Goll et al., 2015

[!ABSTRACT] The claustrum is a mysterious thin sheet of neurons lying between the insular cortex and the striatum. It is reciprocally connected with almost all cortical areas, including motor, somatosensory, visual, auditory, limbic, associative, and prefrontal cortices. In addition, it receives neuromodulatory input from subcortical structures. A decade ago, Sir Francis Crick and Christof Koch published an influential review proposing the claustrum as the ‘seat of consciousness’, spurring a revival of interest in the claustrum. We review the literature on the claustrum, emphasizing recent discoveries, and develop a detailed hypothesis describing a role for the claustrum in the segregation of attention.

Here: role of claustrum mainly as segregating attention

“We propose that the claustrum serves the function of segregating attention between modalities, enabling us to isolate objects of current priority for attention” (Goll et al., 2015, p. 490)

[[CLA contrast]]

“In sum, our hypothesis ascribes a role to the claustrum in figure/background separation – providing deeper contrast for the representation of the selected object while further fading the representation of irrelevant information.” (Goll et al., 2015, p. 492)

CLA attention: as “Spotlight operator”

“According to our hypothesis, the claustrum may act as a spotlight operator” (Goll et al., 2015, p. 492)

• Spotlight Operator: See Deheane & Neuronal Workspace Theory and other theories of Consciousness

CLA attention: “Our model further implicates the claustrum as a hub for attention, where top-down attentional strategies, as well as bottom-up interventions, are implemented.”

(Goll et al., 2015, p. 490)

CLA connections: “reciprocally connected with almost all cortical areas, including motor, somatosensory, visual, auditory, limbic, associative, and prefrontal cortices.”

(Goll et al., 2015, p. 486)

CLA salience: differentiation between task-relevant and task-irrelevant information & “enabling the organism to ignore irrelevant information and proceed with goal-oriented behavior.”

“We propose that the claustrum, due to the nature of its connectivity with the sensory modalities and its robust prefrontal and neuromodulatory input, functions to enhance the differentiation between task-relevant and task-irrelevant information,” (Goll et al., 2015, p. 486)

enabling the organism to ignore irrelevant information and proceed with goal-oriented behavior.” (Goll et al., 2015, p. 486)

CLA attention: “attentional strategy” defined by prefrontal input to CLA and modulated output to other modalities

“According to our model (Figure 2), the ‘attentional strategy’ at any given time is defined by the prefrontal input to the claustrum (top down), modulating the output of the claustrum to the various cortical modalities.” (Goll et al., 2015, p. 490)

CLA salience: salient shifts & “tuned to respond to the onset of a novel stimulus rather than its content”

“This implies that the claustrum is recruited on salient shifts in the sensory input and is tuned to respond to the onset of a novel stimulus rather than its content” (Goll et al., 2015, p. 490)

CLA salience: “Recently, the claustrum has been suggested to function as a saliency detector, notifying the cortex of incoming novel stimuli”

(Goll et al., 2015, p. 490)

CLA attention: “Finally, it has been suggested that the claustrum is involved in attentional load allocation”

(Goll et al., 2015, p. 490)

CLA connections: piriform Cortex, Subiculum, Entorhinal cortex, vmPFC, Sensory Cortex as well as location, physical and emotional state

“Several allocortical regions receive inputs from the claustrum, including the piriform cortex, subiculum, and entorhinal cortex, as well as the ventral zones of the prefrontal cortex [30,31]. Thus, the claustrum is strongly tied to areas processing sensory information as well as regions processing information regarding the location of the organism and its physical and emotional state.” (Goll et al., 2015, p. 486)

Emotional state -> der Grund, wieso wir das erheben sollen

CLA periphery preference

“Furthermore, the claustrum displays a significant preference for peripheral sensory information.” (Goll et al., 2015, p. 486)

“Claustral neurons fire at low basal frequency and respond optimally to motion at the periphery of the visual field or the onset of noisy stimuli” (Goll et al., 2015, p. 490)

CLA periphery : “The visual claustrum seems to be concerned with the peripheral visual field, comprising binocular cells that have elongated receptive fields and no orientation selectivity”

(Goll et al., 2015, p. 488)

