Frontal Lob Anatomisi İşlevleri

1. Frontal LobAnatomisi İşlevleri Prof Dr Süheyla Ünal

2. Motor cortex Primary Premotor Supplementary Frontal eye field Broca’s speech area Prefrontal cortex Dorsolateral Medial Orbitofrontal Functional Frontal Lobe Anatomy

3. PFK,korteksin en çok bağlantıya sahip bölgesidir • PFK bölgelerinin dış uyaranların işlendiği duyu alanları ile bağlantıları vardır (işlenmiş dış uyaran bilgisi) • PFK bölgelerininemosyonel durumların gözlendiği ve düzenlendiği bölgeler ile bağlantıları vardır (içsel bilgi) • PFK bölgelerininmotor işlevlerden sorumlu olan bölgeler ile bağlantıları vardır PFK konumu ve bağlantıları dış uyaranların içsel bilgiler ile entegre edilmesine olanak sağlayacak şekildedir

4. The prefrontal cortex has expanded over mammalian and primate evolution. A greatly enlarged prefrontal cortex is a distinctively human and primate feature. • According to Brodmann (1909), the prefrontal cortex accounts for 29% of total cortex in humans, 17% in the chimp, 11.5% in the macaque, and 3.5% in the cat. • While whales and dolphins have large brains, it is the parietal rather than frontal cortex that has expanded in these mammals. Cognition, Brain and Consciousness: An Introduction to Cognitive Neuroscience Edited by Bernard J. Baars and Nicole M. Gage 2007 Academic Press

5. Prefrontal cortex can be divided into lateral (side), medial (midline), ventral (bottom), and dorsal (top) regions. The lateral division divides into dorsal and ventral halves separated by a major horizontal fold, the inferior lateral sulcus

6. Dorsolateral • Input mainly from medial, dorsolateral cortical areas. (somatosensory, visuospatial information) • Lateral • Inputs mainly from ventrolateral and ventromedial cortical areas (auditory, visual pattern information)

7. The dorsomedial thalamic nucleus is a point of convergence, the ‘summit’ of the integration occurring within the specific thalamic nuclei.

8. The Frontal Cortex • Confers emotional meaning (semantic content) onto objects in the world • Emotional salience (attachment) • Seat of the Self and Personality • Love, Morality, Decency, Responsibility, Spirituality • Conscious “choice”

9. Prefrontal cortex • Effortful Control: Involves explicit processing • Delay of gratification • Inhibition of dominant responses (overlearned or innate); e.g., turning your head away from a light stimulus (anti-saccade); not peeking at a present for a child • Pay close attention to detail (= focused attention) • Persevere in unpleasant tasks

10. ventro-medial Prefrontal Cortex • Damasio A, Bechara A: research on patients with vmPFC lesions • “Myopia for the future,” cognitive impulsiveness - prefer immediate but disadvantageous rewards over rewards that are delayed but advantageous in the long run - guided primarily by immediate prospects and insensitive to pos or neg future consequences - deny or are unaware of the problem (analogous to “denial”) • vmPFC patients are similar to Substance Abusing pts

11. Working memory is The ability to keep information in your mind for a short period of time (seconds)andbe able to use this information in your thinking.

12. Working memory is closely linked to the critical role the frontal lobes play in the temporal organization of behavior and controlling the proper sequence in which various mental operations are enacted. • Since the selection of information required to solve the problem at hand is made in the frontal lobes, they must ‘know’, at least roughly, where in the brain the information is stored.

14. Executive system • An organism’s ability to guide its behavior by internal representations -- the formulation of plans and then guiding behavior according to those plans 2. An organism’s ability not only to guide its behavior by internal representations, but also the capacity of ‘switching gears’ when something unexpected happens

15. DLPFC

17. Poor organizational strategies • Poor memory search strategies • Stimulus-bound behavior/environmental dependency • Impaired set shifting and maintenance

20. Frontal Lob Anatomisi • Motor Korteks • Primer • Premotor • Suplementer • Frontal göz alanı • Broca konuşma merkezi

21. Motor korteks Primary motor area Premotor area B4 B6 Central sulcus Supplementary motor area (medially) Frontal eye field B 8 Lateral sulcus/ Sylvian fissure Motor speech area of Broca B 44, 45

