1、Interpreting Neurolinguistic Evidence Careless thinking and critical thinking,Ling 411 21,Schedule of Presentations,Tu Apr 13 Th Apr 15 Tu Apr 20 Th Apr 22,Interpreting Linguistic Evidence Careless thinking and critical thinking,Wernickes area and speech production Brocas area and speech production
2、Brocas area and Wernickes area in syntax The meanings of words “Mirror neurons” very smart? Invoking the computer metaphor Retrieval of words, meanings Communication between subsystems,Wernickes area and speech production,Examples of careless thinking:Steven Pinker: Wernickes area was once thought t
3、o underlie language comprehension. But that would not explain why the speech of these patients sounds so psychotic.The Language Instinct (1994)Friedemann Pulvermller:patients with Wernickes aphasia have difficulty speaking. These deficits are typicaland cannot be easily explained by assuming a selec
4、tive lesion to a center devoted to language comprehension.The Neuroscience of Language (2002),Perceptual structures in motor production,Perceptual structure is used in two ways Planning (e.g. visualizing while painting) Monitoring Examples Phonological recognition in speech production Cf. Wernickes
5、aphasia Painting Musical production Baseball, soccer, tennis, etc.,Interpreting Linguistic Evidence Careless thinking and critical thinking,Wernickes area and speech production Brocas area and speech production Brocas area and Wernickes area in syntax The meanings of words “Mirror neurons” very smar
6、t? Invoking the computer metaphor Retrieval of words, meanings Communication between subsystems,Brocas area and speech production - I,Careless thinking previously considered: John Pinel (Biopsychology textbook):Surgical excision of Brocas area failed to result in loss of speech production (after rec
7、overy from surgery),Brocas Area: Not for Speech Production?,Surgical excision was done in two stages. Following completion of the second stage, no speech-related problems were reported.,John Pinel, Biopsychology (1990:560), Adapted from Penfield & Roberts, 1959,Patient D.H.,Brocas Area: Not for Spee
8、ch Production?,What Pinel neglects to mention, but it is in Penfield & Roberts: Patient D.H. was a young boy who had been having seizures, originating in this part of his brain.,John Pinel, Biopsychology (1990:560), Adapted from Penfield & Roberts, 1959,Patient D.H.,More on patient D.H.,Eighteen yea
9、rs old at time of surgery Had suffered from seizures causing an inability to speak from the age of 3 1/2 Apparently, “the congenital abnormality had caused displacement of function”,Penfield & Roberts Speech and Brain Mechanisms (1959: 163),Brocas area and speech production - II,Influential paper by
10、 Alexander et al. (1990) Motivation for the study Maybe its not just Brocas area damage that is responsible for some of the symptoms of “Brocas aphasia” Maybe some of them result instead from damage to neighboring areas They studied a group of patients Distinguished 3 subtypes of Brocas aphasia,Thre
11、e subtypes in Alexander study,Impaired speech initiation Symptom traditionally attributed to transcortical motor aphasia Area of damage: frontal operculum Disturbed articulatory function Area of damage: lower primary motor cortex The classical Brocas aphasia syndrome More extensive damage,Type I,One
12、 patient Area of damage Frontal operculum Adjacent middle frontal gyrus Subjacent subcortical white matter Speech quality normal Normal repetition Speech terse and delayed in initiation Speech grammatically correct! Anomia and semantic paraphasias,Insula and opercula View with opercula pulled back t
13、o expose insula,Original Brodmann Map - Colorized Outlines - with Functional Attribution,Type I critical appraisal,Area of damage Frontal operculum Adjacent middle frontal gyrus Subjacent subcortical white matter Symptoms Speech quality normal Normal repetition Speech terse and delayed in initiation
14、 Speech grammatically correct! Anomia and semantic paraphasias The symptoms are those of transcortical motor aphasia,Type I (contd) (from Alexander study),Other relevant studies Patients with frontal operculum lesion but with primary motor cortex spared Symptoms like those usually called TCMA Speech
15、 output “Terse, laconic” Grammatical, sentence-length Semantic paraphasias Normal articulation Evidently, damage to subjacent white matter “is essential for lasting aphasia after lesions in the frontal operculum” (Alexander et al. 1990” 357),Type I (contd) (from Alexander study),Other relevant studi
16、es Patients with frontal operculum lesion but with primary motor cortex spared Symptoms like those usually called TCMA Speech output “Terse, laconic” Grammatical, sentence-length Semantic paraphasias Normal articulation Evidently, damage to subjacent white matter “is essential for lasting aphasia af
17、ter lesions in the frontal operculum” (Alexander et al. 1990” 357),Type I (contd) (from Alexander study),Other relevant studies Patients with frontal operculum lesion but with primary motor cortex spared Symptoms like those usually called TCMA Speech output “Terse, laconic” Grammatical, sentence-len