Claustrum: Claustro-cortical loops receiving Visual input & projecting back

“The visual claustrum of the cat receives convergent input from several visual cortical areas and projects back to these same areas. These claustro-cortical loops are organized retinotopically, such that the claustral regions receiving visual input deal with the same region in the visual space as the cortical region with which it interacts” (Goll et al., 2015, p. 486)

CLA visual & contradicts CLA contrast

“Most claustral neurons are binocular and prefer elongated moving stimuli while being tolerant of direction, velocity, width, and contrast, in contrast to their cortical input, which is direction selective and largely monocular” (Goll et al., 2015, p. 487)

“The auditory responsive cells prefer long latency stimuli

(from either ear) and have broad tuning that extends over several octaves as well as a strong preference for noisy stimuli over pure tones” (Goll et al., 2015, p. 487)

“These properties obviously contrast with those of neurons in the tonotopic auditory field” (Goll et al., 2015, p. 487)

“Similarly, cells in the auditory claustrum are not tightly tuned, have broad receptive fields, and show preference for noise coming from either ear.” (Goll et al., 2015, p. 488)

CLA evolution: topographical arrangement differences in species

“Furthermore, while we do not elaborate on this point, the topographical arrangement of the claustrum appears to differ between rats, cats, and primates” (Goll et al., 2015, p. 488)

Claustro-cortical: “This type of connectivity could, in principle, generate Feed-forward inhibition on cortical function and dramatically affect cortical processing and output.”

(Goll et al., 2015, p. 488)

Claustro-cortical: input from other regions bilateral / ipsilateral / contralateral while output mostly ipsilateral

“inputs from frontal cortical regions appear to be bilateral, inputs from the cortical modalities appear to have an ipsilateral preference and inputs from the motor cortex show a contralateral preference” (Goll et al., 2015, p. 488)

“output from the claustrum to cortex is almost exclusively ipsilateral.” (Goll et al., 2015, p. 488)

“Electrical stimulation of the claustrum in cats has been found to suppress neuronal firing in several cortical areas, including the Motor Cortex”

(Goll et al., 2015, p. 489)

CLA neurotransmitter projections

“The claustrum receives a wide array of neuromodulatory afferent projections. Among others, adrenoceptors [57] and receptors for opiates [58], dopamine [59], serotonin [60], oxytocin, acetylcholine [59], and Endocanabinoids [61] have been found in the claustrum, and several of these have been found to functionally affect the firing of claustral neurons in vivo” (Goll et al., 2015, p. 489)

Claustro-cortical connectivity mediated by Glutamatergic projection neurons

“Claustrocortical connectivity is mediated by the action of claustral glutamatergic projection neurons, which project primarily to layer IV, as well as layers I&II and VI” (Goll et al., 2015, p. 488)

“Experiments in cats and monkeys using retrograde tracers have demonstrated that the claustrum primarily receives glutamatergic input from cortical layer VI. The claustral neurons that receive input from the cortex are thought to be excitatory projection neurons [49,50] providing reciprocal input back to the cortex, terminating mainly in layer IV” (Goll et al., 2015, p. 488)

CLA connections: Claustro-cortical Input primarily Glutamatergic & excitatory projection neurons

“Experiments in cats and monkeys using retrograde tracers have demonstrated that the claustrum primarily receives glutamatergic input from cortical layer VI. The claustral neurons that receive input from the cortex are thought to be excitatory projection neurons [49,50] providing reciprocal input back to the cortex, terminating mainly in layer IV” (Goll et al., 2015, p. 488)

Serotonergic inputs highly spread in CLA & of high relevance for CLA attention

“Serotonergic inputs are potentially of high interest in the context of a model ascribing a role to the claustrum in attention, as we discuss below, and have been found to be spread throughout the claustrum [44,60,62,64], similar to prefrontal cortical inputs” (Goll et al., 2015, p. 489)

“Other neurons in the claustrum are likely to be GABAergic and display characteristics of local circuit interneurons, albeit with some variatio” (Goll et al., 2015, p. 489)

“The most common cell type in the claustrum (90% of claustral neurons) is Glutamatergic”

(Goll et al., 2015, p. 489)

