B5 W4 Flashcards
Rapid, alternating movements
Disadiadochokinesis
Contralateral upper limb weakness, hemiananaesthesia, hemianopia, hemineglect
Middle cerebral artery
Nigrostriatal pathway
Input pathway to the basal ganglia from the substantia nigra pars compacta via dopamine
Output branch of granule cells
Parallel fibres- innervated by mossy fibres
Area of frontal cortex for rapid alternating movements
Supplementary motor cortex
Cerebrocerebellum
Region of cerebellum which plans, controls and modulates highly skilled movement.
Purkinje fibres
Receives error input from climbing or mossy fibres and projects using GABA to the output of the cerebellum which is the deep cerebellar nuclei to the cortex to correct movement
Area of the temporal lobe for understanding language
Wernicke’s area
Rapid, jerky movements
Chorea caused by Huntington’s
Efferent pathway of the cerebellum
Superior cerebellar peduncles
Afferent pathway of the cerebellum
Middle cerebellar peduncles
Afferent and efferent pathway of the cerebellum
Inferior cerebellar peduncles
Huntington’s disease
Death of striatal input to the globus pallidus external segment and reduced inhibition of the subthalamic nucleus and thalamus and less excitation of the globus pallidus internal segment
Disconnection syndrome
Interruption of information between brain regions due to white matter lesions
Jerky movements
Hyperkinesia
Increased muscular tone
Spasticity
Pyramidal tracts
Motor pathway for the control of face and body muscles- Corticospinal and corticobulbar tracts
Broca’s area
Area in posteroinferior frontal lobe where speech is produced. Only whistling and singing is preserved in a lesion which causes expressive aphasia.
Symptoms of Parkinson’s disease
Tremor, rigidity, akinesia, postural problems. This is due to overactivity of the indirect pathway due to substantia nigra death.
Reticulospinal tract
Reticular formation to ipsilateral skeletal muscles of trunk, proximal muscles for regulating muscle tone
Chronic alcohol misuse damages this region
Anterior cerebellum which affects the lower limbs
Output nuclei of spinocerebellum
Interposed nuclei
Middle cerebellar peduncles
Relay neurons in the pons which decussate to contralateral cerebellar hemisphere
Spinocerebellum
Nuclei is intersposed and fastigial. Co-ordinates motor execution. Lesion causes impaired gait
Commissural fibres
Horizontal fibres which connect the grey matter of two hemispheres
Hemiballismus
Rapid flinging movements due to damage to the subthalamic nucleus
Taste and flavour region
Region in the temporal lobe
Climbing fibres
Error signals from the inferior olive of the medulla to correct error movements to the parallel inputs to the Purkinje cells
Descending tracts which decussate at the pyramids
Lateral corticospinal tract
Dentothalamic nuclei
Fibres from the dendate nucleus of cerebellum to the thalamus with branches to the red nuclei and terminate at the cortex. Regulates movement.
Mossy fibres
Cerebellar input from everything excluding the inferior olive which synapses with interneurones
Supramarginal gyrus
Part of the somatosensory cortex for agnosia, left-right discrimination
Spiny motor neurons
Striata output which uses GABAnergic inhibitory neuron
Cerebellar peduncle for afferent and efferent pathway
Inferior cerebellar peduncle
Medium spiny neurons
Neurons in striata which receive input from other structures
Output nuclei of vestibulocerebellum
Fastigial and vestibular nuclei. Controls motor execution and lesion leads to issues with balance and eye movement
Output zones of basal ganglia
Globus pallidus, substantia nigra pars reticulata
Input zones of basal ganglia
Caudate and putamen (striata)
Location of the vestibulocerebellum which maintains equlibirum and balance
Nodule and flocculus
Paresis
Paralysis
Primary auditory cortex
Temporal lobe
Receptive aphasia
Damage to Wernicke’s area/ lesion at junctio of temporal, parietal and occipital lobe
Indirect pathway
Suppresses movement via D2 receptors- Inhibits the external segment of the globus pallidus which disinhibits the subthalamic nuclei.
Primary motor cortex lesion
Contralateral flaccid paralysis and positive Babinski’s sign
Clonus
Involuntary rhythmic muscle contractions
Direct pathway
Inhibits the internal segment of the globus pallidus to remove thalamic inhibiton and allow movement following glutamergic stimulation. D1 modulates this
Projection fibres
Carries information in and out of the cortex
Hypertonia
Increased muscle tone
Expressive aphasia
Broca’s area
Output structure of the cerebellum
Deep cerebellar nuclei. Transmit information from the cerebellum to the:
ventrolateral thalamus -> cortex and brainstem to correct movement cortex to the ventrolateral complex in the thalamus
Neuropathologies of the basal ganglia
Parkinson’s disease, Huntington’s disease, hemiballismus
Hemihypesthesia
Reduced sensitivity
Cerebellar peduncles
White matter tracts which connect the cerebellum to the pons
Main components of the basal ganglia
Caudate nucleus, putamen and globus pallidus internal and external
Primary cortical areas
Regions of the cortex of the brain which receives sensory information from peripheral receptors or execute motor tasks.
