Cerebral Cortex and Diencephalon Flashcards
what is grey and white matter
the brain undergoes myelination until what age
what regions are the last to become myelinated
grey: sheet of neural tissue that makes up the outer layer of the brain (made up of cell bodies)
white: nerve fibres that connect neurons in different brain regions into functional circuits
30
frontal regions which carry out higher level executive functions
the frontal lobe makes up __% of the cortex
what areas make up the frontal lobe
40%
primary motor area, premotor area, supplementary motor area, frontal eye fields, Broca’s area, prefrontal area
what are the functions of the frontal lobe
movement control, conjugate eye movements, speech production, personality
where is the primary motor area located
what areas make up the primary motor area
posterior to the precentral sulcus and non primary motor areas
premotor cortex, supplementary motor area, cingulate motor area
where do conjugate eye movements occur
what do conjugate eye movements do
in the frontal eye fields
allows eyes to act in a coordinated fashion with each other, the right frontal eye field leads the movement of the both eyes to the left
what area of the brain is responsible for speech production
this area processes information from which cortex
what does it do with the information it processes
broca’s area
temporal cortex
writes a script for speech execution passed to primary motor cortex
damage to the frontal lobe results in what 5 types of personality changes
hypo-emotionality/de-energization, executive disturbances, disturbed social behaviour, emotional dysregulation, distress, decision making
what 5 things can frontal lobe lesions cause
what is apraxia and aphasia
hemiplegia (unilateral paralysis), weakness, apraxia, personality disorders, aphasia
apraxia: unable to perform learned movements even when knowing what to do and wanting to do it
aphasia: deficits in language expression
what two major discoveries were made from Phineus Gage’s case
first understanding that personality might reside within the cortex and that specific parts of the cortex might be responsible for specific functions
the parietal lobe makes up __% of the cortex?
what areas of the brain make up the parietal lobe
20
primary somatosensory cortex, secondary somatosensory cortex, association areas
association areas in the parietal lobe have connections to what other areas
widespread connections to other sensory, visual and motor areas
what are the functions of the parietal lobe
what dysfunctions are seen with a parietal lobe lesion
sensation, integration of sensory information with other modalities for higher order functions
loss of sensation, sensory apraxia, asomatognosia
the parietal lobe receives a majority of sensory inputs from which brain structure
the parietal lobe is responsible for interpreting which somatosensory signals
what is the strongest driver of neuroplasticity
thalamus
touch, position, vibration, pressure, temperature
afferent input (changing touch, position, vibration…)
the parietal lobe integrates what other information with sensory information for higher order functions
motor planning, learning, language, spatial recognition, stereognosis
what is stereognosis, sensory apraxia and asomatognosia
stereognosis: ability to differentiate between objects based on size, shape, weight
sensory apraxia: unable to use an object because they are unable to perceive it’s purpose (not knowing what to do with scissors)
asomatognosia: denial of existence of body parts, the feeling that one’s own body has ceased to exist
what is neglect syndrome
what would you see individuals with neglect syndrome do when drawing a picture
what is neglect syndrome caused by
failure to recognize the opposite side of the body and its surroundings
draw a picture with only one side of the picture completed
damage to the area of the brain which processes sensory information (parietal lobe)
the occipital lobe makes up __% of the brain
what is the occipital lobe responsible for
what areas of the brain make up the occipital lobe
15%
vision
primary visual area, visual association areas
what are the functions of the occipital lobe
what do occipital lobe lesion result in
visual processing and interpretation
receive, process, interpret visual information
processed information is sent to other regions of the brain to be further analyzed and acted upon
blindness, colour blindness, inability to detect moving objects
the temporal lobe makes up __% of the cortex
the temporal lobe contains areas involved in what two things
what areas of the brain make up the temporal lobe
25%
hearing and memory
primary and secondary auditory areas, auditory association areas, areas associated with emotion, memory, speech (wernicke’s area)
what are the functions of the temporal lobe
translating and processing all sounds and tones, phonological representation of words, semantic retrieval, semantic memory, visual and facial perception, declarative memory, familiarity
what is semantic retrieval and semantic memory
what is declarative memory
retrieval: assigns meaning to words
memory: remembering thoughts or objectives that are common knowledge
declarative memory: remembering concepts or events that happened or were learned throughout life
what impairments would you see in an individual with a temporal lobe lesion
phenomic paraphasia, memory impairments, visual hallucinations, inability to recognize faces of others and self, impaired language comprehension
what is phenomic paraphasia
why doesn’t a unilateral lesion in the temporal lobe produce significant hearing loss
sound substitution or rearrangement (tephelone instead of telephone)
because of bilateralism of auditory pathways (but can influence details such as localization of sound)
what are the 4 regions of the diencephalon
what is the thalamus
thalamus, hypothalamus, epithalamus, subthalamus
two oval collections of nuclei that receives all sensory information (except smell) before proceeding to the cortex
the thalamus is divided into what
what are the functions of the diecephalon
nuclei that all posses functional specializations
primary relay and processing centre for sensory information and autonomic control, controls autonomic functions, connects structures of endocrine system, limbic system (manage emotions/memories), motor function, hearing, vision, smell, taste, touch perception
what is the medial and lateral geniculate nuclei, ventral posterior nuclei and anterior nuclei responsible for in the thalamus
medial: hearing
lateral: vision
ventral: taste and somatic sensations (pressure)
anterior: emotions and memory
what effects can a lesion to the diencephalon have on an individual
memory loss, lack of interest or enthusiasm
trouble with attention/loss of alertness
trouble processing sensory information
impaired movement, sleepiness or unconsciousness
insomnia/fatal familial insomnia, thalamic aphasia (jumbled words, meaningless speech)
vision problems (vision loss or light sensitivity)
thalamic pain syndrome (tingling/burning pain)
what do intracortical, association, commissural and projection fibres connect
intracortical: neurons in a localized area
association: between gyri and from lobe to lobe in the same hemisphere (superior longitudinal fasciculus)
commissural: homologous areas of the two hemispheres (corpus collosum)
projection: cortex with subcortical nuclei
corticofugal projection fibres are ___
corticopetal projection fibres are ___
the strength between projection fibres allow for what
efferent
afferent
synaptic plasticity
what movements does the corpus collosum prevent
which type of functions are lateralized to one hemisphere
mirror movements, inhibits the same movement on the other side of the body so we can perform unilateral movements
higher functions
what individual differences are there in brains
positioning of sulci, connections and how these are activated, R vs L handed individuals, sex differences, influence of experience (neuroplasticity, connections we form are very individual)
define neuroplasticity
why is neuroplasticity important
ability of the nervous system to rewire throughout life
underpins learning and memory, recovery of function after injury, fundamental mechnism through which rehabilitation works to improve patient outcomes
what type of input is the most powerful drive of plasticity
in what two situations is plasticity not beneficial
afferent
stroke: the uninjured hemisphere takes over and impairs recovery of the injured hemisphere (injured hemisphere doesn’t get afferent input or feedback it needs to heal)
chronic pain: maladaptive rewiring ingrains pain within the NS even after tissues have healed