22. Prefrontal Korteks • Bütün kaynaklardan (duyusal sistemler, limbik sistem, subkortikal yapılar) gelen bilgileri toplar, bütünleştirir, formülleştirir, uygular, denetler, değişiklikler yapar ve yargılar. Sonuçta ortaya çıkarılacak davranışa karar verir

23. Prefrontal korteks 1- Dorsal prefrontal korteks 2- Medial prefrontal korteks 3- Ventral orbitofrontal korteks • Dış dünyayla ilgili algılar, dünya hakkındaki düşünceler, bedenin kendisindeki olaylar bu bölgelerden gelen bilgiler aracılığı ile oluşturulur

24. Ventromedial Prefrontal Cortex and Somatic Markers • Somatic marker “biasing signals” are regulated by VM premotor cortex; these signals help regulate decision-making in uncertainty

25. The somatic marker hypothesis posits that deficits in emotional signalling (somatic states) lead to poor judgment in decision-making, especially in the personal and social realms. Similar to this hypothesis is the concept of emotional intelligence, which has been defined as an array of emotional and social abilities, competencies and skills that enable individuals to cope with daily demands and be more effective in their personal and social life. Patients with lesions to the ventromedial (VM) prefrontal cortex have defective somatic markers and tend to exercise poor judgment in decision-making, which is especially manifested in the disadvantageous choices they typically make in their personal lives and in the ways in which they relate with others. Furthermore, lesions to the amygdala or insular cortices, especially on the right side, also compromise somatic state activation and decision-making. This suggests that the VM, amygdala and insular regions are part of a neural system involved in somatic state activation and decision-making.

26. the prefrontal cortex is an ability to deal with cognitive novelty. • The dark areas in this composite brain image show regions that control novel actions, but which lose activity when the identical actions becomes automatic with practice.

28. Ayna Nöronlar • Class of neurons in F5 (BA 44) and ventral premotor cortex that discharge both: • when animal performs object-directed action • when animal observes OD action in others • Subset appear to be “communicative” motor neurons • Functions • Imitation • Action understanding • Potentially important for understanding social learning and imitation effects

29. To do that, you must have the capacity to form an internal representation of the other person’s mental life -- or as it is called in cognitive psychology, to have a theory of mind. Your actions will be chosen under the influence of your theory of the other person’s mind formulated in your own mind. • This makes the executive processes required for success in an interactive environment much more complex than those required in a solitary situation.

30. The prefrontal cortex 1) orbitofrontal cortex2) lateral prefrontal cortex3) ventromedial (sub-genual) cortex4) limbic system 5) anterior cingulate cortex

33. Ingvar (1985) coined the phrase ‘memories of the future‘ referring to one of the most important functions of advanced organisms: making plans and then following the plans to guide behavior. • Unlike primitive organisms, humans are active, rather than reactive, beings. We are able to form goals, our visions of the future. Then we act according to our goals. • In order to guide our behavior in a sustained fashion, these mental images of the future must become the content of our memory: thus the ‘memories of the future’ are formed

35. Orbito-frontal cortex : processing site fpr learmed associations between affective stimuli and their reinforcement value (reward/punishment), thus playing a crucial role in subsequent decision making; role is in repeated learning; impulse control and social cognitive skills including theory of mind tasks • Severe lesions: oblivious to social and emotional cues, poor decision making capacity, sociopathic tendencies, loss of fear regulation: inhibition of inappropriate thoughts and actions. • Anterior cingulate: experience of emotion, helps to focus attention and may be required to properly integrate emotion and cognitionto tune in on one’s own thoughts

36. Orbitofrontal cortex inhibits hypothalamus, the area responsible for basic appetitive behaviors such as feeding, fighting, fleeing, and mating.