Includes the primary motor cortex, supplementary motor cortex, somatosensory cortex, auditory cortex, gustatory cortex and visual cortex.
Additional areas of the basal ganglia
Substantia nigra and subthalamic nucleus
Lesion in the somatosensory cortex
Contralateral loss of sensation
Somatotropic organisation
Feet are most medial and face and upper body are most lateral
Non motor function of basal ganglia
Cognition, working memory and attention
Spinocerebellar pathway
Unconscious sensory tract for propioception to co-ordinate muscles.
Receptor from the muscle/joint receptor
synapses with first order neuron- dorsal root ganglion of spinal cord
synapses with second order neuron- dorsal horn of spinal cord
It ascends ipsilaterally and enters the cerebellum via the inferior cerebellar peduncles.
Central region of cerebellum moves proximal muscles. Lateral region moves distal muscles
Motor input to the cerebellum
Middle cerebellar peduncle- via the cerebral cortex which synapses with the relay neuron of the pons.
Sensory input to the cerebellum
Inferior cerebellar peduncles via the spinocerebellar tract, conveying information about muscle propioception
Modulatory input to the cerebellum
Inferior olives of the medulla which sends error signals for timing, learning and memory via the climbing fibres to purkinje cells of the cerebellum
Anterior corticospinal tract
Remains ipsilateral through the pyramids of the medulla. It decussates at the level it synapses with lower motor neurons.
Agraphethesia
Inability to recognise letters, symbols and numbers traced in the skin.
Hemianopia
Loss of half of vision
How does the deep cerebellar nuclei transmit information to the cortex?
Via the ventrolateral complex of the thalamus
Treatment of Parkinson’s via the brain
Deep brain surgery with removal of thalamus/globus pallidus or inactivation of the globus pallidus/subthalamic nucleus/ thalamus
Granule cells
Most numerous cell in the cerebellum. Receives error input from mossy fibres and output parallel branches to the Purkinje cells.
Anterior cerebral artery lesion
Contralateral cortical type sensory loss, frontal lobe behavioural abnormalities. Involved in sensory and motor function of defeacation and urination.
Middle cerebral artery lesion
Global aphasia (loss of receptive and expressive aphasia, ipsilateral gaze preference. Deep branches supply the globus pallidus, internal capsule and thalamus.
Chronic alcohol misuse effect on gait-reason
Damage to the anterior cerebellum which controls the lower limbs. Posterior cerebellum controls the upper limbs
Mossy fibres
Carry input from the cortex, spinal cord, brainstem and vestibular system to the cerebellum
Posterior lobe of cerebellum
Controls upper limbs and hands
Pathologies of the cerebellum
Huntington’s, Parkinson’s and Hemiballismus.
Angular gyrus
Translates speech into writing. Lesion causes dyslexia, alexia and dysgraphia.
Direct pathway
Increases movement via D2
-> Inhibits the globus pallidus internal segment and pars reticulata and subthalamic nucleus
-> excitation of external globus pallidus
This excites the thalamus
Indirect pathway
Inhibits movement via D2
->inhibits external globus pallidus
-> less inhibition on internal globus pallidus and subthalamic nucleus increases inhibition on the thalamus
Caudate nucleus
C shape with other structures of basal ganglia present inside.
Limbic lobe
Unconscious insinctive behaviour
Non-dominant hemisphere
Prosody, muscial ability and sense of direction
Dominant
Language, praxis, musical ability and sense of direction
Folia of cerebellum
Grey matter
Superior temporal gyrus
Processing and receiving of sound
Prefrontal cortex
Includes thalamus and limbic system for decision making and cognition.
Primary visual cortex
Occipital lobe, where it is concentrated in the calcarine sulcus
Supplementary motor cortex
Rapid sequence of movement like moving your eyes quickly to opposite sides
Cerebellar lesion- side
Ipsilateral
Cortical lesion-side
Contralateral
Dyssernegia
Loss of synchronous multi joint movement due to cerebellar damage
Inferior olive
Receives input from all systems
Lesion to primary motor cortex
Positive babinski and contralateral flaccid paralysis
Parietal lobe
Dominant hemisphere will control language and calculation. Visuospatial skills on non dominant.
Reticulospinal tract
Reticular formation to ipsilateral muscles for muscle tone in ongoing movement and posture
Supramarginal gyrus
Secondary association area of the somatosensory cortex for propioception, left-right discrimination and pain
Association areas
Receive information from primary cortical areas to interpret and process
Astereoagnosia
Can’t recognise objects by touch
Corticospinal tract
Controls skeeltal muscle and fine movement
Which part of the basal ganglia inhibits the thalamus?
Pars reticulata and internal segment of globus pallidus via GABA
