, motor activity and generates
postural reflex
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Confined to the brain, no role on LMNs or Spinal
Cord
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Caudate Nucleus, Corpus Striatum, Lentiform
Nucleus (Globus Pallidus + Putamen), Subthalamic
Nuclei, Substantia Nigra
IC (white matter) runs between the CN and the LN = Corpus Striatum
Artery of Stroke
Pure damage to Basal Ganglia = No corticospinal symptoms, No neuropsychological dysfunction,
No cognitive Dysfunction, contra lateral
Result of biochemical not usually structural, B/L, slow progress
Cerebrum + BG = inv Mov + cognitive &/or psychiatric Sx
Basal Ganglia and Limbic System
Hippocampal Formation & Amygdala
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Hippocampal Formation
Dentate gyrus + the hippocampus proper + Subiculum
Memory, spatial navigation and attention
Amygdala
Via hypothalamus activates the ANS
Activation of Neurotransmitters
Emotional Learning – Conditioning
Memory modulation
Kluver Bucy Syndrome – Docility: diminished fear responses, dietary
changes, Hyperorality, Hypersexuality, Visual Agnosia,
Hypermetamorphosis: irresistible impulse to notice and react to
everything, memory loss
Papez Circuit
Function of the Limbic System
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Affective functions
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Playful moods
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Emotions and feelings,
like wrath, fright,
passion, love, hate, joy
and sadness
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self preservation
Dopamine Pathways
HT
VTA
Serotonin Pathways
Serotonin and Depression
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Serotonin transmission - Caudal raphe nuclei and
Rostal raphe nuclei is reduced in depression
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Increasing the levels of serotonin in these
pathways, by reducing serotonin reuptake =
treatment
Serotonin and Depression
Serotonin in Schizophrenia
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Dorsal raphe nuclei - Substantia Nigra
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Rostral raphe nuclei - cerebral cortex, limbic regions and
basal ganglia
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The up-regulation of Serotonin pathways leads to the
hypofunction dopamine pathways = negative symptoms
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The serotonergic nuclei in the brainstem that give rise to
descending serotonergic axons remain unaffected in
schizophrenia
Serotonin and Schizophrenia
Brain Stem
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Brain Stem: Midbrain, Pons, Medulla
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Contains CNs, CS Tract and other ‘long’ Tracts
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Positive evidence of localization and negative evidence
of cerebral injury
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Example – Diplopic but no effect on visual acuity or
fields
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Brain stem injures -Massive infarcts, Overdoses etc
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Simultaneous damage of BS and Cerebrum RARE
exceptions: MS, tumours etc
Cerebellum
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Controls the coordination of movements/limbs –
Ipsilateral
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Muscle Hypotonia and Pendular DTRs
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No obvious cognitive role
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Intentional Tremor
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Gait Ataxia, Scanning speech, tandem gait failure
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Cognitive Impairment?
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Alcohol – Thiamine, AIDS, toxins, Vitamin E, Phenytoin
Psychiatry and Neurology
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Psychogenic Paresis and Hoover’s Sign
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La Belle Indifference
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MS
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Sleep Disorders
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Parkinsonism, Huntington, Wilson’s disease
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Frontal Lobe issues, Dementia
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Seizures of Non epileptic origin and NEADs, Sensory
seizures
CASE STUDY 1
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An elderly man has left ptosis and a dilated and
unreactive left pupil with external deviation of the left
eye, right hemiparesis, right sided hyperactive DTRs
and positive Babinski, no aphasia or hemianopia
where is the lesion?
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Cerebrum
Cerebellum
Pons
Midbrain
Medulla
None of the above
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CASE STUDY 2
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A 20 year old woman reports having lost all vision in
her right eye and right hemi-sensory loss. Pupil and
DTRs are normal. She does not press down with her
left leg while attempting to lift her right leg. where is
the lesion?
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Cerebrum
Cerebellum
Pons
Midbrain
Medulla
None of the above
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CASE STUDY 3
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50 yr old man with mild dementia has absent
reflexes, loss of position and vibration sense and
ataxia. Which areas are affected?
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The cerebrum
The CNS
The CNS and the PNS
The CNS and the spinal cord’s posterior columns
The ANS
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CASE STUDY 4
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After having suffered from increasing severe
depression for 3 years the psychiatrist finds the 55
year old woman to have right sided optic atrophy
and left sided papilledema. Where is the lesion?
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Occipital Lobe
Frontal Lobe
Parietal Lobe
Temporal Lobe
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None of the above
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QUESTION
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Where is the primary damage in Wilson's disease,
Huntington's Chorea and Choreiform Cerebral
Palsy?
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Extra pyramidal system
Pyramidal system
Entire CNS
Cerebellar outflow tracts
None of the above
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SOME CORRECTIONS
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EMI -2