5. Thinking, Planning, Language Flashcards
How does the brain understand perceptions?
Relies on associations assembled from previous experience.
How does the brain work around its limited short-term memory?
It builds simple representations of things as references
Semantic memory
Form of declarative knowledge that includes facts and data. Construction of representations of things relies on semantic memory.
Concept cells
Specific, single cells that fire when looking at a particular person, but remain quiet when looking at something else. Work together in assemblies. Form basis of semantic memory. Located in the temporal lobe, which specializes in object recogntion
D.B.O
Case of a 72-year old man who had multiple strokes. He could only identify 1 out of every 20 common objects by sight, but could easily identify objects by feeling or hearing them. It was concluded that the strokes prevented visual input from being conveyed to the anterior temporal regions where semantic processing occurs
Agnosia
Like D.B.O. Damage to certain areas of the temporal lobes leads to problems with recognition of visual stimuli
Areas of temporal lobe involved in identification of visual stimuli
Fusiform face area: underside of temporal lobe, critical for recognizing faces. Damage results in prosopagnosia
Parahippocampal place area: responds to locations
Regions of the brain that encode words
Posterior parietal cortex, parts of the temporal lobe, regions of the prefrontal cortex. Together, form the semantic system. Occupies a significant portion of the brain, especially compared to other primates. May explain humans’ unique ability for language
Studies using _____ found more extensive activation in ___________ in response to ______, but when presented in a ________ or ________, _______ were activated.
fMRI, left hemisphere, words, narrative, other context, both hemispheres
Additional areas of brain involved in processing written language
Visual word form area in fusiform gyrus recognizes written language, a fact that is consistent across speakers of different languages
Areas of brain involved in processing numbers
Parietal cortex with input from occipitotemporal cortex, a region that participates in visual recognition and reading
Patient Tan
Louis Victor Leborgne, could only say “tan”. Pierre Paul Broca learned that he could understand speech but could only say “tan”. After Leborgne died, Broca performed autopsy and found large lesion in a part of frontal lobe (Broca’s area), which is now known to be vital for speech production.
Broca’s aphasia
Non-fluent aphasia. Damage to left frontal lobe. Speech is slow and halting, but language can still be understood
Wernicke’s aphasia
Fluent aphasia. Damage to left temporal lobe. Difficulty in comprehending speech, but not in producing it
Pure word deafness
Damage to superior temporal lobes in both hemispheres. Unable to comprehend heard speech on any level, but are not deaf. Just cannot link sound of words to meaning. Can make perfect sense of written language.
Important gene in language research
FOXP2. Codes for protein that switches other genes on and off in particular parts of the brain. Mutations result in difficulty making mouth and jaw movements for speech. Disability accompanied by difficulty with spoken and written language. May have influenced development of spoken language in humans
Significance of birds in language research
Possible to induce genetic mutations and study effects on singing. FOXP2 mutations can disrupt song development in young birds
Dorsal striatum
Part of basal ganglia. Disruption of FOXP2 can affect signalling in this area. Specialized neurons here express high levels of FOXP2’s product. Mutations affect this and result in speech deficits
Brain regions involved in accessing meaning of words
Parts of middle and inferior temporal lobe
Suspected site of sentence-level comprehension
Anterior temporal lobe
Sensory-motor circuit for speech
In left posterior temporal lobe. Involved in speech development, likely supports verbal short-term memory
Prefrontal cortex
Outer folded layers just behind forehead, once of the last regions to develop, doesn’t reach full maturity until adulthood. Supervises everything the brain does. Interacts with large network of posterior cortical areas that encode specific types of information.
Executive function
Blend of three core skills: inhibition, working memory, shifting
Working memory
Depends on PFC and parietal lobe
Shifting
Mental flexibility, adjustment of ongoing behaviour when situation requires it. Card game. People with damaged PFCs can’t switch rules.
What happens to the activity level associated with executive function as age increases, and why?
Activity decreases because circuits become more efficient
Two types of decision making
Logical and emotional (affective). Both involve PFC
Role of lateral PFC in decision making
Overrides emotional responses. One of the last areas to mature, which is why teens are dumb
Role of orbitofrontal cortex in decision making
Important in affective decision making, especially in situations involving reward and punishment. Implicated in addiction and social behaviour
Mentalizing
Making sense of your own thought processes and those of others.
Brain areas involved in mentalizing
Medial PFC (makes judgements and self and others) and some areas of lateral PFC. Temporoparietal junction focuses on others but not on self. Activated when we watch others engage in deceptive actions.
Mirror neurons
Neurons in motor cortex of rhesus macaques that fired when they performed a certain task. Also fired when watching others perform that task. Controversial.
