Lecture 5 - Frontal & Temporal Lobes Flashcards
What are the diverse functions of the temporal lobe ?
- Sensory processing (auditory, visual, olfactory)
- Object recognition, categorization & memorizing
- Spatial navigation
- Affective processing
What structures & cortices are in the temporal lobe ?
- Sensory regions : primary auditory & olfactory cortices
- Association regions : visual & auditory association cortices
- Subcortical structures : hippocampus & amygdala
What are the functions of the amygdala & hippocampus ?
- Amygdala : linking sensory information to emotions
- Hippocampus (& paralimbic region) : long-term memory formation
What specific functions of the auditory areas are localized in the L-hemisphere?
Speech sounds :
- Recognition
- Temporal dissociation
- Comprehension
What specific functions of the auditory areas are localized in the R-hemisphere?
Musical sounds :
- Frequency, pitch, timbre, rhythm, harmony
- Recognition of musical instruments
- Link to emotion & memory
What’s the region in the secondary visual area specialized in processing faces ?
Fusiform face area (FFA)
What’s the region of the secondary visual area specialized in processing places or complex scenes ?
- Parahippocampal place area
- Fusiform gyrus (complex scenes)
What are the different connections of the temporal lobe ?
- Between superior & ventral temporal lobe (STS stream)
- From auditory areas to parietal cortex (dorsal stream)
- From primary auditory & visual areas to the temporal pole (ventral stream)
What is the role of the STS in sensory processing ?
- Categorizing auditory & visual stimuli into object categories
- Cross-modal matching
How does the STS contribute to social cognition ?
- Analyzing social meaning of facial expression, body gesture, vocalization, gaze direction…
- Theory of Mind (ToM)
What are the 2 major projections of the temporal lobe ?
- Medial temporal projection (to hippocampus and/or amygdala) : LTM
- Frontal lobe projection : working memory, language, evaluation of emotional meaning of stimuli
What are the perceptual disorders linked to temporal cortex’ dysfunction ?
- Disorders of auditory, visual or odor perception
- Memory dysfunction
- Affect & personality
- Object & word categorization
What’s the difference between L-R temporal lobes ?
- R temporal lobe : non-verbal information (music, sounds, pictures
- L temporal lobe : verbal information, word recognition & categorization, speech comprehension
What happens if the L primary auditory cortex is damaged ?
- Auditory agnosia : general inability to perceive & identify complex sounds despite intact hearing
- Verbal auditory agnosia : word deafness
What specific symptoms are associated with damage to the L auditory areas ?
- Problems with discrimination of sounds
- Evaluating temporal order of sounds
- “people talk too quickly”
- Linked to Wernicke’s aphasia
What happens if the R primary auditory cortex is damaged ?
- Problems in musical perception
- Congenital amusia : tone deafness
What specific symptoms are associated with damage to the R auditory areas ?
- Problems in musical perception
- Amusica : not being able to recognize song
What specific symptoms are associated with damage to the L ventral stream ?
- Problems processing verbal information (auditory or written)
- Associative agnosia
- Word recognition (alexia)
- Problems with semantic categorization
- Problems using contextual information to extract meaning of verbal information
- Recall of verbal memory
What specific symptoms are associated with damage to the R ventral stream ?
- Problems processing non-verbal information
- Apperceptive agnosia
- Impairment in visual recognition : difficulty copying complex figures, unable to recognize faces in ambiguous shadow
What symptoms can we expect of temporal lobe lesions on personality & affect ?
- Affective & personality changes
- Egocentrism, paranoia, psychosis, burst of anger
- Hallucinatory experiences
- Loss of fear response
What’s the role of the frontal lobe ?
- Connects sensory & spatial information with action plans
- Controls behavior
- Inhibits inappropriate responses
- Planning, decision-making, motivation
- Keeps track of what already happened & what is to come (working memory)
- Cognitive control : ignoring irrelevant external stimuli