37. The amygdala and orbitofrontal cortex influence autonomic and endocrine function via their connections with the brainstem and hypothalamus. He does not agree that “somatic states” generate emotions (i.e., James-Lange Theory or Damasio’s Somatic Marker Hypothesis) but rather thinks that these states prepare the animal for different types of action including fight, flight, feeding and sex. • The amygdala and orbitofrontal cortex can influence the selection of behavioral actions through 1) brain systems that operate implicitly and have been present in primates and some other mammals for millions of years, such as the ventral striatum and other parts of the basal ganglia; and in humans 2) higher cortical systems that can process multiple “If..the” statements to implement a plan to obtain a reward or avoid punishment. Deferring action may be part of the plan.

38. Lesions to the ventral frontal lobes can result in difficulties altering behavioral strategies in response to a change in environmental reinforcement contingencies (Rolls, 2000) • Damage is associated with changes in social behavior (disinhibition) and problems identifying vocal and facial emotional expression (Rolls, 2000; Phillips, 2003) • Studies described later indicate that bilateral orbitofrontal lesions cause more severe problems with social and emotional functions, but that unilateral lesions cause some subtle difficulties. Problems also appear to be more severe in patients with more diffuse damage (e.g., caused by head trauma or stroke versus surgical lesions) • Results of studies are inconsistent regarding whether the laterality of the lesion is important in symptom presentation (Honak et al., 2003; Tranel et al., 2002.

39. Thayer and Lane (2000) propose that the ACC serves as a point of integration for viseral, attentional and affective information that is critical for self-regulation and adaptability. • The ACC seems to be associated with the conscious allocation of attention (I.e. including inhibition of irrelevant informaton). • The ventral and rostral regions of the ACC are associated with affective, motivated and autonomic behavior; whereas the dorsal region is associated with response selection as well as pain

40. PFK alt alanları • Dorsolateral: 9,46 • Ventrolateral:44,45,47 • Orbitofrontal: 10,11 - Anterior: 8, 10 - Medial: 11, 25, 32

41. İşlevsel Frontal Lob Anatomisi • Frontal-Subkortikal Döngüler Globus Pallidus & Substantia Nigra Striatum Caudate & Putamen Thalamus DM & CM nuclei Frontal cortex

42. 5 Frontal-Subkortikal Döngü 1-Motor döngü 2- Okulomotor döngü 3- Dorsolateral döngü 4- Lateral orbitofrontal döngü 5-Limbikdöngü

43. VL Globus Pallidus Hypo-thalamus SMA, Premotor,Motor Putamen VL, VA, CM Thalamus 1. Motor Döngü Dil • Suplementar Motor & Premotor: motor programların planlanması, başlatılması ve depolanması, hareketlerin ince ayarı • Motor: hareketin plana göre yönetilmesi • Konuşma

44. 1. Motor Döngü

45. DM Globus Pallidus VA, MD Thalamus Frontal Eye Field Central Caudate Substantia Nigra 2. Okulomotor Döngü • İstemli tarayıcı göz hareketleri • Bağımsız görsel uyaranlar

46. DM Globus Pallidus VA, MD Thalamus Lateral Prefrontal DL Caudate Substantia Nigra 3. Dorsolateral Prefrontal Döngü • Yönetsel işlevler: motor planlama, dikkati yönlendirme, bilişsel setleri değiştirme • Dikkat ve işlem belleği aracılığı ile davranışı monitorize etme ve uyumlandırma

47. Dorsal prefrontal korteks İşlem belleği ve motor planlama ile ilişkilidir.

48. dorsal system (incl. hippocampus, dorsal ACC & dorsolateral PFC) • Dorsal ACC: involved in target & motor response selection, error detection & performance monitoring, novelty detection, motivational valence assignment & reward based decision making • if not working properly likely difficulty in becoming motivated or interested in new things & looking forward to rewards

49. DLPFC: things held in mind here, working memory, with volition; integrating the outcome of two or more separate cognitive operations in pursuit of a higher behavioural goal” in addition to executive function at an abstract level; • Ventromedial PFC: involved in extinction of fear responses

50. Infero-lateral prefrontal DM Globus Pallidus VA, MD Thalamus VM Caudate Substantia Nigra Orbito-frontal 4. Lateral Orbitofrontal Döngü • Duygusal yaşam ve kişilik yapısı • Uyarılma, motivasyon, duygu, çeldirici uyaranların baskılanması • Bilinçlilik, ödül sistemi • Sosyal biliş