ch 16 frontal lobe Flashcards
anatomy
tissue anterior to central sulcus-motor, premotor, prefrontal
subdivisions
premotor and supplementary motor cortex, frontal and supplementary eye field
prefrontal cortex
area of the frontal lobe that receives input from the dorsomedial nucleus of thalamus
divisions: dorsolateral inferior, medial
motor area connections
projects to spinal motor neurons, cranial nerves that control the face, basal ganglia and red neuclues
premotor area connections
direct movement through coticospinal projections or motor projections, gets input from posterior parietal regions and dorsolateral prefrontal area
eye fields
receive from PG and superior colliculus
all premotor areas get projections from
dorsolateral prefrontal cortex–controls eye and limb movement
prefrontal area connections
end points of ventral (object recognition) and dorsal (spatial info) visual streams
dorsolateral prefrontal area-reciprocal connections with post pari and STS, extensive connections with cingulate cortex, basal ganglia, superior colliculus, input from dopamingeric cells in tegmentum
orbital frontal cortex connections
input from temporal lobe, amygdala, gustatory cortex, somatosensory cortex, olfactory cortex, dopamingeric cells in tegmentum, projects to hypothalamus and amygdala
theory of function for frontal lobe
planning and selecting, persistence and ignoring other stimuli, keeping track of whats been done–all executive functions, responds to internal external and context clues
theory of function for preomotor cortex
- selects movements to be executed, choose behavior in response to external cues, increase in premotor activity when cues are associated with movement
- supplementary motor role in selecting and directing internal motor sequences
prefrontal cortex functions
- controls cognitive processes so that appropriate movements are selected at correct time
- internal cues-temporal memory (what has just happened, can be related to things or movements), prefrontal cortex, dorsolateral
- external cues-feedback about rewarding properties of stimuli, orbital frontal cortex learning by association, with memory damage use external cues to know how to act
- context clues-orbital frontal, social interactions, detailed sensory info to inferior from temp lobe/affective cortex(amyg)
- autonoetic awareness-self knowledge, continuous
motor___movements
premotor___movements
prefrontal____movements___
makes
picks
makes sure, done at right time and place
left asymmetry
language, encoding memories
right asymmetry
nonverbal movements, facial expressions, retrieving memories
differences in frontal lobe function
performs variety of functions, damage is unlikely to produce impairment to all functions-diff funct in diff sites
disturbances of motor function
- loss of fine movements, speed, and strength-after primary motor damage, loss of corticospinal projections to motor neurons, lose speed and strength contralaterally
- loss of movement programming-damage to premotor or dorsolateral cortex, serially ordering behavior, supplementary motor cortex-improves rapidly expect in fingers, copying movements
- changes in voluntary gaze-damage to frontal eye fields, hard to focus on specific things
- corollary discharge or reafference-internal neural signal that movement will occur, damage disrupts discharge, voluntary movements require command and signal
- speech-brocas(agrammatism-inability to use verbs, words based on cues), supplementary motor cortex(mute, returns if have unilateral lesion)
convergent thinking
there is only 1 answer to the question
divergent thinking
there are multiple answers to the questions, frontal lobe damage-cant do it
behavioral spontaneity
spontaneous speech (can’t come up with many random words), decreased verbal fluency design fluency general behaviors, L orbitofrontal region, some have difficulty with doodles
symptoms of frontal lobe lesions
increased perseveration, inability to make strategy(worse when doing new thing)-, loss of response inhibition(wisconsin card sorting task, stroop test)-cant change responses, flexibility in behavior broken risk taking(iowa gambling task)-appears after damage to orbitofrontal cortex, cant follow instructions self regulation decifits-loss of autonoetic awareness loss of associative learning-inability to select from competing responses/learn from experience impaired social and sexual behaviors-phineas gage
poor temporal memory
animal experiments show that frontal lobe plays role in temporal memory
area 46-provide internal representation of spatial info, delayed response test
medial regions-object recognition
dorsolateral cortex plays role in monitoring self generated responses
in humans-recency memory(order in which things have occured), prefrontal cortex
changes in sexual and social behavior
pseudodepression/psychopathy, orbitofrontal lesions-abnormal sex behavior loss of cells that code facial expressions, dorsolateral reduce interest in sex,
pseudodepression
change from involved and outgoing to quiet and remote after frontal lobe damage, L frontal lobe, loss of initiative, interest in sex, quiet