18、gth Semantic paraphasias Normal articulation Evidently, damage to subjacent white matter “is essential for lasting aphasia after lesions in the frontal operculum” (Alexander et al. 1990” 357),Type II,Patients 2-6 in Alexander et al. (1990) study Areas of damage Frontal operculum Lower primary motor
19、cortex Anterior insula White matter deep to these regions Right facial paresis and mild right hand weakness Defective articulation Sentence-length grammatically normal utterances! Except for initiation struggle Except for patient #6: single word utterances,Type II (contd),Other studies support the a
20、ttribution of dysarthria to primary motor cortex Patients with Small shallow lesions in lower motor cortex Frontal operculum not involved Labels that have been used Aphemia Cortical dysarthria Apraxia,(Alexander et al. 1990: 357),Type III,Patients 7-9 in Alexander et al. (1990) study Areas of damage
21、: Lower motor cortex and/or subjacent white matter Anterior superior insula Lateral putamen (a nearby subcortical structure) Frontal operculum spared Right central facial paresis Aphasia symptoms similar to Type II Including absence of agrammatism Phonemic paraphasias in repetition One patient (#9)
22、had virtually no speech output,Receptive agrammatism,“All cases had some impairments in auditory comprehension at the level of complex sentences or multistep commands.” (Alexander et al. 1990: 360) Indicates short-term memory deficit,Confounding factors,“We did not evaluate any of the patients in th
23、e acute phase of their illnesses; all were referred to the Boston VAMC for speech and language therapy.” (Alexander et al. 1990: 353) Localization of lesions was done by CT scan not sensitive enough to detect small areas of damage (360),The importance of plasticity,“In the acute phase, these patient
24、s may have traditional, nonfluent aphasia articulation impairment, prosodic impairment, and agrammatical, shortened utterances. The evolved disorder is, however, much less severe than that; grammatical, sentence-length utterances return, albeit still labored and paraphasic and with speech impairment
25、.” (Alexander et al. 1990:361) Recovery is not so good if extensive white matter involvement,Another study,Taubner, Raymer, and Hellman 1999, “Frontal-opercular Aphasia”: 5 types: “Verbal akinesis” like Trans-cortical motor aphasia supplementary motor area and cingulate gyrus Disorders of grammar pa
26、rs opercularis Phonemic disintegration primary motor cortex Defects of lexical access pars triangularis and adjacent frontal cortex Mixed defects,Proceed with Caution!,How should we interpret the results of the Alexander study? Some researchers have concluded that damage to Brocas area is not respon
27、sible for Brocas aphasia after all Reason: No lasting impairment of speech production if only Brocas area is damaged, without white matter involvement Alternative explanation?,Alternative explanation,Plasticity N.B. Patients were examined only after they had had time to recover, not in the acute pha
28、se The evidence indicates that Functions of Brocas area can be partly regained by recruitment of neighboring area(s) But: such recovery is impaired if there is also damage to subjacent white matter,Interpreting Linguistic Evidence Careless thinking and critical thinking,Wernickes area and speech pro
29、duction Brocas area and speech production Brocas area and Wernickes area in syntax The meanings of words “Mirror neurons” very smart? Invoking the computer metaphor Retrieval of words, meanings Communication between subsystems,Friederici Fig. 1,Syntactic networks in the human brain. (a) Depicts the
30、two neural networks for syntactic processing and their fronto-temporal involvement (function) schematically.,(b) Shows fiber tracting as revealed by DTI (structure) in an individual subject: top right, with the starting point (green dot) being BA 44 and bottom right, with the starting point (blue do
31、t) being the frontal operculum.,Friederici Figure 2,Fiber tracts between Brocas and Wernickes area. Tractography reconstruction of the arcuate fasciculus using the two-region of interest approach. Brocas and Wernickes territories are connected through direct and indirect pathways. The direct pathway
32、 (long segment shown in red) runs medially and corresponds to classical descriptions of the arcuate fasciculus. The indirect pathway runs laterally and is composed of an anterior segment (green), connecting Brocas territory and the inferior parietal cortex (Geschwinds territory), and a posterior seg
33、ment (yellow), connecting Geschwinds and Wernickes territories.,Wernickes & Brocas areas for syntax?,Combining functional MRI and DTI, two of these pathways were defined as being relevant for syntactic processes 44. Functionally, two levels of syntactic processing were distinguished, one dealing wit