CLA lesion: visual and auditory Hallucinations in 21yo man

“More recently, a 21-year-old man diagnosed with an infection of mumps virus that resulted in bilateral claustrum lesions suffered visual and auditory hallucinations” (Goll et al., 2015, p. 489)

Schizophrenia: “negative correlations between the volume of gray matter in the claustrum and the severity of auditory hallucinations and delusions”

“Researchers have found negative correlations between the volume of gray matter in the claustrum and the severity of auditory hallucinations and delusions in schizophrenia patients” (Goll et al., 2015, p. 489)

“Increased efficacy of cortical responses and improved signal/noise ratio have been shown to be the main effects of increased Attention”

(Goll et al., 2015, p. 490)

CLA function Early theories: “Satelite of the corex”, CLA excitatory regulation & relay station

“The widespread Claustro-cortical connections have inspired early theories to describe the claustrum as a satellite of the cortex, having some regulatory role, or acting as a relay station” (Goll et al., 2015, p. 490)

“Other pioneers in claustrum research maintained that the claustrum is more than a simple relay station and has a role in binding information across modalities” (Goll et al., 2015, p. 490)

[[Crick & Koch, 2005]]

“Francis Crick’s last paper, co-written with Christof Koch, in which the authors singled out the claustrum as a possible hub in which sensory information is bound and integrated across and within different modalities to form a single, unified conscious experience” (Goll et al., 2015, p. 490)

“This claim has motivated researchers to search for multimodal neurons in the claustrum or convergence of multimodal input within the claustrum. The prevalent findings in this regard have been negative” (Goll et al., 2015, p. 490)

CLA oscillation synchronization: “A modified hypothesis has been proposed whereby the claustrum acts as an amplifier for cortical oscillations” (on Smythies et al., 2014)

(Goll et al., 2015, p. 490)

“the tight dimensions of the claustrum could cause neighboring claustral areas to oscillate in a correlated fashion, and claustrum projections from these areas are expected to induce oscillations in other cortices” (Goll et al., 2015, p. 490)

“The authors suggest that the claustrum can thus synchronize oscillations between distant cortical areas without the requirement for multimodal neurons. This coordination of cortical oscillatory activity was suggested to be involved in cognitive tasks” (Goll et al., 2015, p. 490)

“Based on a similar conceptual framework, another model proposes that control of the claustrum over cortical oscillations could enable switching between resting-state and task-associated cortical networks” (Goll et al., 2015, p. 490)

“subcortical input from the Amygdala, Entorhinal cortex, and Hippocampus could play a role in subconscious coordination of attention with regard to spatial, social, and emotional elements” (Goll et al., 2015, p. 491)

CLA connections with Motor Cortex and Eye-Movement for CLA attention

“The projections of the claustrum to motor and oculomotor centers could allow the claustrum to promote motor responses important for focusing attention toward salient stimuli by supporting shifts in gaze or head/ body orientation” (Goll et al., 2015, p. 491)

Claustrum (CLA) similarities with Thalamus, like mechanisms for Selective Attention and common CLA connections

(Goll et al., 2015, p. 491) “Thalamus acts as the relay station for sensory information on its way to the primary sensory regions in the cortex” (Goll et al., 2015, p. 491)

“Each of the primary sensory relay areas in the thalamus receives strong feedback connections from the cortex [111,112]. These connections have been shown to impact information processing in the thalamus, demonstrating that the flow of information to the cortex can be modulated within the thalamus” (Goll et al., 2015, p. 491)

“Thalamic Reticular Nucleus (TRN)” … is a … “capsule around the thalamus, is a GABAergic nucleus whose function is to provide strong inhibitory drive onto thalamic nuclei” (Goll et al., 2015, p. 491)

-> “mechanism for selective attention by blocking information from the modalities even before they reached the cortex” (Goll et al., 2015, p. 491)

“the claustrum and the thalamus share projections to common frontal cortical targets” (Goll et al., 2015, p. 491)

“both the thalamus and the claustrum have the capacity to focus attention, albeit at different stages of sensory processing”

“We propose that both the thalamus and the claustrum have the capacity to focus attention, albeit at different stages of sensory processing. The thalamus can gate the access of information to the cortex early in the process of sensory selection [116], while the function of the claustrum may be to define gain control on information after it has been processed in the cortex, limiting the access of this information from the cortex to the rest of the brain” (Goll et al., 2015, p. 491)

