Cerebral Cortex Flashcards
What is the cerebral cortex?
Thin layer that Covers entire surface of the brain
Together with deep nuclei, contains grey matter
Highly folded with gyri and sulci
Organised into lobes
How is the cerebral cortex arranged?
In layers and columns
eg. pyramidal and granular
What are the Brodmann regions?
52 regions based on cytoarchitecture- cell size, spacing or packing density and layers
What divides the frontal and parietal lobe?
Central sulcus
What are the functions of the frontal lobe?
Regulating and initiating motor function
Language
Cognitive function (executive function (e.g. planning))
Attention
Memory
What are the functions of the parietal lobe?
Sensation - touch, pain
Sensory aspects of language
Spatial orientation and self-perception
What is the function of the occipital lobe?
Processing visual information
What is the function of the temporal lobe?
Processing auditory information
Emotions
Memories
What is the limbic lobe composed of?
What is its function?
Includes the amygdala, hippocampus, mamillary body, and cingulate gyrus
Concerned with learning, memory, emotion, motivation and reward
What is the insular cortex?
Lies deep within lateral fissure
Concerned with visceral sensations, autonomic control, and interoception, auditory processing, visual-vestibular integration
What is the grey matter composed of?
Neuronal cell bodies and glial cells - around 85 billion of each
What is the white matter composed of?
Myelinated neuronal axons arranged in tracts
What section is this?*
Axial section?
What is the purpose of white matter tracts?
Connect cortical areas
What are association fibres?
Connect areas within the same hemisphere
What are commissural fibres?
Connect homologous structure in left and right hemispheres
What are projections fibres?
Connects cortex with lower brain structures (e.g. thalamus, brain stem and spinal cord)
What is the superior longitudinal fasciculus?
Connects frontal and occipital lobes
Association fibres
What is the arcuate fasciulus?
Connects frontal and temporal lobes
Association fibres
What is the inferior longitudinal fasciculus?
Connects temporal and occipital lobes
Association fibres
Name the association fibre tracts
What is the uncinate fasciculus?
Connects anterior frontal and temporal lobes
What are commissural fibres?
They connect homologous structures in left and right hemispheres
What is the corpus callosum?
Biggest commissural fibre tract
Disconnected in untreatable epilepsy - corpus colostomy- irreversible - to prevent spreading of seizures
Name 2 commissural fibre tracts?
Corpus callosum
Anterior commissure
What are projection fibres?
Connect cortex with lower brain structures (e.g. thalamus, brain stem and spinal cord)
Name two types of projection fibres
Afferent - towards cortex
Efferent - away from cortex
Deeper to cortex radiate at the corono radiata
Converge through internal capsule between thalamus and basal ganglia
What view is this?
Coronal
What view is this?
Axial
What is the basal ganglia concerned with?
Co-ordinating movements
What is the difference between primary cortices and secondary cortices?
What does the primary motor cortex in the frontal lobe control?
Controls fine, discrete, precise voluntary movements
Provides descending signals to execute movements
What is the supplementary motor area for?
What is the premotor area for?
Involved in planning complex movements (e.g. internally cued)
Involved in planning movements (e.g. externally cued)
What is the function of the primary somatosensory in the parietal lobe?
Processes somatic sensations arising from receptors in the body (e.g. fine touch, vibration, tow-point discrimination, proprioception, pain and temperature)
What is the function of the somatosensory association?
Interpret significance of sensory information, e.g. recognising an object placed in the hand.
Awareness of self and awareness of personal space
What is the function of the primary visual cortex in the occipital lobe?
Processes visual stimuli
What is the function of the visual association cortex in the occipital lobe?
Gives meaning and interpretation of visual input
What is the function of the primary auditory cortex in the temporal lobe?
Processes auditory stimuli
What is the function of the auditory association cortex in the temporal lobe?
Gives meaning and interpretation of auditory input
What is the prefrontal cortex associated with?
Attention
Adjusting to social behaviour
Planning
Personality expression
Decision making
What is the function of Broca’s area?
Production of language
What is the function of Wernicke’s area?
Understanding of language
What does frontal lobe lesions result in?
Changes in personality
Inappropriate behaviour
What is an example of a parietal lobe lesion?
And what does it result in?
Lesion in right hemisphere
Contralateral neglect
-Lack of awareness of self on left side
-Lack of awareness of left side of extra personal space
What are examples of temporal lobe lesions?
What does it result in?
Lateral/medial lesions
Leads to agnosia, inability to recognise
Bilateral resection of anterior medial temporal lobe structures to cure epilepsy
Could not form new memories - anterograde amnesia
What does a lesion to Broca’s area result in?
Expressive aphasia - poor production of speech comprehensno intact
What does a lesion to Wernicke’s area?
Receptive aphasia - poor comprehension of speech, production is fine
What association fibre connects Broca’s area and Wernicke’s area?
Arcuate fasciculus
What does a lesion to the primary visual cortex do?
What does a lesion in the visual association do?
Blindness in the corresponding part of the visual field
Deficits in interpretation of visual information e.g. prosopagnosia : inability to recognise familiar faces of learn new faces (face blindness)
How do you assess cortical function?
Position emission tomography (PET)
-Blood flow directly to a brain region
Functional magnetic resonance imaging (MRI)
-amount of blood oxygen in a brain region
How do you record brain activity?
Electroencephalography (EEG)
-Measures electrical signals produced by the brain
Magnetoencephalography (MEG
-Measures magnetic signals produced by the brain
Event related potentials / evoked potentials
What are somatosensory evoked potentials?
Series of waves that reflect sequential activation of neural structures along the somatosensory pathways
e.g. somatosensory activity
thalamic activity
mid cervical cord activity
impulses arriving at shoulder
How to assess cortical function using brain stimulation and why?
Assess the functional integrity of neural circuits
Uses electromagnetic induction to stimulate neurons
Transcranial magnetic stimulation (TMS)
Investigate neural interactions controlling movement following spinal cord injury
What is Transcranial direct current stimulation (tDCS)
Uses low direct current over the scalp to increase or decrease neuronal firing rates
How can we see how brain regions are connected
Using diffusion tensor imaging (DTI)
-Based on diffusion of water molecules