34、h building a local phrase (i.e. a noun phrase consisting of a determiner and a noun the boy) and one dealing with building complex, hierarchically structured sequences (like embedded sentences This is the girl who kissed the president). DTI data 44 revealed that the frontal operculum supporting loca
35、l phrase structure building 14 and 44 was connected via the UF to the anterior STG which has been shown to be involved in phrase structure building as well 14. The dorsal pathway connects BA 44 which supports hierarchical structure processing 42 and 45, via the SLF to the posterior portion of the ST
36、G/STS, which is known to subserve the processing of syntactically complex sentences 51 I. Bornkessel et al., Who did what to whom? The neural basis of argument hierarchies during language comprehension, Neuroimage 26 (2005), pp. 221233. Article | PDF (300 K) | View Record in Scopus | Cited By in Sco
37、pus (53)51. This latter network was, therefore, taken to have a crucial role in the processing of syntactically complex, hierarchically structured sentences. (Friederici 2009, p. 179),Critique of Friederici paper by Weiller et al. (August 2009),Friederici claims the dorsal pathway to be crucial for
38、the evolution of human language, which is characterized by the ability to process syntactically complex sentences. As suggested in our paper, the involvement of the dorsal stream for processing of complex syntactic operations might be partially explained as a result of an increase in syntactic worki
39、ng memory load 2. Syntax and memory are hard to keep apart.Trends in Cognitive Sciences vol. 13, Issue 8, September 2009. pp. 369-370.,Hickok on phonological working memory,“ Brocas area and the SMG are involved in speech perception only indirectly through their role in phono- logical working memory
40、 which may be recruited during the performance of certain speech perception tasks.”Hickok 2000: 97“The sound-based system interfaces not only with the conceptual knowledge system, but also with frontal motor systems via an auditory-motor interface system in the inferior parietal lobe. This circuit i
41、s the primary substrate for phonological working memory, but also probably plays a role in volitional speech production.Hickok 2000: 99,Interpreting Linguistic Evidence Careless thinking and critical thinking,Wernickes area and speech production Brocas area and speech production Brocas area and Wern
42、ickes area in syntax The meanings of words “Mirror neurons” very smart? Invoking the computer metaphor Retrieval of words, meanings Communication between subsystems,Impairment of nominal concepts,Access to nominal concepts is impaired in extra-sylvian sensory aphasia Type I Damage to temporal-pariet
43、al-occipital junction area I.e., lower angular gyrus and upper area 37 Poor comprehension Naming strongly impaired Semantic paraphasia Type II Damage to upper angular gyrus Variable ability to comprehend speech Naming strongly impaired Few semantic paraphasias Many circumlocutions,2 Cases of Rapp &
44、Caramazza (1995),E.S.T. (901b) Left temporal damage “Meaning spared, couldnt say the word”: R&CJ.G. (902a) Left posterior temporal-parietal Meaning spared, couldnt spell the word correctly, but phonological recognition okay,Cf. Rapp & Caramazza, Disorders of lexical processing and the lexicon (1995)
45、,Patient E.S.T. (Rapp&Caramazza 1995:901b),Left temporal damage Shown picture of a snowman Unable to name it “Its cold, its a ma cold frozen.” Shown picture of a stool “stop, step seat, small seat, round seat, sit on the” Shown written form steak “Im going to eat something its beef you can have a s
46、different costs more ” What can we conclude?,Assessment of E.S.T. by Rapp & Caramazza,Responses of E.S.T. indicate awareness of the meanings (SNOWMAN, STOOL, STEAK) Therefore, “meaning is spared” (according to Rapp & Caramazza),Warning: Proceed with caution,The assumption of Rapp&Caramazza is easy t
47、o make I.e., that meaning (conceptual information) is spared But theres more to this than meets the eye! As we have seen, conceptual information is widely distributed We only have evidence that some of the conceptual information is spared,Patient E.S.T. a closer look,Left temporal damage Picture of
48、a snowman “Its cold, its a ma cold frozen.” Picture of a stool “stop, step seat, small seat, round seat, sit on the” Written form steak “Im going to eat something its beef you can have a s different costs more ” These are not definitions This is connotative information Vague semantic notions about t
49、he meanings,Compare patient J.G. (902a),Damage: Left posterior temporal-parietal Meaning spared, couldnt spell the word correctly, but phonological recognition okay digit: D-I-D-G-E-T “A number” thief: T-H-E-F-E “A person who takes things” These are actual definitions,The Role of RH in semantics,Conceptual information, even for a single item, is widely distributed A network Occupies both hemispheres RH information is more connotative LH information more exact,