“A refinement of the model could therefore propose that the claustrum enables attention to selected objects while reducing the output from the cortical representation of irrelevant information” (Goll et al., 2015, p. 492)

Feed-forward inhibition to claustrum through PFC-inhibition

“Our model proposes that the prefrontal input to the claustrum defines the attentional strategy, which is implemented primarily through the feedforward inhibition that the claustrum exerts on the cortical modalities” (Goll et al., 2015, p. 492)

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Random

“Projections from the claustrum are to cortical layers I&II, IV, and VI and have been reported to innervate pyramidal neurons in all layers (layers I&II, IV, and VI), with preferential input onto local inhibitory interneurons in layer IV. This architecture may generate feedforward inhibition whereby claustral activation causes fast excitation of layer IV pyramidal neurons followed by prolonged inhibition of the defined cortical circuit through activation of local interneurons.” (Goll et al., 2015, p. 490)

Bottom-up vs. Top-down general

“The bottom-up system is faster than the top-down system [71,72]. Peripheral cues grab bottom-up attention in an automatic, stimulus-driven manner and are typically effective within a time window of 80–130 ms after the cue onset, whereas the allocation of top-down attention is slower, becoming effective within about 300 ms” (Goll et al., 2015, p. 490)

James, William: definition of Attention

“William James, in The Principles of Psychology, defined attention as ‘taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought…It implies withdrawal from some things in order to deal effectively with others’ [1]. This definition captures a key property of attention: enhanced processing of task-relevant information, while suppressing task-irrelevant information” (Goll et al., 2015, p. 486)

[[CLA future research]]

“As championed by Crick and Koch, it is clear that for the next decade to provide more concrete results about the function of the claustrum, genetic access to claustral neurons is essential. Such access, in the context of the rapidly developing optogenetic and pharmacogenetic toolbox, is expected to revolutionize the field, as it will enable manipulation of the activity of claustral neurons to test their behavioral consequences” (Goll et al., 2015, p. 493)

2024-12-01 - new annotations

Claustrum has many connections to and from the cortex and sub-cortex. The claustrum is an interconnected region of the brain. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 1]

The claustrum has the highest connectivity in the brain per regional volume [3], displaying extensive reciprocal connections with the visual, auditory, somatosensory, and motor cortical regions as well as all cortical and subcortical regions (Figure 1) [4–17]. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 1]

There is a topographic organisation of the claustrum connections. These topographic connections [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 1]

inputs to the claustrum display anterior–posterior and dorsal–ventral organization, with reciprocal connectivity back to the cortex from within the same region in the claustrum [8–10,12,18–28] (Figure 1). [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 1]

Claustrum is involved in selective attention in terms of selecting the information in a particular sensory modailty to help guide our attention towards that sensory modaility [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

We propose that the claustrum serves the function of segregating attention between modalities, enabling us to isolate objects of current priority for attention. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

Top-down attention is where information from higher-level areas “flows” down to lower-level areas. That is, higher order thinking and reasoning that guides our attention (top in the hierachy of brain regions) info flows to the sesnroy coritcies (bottom of the hierachy) [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

Top-down processing is defined as the flow of information from ‘higher’ to ‘lower’ centers, carrying knowledge derived from previous experience rather than sensory stimulation. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

Top-down attention controlled by cognitive factors [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

Top-down modulation, sometimes called the endogenous system, is controlled by cognitive factors such as knowledge, expectation, and current goals and is believed to depend on activity in prefrontal cortical regions [69]. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

Bottom-up attention is rapid flow of information as it comes from our sensory coticies and reaches the frontal regions of the brain. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

Bottom-up modulation, or the exogenous system, refers to the rapid and involuntary shifting of attention toward salient sensory stimuli of potential importance [70,71]. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

propose that the claustrum acts to control the output from the cortical representations of each of the sensory modalities. The claustrum may control which cortical output is attended, promoting the preferred modality, while reducing the efficacy of other, competing cortical modalities. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]

the claustrum as a hub for attention, where top-down attentional strategies, as well as bottom-up interventions, are implemented. [@MVFPDFSX#Goll_Atlan_Citri-2015, p. 5]