Cognitive circuits in neurology
- 2. Cognitive-Behavioral Neuroanatomy Refrence : Bradly , Chapter 9, page 94-97 By : Fadakar Nima M.D.
- 3. five major functional cortial subtypes : •primary sensory-motor •unimodal association •heteromodal association •Paralimbic •limbic
- 4. primary motor •The primary motor cortex conveys complex motor programs to motor neurons in the brainstem and spinal cord
- 5. sensory •Processing of sensory information occurs as information moves from primary sensory areas to adjacent unimodal association areas
- 6. •The unimodal and heteromodal cortices are involved in perceptual processing and motor planning
- 7. •The complexity of processing increases as information is then transmitted to heteromodal association areas which receive input from more than one sensory modality
- 8. Examples of heteromodal association •prefrontal cortex •posterior parietal cortex •parts of the lateral temporal cortex •portions of the parahippocampal gyrus
- 9. paralimbic •Further cortical processing occurs in areas designated as paralimbic •These regions demonstrate a gradual transition of cortical architecture from the sixlayered to the more primitive and simplified allocortex of limbic structures •Cognitive, emotional, and visceral inputs merge in these regions
- 10. paralimbic •orbitofrontal cortex •Insula •temporal pole •parahippocampal cortex •cingulate cortex
- 11. limbic •The limbic region is intimately involved with regulation of emotion, memory, motivation, autonomic, and endocrine function
- 12. Limbic areas : •Hippocampus •Amygdala •substantia innominate •prepiriform olfactory cortex •septal area
- 13. •These structures are to a great extent reciprocally interconnected with the hypothalamus
- 16. transmodal areas •The highest level of cognitive processing occurs in regions referred to as transmodal areas •These areas are composed of heteromodal, paralimbic, and limbic regions, which are collectively linked, in parallel, to other transmodal regions
- 17. •Interconnections among transmodal areas (e.g., Wernicke area, posterior parietal cortex, hippocampal-enterorhinal complex) allow integration of distributed perceptual processing systems, resulting in perceptual recognition
- 18. Cortical Networks •language network •spatial awareness •memory and emotional network •executive function–working memory network •face-object recognition network
- 19. language network •the language network, which includes transmodal regions or “epicenters” in Broca and Wernicke areas;
- 20. spatial awareness •spatial awareness, based in transmodal regions in the frontal eye fields and posterior parietal area
- 21. memory and emotional network •memory and emotional network, located in the hippocampalenterorhinal region and amygdala
- 22. executive function–working memory network •the executive function–working memory network, based in transmodal regions in the lateral prefrontal cortex and possibly the inferior parietal cortices; and
- 23. face-object recognition network •the face-object recognition network, based in the temporopolar and midtemporal cortices
- 24. •Lesions of transmodal cortical areas result in global impairments such as hemineglect, anosognosia, amnesia, and multimodal anomia •Disconnection of transmodal regions from a specific unimodal input will result in selective perceptual impairments such as category- specific anomias, prosopagnosia, pure word deafness, or pure word blindness.
- 25. human mirror neuron system •The ability to empathize with another person’s psychological and physical circumstances is a foundation for social and moral behavior
- 26. human mirror neuron system •The parietofrontal mirror system •limbic mirror system
- 27. The parietofrontal mirror system •includes the parietal lobe and the premotor cortex plus the caudal part of the inferior frontal gyrus, is involved in recognition of voluntary behavior in other people
- 28. limbic mirror system •insula and the anterior mesial frontal cortex, is devoted to the recognition of affective behavior •Dysfunction of this system is postulated to underlie deficits in theory of mind and has been proposed as an explanation for the social deficits seen in autistic disorders
- 29. Frontosubcortical Networks •Five frontosubcortical circuits subserve cognition, behavior, and movement •Disruption of these networks at the cortical or subcortical level can be associated with similar neuropsychiatric symptoms.
- 30. Components common in circuits: •Each of these circuits shares the same components: •frontal cortex •striatum (caudate, putamen, ventral striatum) •globus pallidus and substantia nigra •thalamus (which then projects back to frontal cortex)
- 32. Neurotransmitters •Dopamine •Glutamate •γ-aminobutyric •Acetylcholine •Norepinephrine •serotonin
- 33. frontosubcortical networks naming : • The frontosubcortical networks are named according to their site of origin or function : • Somatic motor function • Oculomotor function • cognitive and behavioral (Three of the five circuits )
- 34. Somatic motor function •Somatic motor function is subserved by the motor circuit originating in the supplementary motor area
- 35. Oculomotor function •Oculomotor function is governed by the oculomotor circuit originating in the frontal eye fields.
- 36. cognitive and behavioral circuits •dorsolateral prefrontal •Orbitofrontal •anterior cingulate
- 37. dorsolateral prefrontal circuit •governs executive functions •Executive dysfunction is a principal component of subcortical dementias.
- 38. executive functions •ability to plan and maintain attention •problem solving •Learn •retrieveremote memories •sequence the temporal order of events •Shift cognitive and behavioral sets •generate motor programs
- 39. •Executive dysfunction is a principal component of subcortical dementias: •Vascular dementias •PD •HD
- 40. Executive dysfunction: •slowed information processing •memory retrieval deficits •mood and behavioral changes •gait disturbance •Dysarthria •other motor impairments
- 41. orbitofrontal circuit •governs appropriate responses to: •social cues •Empathy •social judgment •interpersonal sensitivity
- 42. •The orbitofrontal circuit connects frontal monitoring functions to the limbic system •It pairs thoughts, memories, and experiences with corresponding visceral and emotional states. •heavily involved in the process of decision making and evaluating the costs and benefits of specific behavioral responses to the environment
- 43. orbitofrontal cortex (OFC) •medial orbitofrontal cortex (OFC) •lateral OFC •anterior OFC •posterior OFC
- 44. medial orbitofrontal cortex (OFC) •evaluates reward
- 45. anterior OFC •reward value for more abstract and complex secondary reinforcing factors such as money
- 46. posterior OFC •more concrete factors such as touch and taste are encoded in the posterior OFC areas •The posterior OFC is thought to have an important role in evaluating the emotional significance of stimuli
- 47. • Dysfunction in this circuit can lead to disinhibition, irritability, aggressive outbursts, inappropriate social responses, and impulsive decision making • show deficits in both the production and recognition of emotional expression from the face, voice, or gestures
- 48. •Schizophrenia •HD •Closed head trauma •rupture of anterior communicating aneurysms •subfrontal meningiomas
- 49. •Persons with bilateral OFC lesions may manifest “theory of mind” deficits •Theory of mind is a model of how a person understands and infers other people’s intentions, desires, mental states, and emotions
- 50. lateral OFC •Monitors and decodes punishment as it pertains to motivating behavioral change.
- 51. anterior cingulate circuit • involved in motivated behavior. • includes the nucleus accumbens • has both afferent and efferent connections to : • dorsolateral prefrontal cortex (DLPFC) • amygdala
- 52. Lesions in this circuit result in : •Apathy •Abulia •akinetic mutism •decrease in the ability to understand new thoughts and participate in the creative thought process
- 53. medial prefrontal cortex •play a significant role in : •generating emotions related to empathy •cognitive functions related to theory of mind, •ability to recognize a moral dilemma
- 54. ventromedial frontal lobe •evaluates the current relative value of stimuli helping to guide decision making by determining the goals toward which behavior is directed and through judging outcomes
- 55. •AD •FTD •PD •HD •Head trauma •brain tumors •cerebral infarcts •Obstructive hydrocephalus