Corticol Organisation And Function Flashcards
what is the cerebral cortex and where is it found?
Surface of brain covers it all
Organisation of cerebral cortex
organised into lobes → frontal, temporal x2, parietal x2, occipital
Further organized unto cortical layers and columns
What are folds called
gyri (ridges) and sulci (grooves)
define cytoarchitecture?
e.g. cell size, spacing/packing density and layering
Frontal lobe
regulate + initiate motor function
language
cognitive functions e.g. planning
memory
attention
Parietal lobe
Sensation
Sensory aspects of language
Spatial orientation
Self perception
Occipital and temporal lobe
Visual info
Temporal-hearing emotions and memory
what does the limbic lobe include?
amygdala, hippocampus, cingulate gyrus, mamillary body
What’s Limbic lobe concerned with
Memory
Emotion
Motivation
Learning
Insular cortex
In lateral fissure
Concerned with visceral sensation autonomic control and interoreception
grey matter vs white matter → what is each made of, which is the outer layer?
grey matter on the outside
grey = neuronal cell bodies, glial cells
white = myelinated axons arranged in tracts
three types of white matter tracts?
- association fibresconnect areas in the same hemisphere
- commissural fibresconnect homologous structures in opposite hemispheres
- projection fibresconnect cortex with lower brain structures
association fibres split into which categories?
Short and long fibres
main association fibres → what do they connect?
- superior longitudinal fasciculusfrontal ↔ occipital
- arcuate fasciculusfrontal ↔ temporal
- inferior longitudinal fasciculustemporal ↔ occipital
- uncinate fasciculus (under arcuate and shorter)anterior frontal ↔ temporal
main commissural fibres?
corpus callosum
anterior commissure
two types of projection fibres for projection
afferent (towards cortex) and efferent (away from cortex)
- deeper to cortex radiate as coronaradiatainternal capsule → between thalamus and basal ganglia
where do projection fibres converge?
internal capsule → between thalamus and basal ganglia
difference between primary and secondary/association cortices?
predictable vs less predictable function
topographical organisation present vs absent
left-right symmetry present vs weak/absent
- premotor area (more lateral) and supplementary area (more medial) → both anterior
association cortices for frontal lobe
premotor area (more lateral) and supplementary area (more medial) → both anterior and primary motor area
what are these three involved in?frontal
primary controls fine voluntary movement, provides descending signals to execute these
supplementary area involved in planning internally cued complex movements
pre-motor area involved in planning externally cued complex movements
where is the primary somatosensory cortex and what is its secondary cortex?
found posterior to central sulcus → postcentral gyrus, posterior to that is somatosensory association
difference in function between these two? Parietal
primary processes somatic sensations from receptors eg fine touch vibration two point discrimination proprioreception and pain and temp
Somatosensory association interorets significance of sensory info e.g. recognising object in hand, awareness of self and personal space
occipital lobe → primary visual vs visual association functions?
primary processes visual stimuli, visual association gives meaning and interpretation
temporal lobe → primary auditory vs auditory association functions?
processes stimuli / gives meaning and interpretation
main other association areas?
prefrontal cortex, Broca’s area, Wernicke’s area
difference between Broca and Wernicke?
Broca = production of language, Wernicke = understanding of language
lesions cause expressive aphasia / receptive aphasia
function after lesion impairment → examples?
- frontalbehavioural change
- parietalcontralateral neglect, lack of awareness of self/personal space on one side
- temporalloss of ability to form new memories, recognise stuff
- occipitalblindness for primary / deficits in interpretation for association e.g. prosopagnosia → inability to recognise faces
Broca’s area
Expressive aphasia poor production of speech
Wernickes
Receptive aphasia poor comprehension of speech production is fine
what does a PET scan show?
positron emission tomography → blood flow directly to a brain region
what does an fMRI scan show?
functional magnetic resonance imaging → amount of blood oxygen in a brain region
what do MEG and EEGs show?
magnetoencephalography & electroencephalography → event-related magnetic/electrical potentials
what is TMS and what does it do?
transcranial magnetic stimulation → helps stimulate the brain and assess functional integrity of circuits, investigate function of a brain area
what is tDCS?
transcranial direct current stimulation → direct current over the scalp to increase/decrease neuronal firing rates
what is DTI and what is it useful for?
diffusion tensor imaging → assess structure based on diffusion of water molecules
Prefrontal cortex
Attention
Adjusting social behaviour
Planning
Personality expression
Decision making
DTI with tractography
3D recronstruction to assess neural tracts
Cortex organization microscopically
Organized into layers and columns
6 layers I most superficial and multiple columns
What do white matter tracts do
Connect cortical areas
Association commissaral and projection fibres
What does a lesion to arcuate fasiculus cause
Conduction aphasia inability to repeat speech
What does bilateral resection if the anterior medial temporal lobe cause
Anterograde amnesia
