Cerebrum Flashcards
What is the main source of afferent fibres for the first somatic sensory area?
Ventral posterior nucleus of the thalamus
Site of termination of all fibres from the medial lemniscus tracts as well as the spinothalamic and trigeminothalamic tracts.
Where does the somesthetic association cortex receive fibres from?
Primary somesthetic area and it’s thalamic connections are with the lateral posterior nucleus and the pulvinar
What are the afferent fibres for the primary visual cortex?
Lateral geniculate body of the thalamus by way of the geniculocalcarine tract
What does the dorsal stream of visual processing analyse?
Where - analyses motion and spatial relations
What does the ventral stream visual processing analyse?
What - identifies colours and familiar shapes such as faces and letters
What condition occurs when a lesion develops in the visual association cortex?
Visual agnosia
What is the importance of the corticotectak fibres in visual processing?
Connects the visual cortex, the visual association cortex, and the posterior part of the parietal lobe with the superior colliculus of the midbrain.
In visual processing, what does the superior colliculus control through indirect connections?
Controls the oculomotor, trochlear and abducens nuclei.
What are the principal source of axons that end in the primary auditory cortex?
Media, geniculate body of the thalamus, with these fibres constituting the auditory radiation in the cerebral white matter.
Describe pathway for the gustatory nerves
Taste buds
Gustatory nucleus in the brain stem ( solitary nucleus )
Medial part of the medial division of the ventral posterior nucleus of the thalamus via the ipsilatera, central tegmental tract
Thalamocortical fibres complete
What does the cortical projections of the vestibular system contribute to?
Motor regulation, awareness of spatial orientation, and sensations of vertigo and nausea associated with excessive vestibular stimulation
What are the main sources of input to the primary motor area?
Other motor areas of the cortex
Somesthetic cortex
Posterior division of the ventral lateral thalamus nuclei (receives input from the cerebellum)
Where does the pre motor area receive fibres from?
Other cortical areas
Ventral anterior division of the thalamus
Anterior division of the ventral lateral nucleus of the thalamus
What is the purpose of the prefrontal cortex?
Monitors behaviour and exercises control based on such higher mental faculties as judgement and foresight
How does Broca’s area and Wernickes area communicate?
Superior longitudinal (arcuate) fasciculus
What is the most numerous fibres in the CNS?
Association fibres
What is an association fasciculus in the limbic lobe?
Cingulum
What does the cingulum connect to?
Cingulaye GYRUS
PARAHIPPOCAMPAL GYRUS of the temporal lobe
Septal area below the genus of the corpus CALLOSUM
What does the superior longitudinal fasciculus provide?
Communications between cortices of the parietal, temporal and occipital lobes and the cortex of the frontal lobe
What does the arcuate fasciculus connect to?
Receptive (sensory) and expressive (motor) language areas
Where do the fibres of the superior occipitofrontal fasciculus spread to?
Cortex of the frontal lobe and to cortex in the posterior part of the hemisphere.
What are the two commissural fibres?
Corpus CALLOSUM
Anterior commissure
What is the purpose of the fornix?
Connects the hippocampal formation of each temporal lobe with the hypothalamus and the septal area of the forebrain.
What is the purpose of the anterior commissure?
Provides additional communication between the temporal lobes
Where are the projection fibres concentrated?
Internal capsule
What does the internal capsule consist of?
Anterior limb
GENU
Posterior limb
Retrolentiform part
Sublentiform part
What radiations are located in the internal capsule
Thalamic radiations
Where is the anterior thalamic radiation and where does it connect to?
Anterior limb of the internal capsule
Connecting mediodorsal thalamic nucleus and prefrontal cortex
Where is the middle thalamic radiation located and what does it connect to?
Posterior limb of the internal capsule
Somatosensory projection from the ventral posterior thalamic nucleus to the somesthetic area in the parietal lobe
Via the posterior limb, fibres from the ventral anterior and ventral lateral nucleus of the thalamus reach the primary motor, premotor, supplementary motor, and cingulate motor areas of the frontal lobe.
What does the posterior thalamic radiation connect to?
Thalamus and cortex of the occipital lobe
Describe the geniculocalcarine tract
Visual cortex pathway
Lateral geniculate body
Sublentiform and retrolentiform parts of the internal capsule
Occipital lobe
What does the inferior thalamic radiation connect to.
Thalamic nuclei with the cortex of the temporal lobe
What kind of fibres are corticofugal?
Projection fibres
Where do the corticobulbar and corticospinal tracts originate from?
Primary motor, premotor, supplementary motor and cingulate motor areas in the frontal lobe and in the ROSTRAL parts of the parietal lobe.
Where does corticobulbar and corticospinal tracts descend to?
Anterior half of the posterior limb of the internal capsule
Where does the corticopontind fibres originate from and where do they terminate?
All four lobes
Pontine nuclei in the basal part of the pons
