Basics of Perception and Sensory Processing

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1 BMT 823 Neural & Cognitive Systems Slides Series 3 Basics of Perception and Sensory Processing Prof. Dr. rer. nat. Dr. rer. med. Daniel J. Strauss

2 Schools of psychology Structuralism Functionalism Behaviorism Gestalt psychology Genetic epistemology Individual differences Cognitive psychology (cognitive revolution)

3 Schools of psychology Structuralism Attempted to find simplest units of the mind (like a period table of elements) More complex behaviors explained by combining different elements (research never really got this far) Method: Introspection

4 Schools of psychology Functionalism Asked the question Why? Why does the mind work the way it does? Why does this behavior help a person adapt to their environment? Method: Observations in real life

5 Schools of psychology Behaviorism Goal: to predict and control behavior Method: Observation of only visible, measurable behaviors (mental states cannot be studied)

6 Schools of psychology Gestalt psychology The mind is not divisible The mind is a whole entity, and imposes its own structure on how to interpret stimuli It is the relationship between elements that matters Method: Experimentation with perception, problem solving

7 Schools of psychology Genetic epistemology the mind changes over time The mind goes through different stages, which can be separated from each other by the different cognitive abilities present at each stage (Piaget)

8 Schools of psychology Individual differences Tried to determine if a mental characteristic (eg., intelligence) was inherited or acquired later from the environment Type of statistics typical used in cognitive psychology developed

9 Schools of psychology Cognitive psychology Proposed that mental states could be studied (reaction to behaviorists) Some results Human factors engineering Limited-capacity processors Linguistics

10 More results Localization of function / plasticity of nervous system Computer metaphor / artificial intelligence Cognitive neuroscience

11 Paradigms of Cognitive Psychology Information Processing Connectionism Evolution Ecology

12 Figure 1-4 (p. 29) A typical information-processing model.

13 Figure 1-5 (p. 31) A typical connectionist model.

14 Paradigms of Cognitive Psychology Evolution Our minds are biological systems which evolve and adapt to our environment, and is subject to the laws of natural selection For each type of problem, we therefore have specialpurpose programs to solve them Ecology Cognition occurs in the context of culture, not in a vacuum

Cognitive Research Rembrand. Anatomy of Dr.

15 Non-Engineering) Basics of Neural Engineering Perceptual and Cognitive Modeling Medical Research Cognitive Research Rembrand. Anatomy of Dr. Tulp, Oil on Canvas, 1632 Dali. Three Sphinxes of Bikini, Oil on Canvas, 1947

16 Perceptual and Cognitive Modeling: Exogenous and Subconscious Processing

17 Primitive Grouping

18 Gestalt-Approach (contra classical structuralism)

19 Gestalt-Principles Common fate: elements whose elements change in a similar way over time tend to be grouped together Similarity: elements that are similar in physical attributes (such as timbre, pitch, or loudness) tend to be grouped Proximity: grouping strength between elements, or clusters of elements, is proportional to the distance between them Continuity: provided the changes between consecutive elements are smooth then the elements tend to be grouped together Closure: elements that form a complete, but possible partially obscured object tend to be grouped

20 Law of Simplicity Of several geometrically possible organisations the one will actually occur which possesses the best, simplest and most stable shape

21 Figure-Background-Principle

23 Law of Proximity

24 Law of Similarity

25 Law of Good Continuation

26 Law of Closure

30 Example: Color Selection Viewer can rapidly and accurately determine whether the target (red circle) is present or absent. Difference detected in color.

31 Example: Shape Selection Viewer can rapidly and accurately determine whether the target (red circle) is present or absent. Difference detected in form (curvature)

32 Pre-attentive Processing < ms qualifies as pre-attentive eye movements take at least 200ms yet certain processing can be done very quickly, implying low-level processing in parallel If a decision takes a fixed amount of time regardless of the number of distractors, it is considered to be preattentive.

Example: Conjunction of Features Viewer cannot rapidly and accurately determine whether the target (red circle) is present or absent when target has two or more features,

33 Example: Conjunction of Features Viewer cannot rapidly and accurately determine whether the target (red circle) is present or absent when target has two or more features, each of which are present in the distractors. Viewer must search sequentially. All Preattentive Processing figures from Healey 97

34 Wrigley et al., Comp. Model of Atten., IEEE Trans. on NN, 2005

35 Wrigley et al., Comp. Model of Atten., IEEE Trans. on NN, 2005

37 Advanced Models of Top-Down Processing

38 Adaptive Resonance Theory (ART) activation of cells by bottom -up signals bottom-up (feedforward stimulus processing) sensory input internal representation top-town (expectation driven) perception & evaluation priming/modulating cells by expectation top-down input match a cell can fire if it receives a large convergent bottom-up and top-down inputs mismatch the cell activity is suppressed by top-down signals, even if the cell receives a large enough bottom-up input the learned top-down expectations focus attention on information that matches to them

