A Functional Framework for Cognition

1. Cognitive Architectures A Functional Framework for Cognition Based on book Cognition, Brain and Consciousness ed. Bernard J. Baars Janusz A. Starzyk

2. It seems that the human mind has first to construct forms independently before we can find them in things… Knowledge cannot spring from experience alone, but only from a comparison of the inventions of the intellect with observed fact. Albert Einstein (1949)

3. Functional Framework • The functional framework used combines two classical models of cognition • Baddeley & Hitch, 1974 • Atkinson & Shiffrin, 1968 • Yellow arrows symbolize voluntary (top-down) and spontaneous (bottom-up) attention. • Long-term memories, knowledge and skills are shown in grey boxes at the bottom • Recent version of Baddeley’s Working Memory (2002) is in the center

4. A functional framework. Sensory Input Sensory buffers Bottom up attentional capture Central Executive Top-down Voluntary Attention Action planning Vision Response output Hearing Working Storage Touch Verbal Rehearsal Visuospatial Sketchpad Learning & retrieval Stored memories, knowledge & skills: Perceptual Memory Autobiographical Memory Linguistic & Semantic Visual knowledge Declarative knowledge Habits & Motor skills 4

5. Major Functions of Human Brain

6. Working Memory Working Memory Sensory buffers Bottom up attentional capture Central Executive Top-down Voluntary Attention Action planning Vision Response output Hearing Working Storage Touch Verbal Rehearsal Visuospatial Sketchpad Learning & retrieval Stored memories, knowledge & skills: Perceptual Memory Autobiographical Memory Linguistic & Semantic Visual knowledge Declarative knowledge Habits & Motor skills 6

7. Working Memory • The middle column of boxes are components of the working memory. • The central executive is believed to be part of the prefrontal lobes and has a role similar to executive of a large company. • Deals with learning tasks, • Supervisory control over all voluntary activities • Working storage involves the medial temporal cortex and prefrontal regions. • Is dynamic, hence more vulnerable to disruption.

8. The executive part of Working Memory involves the prefrontal lobe. The verbal part --- such as rehearsing words or numbers silently --- involves the speech areas of the cortex (especially the dominant hemisphere). E.g., Broca and Wernicke's areas. The visual part --- such as visual imagery to think about how to walk from one place to another --- seems to involve visual regions. Working Memory

9. Working Memory • Inner senses, verbal rehearsal and visuospatial sketchpad, interact constantly with the long-term stores. • Verbal rehearsal/inner speech is for rehearsing and memorizing information and commentary on our current concerns, while vocal tract is inhibited. • Tied to linguistic and semantic component • Ability to temporarily hold visual and spatial information is referred to as Visuospatial sketchpad. • Also involves abstract and cross-modal (more than one sense) spatial information • Sensory systems begin as domain specific, but are interpreted as part of multimodal space.

10. Working Memory • Long term stores are for knowledge and practiced expertise. • Not conscious once stored, but interact constantly with active functions. • Parts of system work with others, but can also compete against some. • The output components are under frontal control and are related to voluntary motor functions, control of skeletal muscles and some mental functions.

11. Working Memory Hippocampus plays an important role in forming new episodic memories • Damage to the brain, medial temporal lobe (MTL) can result in inability to move information • Cognitive functions are spared, but • Ability to encode and retrieve new experiences are lost. • Immediate memory is needed to perform all tasks.

12. Working Memory In case of the damage to MTL there is no link from working memory to stored memories. Subsequently these new episodes cannot be recalled.

13. Immediate Memory • It involves sensory-motor coordination to do cognitive tasks. • Immediate memory is needed even for simple activities like • Reading. • Face recognition. • Eating food. • Tying shoes.

14. Limited and Large Memory Capacity • Brain is large, but its memory capacity is limited. • Brain has billions of neurons and involves complex sensory and motor processes. • Large long-term memory (LTM). • Short-term memory (STM) is limited to 7+/-2. • Efficiency increased by chunking, i.e., condense information. • Low efficiency during multitasking, difficult to do even 2 conscious tasks. • Practice can improve efficiency. • Limited functions are associated with conscious experience and large capacity functions are generally unconscious.

15. Limited and Large Memory Capacity • Dual Task limits • In dual tasks test, as cognitive demands of one goes up, the efficiency of the other one goes down. • Novel problems require much effort, brain makes errors and tend to do them sequentially. • When skills refine they may be performed with less conscious effort. • Some memories are very large. • Episodic and biographical memories are estimated at 1 bln bits (Landauer, 1986). • Semantic and procedural memories are also very large. • Large language vocabulary with related ideas, sounds and written words.

16. Measuring Working Memory • Working memory is tested by presenting a number of visual stimuli for recall • Test may involve recalling a one shown before, two slides ago, three slides ago etc.. • The longer the delay the more difficult the recall. • Measured is the recall accuracy and speed. • Brain activity increases with difficult tasks

17. The mind’s eye, ear and voice • In 4th century BC Aristotle suggested that visual images were “faint copies” of the visual sensations • Recent research confirms the he was right. • C.W. Perky (1910) showed that people confuse faint visual pictures with their own mental images. • Ganis (2004) write that “visual imagery and visual perception use the same neural machinery”.

18. The mind’s eye, ear and voice • Imagery tasks • Classic rotation stimuli • check whether two arbitrary shapes are the same or different • To answer the question subject mentally rotates one shape to match the other • Classic ‘tower’ task • Roll color ball from one pocket to another one • How to transform the upper picture to the lower one • Subjects use visual imagery but the task is different.

19. The mind’s eye, ear and voice • Most people talk to themselves • Ask a person to tell about his private monologue • Or write down an internal speech as it occurs • Dell and Sullivan (2004) showed that internal tongue-twisters create very similar errors to regular ones • Try repeating “Peter piper picked a peck of pickled peppers’ in internal speech as quickly as possible • Did you noticed inner pronunciation errors in spite of not really using your tongue? • Inner talk is confirmed by functional brain imaging

20. Sensory Functions A functional framework. Sensory Input Sensory buffers Bottom up attentional capture Central Executive Top-down Voluntary Attention Action planning Vision Response output Hearing Working Storage Touch Verbal Rehearsal Visuospatial Sketchpad Learning & retrieval Stored memories, knowledge & skills: Perceptual Memory Autobiographical Memory Linguistic & Semantic Visual knowledge Declarative knowledge Habits & Motor skills 20

21. Sensory functions and sensory memory tend to be in the posterior half of cortex. Left lateral view (Left hemisphere) SENSORY Functions Medial view (Right hemisphere) 21

22. Motor and executive functions. A functional framework. Sensory Input Sensory buffers Bottom up attentional capture Central Executive Top-down Voluntary Attention Action planning Vision Response output Hearing Working Storage Touch Verbal Rehearsal Visuospatial Sketchpad Learning & retrieval Stored memories, knowledge & skills: Perceptual Memory Autobiographical Memory Linguistic & Semantic Visual knowledge Declarative knowledge Habits & Motor skills 22

23. Motor functions and planning are frontal. Left lateral view (Left hemisphere) Medial view MOTOR Functions (Right hemisphere) 23

24. Central Executive • The prefrontal lobes play an important executive role in the brain. • They are needed for voluntary control over actions. • Prefrontal also support emotional processes and are necessary to control one’s unwanted impulses. • Stroop Color-naming task is used to test for frontal lobe damage. • Conflict between reading a word and and naming its color. • Highly practiced actions (reading) tend to be automatic, while novel and unpredictable ones tend to remain under voluntary control. • Automatic and voluntary control work hand in hand 24

25. Selective attention and conscious (reportable) events. A functional framework. Sensory Input Sensory buffers Bottom up attentional capture Central Executive Top-down Voluntary Attention Action planning Vision Response output Hearing Conscious event Working Storage Touch Verbal Rehearsal Visuospatial Sketchpad Learning & retrieval Stored memories, knowledge & skills: Perceptual Memory Autobiographical Memory Linguistic & Semantic Visual knowledge Declarative knowledge Habits & Motor skills 25

26. Selective Attention and Conscious (reportable) Events Attention improves our ability to perceive stimuli. In the case of executive attention, the executive regions of the prefrontal lobe shapes perceptual activity in the posterior half of cortex. Conscious events seem to mobilize frontal and parietal regions of cortex. Voluntary actions become automatic with practice and they do not need executive control. Brain uses combination of voluntary and spontaneous control

27. Executive (Voluntary) and Spontaneous Attention Spontaneous attention to find a target on the left. Voluntary attention to find a target on the right

28. Voluntary Action Control Motor hierarchy begins with general goals The goals are represented in the prefrontal area and proceed to supplementary and pre-motor regions which triggers intention to act The primary cortical motor region (M1) triggers movements of skeletal muscles. The brain regions activated in pushing a button with the right hand

29. A functional framework. Sensory Input Sensory buffers Bottom up attentional capture Central Executive Top-down Voluntary Attention Action planning Vision Response output Hearing Working Storage Touch Verbal Rehearsal Visuospatial Sketchpad Long term Memories Learning & retrieval Stored memories, knowledge & skills: Perceptual Memory Autobiographical Memory Linguistic & Semantic Visual knowledge Declarative knowledge Habits & Motor skills 29

30. Consolidation of Events into LTM

31. Long-term Memories Long-term memory functions are widely distributed throughout the brain by means of long lasting connections. Posterior half of cortex involves perceptual regions, while executive and motor memory, such as plans for future actions, engage frontal regions. Hippocampus is involved with episodic memory, while subcortical basal ganglia and cerebellum are responsible for motor learning.

32. Summary • We discussed broad concepts for cognitive neuroscience. • Working memory is a foundation of learning and cognition. • Immediate memory seems to depend on medial temporal lobe including two hippocampi. • Damage to this regions impairs formulation of long term memories. • The rear half of cortex is involved in sensory processing and in sensory-perceptual memory. • The front half of cortex is involved with motor and executive functions and long term memory for these processes.