39 Attention model (spotlight/gradient)

41 Application of Models of Attention: Quantification of Tinnitus Decompensation

exclusively from the activity within the nervous system without

42 What is Tinnitus? Tinnitus is defined as the perception of a sound that results exclusively from the activity within the nervous system without any corresponding mechanical, vibrating activity within the cochlea. it just sounds like that OnVista Media GmbH

43 Tinnitus (De)compensation Compensated Tinnitus Patients the internal noise is not annoying for them they get accustomed to the noise their brain is able to compensate the noise Decompensated Tinnitus Patients they are troubled by the noise they may develop psychiatric symptoms ( e.g., insomnia, concentration problems, depression) their brain is unable to compensate the noise

44 Objective of the Study Detection of neural correlates of the tinnitus (de-)compensation which can be used to verify psychoacoustical tinnitus models and may help to better understand the tinnitus pathogensis

45 Jastreboff Tinnitus Model main result: the annoyance due to tinnitus is exclusively determined by non-auditory factors, especially the limbic and autonomic nervous system

46 Adaptive Resonance Theory (ART) by Stephen Grossberg activation of cells by bottom -up signals bottom-up (feedforward stimulus processing) sensory input internal representation top-town (expectation driven) perception & evaluation priming/modulating cells by expectation top-down input match a cell can fire if it receives a large convergent bottom-up and top-down inputs mismatch the cell activity is suppressed by top-down signals, even if the cell receives a large enough bottom-up input the learned top-down expectations focus attention on information that matches to them

47 Combining the Models Linking the Jastreboff model to ART influences of limibic and autonomic nervous system top-down processes and neural modulation decompensated tinnitus patients the attentional focus is on the tinnitus signal (i.e., the tinnitus signal is expected) subcortical and cortico-cortical top-down projections suppress other auditory information which differs from the tinnitus signal synchronization and amplification of the activity of cells within the attentional focus - suppression of others oscillatory neural tinnitus model

Neurobiological Evidence Studies in the bat showed that the conditioning of an auditory with a pain stimulus results in a reorganization of the auditory cortex by top-down processes.

48 Neurobiological Evidence Studies in the bat showed that the conditioning of an auditory with a pain stimulus results in a reorganization of the auditory cortex by top-down processes. In further auditory experiments the conditioning with these negative associations precipitated a strengthened representation of the auditory stimulus in cortical areas. Ji & Suga. Development of reorganization of the auditory cortex caused by fear conditioning: effect of antropine. J. Neuroscience (2003) Neurobiological evidence of such attentionsynchronization mechanism was found in the visual system where the synchronity of neural groups in the visual cortex is strongly influenced by Fries attention. et al. Modulation of oscillatory neuronal synchronization by selective visual attention. Science. (2001)

49 Hypotheses Since too much attention is paid to the tinnitus signal, other signals will be suppressed due to subcortical and cortico-cortical top-down projections. Decompensated patients can hardly habituate to other signals than the tinnitus signal which leads to a less synchronized activity. The less synchronized activity has to be reflected in the neural synchronization stability (phase looking with stimulus) of non-invasively measurable large-scale brain signals related to higher auditory areas.

50 Auditory Late Response auditory cortex 5µV P2 the N1 and P2 waves are anatomically associated with the auditory cortex 0µV -5µV -10µV -15µV -20µV -25µV -30µV N1 0ms 100ms 200ms 300ms 400ms

51 Neural Synchronization Stability complex wavelet transform set of M ALRs we define neural synchronization stability by

52 Neural Synchronization Stability note: relation to phase locking (wavelet phase coherence) of two oscillators (y is a constant reference signal) compensated patients: decompensated patients: averaged difference of the synchronization stability

53 Results I significance map

54 Results II

55 Results D. J. Strauss, W. Delb, R. D'Amelio, and P. Falkai. Adaptive Resonance and Attention in the Tinnitus Decompensation: Neural Correlates in Auditory Evoked Potentials, IEEE Trans. on Biomed. Eng. (submitted)

56 Conclusions Linking the Jastreboff model to ART provides a powerful oscillatory tinnitus model which may be the basis for advanced neural examinations. The neural synchronization stability of ALR sequences seems to reflect cortico-cortical top-down projections. The synchronization stability might be a decompensation correlate for the objective tinnitus assessment in clinical applications. These results have to be supported by other examinations on the neural level.

57 Multiscale Brain Modelling macroscale-model ERP-Simulation (Robinson et al.) microscale-model selective auditory attention is resolved at the neural scale (tinnitus model of adaptive resonance)

Theoretical Neuroscience: The Binding Problem Jan Scholz, , University of Osnabrück

Theoretical Neuroscience: The Binding Problem Jan Scholz, , University of Osnabrück The Binding Problem This lecture is based on following articles: Adina L. Roskies: The Binding Problem; Neuron 1999 24: 7 Charles M. Gray: The Temporal Correlation Hypothesis of Visual Feature Integration: